feat(dmabuf): linux-dmabuf v4 and Vulkan import

Clients send GPU buffers through zwp_linux_dmabuf_v1 v4 with default
feedback. The Vulkan renderer imports single-plane modifiers, waits on
implicit fences via DMA_BUF_IOCTL_EXPORT_SYNC_FILE and blits them into
the output image. Imports are cached per buffer and evicted after 120
undrawn frames; params are bounds-checked against the plane file.

commit: 0859b0ffcc0d7953e8225e6997e27e25162b7372
author: brice · 28d ago · 2026-09-25 06:32 UTC
parent: 07694a3
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

14 files · +1082 -24

M internal/adapters/drm/output.go +1 -1


@@ -178,7 +178,7 @@ func (o *Output) Run(ctx context.Context, newRenderer func(w, h int) (ports.Rend
178	178		}
179	179		scene, haveScene, dirty = s, true, true
180	180		case c := <-contents:
181		-	if c.Pixels == nil {
	181	+	if c.Empty() {
182	182		delete(surfaces, c.ID)
183	183		} else {
184	184		surfaces[c.ID] = c


@@ -178,7 +178,7 @@ func (o *Output) Run(ctx context.Context, newRenderer func(w, h int) (ports.Rend
178		}	178		}
179		scene, haveScene, dirty = s, true, true	179		scene, haveScene, dirty = s, true, true
180		case c := <-contents:	180		case c := <-contents:
181	-	if c.Pixels == nil {	181	+	if c.Empty() {
182		delete(surfaces, c.ID)	182		delete(surfaces, c.ID)
183		} else {	183		} else {
184		surfaces[c.ID] = c	184		surfaces[c.ID] = c

M internal/adapters/headless/output.go +1 -1


@@ -36,7 +36,7 @@ func Run(ctx context.Context, opts Options, scenes <-chan ports.Scene, contents
36	36		frame := 0
37	37		cursorScale := -1.0 // not loaded yet
38	38		update := func(c ports.SurfaceContent) {
39		-	if c.Pixels == nil {
	39	+	if c.Empty() {
40	40		delete(surfaces, c.ID)
41	41		} else {
42	42		surfaces[c.ID] = c


@@ -36,7 +36,7 @@ func Run(ctx context.Context, opts Options, scenes <-chan ports.Scene, contents
36		frame := 0	36		frame := 0
37		cursorScale := -1.0 // not loaded yet	37		cursorScale := -1.0 // not loaded yet
38		update := func(c ports.SurfaceContent) {	38		update := func(c ports.SurfaceContent) {
39	-	if c.Pixels == nil {	39	+	if c.Empty() {
40		delete(surfaces, c.ID)	40		delete(surfaces, c.ID)
41		} else {	41		} else {
42		surfaces[c.ID] = c	42		surfaces[c.ID] = c

A internal/adapters/vulkan/dmabuf.go +297 -0

@@ -0,0 +1,297 @@
	1	+	package vulkan
	2	+
	3	+	import (
	4	+	"fmt"
	5	+	"os"
	6	+	"slices"
	7	+	"unsafe"
	8	+
	9	+	"github.com/bnema/nefertty/internal/ports"
	10	+	vk "github.com/bnema/purego-vulkan/vulkan"
	11	+	"golang.org/x/sys/unix"
	12	+	)
	13	+
	14	+	// dmabuf import (linux-dmabuf clients): each client buffer becomes a
	15	+	// VkImage bound to its imported memory, cached by buffer ID while the
	16	+	// client keeps attaching it, and blitted into the output image. Sync is
	17	+	// implicit: before sampling, the renderer waits on the fences the client's
	18	+	// driver attached to the buffer (DMA_BUF_IOCTL_EXPORT_SYNC_FILE), imported
	19	+	// as a semaphore.
	20	+
	21	+	// deviceExtensions are enabled when all present; without them the renderer
	22	+	// has no dmabuf support and clients fall back to wl_shm.
	23	+	var deviceExtensions = []string{
	24	+	vk.KHRExternalMemoryFDExtensionName,
	25	+	vk.EXTExternalMemoryDMABUFExtensionName,
	26	+	vk.EXTImageDRMFormatModifierExtensionName,
	27	+	vk.EXTQueueFamilyForeignExtensionName,
	28	+	vk.KHRExternalSemaphoreFDExtensionName,
	29	+	// The render node advertised to clients in dmabuf feedback.
	30	+	vk.EXTPhysicalDeviceDRMExtensionName,
	31	+	}
	32	+
	33	+	// fourcc → Vulkan format. DRM formats name the packed pixel from the high
	34	+	// byte, little-endian: ARGB8888 is B,G,R,A in memory, like B8G8R8A8.
	35	+	var dmabufFormats = []struct {
	36	+	fourcc uint32
	37	+	format vk.Format
	38	+	opaque bool
	39	+	}{
	40	+	{fourcc('A', 'R', '2', '4'), vk.FormatB8g8r8a8Unorm, false},
	41	+	{fourcc('X', 'R', '2', '4'), vk.FormatB8g8r8a8Unorm, true},
	42	+	{fourcc('A', 'B', '2', '4'), vk.FormatR8g8b8a8Unorm, false},
	43	+	{fourcc('X', 'B', '2', '4'), vk.FormatR8g8b8a8Unorm, true},
	44	+	}
	45	+
	46	+	func fourcc(a, b, c, d byte) uint32 {
	47	+	return uint32(a) \| uint32(b)<<8 \| uint32(c)<<16 \| uint32(d)<<24
	48	+	}
	49	+
	50	+	func vkFormat(f uint32) (vk.Format, bool, bool) {
	51	+	for _, v := range dmabufFormats {
	52	+	if v.fourcc == f {
	53	+	return v.format, v.opaque, true
	54	+	}
	55	+	}
	56	+	return 0, false, false
	57	+	}
	58	+
	59	+	// hasExtensions reports whether the device offers every dmabuf extension.
	60	+	func (r *Renderer) hasExtensions(physical vk.PhysicalDevice) bool {
	61	+	var n uint32
	62	+	if r.id.EnumerateDeviceExtensionProperties(physical, nil, &n, nil) != vk.Success \|\| n == 0 {
	63	+	return false
	64	+	}
	65	+	props := make([]vk.ExtensionProperties, n)
	66	+	if r.id.EnumerateDeviceExtensionProperties(physical, nil, &n, &props[0]) != vk.Success {
	67	+	return false
	68	+	}
	69	+	have := map[string]bool{}
	70	+	for _, p := range props[:n] {
	71	+	have[cstring(p.ExtensionName[:])] = true
	72	+	}
	73	+	for _, e := range deviceExtensions {
	74	+	if !have[e] {
	75	+	return false
	76	+	}
	77	+	}
	78	+	return true
	79	+	}
	80	+
	81	+	func cstring(b []byte) string {
	82	+	if i := slices.Index(b, 0); i >= 0 {
	83	+	b = b[:i]
	84	+	}
	85	+	return string(b)
	86	+	}
	87	+
	88	+	// probeDMABuf lists the fourcc/modifier pairs the device imports as
	89	+	// single-plane blit sources, and the render node.
	90	+	func (r *Renderer) probeDMABuf(physical vk.PhysicalDevice) ports.DMABufSupport {
	91	+	var sup ports.DMABufSupport
	92	+	drm := vk.PhysicalDeviceDrmPropertiesEXT{SType: vk.StructureTypePhysicalDeviceDRMPropertiesEXT}
	93	+	props := vk.PhysicalDeviceProperties2{SType: vk.StructureTypePhysicalDeviceProperties2, Next: unsafe.Pointer(&drm)}
	94	+	r.id.GetPhysicalDeviceProperties2(physical, &props)
	95	+	if drm.HasRender != 0 {
	96	+	sup.Device = unix.Mkdev(uint32(drm.RenderMajor), uint32(drm.RenderMinor))
	97	+	}
	98	+	for _, f := range dmabufFormats {
	99	+	list := vk.DrmFormatModifierPropertiesListEXT{SType: vk.StructureTypeDRMFormatModifierPropertiesListEXT}
	100	+	fp := vk.FormatProperties2{SType: vk.StructureTypeFormatProperties2, Next: unsafe.Pointer(&list)}
	101	+	r.id.GetPhysicalDeviceFormatProperties2(physical, f.format, &fp)
	102	+	if list.DrmFormatModifierCount == 0 {
	103	+	continue
	104	+	}
	105	+	mods := make([]vk.DrmFormatModifierPropertiesEXT, list.DrmFormatModifierCount)
	106	+	list.DrmFormatModifierProperties = &mods[0]
	107	+	r.id.GetPhysicalDeviceFormatProperties2(physical, f.format, &fp)
	108	+	for _, m := range mods[:list.DrmFormatModifierCount] {
	109	+	// Multi-plane modifiers (compression metadata) are left to a
	110	+	// later step; the blit needs a source.
	111	+	if m.DrmFormatModifierPlaneCount != 1 \|\| m.DrmFormatModifierTilingFeatures&vk.FormatFeatureBlitSrcBit == 0 {
	112	+	continue
	113	+	}
	114	+	if r.importable(physical, f.format, m.DrmFormatModifier) {
	115	+	sup.Formats = append(sup.Formats, ports.DMABufFormat{Format: f.fourcc, Modifier: m.DrmFormatModifier})
	116	+	}
	117	+	}
	118	+	}
	119	+	return sup
	120	+	}
	121	+
	122	+	// importable asks whether an image of that format and modifier can be
	123	+	// imported from a dmabuf.
	124	+	func (r *Renderer) importable(physical vk.PhysicalDevice, format vk.Format, modifier uint64) bool {
	125	+	mod := vk.PhysicalDeviceImageDrmFormatModifierInfoEXT{SType: vk.StructureTypePhysicalDeviceImageDRMFormatModifierInfoEXT, DrmFormatModifier: modifier, SharingMode: vk.SharingModeExclusive}
	126	+	ext := vk.PhysicalDeviceExternalImageFormatInfo{SType: vk.StructureTypePhysicalDeviceExternalImageFormatInfo, Next: unsafe.Pointer(&mod), HandleType: vk.ExternalMemoryHandleTypeDMABUFBitEXT}
	127	+	info := vk.PhysicalDeviceImageFormatInfo2{SType: vk.StructureTypePhysicalDeviceImageFormatInfo2, Next: unsafe.Pointer(&ext), Format: format, Type: vk.ImageType2d, Tiling: vk.ImageTilingDRMFormatModifierEXT, Usage: vk.ImageUsageTransferSrcBit}
	128	+	extOut := vk.ExternalImageFormatProperties{SType: vk.StructureTypeExternalImageFormatProperties}
	129	+	out := vk.ImageFormatProperties2{SType: vk.StructureTypeImageFormatProperties2, Next: unsafe.Pointer(&extOut)}
	130	+	if r.id.GetPhysicalDeviceImageFormatProperties2(physical, &info, &out) != vk.Success {
	131	+	return false
	132	+	}
	133	+	return extOut.ExternalMemoryProperties.ExternalMemoryFeatures&vk.ExternalMemoryFeatureImportableBit != 0
	134	+	}
	135	+
	136	+	// DMABuf reports the formats this renderer imports.
	137	+	func (r *Renderer) DMABuf() ports.DMABufSupport { return r.dmabuf }
	138	+
	139	+	// imported is a client dmabuf bound to a VkImage.
	140	+	type imported struct {
	141	+	image vk.Image
	142	+	memory vk.DeviceMemory
	143	+	fd int // our duplicate of plane 0, for implicit sync
	144	+	// last is the frame that drew it, for eviction.
	145	+	last uint64
	146	+	}
	147	+
	148	+	// importTTL is how many frames an import survives undrawn: clients cycle
	149	+	// through 2-4 buffers, and a destroyed buffer is freed shortly after.
	150	+	const importTTL = 120
	151	+
	152	+	// importDMABuf returns the image of a client buffer, importing it once.
	153	+	func (r Renderer) importDMABuf(b ports.DMABuf) (*imported, error) {
	154	+	if im := r.imports[b.ID]; im != nil {
	155	+	im.last = r.frame
	156	+	return im, nil
	157	+	}
	158	+	if len(r.dmabuf.Formats) == 0 {
	159	+	return nil, fmt.Errorf("dmabuf unsupported")
	160	+	}
	161	+	format, _, ok := vkFormat(b.Format)
	162	+	if !ok \|\| len(b.Planes) != 1 \|\| b.Width <= 0 \|\| b.Height <= 0 {
	163	+	return nil, fmt.Errorf("dmabuf format %#x with %d planes unsupported", b.Format, len(b.Planes))
	164	+	}
	165	+	fd, err := dupFile(b.Planes[0].File)
	166	+	if err != nil {
	167	+	return nil, err
	168	+	}
	169	+	im := &imported{fd: fd, last: r.frame}
	170	+	ok = false
	171	+	defer func() {
	172	+	if !ok {
	173	+	r.release(im)
	174	+	}
	175	+	}()
	176	+	d := r.dd
	177	+	layout := vk.SubresourceLayout{Offset: vk.DeviceSize(b.Planes[0].Offset), RowPitch: vk.DeviceSize(b.Planes[0].Stride)}
	178	+	explicit := vk.ImageDrmFormatModifierExplicitCreateInfoEXT{SType: vk.StructureTypeImageDRMFormatModifierExplicitCreateInfoEXT, DrmFormatModifier: b.Modifier, DrmFormatModifierPlaneCount: 1, PlaneLayouts: &layout}
	179	+	external := vk.ExternalMemoryImageCreateInfo{SType: vk.StructureTypeExternalMemoryImageCreateInfo, Next: unsafe.Pointer(&explicit), HandleTypes: vk.ExternalMemoryHandleTypeDMABUFBitEXT}
	180	+	ii := vk.ImageCreateInfo{SType: vk.StructureTypeImageCreateInfo, Next: unsafe.Pointer(&external), ImageType: vk.ImageType2d, Format: format, Extent: vk.Extent3D{Width: uint32(b.Width), Height: uint32(b.Height), Depth: 1}, MipLevels: 1, ArrayLayers: 1, Samples: vk.SampleCount1Bit, Tiling: vk.ImageTilingDRMFormatModifierEXT, Usage: vk.ImageUsageTransferSrcBit, SharingMode: vk.SharingModeExclusive, InitialLayout: vk.ImageLayoutUndefined}
	181	+	if err := checked("vkCreateImage(dmabuf)", d.CreateImage(r.device, &ii, nil, &im.image)); err != nil {
	182	+	return nil, err
	183	+	}
	184	+	fdProps := vk.MemoryFdPropertiesKHR{SType: vk.StructureTypeMemoryFDPropertiesKHR}
	185	+	if err := checked("vkGetMemoryFdPropertiesKHR", d.GetMemoryFdPropertiesKHR(r.device, vk.ExternalMemoryHandleTypeDMABUFBitEXT, int32(fd), &fdProps)); err != nil {
	186	+	return nil, err
	187	+	}
	188	+	var req vk.MemoryRequirements
	189	+	d.GetImageMemoryRequirements(r.device, im.image, &req)
	190	+	kind, err := r.findMemoryType(req.MemoryTypeBits&fdProps.MemoryTypeBits, 0)
	191	+	if err != nil {
	192	+	return nil, err
	193	+	}
	194	+	// Vulkan owns the fd it imports on success: hand it its own duplicate.
	195	+	memFD, err := unix.FcntlInt(uintptr(fd), unix.F_DUPFD_CLOEXEC, 0)
	196	+	if err != nil {
	197	+	return nil, err
	198	+	}
	199	+	dedicated := vk.MemoryDedicatedAllocateInfo{SType: vk.StructureTypeMemoryDedicatedAllocateInfo, Image: im.image}
	200	+	imp := vk.ImportMemoryFdInfoKHR{SType: vk.StructureTypeImportMemoryFDInfoKHR, Next: unsafe.Pointer(&dedicated), HandleType: vk.ExternalMemoryHandleTypeDMABUFBitEXT, Fd: int32(memFD)}
	201	+	alloc := vk.MemoryAllocateInfo{SType: vk.StructureTypeMemoryAllocateInfo, Next: unsafe.Pointer(&imp), AllocationSize: req.Size, MemoryTypeIndex: kind}
	202	+	if err := checked("vkAllocateMemory(dmabuf)", d.AllocateMemory(r.device, &alloc, nil, &im.memory)); err != nil {
	203	+	unix.Close(memFD)
	204	+	return nil, err
	205	+	}
	206	+	if err := checked("vkBindImageMemory(dmabuf)", d.BindImageMemory(r.device, im.image, im.memory, 0)); err != nil {
	207	+	return nil, err
	208	+	}
	209	+	ok = true
	210	+	r.imports[b.ID] = im
	211	+	return im, nil
	212	+	}
	213	+
	214	+	// dupFile duplicates the descriptor while the file is held open, so a close
	215	+	// on the wayland goroutine cannot swap it for a reused number.
	216	+	func dupFile(f *os.File) (int, error) {
	217	+	if f == nil {
	218	+	return -1, fmt.Errorf("dmabuf plane without file")
	219	+	}
	220	+	raw, err := f.SyscallConn()
	221	+	if err != nil {
	222	+	return -1, err
	223	+	}
	224	+	fd, dupErr := -1, error(nil)
	225	+	if err := raw.Control(func(v uintptr) { fd, dupErr = unix.FcntlInt(v, unix.F_DUPFD_CLOEXEC, 0) }); err != nil {
	226	+	return -1, err
	227	+	}
	228	+	return fd, dupErr
	229	+	}
	230	+
	231	+	func (r Renderer) release(im imported) {
	232	+	if im.image != 0 {
	233	+	r.dd.DestroyImage(r.device, im.image, nil)
	234	+	}
	235	+	if im.memory != 0 {
	236	+	r.dd.FreeMemory(r.device, im.memory, nil)
	237	+	}
	238	+	if im.fd >= 0 {
	239	+	unix.Close(im.fd)
	240	+	}
	241	+	}
	242	+
	243	+	// dropUnused frees imports not drawn for importTTL frames: the client moved
	244	+	// on to other buffers or went away. Called after a frame completes.
	245	+	func (r *Renderer) dropUnused() {
	246	+	r.frame++
	247	+	for id, im := range r.imports {
	248	+	if r.frame-im.last > importTTL {
	249	+	r.release(im)
	250	+	delete(r.imports, id)
	251	+	}
	252	+	}
	253	+	}
	254	+
	255	+	// dmaBufSync is struct dma_buf_export_sync_file.
	256	+	type dmaBufSync struct {
	257	+	flags uint32
	258	+	fd int32
	259	+	}
	260	+
	261	+	// DMA_BUF_IOCTL_EXPORT_SYNC_FILE = _IOWR('b', 2, struct dma_buf_export_sync_file)
	262	+	const ioctlExportSyncFile = 0xc0086202
	263	+	const dmaBufSyncRead = 1
	264	+
	265	+	// readFence returns a semaphore signalled when the client's pending writes
	266	+	// to the buffer finish, or 0 when the kernel cannot export them (older than
	267	+	// 5.20): the buffer is then read as is.
	268	+	func (r Renderer) readFence(im imported) vk.Semaphore {
	269	+	arg := dmaBufSync{flags: dmaBufSyncRead, fd: -1}
	270	+	if _, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(im.fd), ioctlExportSyncFile, uintptr(unsafe.Pointer(&arg))); errno != 0 \|\| arg.fd < 0 {
	271	+	return 0
	272	+	}
	273	+	var sem vk.Semaphore
	274	+	si := vk.SemaphoreCreateInfo{SType: vk.StructureTypeSemaphoreCreateInfo}
	275	+	if r.dd.CreateSemaphore(r.device, &si, nil, &sem) != vk.Success {
	276	+	unix.Close(int(arg.fd))
	277	+	return 0
	278	+	}
	279	+	imp := vk.ImportSemaphoreFdInfoKHR{SType: vk.StructureTypeImportSemaphoreFDInfoKHR, Semaphore: sem, Flags: vk.SemaphoreImportTemporaryBit, HandleType: vk.ExternalSemaphoreHandleTypeSyncFDBit, Fd: arg.fd}
	280	+	if r.dd.ImportSemaphoreFdKHR(r.device, &imp) != vk.Success {
	281	+	unix.Close(int(arg.fd))
	282	+	r.dd.DestroySemaphore(r.device, sem, nil)
	283	+	return 0
	284	+	}
	285	+	return sem
	286	+	}
	287	+
	288	+	// Probe reports the dmabuf formats of the device renderers use, or none
	289	+	// when Vulkan or the extensions are missing.
	290	+	func Probe() ports.DMABufSupport {
	291	+	r, err := New(1, 1)
	292	+	if err != nil {
	293	+	return ports.DMABufSupport{}
	294	+	}
	295	+	defer r.Close()
	296	+	return r.DMABuf()
	297	+	}

@@ -0,0 +1,297 @@
	1	+	package vulkan
	2	+
	3	+	import (
	4	+	"fmt"
	5	+	"os"
	6	+	"slices"
	7	+	"unsafe"
	8	+
	9	+	"github.com/bnema/nefertty/internal/ports"
	10	+	vk "github.com/bnema/purego-vulkan/vulkan"
	11	+	"golang.org/x/sys/unix"
	12	+	)
	13	+
	14	+	// dmabuf import (linux-dmabuf clients): each client buffer becomes a
	15	+	// VkImage bound to its imported memory, cached by buffer ID while the
	16	+	// client keeps attaching it, and blitted into the output image. Sync is
	17	+	// implicit: before sampling, the renderer waits on the fences the client's
	18	+	// driver attached to the buffer (DMA_BUF_IOCTL_EXPORT_SYNC_FILE), imported
	19	+	// as a semaphore.
	20	+
	21	+	// deviceExtensions are enabled when all present; without them the renderer
	22	+	// has no dmabuf support and clients fall back to wl_shm.
	23	+	var deviceExtensions = []string{
	24	+	vk.KHRExternalMemoryFDExtensionName,
	25	+	vk.EXTExternalMemoryDMABUFExtensionName,
	26	+	vk.EXTImageDRMFormatModifierExtensionName,
	27	+	vk.EXTQueueFamilyForeignExtensionName,
	28	+	vk.KHRExternalSemaphoreFDExtensionName,
	29	+	// The render node advertised to clients in dmabuf feedback.
	30	+	vk.EXTPhysicalDeviceDRMExtensionName,
	31	+	}
	32	+
	33	+	// fourcc → Vulkan format. DRM formats name the packed pixel from the high
	34	+	// byte, little-endian: ARGB8888 is B,G,R,A in memory, like B8G8R8A8.
	35	+	var dmabufFormats = []struct {
	36	+	fourcc uint32
	37	+	format vk.Format
	38	+	opaque bool
	39	+	}{
	40	+	{fourcc('A', 'R', '2', '4'), vk.FormatB8g8r8a8Unorm, false},
	41	+	{fourcc('X', 'R', '2', '4'), vk.FormatB8g8r8a8Unorm, true},
	42	+	{fourcc('A', 'B', '2', '4'), vk.FormatR8g8b8a8Unorm, false},
	43	+	{fourcc('X', 'B', '2', '4'), vk.FormatR8g8b8a8Unorm, true},
	44	+	}
	45	+
	46	+	func fourcc(a, b, c, d byte) uint32 {
	47	+	return uint32(a) \| uint32(b)<<8 \| uint32(c)<<16 \| uint32(d)<<24
	48	+	}
	49	+
	50	+	func vkFormat(f uint32) (vk.Format, bool, bool) {
	51	+	for _, v := range dmabufFormats {
	52	+	if v.fourcc == f {
	53	+	return v.format, v.opaque, true
	54	+	}
	55	+	}
	56	+	return 0, false, false
	57	+	}
	58	+
	59	+	// hasExtensions reports whether the device offers every dmabuf extension.
	60	+	func (r *Renderer) hasExtensions(physical vk.PhysicalDevice) bool {
	61	+	var n uint32
	62	+	if r.id.EnumerateDeviceExtensionProperties(physical, nil, &n, nil) != vk.Success \|\| n == 0 {
	63	+	return false
	64	+	}
	65	+	props := make([]vk.ExtensionProperties, n)
	66	+	if r.id.EnumerateDeviceExtensionProperties(physical, nil, &n, &props[0]) != vk.Success {
	67	+	return false
	68	+	}
	69	+	have := map[string]bool{}
	70	+	for _, p := range props[:n] {
	71	+	have[cstring(p.ExtensionName[:])] = true
	72	+	}
	73	+	for _, e := range deviceExtensions {
	74	+	if !have[e] {
	75	+	return false
	76	+	}
	77	+	}
	78	+	return true
	79	+	}
	80	+
	81	+	func cstring(b []byte) string {
	82	+	if i := slices.Index(b, 0); i >= 0 {
	83	+	b = b[:i]
	84	+	}
	85	+	return string(b)
	86	+	}
	87	+
	88	+	// probeDMABuf lists the fourcc/modifier pairs the device imports as
	89	+	// single-plane blit sources, and the render node.
	90	+	func (r *Renderer) probeDMABuf(physical vk.PhysicalDevice) ports.DMABufSupport {
	91	+	var sup ports.DMABufSupport
	92	+	drm := vk.PhysicalDeviceDrmPropertiesEXT{SType: vk.StructureTypePhysicalDeviceDRMPropertiesEXT}
	93	+	props := vk.PhysicalDeviceProperties2{SType: vk.StructureTypePhysicalDeviceProperties2, Next: unsafe.Pointer(&drm)}
	94	+	r.id.GetPhysicalDeviceProperties2(physical, &props)
	95	+	if drm.HasRender != 0 {
	96	+	sup.Device = unix.Mkdev(uint32(drm.RenderMajor), uint32(drm.RenderMinor))
	97	+	}
	98	+	for _, f := range dmabufFormats {
	99	+	list := vk.DrmFormatModifierPropertiesListEXT{SType: vk.StructureTypeDRMFormatModifierPropertiesListEXT}
	100	+	fp := vk.FormatProperties2{SType: vk.StructureTypeFormatProperties2, Next: unsafe.Pointer(&list)}
	101	+	r.id.GetPhysicalDeviceFormatProperties2(physical, f.format, &fp)
	102	+	if list.DrmFormatModifierCount == 0 {
	103	+	continue
	104	+	}
	105	+	mods := make([]vk.DrmFormatModifierPropertiesEXT, list.DrmFormatModifierCount)
	106	+	list.DrmFormatModifierProperties = &mods[0]
	107	+	r.id.GetPhysicalDeviceFormatProperties2(physical, f.format, &fp)
	108	+	for _, m := range mods[:list.DrmFormatModifierCount] {
	109	+	// Multi-plane modifiers (compression metadata) are left to a
	110	+	// later step; the blit needs a source.
	111	+	if m.DrmFormatModifierPlaneCount != 1 \|\| m.DrmFormatModifierTilingFeatures&vk.FormatFeatureBlitSrcBit == 0 {
	112	+	continue
	113	+	}
	114	+	if r.importable(physical, f.format, m.DrmFormatModifier) {
	115	+	sup.Formats = append(sup.Formats, ports.DMABufFormat{Format: f.fourcc, Modifier: m.DrmFormatModifier})
	116	+	}
	117	+	}
	118	+	}
	119	+	return sup
	120	+	}
	121	+
	122	+	// importable asks whether an image of that format and modifier can be
	123	+	// imported from a dmabuf.
	124	+	func (r *Renderer) importable(physical vk.PhysicalDevice, format vk.Format, modifier uint64) bool {
	125	+	mod := vk.PhysicalDeviceImageDrmFormatModifierInfoEXT{SType: vk.StructureTypePhysicalDeviceImageDRMFormatModifierInfoEXT, DrmFormatModifier: modifier, SharingMode: vk.SharingModeExclusive}
	126	+	ext := vk.PhysicalDeviceExternalImageFormatInfo{SType: vk.StructureTypePhysicalDeviceExternalImageFormatInfo, Next: unsafe.Pointer(&mod), HandleType: vk.ExternalMemoryHandleTypeDMABUFBitEXT}
	127	+	info := vk.PhysicalDeviceImageFormatInfo2{SType: vk.StructureTypePhysicalDeviceImageFormatInfo2, Next: unsafe.Pointer(&ext), Format: format, Type: vk.ImageType2d, Tiling: vk.ImageTilingDRMFormatModifierEXT, Usage: vk.ImageUsageTransferSrcBit}
	128	+	extOut := vk.ExternalImageFormatProperties{SType: vk.StructureTypeExternalImageFormatProperties}
	129	+	out := vk.ImageFormatProperties2{SType: vk.StructureTypeImageFormatProperties2, Next: unsafe.Pointer(&extOut)}
	130	+	if r.id.GetPhysicalDeviceImageFormatProperties2(physical, &info, &out) != vk.Success {
	131	+	return false
	132	+	}
	133	+	return extOut.ExternalMemoryProperties.ExternalMemoryFeatures&vk.ExternalMemoryFeatureImportableBit != 0
	134	+	}
	135	+
	136	+	// DMABuf reports the formats this renderer imports.
	137	+	func (r *Renderer) DMABuf() ports.DMABufSupport { return r.dmabuf }
	138	+
	139	+	// imported is a client dmabuf bound to a VkImage.
	140	+	type imported struct {
	141	+	image vk.Image
	142	+	memory vk.DeviceMemory
	143	+	fd int // our duplicate of plane 0, for implicit sync
	144	+	// last is the frame that drew it, for eviction.
	145	+	last uint64
	146	+	}
	147	+
	148	+	// importTTL is how many frames an import survives undrawn: clients cycle
	149	+	// through 2-4 buffers, and a destroyed buffer is freed shortly after.
	150	+	const importTTL = 120
	151	+
	152	+	// importDMABuf returns the image of a client buffer, importing it once.
	153	+	func (r Renderer) importDMABuf(b ports.DMABuf) (*imported, error) {
	154	+	if im := r.imports[b.ID]; im != nil {
	155	+	im.last = r.frame
	156	+	return im, nil
	157	+	}
	158	+	if len(r.dmabuf.Formats) == 0 {
	159	+	return nil, fmt.Errorf("dmabuf unsupported")
	160	+	}
	161	+	format, _, ok := vkFormat(b.Format)
	162	+	if !ok \|\| len(b.Planes) != 1 \|\| b.Width <= 0 \|\| b.Height <= 0 {
	163	+	return nil, fmt.Errorf("dmabuf format %#x with %d planes unsupported", b.Format, len(b.Planes))
	164	+	}
	165	+	fd, err := dupFile(b.Planes[0].File)
	166	+	if err != nil {
	167	+	return nil, err
	168	+	}
	169	+	im := &imported{fd: fd, last: r.frame}
	170	+	ok = false
	171	+	defer func() {
	172	+	if !ok {
	173	+	r.release(im)
	174	+	}
	175	+	}()
	176	+	d := r.dd
	177	+	layout := vk.SubresourceLayout{Offset: vk.DeviceSize(b.Planes[0].Offset), RowPitch: vk.DeviceSize(b.Planes[0].Stride)}
	178	+	explicit := vk.ImageDrmFormatModifierExplicitCreateInfoEXT{SType: vk.StructureTypeImageDRMFormatModifierExplicitCreateInfoEXT, DrmFormatModifier: b.Modifier, DrmFormatModifierPlaneCount: 1, PlaneLayouts: &layout}
	179	+	external := vk.ExternalMemoryImageCreateInfo{SType: vk.StructureTypeExternalMemoryImageCreateInfo, Next: unsafe.Pointer(&explicit), HandleTypes: vk.ExternalMemoryHandleTypeDMABUFBitEXT}
	180	+	ii := vk.ImageCreateInfo{SType: vk.StructureTypeImageCreateInfo, Next: unsafe.Pointer(&external), ImageType: vk.ImageType2d, Format: format, Extent: vk.Extent3D{Width: uint32(b.Width), Height: uint32(b.Height), Depth: 1}, MipLevels: 1, ArrayLayers: 1, Samples: vk.SampleCount1Bit, Tiling: vk.ImageTilingDRMFormatModifierEXT, Usage: vk.ImageUsageTransferSrcBit, SharingMode: vk.SharingModeExclusive, InitialLayout: vk.ImageLayoutUndefined}
	181	+	if err := checked("vkCreateImage(dmabuf)", d.CreateImage(r.device, &ii, nil, &im.image)); err != nil {
	182	+	return nil, err
	183	+	}
	184	+	fdProps := vk.MemoryFdPropertiesKHR{SType: vk.StructureTypeMemoryFDPropertiesKHR}
	185	+	if err := checked("vkGetMemoryFdPropertiesKHR", d.GetMemoryFdPropertiesKHR(r.device, vk.ExternalMemoryHandleTypeDMABUFBitEXT, int32(fd), &fdProps)); err != nil {
	186	+	return nil, err
	187	+	}
	188	+	var req vk.MemoryRequirements
	189	+	d.GetImageMemoryRequirements(r.device, im.image, &req)
	190	+	kind, err := r.findMemoryType(req.MemoryTypeBits&fdProps.MemoryTypeBits, 0)
	191	+	if err != nil {
	192	+	return nil, err
	193	+	}
	194	+	// Vulkan owns the fd it imports on success: hand it its own duplicate.
	195	+	memFD, err := unix.FcntlInt(uintptr(fd), unix.F_DUPFD_CLOEXEC, 0)
	196	+	if err != nil {
	197	+	return nil, err
	198	+	}
	199	+	dedicated := vk.MemoryDedicatedAllocateInfo{SType: vk.StructureTypeMemoryDedicatedAllocateInfo, Image: im.image}
	200	+	imp := vk.ImportMemoryFdInfoKHR{SType: vk.StructureTypeImportMemoryFDInfoKHR, Next: unsafe.Pointer(&dedicated), HandleType: vk.ExternalMemoryHandleTypeDMABUFBitEXT, Fd: int32(memFD)}
	201	+	alloc := vk.MemoryAllocateInfo{SType: vk.StructureTypeMemoryAllocateInfo, Next: unsafe.Pointer(&imp), AllocationSize: req.Size, MemoryTypeIndex: kind}
	202	+	if err := checked("vkAllocateMemory(dmabuf)", d.AllocateMemory(r.device, &alloc, nil, &im.memory)); err != nil {
	203	+	unix.Close(memFD)
	204	+	return nil, err
	205	+	}
	206	+	if err := checked("vkBindImageMemory(dmabuf)", d.BindImageMemory(r.device, im.image, im.memory, 0)); err != nil {
	207	+	return nil, err
	208	+	}
	209	+	ok = true
	210	+	r.imports[b.ID] = im
	211	+	return im, nil
	212	+	}
	213	+
	214	+	// dupFile duplicates the descriptor while the file is held open, so a close
	215	+	// on the wayland goroutine cannot swap it for a reused number.
	216	+	func dupFile(f *os.File) (int, error) {
	217	+	if f == nil {
	218	+	return -1, fmt.Errorf("dmabuf plane without file")
	219	+	}
	220	+	raw, err := f.SyscallConn()
	221	+	if err != nil {
	222	+	return -1, err
	223	+	}
	224	+	fd, dupErr := -1, error(nil)
	225	+	if err := raw.Control(func(v uintptr) { fd, dupErr = unix.FcntlInt(v, unix.F_DUPFD_CLOEXEC, 0) }); err != nil {
	226	+	return -1, err
	227	+	}
	228	+	return fd, dupErr
	229	+	}
	230	+
	231	+	func (r Renderer) release(im imported) {
	232	+	if im.image != 0 {
	233	+	r.dd.DestroyImage(r.device, im.image, nil)
	234	+	}
	235	+	if im.memory != 0 {
	236	+	r.dd.FreeMemory(r.device, im.memory, nil)
	237	+	}
	238	+	if im.fd >= 0 {
	239	+	unix.Close(im.fd)
	240	+	}
	241	+	}
	242	+
	243	+	// dropUnused frees imports not drawn for importTTL frames: the client moved
	244	+	// on to other buffers or went away. Called after a frame completes.
	245	+	func (r *Renderer) dropUnused() {
	246	+	r.frame++
	247	+	for id, im := range r.imports {
	248	+	if r.frame-im.last > importTTL {
	249	+	r.release(im)
	250	+	delete(r.imports, id)
	251	+	}
	252	+	}
	253	+	}
	254	+
	255	+	// dmaBufSync is struct dma_buf_export_sync_file.
	256	+	type dmaBufSync struct {
	257	+	flags uint32
	258	+	fd int32
	259	+	}
	260	+
	261	+	// DMA_BUF_IOCTL_EXPORT_SYNC_FILE = _IOWR('b', 2, struct dma_buf_export_sync_file)
	262	+	const ioctlExportSyncFile = 0xc0086202
	263	+	const dmaBufSyncRead = 1
	264	+
	265	+	// readFence returns a semaphore signalled when the client's pending writes
	266	+	// to the buffer finish, or 0 when the kernel cannot export them (older than
	267	+	// 5.20): the buffer is then read as is.
	268	+	func (r Renderer) readFence(im imported) vk.Semaphore {
	269	+	arg := dmaBufSync{flags: dmaBufSyncRead, fd: -1}
	270	+	if _, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(im.fd), ioctlExportSyncFile, uintptr(unsafe.Pointer(&arg))); errno != 0 \|\| arg.fd < 0 {
	271	+	return 0
	272	+	}
	273	+	var sem vk.Semaphore
	274	+	si := vk.SemaphoreCreateInfo{SType: vk.StructureTypeSemaphoreCreateInfo}
	275	+	if r.dd.CreateSemaphore(r.device, &si, nil, &sem) != vk.Success {
	276	+	unix.Close(int(arg.fd))
	277	+	return 0
	278	+	}
	279	+	imp := vk.ImportSemaphoreFdInfoKHR{SType: vk.StructureTypeImportSemaphoreFDInfoKHR, Semaphore: sem, Flags: vk.SemaphoreImportTemporaryBit, HandleType: vk.ExternalSemaphoreHandleTypeSyncFDBit, Fd: arg.fd}
	280	+	if r.dd.ImportSemaphoreFdKHR(r.device, &imp) != vk.Success {
	281	+	unix.Close(int(arg.fd))
	282	+	r.dd.DestroySemaphore(r.device, sem, nil)
	283	+	return 0
	284	+	}
	285	+	return sem
	286	+	}
	287	+
	288	+	// Probe reports the dmabuf formats of the device renderers use, or none
	289	+	// when Vulkan or the extensions are missing.
	290	+	func Probe() ports.DMABufSupport {
	291	+	r, err := New(1, 1)
	292	+	if err != nil {
	293	+	return ports.DMABufSupport{}
	294	+	}
	295	+	defer r.Close()
	296	+	return r.DMABuf()
	297	+	}

A internal/adapters/vulkan/dmabuf_test.go +108 -0

@@ -0,0 +1,108 @@
	1	+	package vulkan
	2	+
	3	+	import (
	4	+	"image/color"
	5	+	"os"
	6	+	"slices"
	7	+	"testing"
	8	+	"unsafe"
	9	+
	10	+	"github.com/bnema/nefertty/internal/ports"
	11	+	"golang.org/x/sys/unix"
	12	+	)
	13	+
	14	+	// udmabuf turns memfd pages into a real dmabuf: a linear buffer any GPU
	15	+	// driver imports, like a client's.
	16	+	func udmabuf(t testing.T, w, h int, fill func(x, y int) [4]byte) os.File {
	17	+	t.Helper()
	18	+	dev, err := os.OpenFile("/dev/udmabuf", os.O_RDWR, 0)
	19	+	if err != nil {
	20	+	t.Skipf("udmabuf unavailable: %v", err)
	21	+	}
	22	+	defer dev.Close()
	23	+	size := (wh4 + os.Getpagesize() - 1) / os.Getpagesize() * os.Getpagesize()
	24	+	mem, err := unix.MemfdCreate("dmabuf-test", unix.MFD_ALLOW_SEALING)
	25	+	if err != nil {
	26	+	t.Fatal(err)
	27	+	}
	28	+	defer unix.Close(mem)
	29	+	if err := unix.Ftruncate(mem, int64(size)); err != nil {
	30	+	t.Fatal(err)
	31	+	}
	32	+	data, err := unix.Mmap(mem, 0, size, unix.PROT_READ\|unix.PROT_WRITE, unix.MAP_SHARED)
	33	+	if err != nil {
	34	+	t.Fatal(err)
	35	+	}
	36	+	for y := range h {
	37	+	for x := range w {
	38	+	p := fill(x, y)
	39	+	copy(data[(yw+x)4:], p[:])
	40	+	}
	41	+	}
	42	+	_ = unix.Munmap(data)
	43	+	if _, err := unix.FcntlInt(uintptr(mem), unix.F_ADD_SEALS, unix.F_SEAL_SHRINK); err != nil {
	44	+	t.Fatal(err)
	45	+	}
	46	+	// struct udmabuf_create { u32 memfd; u32 flags; u64 offset; u64 size; }
	47	+	arg := struct {
	48	+	memfd, flags uint32
	49	+	offset, size uint64
	50	+	}{memfd: uint32(mem), flags: 1 /* CLOEXEC */, size: uint64(size)}
	51	+	const udmabufCreate = 0x40187542 // _IOW('u', 0x42, struct udmabuf_create)
	52	+	fd, _, errno := unix.Syscall(unix.SYS_IOCTL, dev.Fd(), udmabufCreate, uintptr(unsafe.Pointer(&arg)))
	53	+	if errno != 0 {
	54	+	t.Skipf("udmabuf create: %v", errno)
	55	+	}
	56	+	f := os.NewFile(fd, "dmabuf")
	57	+	t.Cleanup(func() { f.Close() })
	58	+	return f
	59	+	}
	60	+
	61	+	// A linear ARGB8888 dmabuf is imported and drawn like wl_shm pixels, and
	62	+	// the import is freed once no frame draws it.
	63	+	func TestRendererImportsDMABuf(t *testing.T) {
	64	+	r, err := New(80, 32)
	65	+	if err != nil {
	66	+	t.Skipf("Vulkan unavailable: %v", err)
	67	+	}
	68	+	defer r.Close()
	69	+	linear := ports.DMABufFormat{Format: fourcc('A', 'R', '2', '4'), Modifier: 0}
	70	+	if !slices.Contains(r.DMABuf().Formats, linear) {
	71	+	t.Skipf("linear ARGB8888 not importable: %+v", r.DMABuf())
	72	+	}
	73	+	// Left half red, right half blue (B,G,R,A in memory). 64 pixels wide:
	74	+	// drivers want linear rows aligned (256 bytes on AMD).
	75	+	f := udmabuf(t, 64, 16, func(x, _ int) [4]byte {
	76	+	if x < 32 {
	77	+	return [4]byte{0, 0, 255, 255}
	78	+	}
	79	+	return [4]byte{255, 0, 0, 255}
	80	+	})
	81	+	buf := &ports.DMABuf{ID: 7, Width: 64, Height: 16, Format: linear.Format, Planes: []ports.DMABufPlane{{File: f, Stride: 256}}}
	82	+	scene := ports.Scene{Background: "#000000", Windows: []ports.SceneWindow{{ID: 1, Rect: ports.Rect{X: 4, Y: 4, W: 64, H: 16}}}}
	83	+	contents := map[ports.WindowID]ports.SurfaceContent{1: {ID: 1, Width: 64, Height: 16, DMABuf: buf}}
	84	+	if err := r.Render(scene, contents); err != nil {
	85	+	t.Fatal(err)
	86	+	}
	87	+	px := r.Pixels()
	88	+	for _, c := range []struct {
	89	+	x, y int
	90	+	want color.RGBA
	91	+	}{{4, 4, color.RGBA{255, 0, 0, 255}}, {35, 19, color.RGBA{255, 0, 0, 255}}, {36, 4, color.RGBA{0, 0, 255, 255}}, {67, 19, color.RGBA{0, 0, 255, 255}}, {2, 2, color.RGBA{0, 0, 0, 255}}, {70, 10, color.RGBA{0, 0, 0, 255}}} {
	92	+	if got := px.At(c.x, c.y); got != c.want {
	93	+	t.Errorf("At(%d,%d)=%v want %v", c.x, c.y, got, c.want)
	94	+	}
	95	+	}
	96	+	if len(r.imports) != 1 {
	97	+	t.Fatalf("imports %d", len(r.imports))
	98	+	}
	99	+	// Frames without the buffer: its import is released after importTTL.
	100	+	for range importTTL + 1 {
	101	+	if err := r.Render(scene, nil); err != nil {
	102	+	t.Fatal(err)
	103	+	}
	104	+	}
	105	+	if len(r.imports) != 0 {
	106	+	t.Fatalf("import kept: %d", len(r.imports))
	107	+	}
	108	+	}

@@ -0,0 +1,108 @@
	1	+	package vulkan
	2	+
	3	+	import (
	4	+	"image/color"
	5	+	"os"
	6	+	"slices"
	7	+	"testing"
	8	+	"unsafe"
	9	+
	10	+	"github.com/bnema/nefertty/internal/ports"
	11	+	"golang.org/x/sys/unix"
	12	+	)
	13	+
	14	+	// udmabuf turns memfd pages into a real dmabuf: a linear buffer any GPU
	15	+	// driver imports, like a client's.
	16	+	func udmabuf(t testing.T, w, h int, fill func(x, y int) [4]byte) os.File {
	17	+	t.Helper()
	18	+	dev, err := os.OpenFile("/dev/udmabuf", os.O_RDWR, 0)
	19	+	if err != nil {
	20	+	t.Skipf("udmabuf unavailable: %v", err)
	21	+	}
	22	+	defer dev.Close()
	23	+	size := (wh4 + os.Getpagesize() - 1) / os.Getpagesize() * os.Getpagesize()
	24	+	mem, err := unix.MemfdCreate("dmabuf-test", unix.MFD_ALLOW_SEALING)
	25	+	if err != nil {
	26	+	t.Fatal(err)
	27	+	}
	28	+	defer unix.Close(mem)
	29	+	if err := unix.Ftruncate(mem, int64(size)); err != nil {
	30	+	t.Fatal(err)
	31	+	}
	32	+	data, err := unix.Mmap(mem, 0, size, unix.PROT_READ\|unix.PROT_WRITE, unix.MAP_SHARED)
	33	+	if err != nil {
	34	+	t.Fatal(err)
	35	+	}
	36	+	for y := range h {
	37	+	for x := range w {
	38	+	p := fill(x, y)
	39	+	copy(data[(yw+x)4:], p[:])
	40	+	}
	41	+	}
	42	+	_ = unix.Munmap(data)
	43	+	if _, err := unix.FcntlInt(uintptr(mem), unix.F_ADD_SEALS, unix.F_SEAL_SHRINK); err != nil {
	44	+	t.Fatal(err)
	45	+	}
	46	+	// struct udmabuf_create { u32 memfd; u32 flags; u64 offset; u64 size; }
	47	+	arg := struct {
	48	+	memfd, flags uint32
	49	+	offset, size uint64
	50	+	}{memfd: uint32(mem), flags: 1 /* CLOEXEC */, size: uint64(size)}
	51	+	const udmabufCreate = 0x40187542 // _IOW('u', 0x42, struct udmabuf_create)
	52	+	fd, _, errno := unix.Syscall(unix.SYS_IOCTL, dev.Fd(), udmabufCreate, uintptr(unsafe.Pointer(&arg)))
	53	+	if errno != 0 {
	54	+	t.Skipf("udmabuf create: %v", errno)
	55	+	}
	56	+	f := os.NewFile(fd, "dmabuf")
	57	+	t.Cleanup(func() { f.Close() })
	58	+	return f
	59	+	}
	60	+
	61	+	// A linear ARGB8888 dmabuf is imported and drawn like wl_shm pixels, and
	62	+	// the import is freed once no frame draws it.
	63	+	func TestRendererImportsDMABuf(t *testing.T) {
	64	+	r, err := New(80, 32)
	65	+	if err != nil {
	66	+	t.Skipf("Vulkan unavailable: %v", err)
	67	+	}
	68	+	defer r.Close()
	69	+	linear := ports.DMABufFormat{Format: fourcc('A', 'R', '2', '4'), Modifier: 0}
	70	+	if !slices.Contains(r.DMABuf().Formats, linear) {
	71	+	t.Skipf("linear ARGB8888 not importable: %+v", r.DMABuf())
	72	+	}
	73	+	// Left half red, right half blue (B,G,R,A in memory). 64 pixels wide:
	74	+	// drivers want linear rows aligned (256 bytes on AMD).
	75	+	f := udmabuf(t, 64, 16, func(x, _ int) [4]byte {
	76	+	if x < 32 {
	77	+	return [4]byte{0, 0, 255, 255}
	78	+	}
	79	+	return [4]byte{255, 0, 0, 255}
	80	+	})
	81	+	buf := &ports.DMABuf{ID: 7, Width: 64, Height: 16, Format: linear.Format, Planes: []ports.DMABufPlane{{File: f, Stride: 256}}}
	82	+	scene := ports.Scene{Background: "#000000", Windows: []ports.SceneWindow{{ID: 1, Rect: ports.Rect{X: 4, Y: 4, W: 64, H: 16}}}}
	83	+	contents := map[ports.WindowID]ports.SurfaceContent{1: {ID: 1, Width: 64, Height: 16, DMABuf: buf}}
	84	+	if err := r.Render(scene, contents); err != nil {
	85	+	t.Fatal(err)
	86	+	}
	87	+	px := r.Pixels()
	88	+	for _, c := range []struct {
	89	+	x, y int
	90	+	want color.RGBA
	91	+	}{{4, 4, color.RGBA{255, 0, 0, 255}}, {35, 19, color.RGBA{255, 0, 0, 255}}, {36, 4, color.RGBA{0, 0, 255, 255}}, {67, 19, color.RGBA{0, 0, 255, 255}}, {2, 2, color.RGBA{0, 0, 0, 255}}, {70, 10, color.RGBA{0, 0, 0, 255}}} {
	92	+	if got := px.At(c.x, c.y); got != c.want {
	93	+	t.Errorf("At(%d,%d)=%v want %v", c.x, c.y, got, c.want)
	94	+	}
	95	+	}
	96	+	if len(r.imports) != 1 {
	97	+	t.Fatalf("imports %d", len(r.imports))
	98	+	}
	99	+	// Frames without the buffer: its import is released after importTTL.
	100	+	for range importTTL + 1 {
	101	+	if err := r.Render(scene, nil); err != nil {
	102	+	t.Fatal(err)
	103	+	}
	104	+	}
	105	+	if len(r.imports) != 0 {
	106	+	t.Fatalf("import kept: %d", len(r.imports))
	107	+	}
	108	+	}

M internal/adapters/vulkan/renderer.go +113 -4


@@ -6,6 +6,7 @@ import (
6	6		"math"
7	7		"os"
8	8		"runtime"
	9	+	"slices"
9	10		"strconv"
10	11		"unsafe"
11	12

@@ -36,6 +37,11 @@ type Renderer struct {
36	37		fence vk.Fence
37	38		layout vk.ImageLayout
38	39		memory vk.PhysicalDeviceMemoryProperties
	40	+	family uint32
	41	+	// dmabuf is what clients may send; imports are their buffers by ID.
	42	+	dmabuf ports.DMABufSupport
	43	+	imports map[uint64]*imported
	44	+	frame uint64
39	45		}
40	46
41	47		func checked(name string, result vk.Result) error {

@@ -49,7 +55,7 @@ func New(width, height int) (r *Renderer, err error) {
49	55		if width <= 0 \|\| height <= 0 \|\| width > math.MaxUint32 \|\| height > math.MaxUint32 \|\| uint64(width)*uint64(height) > uint64(math.MaxInt/4) {
50	56		return nil, fmt.Errorf("invalid renderer dimensions %d x %d", width, height)
51	57		}
52		-	r = &Renderer{width: width, height: height, layout: vk.ImageLayoutUndefined}
	58	+	r = &Renderer{width: width, height: height, layout: vk.ImageLayoutUndefined, imports: map[uint64]*imported{}}
53	59		defer func() {
54	60		if err != nil {
55	61		r.Close()

@@ -123,10 +129,22 @@ func New(width, height int) (r *Renderer, err error) {
123	129		return
124	130		}
125	131		r.id.GetPhysicalDeviceMemoryProperties(physical, &r.memory)
	132	+	r.family = family
126	133		priority := float32(1)
127	134		qi := vk.DeviceQueueCreateInfo{SType: vk.StructureTypeDeviceQueueCreateInfo, QueueFamilyIndex: family, QueueCount: 1, QueuePriorities: &priority}
128	135		dynamicRendering := vk.PhysicalDeviceDynamicRenderingFeatures{SType: vk.StructureTypePhysicalDeviceDynamicRenderingFeatures, DynamicRendering: 1}
129	136		di := vk.DeviceCreateInfo{SType: vk.StructureTypeDeviceCreateInfo, Next: unsafe.Pointer(&dynamicRendering), QueueCreateInfoCount: 1, QueueCreateInfos: &qi}
	137	+	// dmabuf import needs every extension; without them clients use wl_shm.
	138	+	var extNames [][]byte
	139	+	var extPtrs []*byte
	140	+	if r.hasExtensions(physical) {
	141	+	for _, e := range deviceExtensions {
	142	+	extNames = append(extNames, append([]byte(e), 0))
	143	+	extPtrs = append(extPtrs, &extNames[len(extNames)-1][0])
	144	+	}
	145	+	di.EnabledExtensionCount = uint32(len(extPtrs))
	146	+	di.PpEnabledExtensionNames = &extPtrs[0]
	147	+	}
130	148		if err = checked("vkCreateDevice", r.id.CreateDevice(physical, &di, nil, &r.device)); err != nil {
131	149		return
132	150		}

@@ -135,6 +153,14 @@ func New(width, height int) (r *Renderer, err error) {
135	153		err = fmt.Errorf("LoadDeviceDispatch: %w", err)
136	154		return
137	155		}
	156	+	runtime.KeepAlive(extNames)
	157	+	runtime.KeepAlive(extPtrs)
	158	+	if len(extPtrs) > 0 {
	159	+	// Clients need the render node to allocate on the right GPU.
	160	+	if sup := r.probeDMABuf(physical); sup.Device != 0 {
	161	+	r.dmabuf = sup
	162	+	}
	163	+	}
138	164		r.dd.GetDeviceQueue(r.device, family, 0, &r.queue)
139	165		extent := vk.Extent3D{Width: uint32(width), Height: uint32(height), Depth: 1}
140	166		ii := vk.ImageCreateInfo{SType: vk.StructureTypeImageCreateInfo, ImageType: vk.ImageType2d, Format: vk.FormatB8g8r8a8Unorm, Extent: extent, MipLevels: 1, ArrayLayers: 1, Samples: vk.SampleCount1Bit, Tiling: vk.ImageTilingOptimal, Usage: vk.ImageUsageTransferSrcBit \| vk.ImageUsageTransferDstBit, SharingMode: vk.SharingModeExclusive, InitialLayout: vk.ImageLayoutUndefined}

@@ -332,6 +358,8 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
332	358		dst, src image.Rectangle
333	359		color [3]uint8
334	360		opaque bool
	361	+	// dma is a client GPU buffer, blitted instead of copied from staging.
	362	+	dma *imported
335	363		}
336	364		var uploads []upload
337	365		used := 0

@@ -350,6 +378,15 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
350	378		if rect.Empty() \|\| src.Empty() {
351	379		return
352	380		}
	381	+	if content.DMABuf != nil {
	382	+	im, err := r.importDMABuf(content.DMABuf)
	383	+	if err != nil {
	384	+	// The window shows its background until a buffer imports.
	385	+	return
	386	+	}
	387	+	uploads = append(uploads, upload{rect: rect, dst: dst, src: src, dma: im})
	388	+	return
	389	+	}
353	390		uploads = append(uploads, upload{rect: rect, offset: used, pixels: content.Pixels, stride: content.Stride, opaque: content.Opaque, dst: dst, src: src})
354	391		used += rect.Dx() * rect.Dy() * 4
355	392		}

@@ -359,7 +396,10 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
359	396		if lw <= 0 \|\| lh <= 0 {
360	397		lw, lh = content.Width, content.Height
361	398		}
362		-	if content.Pixels == nil \|\| lw <= 0 \|\| lh <= 0 \|\| content.Stride < content.Width4 \|\| len(content.Pixels) < (content.Height-1)content.Stride+content.Width*4 {
	399	+	if content.Empty() \|\| lw <= 0 \|\| lh <= 0 {
	400	+	return
	401	+	}
	402	+	if content.DMABuf == nil && (content.Stride < content.Width4 \|\| len(content.Pixels) < (content.Height-1)content.Stride+content.Width*4) {
363	403		return
364	404		}
365	405		vw, vh := min(lw, w), min(lh, h)

@@ -416,7 +456,7 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
416	456		cx, cy, cw, ch := x+b, y+b, w.Rect.W-2b, w.Rect.H-2b
417	457		body := physRect(cx, cy, cw, ch)
418	458		content := contents[w.ID]
419		-	if content.Pixels == nil {
	459	+	if content.Empty() {
420	460		add(body, windowColor(w.ID))
421	461		} else {
422	462		add(body, parseColor(s.Background))

@@ -445,6 +485,9 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
445	485		}
446	486		data := unsafe.Slice((*byte)(r.stagingMapped), r.stagingSize)
447	487		for _, u := range uploads {
	488	+	if u.dma != nil {
	489	+	continue
	490	+	}
448	491		dst := data[u.offset : u.offset+u.rect.Dx()u.rect.Dy()4]
449	492		for row := 0; row < u.rect.Dy(); row++ {
450	493		line := dst[rowu.rect.Dx()4 : (row+1)u.rect.Dx()4]

@@ -502,14 +545,54 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
502	545		barrier.OldLayout = vk.ImageLayoutTransferDstOptimal
503	546		barrier.NewLayout = vk.ImageLayoutTransferDstOptimal
504	547		d.CmdPipelineBarrier(r.command, vk.PipelineStageTransferBit, vk.PipelineStageTransferBit, 0, 0, nil, 0, nil, 1, &barrier)
	548	+	// Client buffers come from the foreign queue family (their driver) and
	549	+	// go back to it after the frame, so the next frame acquires them again.
	550	+	var dmas []*imported
	551	+	for _, u := range uploads {
	552	+	if u.dma != nil && !slices.Contains(dmas, u.dma) {
	553	+	dmas = append(dmas, u.dma)
	554	+	}
	555	+	}
	556	+	ownership := func(acquire bool) {
	557	+	for _, im := range dmas {
	558	+	b := vk.ImageMemoryBarrier{SType: vk.StructureTypeImageMemoryBarrier, Image: im.image, SubresourceRange: rangeInfo}
	559	+	if acquire {
	560	+	// GENERAL, never UNDEFINED: the client's contents must survive.
	561	+	b.OldLayout, b.NewLayout = vk.ImageLayoutGeneral, vk.ImageLayoutTransferSrcOptimal
	562	+	b.SrcQueueFamilyIndex, b.DstQueueFamilyIndex = vk.QueueFamilyForeignEXT, r.family
	563	+	b.DstAccessMask = vk.AccessTransferReadBit
	564	+	} else {
	565	+	b.OldLayout, b.NewLayout = vk.ImageLayoutTransferSrcOptimal, vk.ImageLayoutGeneral
	566	+	b.SrcQueueFamilyIndex, b.DstQueueFamilyIndex = r.family, vk.QueueFamilyForeignEXT
	567	+	b.SrcAccessMask = vk.AccessTransferReadBit
	568	+	}
	569	+	d.CmdPipelineBarrier(r.command, vk.PipelineStageTransferBit, vk.PipelineStageTransferBit, 0, 0, nil, 0, nil, 1, &b)
	570	+	}
	571	+	}
	572	+	ownership(true)
505	573		for i, f := range uploads {
506	574		if i > 0 {
507	575		d.CmdPipelineBarrier(r.command, vk.PipelineStageTransferBit, vk.PipelineStageTransferBit, 0, 0, nil, 0, nil, 1, &barrier)
508	576		}
509	577		rect := f.rect
	578	+	if f.dma != nil {
	579	+	// Map the visible part of dst back onto the buffer.
	580	+	sx := func(x int) int32 { return int32(f.src.Min.X + (x-f.dst.Min.X)*f.src.Dx()/f.dst.Dx()) }
	581	+	sy := func(y int) int32 { return int32(f.src.Min.Y + (y-f.dst.Min.Y)*f.src.Dy()/f.dst.Dy()) }
	582	+	layers := vk.ImageSubresourceLayers{AspectMask: vk.ImageAspectColorBit, LayerCount: 1}
	583	+	blit := vk.ImageBlit{
	584	+	SrcSubresource: layers,
	585	+	SrcOffsets: [2]vk.Offset3D{{X: sx(rect.Min.X), Y: sy(rect.Min.Y)}, {X: sx(rect.Max.X), Y: sy(rect.Max.Y), Z: 1}},
	586	+	DstSubresource: layers,
	587	+	DstOffsets: [2]vk.Offset3D{{X: int32(rect.Min.X), Y: int32(rect.Min.Y)}, {X: int32(rect.Max.X), Y: int32(rect.Max.Y), Z: 1}},
	588	+	}
	589	+	d.CmdBlitImage(r.command, f.dma.image, vk.ImageLayoutTransferSrcOptimal, r.image, vk.ImageLayoutTransferDstOptimal, 1, &blit, vk.FilterNearest)
	590	+	continue
	591	+	}
510	592		region := vk.BufferImageCopy{BufferOffset: vk.DeviceSize(f.offset), ImageSubresource: vk.ImageSubresourceLayers{AspectMask: vk.ImageAspectColorBit, LayerCount: 1}, ImageOffset: vk.Offset3D{X: int32(rect.Min.X), Y: int32(rect.Min.Y)}, ImageExtent: vk.Extent3D{Width: uint32(rect.Dx()), Height: uint32(rect.Dy()), Depth: 1}}
511	593		d.CmdCopyBufferToImage(r.command, r.staging, r.image, vk.ImageLayoutTransferDstOptimal, 1, &region)
512	594		}
	595	+	ownership(false)
513	596		barrier.DstAccessMask = vk.AccessTransferReadBit
514	597		barrier.OldLayout = vk.ImageLayoutTransferDstOptimal
515	598		barrier.NewLayout = vk.ImageLayoutTransferSrcOptimal

@@ -519,14 +602,35 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
519	602		if err := checked("vkEndCommandBuffer", d.EndCommandBuffer(r.command)); err != nil {
520	603		return err
521	604		}
	605	+	// Implicit sync: wait for the client's GPU writes to each buffer.
	606	+	var waits []vk.Semaphore
	607	+	for _, im := range dmas {
	608	+	if sem := r.readFence(im); sem != 0 {
	609	+	waits = append(waits, sem)
	610	+	}
	611	+	}
	612	+	defer func() {
	613	+	for _, sem := range waits {
	614	+	d.DestroySemaphore(r.device, sem, nil)
	615	+	}
	616	+	}()
522	617		submit := vk.SubmitInfo{SType: vk.StructureTypeSubmitInfo, CommandBufferCount: 1, CommandBuffers: &r.command}
	618	+	stages := make([]vk.PipelineStageFlags, len(waits))
	619	+	if len(waits) > 0 {
	620	+	for i := range stages {
	621	+	stages[i] = vk.PipelineStageTransferBit
	622	+	}
	623	+	submit.WaitSemaphoreCount, submit.WaitSemaphores, submit.WaitDstStageMask = uint32(len(waits)), &waits[0], &stages[0]
	624	+	}
523	625		if err := checked("vkQueueSubmit", d.QueueSubmit(r.queue, 1, &submit, r.fence)); err != nil {
524	626		return err
525	627		}
	628	+	runtime.KeepAlive(stages)
526	629		r.layout = vk.ImageLayoutTransferSrcOptimal
527	630		if err := checked("vkWaitForFences", d.WaitForFences(r.device, 1, &r.fence, 1, math.MaxUint64)); err != nil {
528	631		return err
529	632		}
	633	+	r.dropUnused()
530	634		return checked("vkResetFences", d.ResetFences(r.device, 1, &r.fence))
531	635		}
532	636

@@ -537,7 +641,8 @@ func (r Renderer) Pixels() image.RGBA {
537	641		}
538	642		src := unsafe.Slice((*byte)(r.mapped), len(out.Pix))
539	643		for i := 0; i < len(src); i += 4 {
540		-	out.Pix[i], out.Pix[i+1], out.Pix[i+2], out.Pix[i+3] = src[i+2], src[i+1], src[i], src[i+3]
	644	+	// The output is opaque: x-format client buffers leave alpha undefined.
	645	+	out.Pix[i], out.Pix[i+1], out.Pix[i+2], out.Pix[i+3] = src[i+2], src[i+1], src[i], 255
541	646		}
542	647		return out
543	648		}

@@ -564,6 +669,10 @@ func (r *Renderer) Close() {
564	669		if r.device != 0 {
565	670		_ = checked("vkDeviceWaitIdle", d.DeviceWaitIdle(r.device))
566	671		}
	672	+	for id, im := range r.imports {
	673	+	r.release(im)
	674	+	delete(r.imports, id)
	675	+	}
567	676		if r.fence != 0 {
568	677		d.DestroyFence(r.device, r.fence, nil)
569	678		r.fence = 0


@@ -6,6 +6,7 @@ import (
6		"math"	6		"math"
7		"os"	7		"os"
8		"runtime"	8		"runtime"
			9	+	"slices"
9		"strconv"	10		"strconv"
10		"unsafe"	11		"unsafe"
11			12

@@ -36,6 +37,11 @@ type Renderer struct {
36		fence vk.Fence	37		fence vk.Fence
37		layout vk.ImageLayout	38		layout vk.ImageLayout
38		memory vk.PhysicalDeviceMemoryProperties	39		memory vk.PhysicalDeviceMemoryProperties
			40	+	family uint32
			41	+	// dmabuf is what clients may send; imports are their buffers by ID.
			42	+	dmabuf ports.DMABufSupport
			43	+	imports map[uint64]*imported
			44	+	frame uint64
39		}	45		}
40			46
41		func checked(name string, result vk.Result) error {	47		func checked(name string, result vk.Result) error {

@@ -49,7 +55,7 @@ func New(width, height int) (r *Renderer, err error) {
49		if width <= 0 \|\| height <= 0 \|\| width > math.MaxUint32 \|\| height > math.MaxUint32 \|\| uint64(width)*uint64(height) > uint64(math.MaxInt/4) {	55		if width <= 0 \|\| height <= 0 \|\| width > math.MaxUint32 \|\| height > math.MaxUint32 \|\| uint64(width)*uint64(height) > uint64(math.MaxInt/4) {
50		return nil, fmt.Errorf("invalid renderer dimensions %d x %d", width, height)	56		return nil, fmt.Errorf("invalid renderer dimensions %d x %d", width, height)
51		}	57		}
52	-	r = &Renderer{width: width, height: height, layout: vk.ImageLayoutUndefined}	58	+	r = &Renderer{width: width, height: height, layout: vk.ImageLayoutUndefined, imports: map[uint64]*imported{}}
53		defer func() {	59		defer func() {
54		if err != nil {	60		if err != nil {
55		r.Close()	61		r.Close()

@@ -123,10 +129,22 @@ func New(width, height int) (r *Renderer, err error) {
123		return	129		return
124		}	130		}
125		r.id.GetPhysicalDeviceMemoryProperties(physical, &r.memory)	131		r.id.GetPhysicalDeviceMemoryProperties(physical, &r.memory)
			132	+	r.family = family
126		priority := float32(1)	133		priority := float32(1)
127		qi := vk.DeviceQueueCreateInfo{SType: vk.StructureTypeDeviceQueueCreateInfo, QueueFamilyIndex: family, QueueCount: 1, QueuePriorities: &priority}	134		qi := vk.DeviceQueueCreateInfo{SType: vk.StructureTypeDeviceQueueCreateInfo, QueueFamilyIndex: family, QueueCount: 1, QueuePriorities: &priority}
128		dynamicRendering := vk.PhysicalDeviceDynamicRenderingFeatures{SType: vk.StructureTypePhysicalDeviceDynamicRenderingFeatures, DynamicRendering: 1}	135		dynamicRendering := vk.PhysicalDeviceDynamicRenderingFeatures{SType: vk.StructureTypePhysicalDeviceDynamicRenderingFeatures, DynamicRendering: 1}
129		di := vk.DeviceCreateInfo{SType: vk.StructureTypeDeviceCreateInfo, Next: unsafe.Pointer(&dynamicRendering), QueueCreateInfoCount: 1, QueueCreateInfos: &qi}	136		di := vk.DeviceCreateInfo{SType: vk.StructureTypeDeviceCreateInfo, Next: unsafe.Pointer(&dynamicRendering), QueueCreateInfoCount: 1, QueueCreateInfos: &qi}
			137	+	// dmabuf import needs every extension; without them clients use wl_shm.
			138	+	var extNames [][]byte
			139	+	var extPtrs []*byte
			140	+	if r.hasExtensions(physical) {
			141	+	for _, e := range deviceExtensions {
			142	+	extNames = append(extNames, append([]byte(e), 0))
			143	+	extPtrs = append(extPtrs, &extNames[len(extNames)-1][0])
			144	+	}
			145	+	di.EnabledExtensionCount = uint32(len(extPtrs))
			146	+	di.PpEnabledExtensionNames = &extPtrs[0]
			147	+	}
130		if err = checked("vkCreateDevice", r.id.CreateDevice(physical, &di, nil, &r.device)); err != nil {	148		if err = checked("vkCreateDevice", r.id.CreateDevice(physical, &di, nil, &r.device)); err != nil {
131		return	149		return
132		}	150		}

@@ -135,6 +153,14 @@ func New(width, height int) (r *Renderer, err error) {
135		err = fmt.Errorf("LoadDeviceDispatch: %w", err)	153		err = fmt.Errorf("LoadDeviceDispatch: %w", err)
136		return	154		return
137		}	155		}
			156	+	runtime.KeepAlive(extNames)
			157	+	runtime.KeepAlive(extPtrs)
			158	+	if len(extPtrs) > 0 {
			159	+	// Clients need the render node to allocate on the right GPU.
			160	+	if sup := r.probeDMABuf(physical); sup.Device != 0 {
			161	+	r.dmabuf = sup
			162	+	}
			163	+	}
138		r.dd.GetDeviceQueue(r.device, family, 0, &r.queue)	164		r.dd.GetDeviceQueue(r.device, family, 0, &r.queue)
139		extent := vk.Extent3D{Width: uint32(width), Height: uint32(height), Depth: 1}	165		extent := vk.Extent3D{Width: uint32(width), Height: uint32(height), Depth: 1}
140		ii := vk.ImageCreateInfo{SType: vk.StructureTypeImageCreateInfo, ImageType: vk.ImageType2d, Format: vk.FormatB8g8r8a8Unorm, Extent: extent, MipLevels: 1, ArrayLayers: 1, Samples: vk.SampleCount1Bit, Tiling: vk.ImageTilingOptimal, Usage: vk.ImageUsageTransferSrcBit \| vk.ImageUsageTransferDstBit, SharingMode: vk.SharingModeExclusive, InitialLayout: vk.ImageLayoutUndefined}	166		ii := vk.ImageCreateInfo{SType: vk.StructureTypeImageCreateInfo, ImageType: vk.ImageType2d, Format: vk.FormatB8g8r8a8Unorm, Extent: extent, MipLevels: 1, ArrayLayers: 1, Samples: vk.SampleCount1Bit, Tiling: vk.ImageTilingOptimal, Usage: vk.ImageUsageTransferSrcBit \| vk.ImageUsageTransferDstBit, SharingMode: vk.SharingModeExclusive, InitialLayout: vk.ImageLayoutUndefined}

@@ -332,6 +358,8 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
332		dst, src image.Rectangle	358		dst, src image.Rectangle
333		color [3]uint8	359		color [3]uint8
334		opaque bool	360		opaque bool
			361	+	// dma is a client GPU buffer, blitted instead of copied from staging.
			362	+	dma *imported
335		}	363		}
336		var uploads []upload	364		var uploads []upload
337		used := 0	365		used := 0

@@ -350,6 +378,15 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
350		if rect.Empty() \|\| src.Empty() {	378		if rect.Empty() \|\| src.Empty() {
351		return	379		return
352		}	380		}
			381	+	if content.DMABuf != nil {
			382	+	im, err := r.importDMABuf(content.DMABuf)
			383	+	if err != nil {
			384	+	// The window shows its background until a buffer imports.
			385	+	return
			386	+	}
			387	+	uploads = append(uploads, upload{rect: rect, dst: dst, src: src, dma: im})
			388	+	return
			389	+	}
353		uploads = append(uploads, upload{rect: rect, offset: used, pixels: content.Pixels, stride: content.Stride, opaque: content.Opaque, dst: dst, src: src})	390		uploads = append(uploads, upload{rect: rect, offset: used, pixels: content.Pixels, stride: content.Stride, opaque: content.Opaque, dst: dst, src: src})
354		used += rect.Dx() * rect.Dy() * 4	391		used += rect.Dx() * rect.Dy() * 4
355		}	392		}

@@ -359,7 +396,10 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
359		if lw <= 0 \|\| lh <= 0 {	396		if lw <= 0 \|\| lh <= 0 {
360		lw, lh = content.Width, content.Height	397		lw, lh = content.Width, content.Height
361		}	398		}
362	-	if content.Pixels == nil \|\| lw <= 0 \|\| lh <= 0 \|\| content.Stride < content.Width4 \|\| len(content.Pixels) < (content.Height-1)content.Stride+content.Width*4 {	399	+	if content.Empty() \|\| lw <= 0 \|\| lh <= 0 {
			400	+	return
			401	+	}
			402	+	if content.DMABuf == nil && (content.Stride < content.Width4 \|\| len(content.Pixels) < (content.Height-1)content.Stride+content.Width*4) {
363		return	403		return
364		}	404		}
365		vw, vh := min(lw, w), min(lh, h)	405		vw, vh := min(lw, w), min(lh, h)

@@ -416,7 +456,7 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
416		cx, cy, cw, ch := x+b, y+b, w.Rect.W-2b, w.Rect.H-2b	456		cx, cy, cw, ch := x+b, y+b, w.Rect.W-2b, w.Rect.H-2b
417		body := physRect(cx, cy, cw, ch)	457		body := physRect(cx, cy, cw, ch)
418		content := contents[w.ID]	458		content := contents[w.ID]
419	-	if content.Pixels == nil {	459	+	if content.Empty() {
420		add(body, windowColor(w.ID))	460		add(body, windowColor(w.ID))
421		} else {	461		} else {
422		add(body, parseColor(s.Background))	462		add(body, parseColor(s.Background))

@@ -445,6 +485,9 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
445		}	485		}
446		data := unsafe.Slice((*byte)(r.stagingMapped), r.stagingSize)	486		data := unsafe.Slice((*byte)(r.stagingMapped), r.stagingSize)
447		for _, u := range uploads {	487		for _, u := range uploads {
			488	+	if u.dma != nil {
			489	+	continue
			490	+	}
448		dst := data[u.offset : u.offset+u.rect.Dx()u.rect.Dy()4]	491		dst := data[u.offset : u.offset+u.rect.Dx()u.rect.Dy()4]
449		for row := 0; row < u.rect.Dy(); row++ {	492		for row := 0; row < u.rect.Dy(); row++ {
450		line := dst[rowu.rect.Dx()4 : (row+1)u.rect.Dx()4]	493		line := dst[rowu.rect.Dx()4 : (row+1)u.rect.Dx()4]

@@ -502,14 +545,54 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
502		barrier.OldLayout = vk.ImageLayoutTransferDstOptimal	545		barrier.OldLayout = vk.ImageLayoutTransferDstOptimal
503		barrier.NewLayout = vk.ImageLayoutTransferDstOptimal	546		barrier.NewLayout = vk.ImageLayoutTransferDstOptimal
504		d.CmdPipelineBarrier(r.command, vk.PipelineStageTransferBit, vk.PipelineStageTransferBit, 0, 0, nil, 0, nil, 1, &barrier)	547		d.CmdPipelineBarrier(r.command, vk.PipelineStageTransferBit, vk.PipelineStageTransferBit, 0, 0, nil, 0, nil, 1, &barrier)
			548	+	// Client buffers come from the foreign queue family (their driver) and
			549	+	// go back to it after the frame, so the next frame acquires them again.
			550	+	var dmas []*imported
			551	+	for _, u := range uploads {
			552	+	if u.dma != nil && !slices.Contains(dmas, u.dma) {
			553	+	dmas = append(dmas, u.dma)
			554	+	}
			555	+	}
			556	+	ownership := func(acquire bool) {
			557	+	for _, im := range dmas {
			558	+	b := vk.ImageMemoryBarrier{SType: vk.StructureTypeImageMemoryBarrier, Image: im.image, SubresourceRange: rangeInfo}
			559	+	if acquire {
			560	+	// GENERAL, never UNDEFINED: the client's contents must survive.
			561	+	b.OldLayout, b.NewLayout = vk.ImageLayoutGeneral, vk.ImageLayoutTransferSrcOptimal
			562	+	b.SrcQueueFamilyIndex, b.DstQueueFamilyIndex = vk.QueueFamilyForeignEXT, r.family
			563	+	b.DstAccessMask = vk.AccessTransferReadBit
			564	+	} else {
			565	+	b.OldLayout, b.NewLayout = vk.ImageLayoutTransferSrcOptimal, vk.ImageLayoutGeneral
			566	+	b.SrcQueueFamilyIndex, b.DstQueueFamilyIndex = r.family, vk.QueueFamilyForeignEXT
			567	+	b.SrcAccessMask = vk.AccessTransferReadBit
			568	+	}
			569	+	d.CmdPipelineBarrier(r.command, vk.PipelineStageTransferBit, vk.PipelineStageTransferBit, 0, 0, nil, 0, nil, 1, &b)
			570	+	}
			571	+	}
			572	+	ownership(true)
505		for i, f := range uploads {	573		for i, f := range uploads {
506		if i > 0 {	574		if i > 0 {
507		d.CmdPipelineBarrier(r.command, vk.PipelineStageTransferBit, vk.PipelineStageTransferBit, 0, 0, nil, 0, nil, 1, &barrier)	575		d.CmdPipelineBarrier(r.command, vk.PipelineStageTransferBit, vk.PipelineStageTransferBit, 0, 0, nil, 0, nil, 1, &barrier)
508		}	576		}
509		rect := f.rect	577		rect := f.rect
			578	+	if f.dma != nil {
			579	+	// Map the visible part of dst back onto the buffer.
			580	+	sx := func(x int) int32 { return int32(f.src.Min.X + (x-f.dst.Min.X)*f.src.Dx()/f.dst.Dx()) }
			581	+	sy := func(y int) int32 { return int32(f.src.Min.Y + (y-f.dst.Min.Y)*f.src.Dy()/f.dst.Dy()) }
			582	+	layers := vk.ImageSubresourceLayers{AspectMask: vk.ImageAspectColorBit, LayerCount: 1}
			583	+	blit := vk.ImageBlit{
			584	+	SrcSubresource: layers,
			585	+	SrcOffsets: [2]vk.Offset3D{{X: sx(rect.Min.X), Y: sy(rect.Min.Y)}, {X: sx(rect.Max.X), Y: sy(rect.Max.Y), Z: 1}},
			586	+	DstSubresource: layers,
			587	+	DstOffsets: [2]vk.Offset3D{{X: int32(rect.Min.X), Y: int32(rect.Min.Y)}, {X: int32(rect.Max.X), Y: int32(rect.Max.Y), Z: 1}},
			588	+	}
			589	+	d.CmdBlitImage(r.command, f.dma.image, vk.ImageLayoutTransferSrcOptimal, r.image, vk.ImageLayoutTransferDstOptimal, 1, &blit, vk.FilterNearest)
			590	+	continue
			591	+	}
510		region := vk.BufferImageCopy{BufferOffset: vk.DeviceSize(f.offset), ImageSubresource: vk.ImageSubresourceLayers{AspectMask: vk.ImageAspectColorBit, LayerCount: 1}, ImageOffset: vk.Offset3D{X: int32(rect.Min.X), Y: int32(rect.Min.Y)}, ImageExtent: vk.Extent3D{Width: uint32(rect.Dx()), Height: uint32(rect.Dy()), Depth: 1}}	592		region := vk.BufferImageCopy{BufferOffset: vk.DeviceSize(f.offset), ImageSubresource: vk.ImageSubresourceLayers{AspectMask: vk.ImageAspectColorBit, LayerCount: 1}, ImageOffset: vk.Offset3D{X: int32(rect.Min.X), Y: int32(rect.Min.Y)}, ImageExtent: vk.Extent3D{Width: uint32(rect.Dx()), Height: uint32(rect.Dy()), Depth: 1}}
511		d.CmdCopyBufferToImage(r.command, r.staging, r.image, vk.ImageLayoutTransferDstOptimal, 1, &region)	593		d.CmdCopyBufferToImage(r.command, r.staging, r.image, vk.ImageLayoutTransferDstOptimal, 1, &region)
512		}	594		}
			595	+	ownership(false)
513		barrier.DstAccessMask = vk.AccessTransferReadBit	596		barrier.DstAccessMask = vk.AccessTransferReadBit
514		barrier.OldLayout = vk.ImageLayoutTransferDstOptimal	597		barrier.OldLayout = vk.ImageLayoutTransferDstOptimal
515		barrier.NewLayout = vk.ImageLayoutTransferSrcOptimal	598		barrier.NewLayout = vk.ImageLayoutTransferSrcOptimal

@@ -519,14 +602,35 @@ func (r *Renderer) Render(s ports.Scene, contents map[ports.WindowID]ports.Surfa
519		if err := checked("vkEndCommandBuffer", d.EndCommandBuffer(r.command)); err != nil {	602		if err := checked("vkEndCommandBuffer", d.EndCommandBuffer(r.command)); err != nil {
520		return err	603		return err
521		}	604		}
			605	+	// Implicit sync: wait for the client's GPU writes to each buffer.
			606	+	var waits []vk.Semaphore
			607	+	for _, im := range dmas {
			608	+	if sem := r.readFence(im); sem != 0 {
			609	+	waits = append(waits, sem)
			610	+	}
			611	+	}
			612	+	defer func() {
			613	+	for _, sem := range waits {
			614	+	d.DestroySemaphore(r.device, sem, nil)
			615	+	}
			616	+	}()
522		submit := vk.SubmitInfo{SType: vk.StructureTypeSubmitInfo, CommandBufferCount: 1, CommandBuffers: &r.command}	617		submit := vk.SubmitInfo{SType: vk.StructureTypeSubmitInfo, CommandBufferCount: 1, CommandBuffers: &r.command}
			618	+	stages := make([]vk.PipelineStageFlags, len(waits))
			619	+	if len(waits) > 0 {
			620	+	for i := range stages {
			621	+	stages[i] = vk.PipelineStageTransferBit
			622	+	}
			623	+	submit.WaitSemaphoreCount, submit.WaitSemaphores, submit.WaitDstStageMask = uint32(len(waits)), &waits[0], &stages[0]
			624	+	}
523		if err := checked("vkQueueSubmit", d.QueueSubmit(r.queue, 1, &submit, r.fence)); err != nil {	625		if err := checked("vkQueueSubmit", d.QueueSubmit(r.queue, 1, &submit, r.fence)); err != nil {
524		return err	626		return err
525		}	627		}
			628	+	runtime.KeepAlive(stages)
526		r.layout = vk.ImageLayoutTransferSrcOptimal	629		r.layout = vk.ImageLayoutTransferSrcOptimal
527		if err := checked("vkWaitForFences", d.WaitForFences(r.device, 1, &r.fence, 1, math.MaxUint64)); err != nil {	630		if err := checked("vkWaitForFences", d.WaitForFences(r.device, 1, &r.fence, 1, math.MaxUint64)); err != nil {
528		return err	631		return err
529		}	632		}
			633	+	r.dropUnused()
530		return checked("vkResetFences", d.ResetFences(r.device, 1, &r.fence))	634		return checked("vkResetFences", d.ResetFences(r.device, 1, &r.fence))
531		}	635		}
532			636

@@ -537,7 +641,8 @@ func (r Renderer) Pixels() image.RGBA {
537		}	641		}
538		src := unsafe.Slice((*byte)(r.mapped), len(out.Pix))	642		src := unsafe.Slice((*byte)(r.mapped), len(out.Pix))
539		for i := 0; i < len(src); i += 4 {	643		for i := 0; i < len(src); i += 4 {
540	-	out.Pix[i], out.Pix[i+1], out.Pix[i+2], out.Pix[i+3] = src[i+2], src[i+1], src[i], src[i+3]	644	+	// The output is opaque: x-format client buffers leave alpha undefined.
			645	+	out.Pix[i], out.Pix[i+1], out.Pix[i+2], out.Pix[i+3] = src[i+2], src[i+1], src[i], 255
541		}	646		}
542		return out	647		return out
543		}	648		}

@@ -564,6 +669,10 @@ func (r *Renderer) Close() {
564		if r.device != 0 {	669		if r.device != 0 {
565		_ = checked("vkDeviceWaitIdle", d.DeviceWaitIdle(r.device))	670		_ = checked("vkDeviceWaitIdle", d.DeviceWaitIdle(r.device))
566		}	671		}
			672	+	for id, im := range r.imports {
			673	+	r.release(im)
			674	+	delete(r.imports, id)
			675	+	}
567		if r.fence != 0 {	676		if r.fence != 0 {
568		d.DestroyFence(r.device, r.fence, nil)	677		d.DestroyFence(r.device, r.fence, nil)
569		r.fence = 0	678		r.fence = 0

A internal/adapters/wayland/dmabuf.go +300 -0

@@ -0,0 +1,300 @@
	1	+	package wayland
	2	+
	3	+	import (
	4	+	"encoding/binary"
	5	+	"io"
	6	+	"os"
	7	+	"slices"
	8	+
	9	+	"github.com/bnema/nefertty/internal/ports"
	10	+	"github.com/bnema/purego-libwayland/protocol/linuxdmabuf"
	11	+	"github.com/bnema/purego-libwayland/protocol/wayland"
	12	+	"github.com/bnema/purego-libwayland/server"
	13	+	"golang.org/x/sys/unix"
	14	+	)
	15	+
	16	+	// linux-dmabuf v4: clients hand GPU buffers to the renderer without copies.
	17	+	// The formats are those the renderer imports (ports.DMABufSupport); without
	18	+	// any, the global is not advertised and clients use wl_shm.
	19	+
	20	+	const dmabufVersion = 4
	21	+
	22	+	// maxPlanes is the protocol limit (DRM planes).
	23	+	const maxPlanes = 4
	24	+
	25	+	func registerDMABuf(d server.Display, s Server, sup ports.DMABufSupport) error {
	26	+	if len(sup.Formats) == 0 {
	27	+	return nil
	28	+	}
	29	+	table, err := formatTable(sup.Formats)
	30	+	if err != nil {
	31	+	return err
	32	+	}
	33	+	s.dmabuf = &dmabufGlobal{server: s, support: sup, table: table}
	34	+	return linuxdmabuf.NewZwpLinuxDmabufV1Global(d, dmabufVersion, func(c server.Client, v, id uint32) {
	35	+	r, err := linuxdmabuf.NewZwpLinuxDmabufV1(c, int32(v), id, s.dmabuf)
	36	+	if err != nil \|\| v >= 4 {
	37	+	return
	38	+	}
	39	+	// Before v4 formats come as events on bind.
	40	+	for _, f := range sup.Formats {
	41	+	if v >= 3 {
	42	+	r.SendModifier(f.Format, uint32(f.Modifier>>32), uint32(f.Modifier))
	43	+	} else if f.Modifier == 0 {
	44	+	r.SendFormat(f.Format)
	45	+	}
	46	+	}
	47	+	})
	48	+	}
	49	+
	50	+	// formatTable is the shared memfd of 16-byte entries (u32 format, 4 bytes
	51	+	// padding, u64 modifier) feedback clients map read-only.
	52	+	func formatTable(formats []ports.DMABufFormat) (*os.File, error) {
	53	+	data := make([]byte, 16*len(formats))
	54	+	for i, f := range formats {
	55	+	binary.NativeEndian.PutUint32(data[i*16:], f.Format)
	56	+	binary.NativeEndian.PutUint64(data[i*16+8:], f.Modifier)
	57	+	}
	58	+	fd, err := unix.MemfdCreate("nefertty-dmabuf-formats", unix.MFD_CLOEXEC\|unix.MFD_ALLOW_SEALING)
	59	+	if err != nil {
	60	+	return nil, err
	61	+	}
	62	+	f := os.NewFile(uintptr(fd), "dmabuf-formats")
	63	+	if _, err := f.Write(data); err != nil {
	64	+	f.Close()
	65	+	return nil, err
	66	+	}
	67	+	// Clients map it: it must never shrink or change.
	68	+	if _, err := unix.FcntlInt(uintptr(fd), unix.F_ADD_SEALS, unix.F_SEAL_SHRINK\|unix.F_SEAL_GROW\|unix.F_SEAL_WRITE\|unix.F_SEAL_SEAL); err != nil {
	69	+	f.Close()
	70	+	return nil, err
	71	+	}
	72	+	return f, nil
	73	+	}
	74	+
	75	+	type dmabufGlobal struct {
	76	+	server *Server
	77	+	support ports.DMABufSupport
	78	+	table *os.File
	79	+	nextID uint64
	80	+	}
	81	+
	82	+	func (g *dmabufGlobal) close() {
	83	+	if g != nil && g.table != nil {
	84	+	g.table.Close()
	85	+	}
	86	+	}
	87	+
	88	+	func (dmabufGlobal) Destroy(linuxdmabuf.ZwpLinuxDmabufV1) {}
	89	+
	90	+	func (g dmabufGlobal) CreateParams(r linuxdmabuf.ZwpLinuxDmabufV1, id uint32) {
	91	+	p := &params{global: g}
	92	+	res, err := linuxdmabuf.NewZwpLinuxBufferParamsV1(r.Client(), r.Version(), id, p)
	93	+	if err != nil {
	94	+	return
	95	+	}
	96	+	p.resource = res
	97	+	res.OnDestroy = p.closeFiles
	98	+	}
	99	+
	100	+	func (g dmabufGlobal) GetDefaultFeedback(r linuxdmabuf.ZwpLinuxDmabufV1, id uint32) {
	101	+	g.feedback(r, id)
	102	+	}
	103	+
	104	+	// GetSurfaceFeedback sends the default feedback: one renderer, one tranche.
	105	+	// Scanout tranches come with direct scanout.
	106	+	func (g dmabufGlobal) GetSurfaceFeedback(r linuxdmabuf.ZwpLinuxDmabufV1, id uint32, _ *wayland.Surface) {
	107	+	g.feedback(r, id)
	108	+	}
	109	+
	110	+	func (g dmabufGlobal) feedback(r linuxdmabuf.ZwpLinuxDmabufV1, id uint32) {
	111	+	fb, err := linuxdmabuf.NewZwpLinuxDmabufFeedbackV1(r.Client(), r.Version(), id, feedback{})
	112	+	if err != nil {
	113	+	return
	114	+	}
	115	+	dev := make([]byte, 8)
	116	+	binary.NativeEndian.PutUint64(dev, g.support.Device)
	117	+	indices := make([]byte, 2*len(g.support.Formats))
	118	+	for i := range g.support.Formats {
	119	+	binary.NativeEndian.PutUint16(indices[i*2:], uint16(i))
	120	+	}
	121	+	fb.SendFormatTable(int(g.table.Fd()), uint32(16*len(g.support.Formats)))
	122	+	fb.SendMainDevice(dev)
	123	+	fb.SendTrancheTargetDevice(dev)
	124	+	fb.SendTrancheFlags(0)
	125	+	fb.SendTrancheFormats(indices)
	126	+	fb.SendTrancheDone()
	127	+	fb.SendDone()
	128	+	}
	129	+
	130	+	type feedback struct{}
	131	+
	132	+	func (feedback) Destroy(*linuxdmabuf.ZwpLinuxDmabufFeedbackV1) {}
	133	+
	134	+	// params collects the planes of one buffer.
	135	+	type params struct {
	136	+	global *dmabufGlobal
	137	+	resource *linuxdmabuf.ZwpLinuxBufferParamsV1
	138	+	planes [maxPlanes]*plane
	139	+	modifier uint64
	140	+	used bool
	141	+	}
	142	+
	143	+	type plane struct {
	144	+	file *os.File
	145	+	offset, stride uint32
	146	+	}
	147	+
	148	+	func (p *params) closeFiles() {
	149	+	for i, pl := range p.planes {
	150	+	if pl != nil {
	151	+	pl.file.Close()
	152	+	p.planes[i] = nil
	153	+	}
	154	+	}
	155	+	}
	156	+
	157	+	func (p params) Destroy(linuxdmabuf.ZwpLinuxBufferParamsV1) {}
	158	+
	159	+	func (p params) Add(r linuxdmabuf.ZwpLinuxBufferParamsV1, fd int, idx, offset, stride, modHi, modLo uint32) {
	160	+	f := os.NewFile(uintptr(fd), "dmabuf")
	161	+	switch {
	162	+	case p.used:
	163	+	f.Close()
	164	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorAlreadyUsed), "params already used")
	165	+	case idx >= maxPlanes:
	166	+	f.Close()
	167	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorPlaneIdx), "plane index out of bounds")
	168	+	case p.planes[idx] != nil:
	169	+	f.Close()
	170	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorPlaneSet), "plane already set")
	171	+	default:
	172	+	mod := uint64(modHi)<<32 \| uint64(modLo)
	173	+	if p.anyPlane() && mod != p.modifier {
	174	+	f.Close()
	175	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorInvalidFormat), "planes with different modifiers")
	176	+	return
	177	+	}
	178	+	p.modifier = mod
	179	+	p.planes[idx] = &plane{file: f, offset: offset, stride: stride}
	180	+	}
	181	+	}
	182	+
	183	+	func (p *params) anyPlane() bool {
	184	+	return slices.ContainsFunc(p.planes[:], func(pl *plane) bool { return pl != nil })
	185	+	}
	186	+
	187	+	// build validates the planes and turns them into a buffer; ok is false after
	188	+	// a protocol error, failed means the client gets `failed`.
	189	+	func (p params) build(width, height int32, format, flags uint32) (buf dmabufBuffer, failed, ok bool) {
	190	+	r := p.resource
	191	+	if p.used {
	192	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorAlreadyUsed), "params already used")
	193	+	return nil, false, false
	194	+	}
	195	+	p.used = true
	196	+	n := 0
	197	+	for n < maxPlanes && p.planes[n] != nil {
	198	+	n++
	199	+	}
	200	+	if n == 0 \|\| slices.ContainsFunc(p.planes[n:], func(pl *plane) bool { return pl != nil }) {
	201	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorIncomplete), "missing planes")
	202	+	return nil, false, false
	203	+	}
	204	+	if width <= 0 \|\| height <= 0 {
	205	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorInvalidDimensions), "invalid dimensions")
	206	+	return nil, false, false
	207	+	}
	208	+	// Unsupported formats, y-inverted or interlaced buffers: the client
	209	+	// falls back to another format or to wl_shm.
	210	+	want := ports.DMABufFormat{Format: format, Modifier: p.modifier}
	211	+	if flags != 0 \|\| !slices.Contains(p.global.support.Formats, want) {
	212	+	return nil, true, true
	213	+	}
	214	+	// Supported formats are single-plane, 4 bytes per pixel.
	215	+	if n != 1 {
	216	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorIncomplete), "format takes one plane")
	217	+	return nil, false, false
	218	+	}
	219	+	pl := p.planes[0]
	220	+	row := uint64(width) * 4
	221	+	end := uint64(pl.offset) + uint64(pl.stride)*uint64(height-1) + row
	222	+	size, err := pl.file.Seek(0, io.SeekEnd)
	223	+	if uint64(pl.stride) < row \|\| (err == nil && end > uint64(size)) {
	224	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorOutOfBounds), "plane out of bounds")
	225	+	return nil, false, false
	226	+	}
	227	+	p.global.nextID++
	228	+	d := &ports.DMABuf{ID: p.global.nextID, Width: int(width), Height: int(height), Format: format, Modifier: p.modifier}
	229	+	for _, pl := range p.planes[:n] {
	230	+	d.Planes = append(d.Planes, ports.DMABufPlane{File: pl.file, Offset: pl.offset, Stride: pl.stride})
	231	+	}
	232	+	// The buffer owns the files now.
	233	+	p.planes = [maxPlanes]*plane{}
	234	+	return &dmabufBuffer{buf: d}, false, true
	235	+	}
	236	+
	237	+	func (p params) Create(r linuxdmabuf.ZwpLinuxBufferParamsV1, width, height int32, format, flags uint32) {
	238	+	b, failed, ok := p.build(width, height, format, flags)
	239	+	if !ok {
	240	+	return
	241	+	}
	242	+	if failed {
	243	+	r.SendFailed()
	244	+	return
	245	+	}
	246	+	// A server-side wl_buffer: id 0 asks libwayland to allocate one.
	247	+	res, err := wayland.NewBuffer(r.Client(), 1, 0, b)
	248	+	if err != nil {
	249	+	b.close()
	250	+	r.SendFailed()
	251	+	return
	252	+	}
	253	+	p.global.server.addBuffer(res, b)
	254	+	r.SendCreated(res)
	255	+	}
	256	+
	257	+	func (p params) CreateImmed(r linuxdmabuf.ZwpLinuxBufferParamsV1, id uint32, width, height int32, format, flags uint32) {
	258	+	b, failed, ok := p.build(width, height, format, flags)
	259	+	if !ok {
	260	+	return
	261	+	}
	262	+	if failed {
	263	+	// Immediate creation has no failure event: the protocol says to
	264	+	// raise invalid_wl_buffer.
	265	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorInvalidWlBuffer), "unsupported buffer")
	266	+	return
	267	+	}
	268	+	res, err := wayland.NewBuffer(r.Client(), 1, id, b)
	269	+	if err != nil {
	270	+	b.close()
	271	+	return
	272	+	}
	273	+	p.global.server.addBuffer(res, b)
	274	+	}
	275	+
	276	+	func (params) SetSamplingDevice(linuxdmabuf.ZwpLinuxBufferParamsV1, []byte) {}
	277	+
	278	+	// dmabufBuffer is a wl_buffer backed by client GPU memory.
	279	+	type dmabufBuffer struct{ buf *ports.DMABuf }
	280	+
	281	+	func (dmabufBuffer) Destroy(wayland.Buffer) {}
	282	+
	283	+	func (b *dmabufBuffer) close() {
	284	+	for _, pl := range b.buf.Planes {
	285	+	pl.File.Close()
	286	+	}
	287	+	}
	288	+
	289	+	func (b *dmabufBuffer) size() (int, int) { return b.buf.Width, b.buf.Height }
	290	+
	291	+	// content hands the renderer the buffer itself: nothing is copied.
	292	+	func (b *dmabufBuffer) content(id ports.WindowID) (ports.SurfaceContent, bool) {
	293	+	opaque := b.buf.Format == fourccXRGB \|\| b.buf.Format == fourccXBGR
	294	+	return ports.SurfaceContent{ID: id, Width: b.buf.Width, Height: b.buf.Height, Opaque: opaque, DMABuf: b.buf}, true
	295	+	}
	296	+
	297	+	const (
	298	+	fourccXRGB = 'X' \| 'R'<<8 \| '2'<<16 \| '4'<<24
	299	+	fourccXBGR = 'X' \| 'B'<<8 \| '2'<<16 \| '4'<<24
	300	+	)

@@ -0,0 +1,300 @@
	1	+	package wayland
	2	+
	3	+	import (
	4	+	"encoding/binary"
	5	+	"io"
	6	+	"os"
	7	+	"slices"
	8	+
	9	+	"github.com/bnema/nefertty/internal/ports"
	10	+	"github.com/bnema/purego-libwayland/protocol/linuxdmabuf"
	11	+	"github.com/bnema/purego-libwayland/protocol/wayland"
	12	+	"github.com/bnema/purego-libwayland/server"
	13	+	"golang.org/x/sys/unix"
	14	+	)
	15	+
	16	+	// linux-dmabuf v4: clients hand GPU buffers to the renderer without copies.
	17	+	// The formats are those the renderer imports (ports.DMABufSupport); without
	18	+	// any, the global is not advertised and clients use wl_shm.
	19	+
	20	+	const dmabufVersion = 4
	21	+
	22	+	// maxPlanes is the protocol limit (DRM planes).
	23	+	const maxPlanes = 4
	24	+
	25	+	func registerDMABuf(d server.Display, s Server, sup ports.DMABufSupport) error {
	26	+	if len(sup.Formats) == 0 {
	27	+	return nil
	28	+	}
	29	+	table, err := formatTable(sup.Formats)
	30	+	if err != nil {
	31	+	return err
	32	+	}
	33	+	s.dmabuf = &dmabufGlobal{server: s, support: sup, table: table}
	34	+	return linuxdmabuf.NewZwpLinuxDmabufV1Global(d, dmabufVersion, func(c server.Client, v, id uint32) {
	35	+	r, err := linuxdmabuf.NewZwpLinuxDmabufV1(c, int32(v), id, s.dmabuf)
	36	+	if err != nil \|\| v >= 4 {
	37	+	return
	38	+	}
	39	+	// Before v4 formats come as events on bind.
	40	+	for _, f := range sup.Formats {
	41	+	if v >= 3 {
	42	+	r.SendModifier(f.Format, uint32(f.Modifier>>32), uint32(f.Modifier))
	43	+	} else if f.Modifier == 0 {
	44	+	r.SendFormat(f.Format)
	45	+	}
	46	+	}
	47	+	})
	48	+	}
	49	+
	50	+	// formatTable is the shared memfd of 16-byte entries (u32 format, 4 bytes
	51	+	// padding, u64 modifier) feedback clients map read-only.
	52	+	func formatTable(formats []ports.DMABufFormat) (*os.File, error) {
	53	+	data := make([]byte, 16*len(formats))
	54	+	for i, f := range formats {
	55	+	binary.NativeEndian.PutUint32(data[i*16:], f.Format)
	56	+	binary.NativeEndian.PutUint64(data[i*16+8:], f.Modifier)
	57	+	}
	58	+	fd, err := unix.MemfdCreate("nefertty-dmabuf-formats", unix.MFD_CLOEXEC\|unix.MFD_ALLOW_SEALING)
	59	+	if err != nil {
	60	+	return nil, err
	61	+	}
	62	+	f := os.NewFile(uintptr(fd), "dmabuf-formats")
	63	+	if _, err := f.Write(data); err != nil {
	64	+	f.Close()
	65	+	return nil, err
	66	+	}
	67	+	// Clients map it: it must never shrink or change.
	68	+	if _, err := unix.FcntlInt(uintptr(fd), unix.F_ADD_SEALS, unix.F_SEAL_SHRINK\|unix.F_SEAL_GROW\|unix.F_SEAL_WRITE\|unix.F_SEAL_SEAL); err != nil {
	69	+	f.Close()
	70	+	return nil, err
	71	+	}
	72	+	return f, nil
	73	+	}
	74	+
	75	+	type dmabufGlobal struct {
	76	+	server *Server
	77	+	support ports.DMABufSupport
	78	+	table *os.File
	79	+	nextID uint64
	80	+	}
	81	+
	82	+	func (g *dmabufGlobal) close() {
	83	+	if g != nil && g.table != nil {
	84	+	g.table.Close()
	85	+	}
	86	+	}
	87	+
	88	+	func (dmabufGlobal) Destroy(linuxdmabuf.ZwpLinuxDmabufV1) {}
	89	+
	90	+	func (g dmabufGlobal) CreateParams(r linuxdmabuf.ZwpLinuxDmabufV1, id uint32) {
	91	+	p := &params{global: g}
	92	+	res, err := linuxdmabuf.NewZwpLinuxBufferParamsV1(r.Client(), r.Version(), id, p)
	93	+	if err != nil {
	94	+	return
	95	+	}
	96	+	p.resource = res
	97	+	res.OnDestroy = p.closeFiles
	98	+	}
	99	+
	100	+	func (g dmabufGlobal) GetDefaultFeedback(r linuxdmabuf.ZwpLinuxDmabufV1, id uint32) {
	101	+	g.feedback(r, id)
	102	+	}
	103	+
	104	+	// GetSurfaceFeedback sends the default feedback: one renderer, one tranche.
	105	+	// Scanout tranches come with direct scanout.
	106	+	func (g dmabufGlobal) GetSurfaceFeedback(r linuxdmabuf.ZwpLinuxDmabufV1, id uint32, _ *wayland.Surface) {
	107	+	g.feedback(r, id)
	108	+	}
	109	+
	110	+	func (g dmabufGlobal) feedback(r linuxdmabuf.ZwpLinuxDmabufV1, id uint32) {
	111	+	fb, err := linuxdmabuf.NewZwpLinuxDmabufFeedbackV1(r.Client(), r.Version(), id, feedback{})
	112	+	if err != nil {
	113	+	return
	114	+	}
	115	+	dev := make([]byte, 8)
	116	+	binary.NativeEndian.PutUint64(dev, g.support.Device)
	117	+	indices := make([]byte, 2*len(g.support.Formats))
	118	+	for i := range g.support.Formats {
	119	+	binary.NativeEndian.PutUint16(indices[i*2:], uint16(i))
	120	+	}
	121	+	fb.SendFormatTable(int(g.table.Fd()), uint32(16*len(g.support.Formats)))
	122	+	fb.SendMainDevice(dev)
	123	+	fb.SendTrancheTargetDevice(dev)
	124	+	fb.SendTrancheFlags(0)
	125	+	fb.SendTrancheFormats(indices)
	126	+	fb.SendTrancheDone()
	127	+	fb.SendDone()
	128	+	}
	129	+
	130	+	type feedback struct{}
	131	+
	132	+	func (feedback) Destroy(*linuxdmabuf.ZwpLinuxDmabufFeedbackV1) {}
	133	+
	134	+	// params collects the planes of one buffer.
	135	+	type params struct {
	136	+	global *dmabufGlobal
	137	+	resource *linuxdmabuf.ZwpLinuxBufferParamsV1
	138	+	planes [maxPlanes]*plane
	139	+	modifier uint64
	140	+	used bool
	141	+	}
	142	+
	143	+	type plane struct {
	144	+	file *os.File
	145	+	offset, stride uint32
	146	+	}
	147	+
	148	+	func (p *params) closeFiles() {
	149	+	for i, pl := range p.planes {
	150	+	if pl != nil {
	151	+	pl.file.Close()
	152	+	p.planes[i] = nil
	153	+	}
	154	+	}
	155	+	}
	156	+
	157	+	func (p params) Destroy(linuxdmabuf.ZwpLinuxBufferParamsV1) {}
	158	+
	159	+	func (p params) Add(r linuxdmabuf.ZwpLinuxBufferParamsV1, fd int, idx, offset, stride, modHi, modLo uint32) {
	160	+	f := os.NewFile(uintptr(fd), "dmabuf")
	161	+	switch {
	162	+	case p.used:
	163	+	f.Close()
	164	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorAlreadyUsed), "params already used")
	165	+	case idx >= maxPlanes:
	166	+	f.Close()
	167	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorPlaneIdx), "plane index out of bounds")
	168	+	case p.planes[idx] != nil:
	169	+	f.Close()
	170	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorPlaneSet), "plane already set")
	171	+	default:
	172	+	mod := uint64(modHi)<<32 \| uint64(modLo)
	173	+	if p.anyPlane() && mod != p.modifier {
	174	+	f.Close()
	175	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorInvalidFormat), "planes with different modifiers")
	176	+	return
	177	+	}
	178	+	p.modifier = mod
	179	+	p.planes[idx] = &plane{file: f, offset: offset, stride: stride}
	180	+	}
	181	+	}
	182	+
	183	+	func (p *params) anyPlane() bool {
	184	+	return slices.ContainsFunc(p.planes[:], func(pl *plane) bool { return pl != nil })
	185	+	}
	186	+
	187	+	// build validates the planes and turns them into a buffer; ok is false after
	188	+	// a protocol error, failed means the client gets `failed`.
	189	+	func (p params) build(width, height int32, format, flags uint32) (buf dmabufBuffer, failed, ok bool) {
	190	+	r := p.resource
	191	+	if p.used {
	192	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorAlreadyUsed), "params already used")
	193	+	return nil, false, false
	194	+	}
	195	+	p.used = true
	196	+	n := 0
	197	+	for n < maxPlanes && p.planes[n] != nil {
	198	+	n++
	199	+	}
	200	+	if n == 0 \|\| slices.ContainsFunc(p.planes[n:], func(pl *plane) bool { return pl != nil }) {
	201	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorIncomplete), "missing planes")
	202	+	return nil, false, false
	203	+	}
	204	+	if width <= 0 \|\| height <= 0 {
	205	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorInvalidDimensions), "invalid dimensions")
	206	+	return nil, false, false
	207	+	}
	208	+	// Unsupported formats, y-inverted or interlaced buffers: the client
	209	+	// falls back to another format or to wl_shm.
	210	+	want := ports.DMABufFormat{Format: format, Modifier: p.modifier}
	211	+	if flags != 0 \|\| !slices.Contains(p.global.support.Formats, want) {
	212	+	return nil, true, true
	213	+	}
	214	+	// Supported formats are single-plane, 4 bytes per pixel.
	215	+	if n != 1 {
	216	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorIncomplete), "format takes one plane")
	217	+	return nil, false, false
	218	+	}
	219	+	pl := p.planes[0]
	220	+	row := uint64(width) * 4
	221	+	end := uint64(pl.offset) + uint64(pl.stride)*uint64(height-1) + row
	222	+	size, err := pl.file.Seek(0, io.SeekEnd)
	223	+	if uint64(pl.stride) < row \|\| (err == nil && end > uint64(size)) {
	224	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorOutOfBounds), "plane out of bounds")
	225	+	return nil, false, false
	226	+	}
	227	+	p.global.nextID++
	228	+	d := &ports.DMABuf{ID: p.global.nextID, Width: int(width), Height: int(height), Format: format, Modifier: p.modifier}
	229	+	for _, pl := range p.planes[:n] {
	230	+	d.Planes = append(d.Planes, ports.DMABufPlane{File: pl.file, Offset: pl.offset, Stride: pl.stride})
	231	+	}
	232	+	// The buffer owns the files now.
	233	+	p.planes = [maxPlanes]*plane{}
	234	+	return &dmabufBuffer{buf: d}, false, true
	235	+	}
	236	+
	237	+	func (p params) Create(r linuxdmabuf.ZwpLinuxBufferParamsV1, width, height int32, format, flags uint32) {
	238	+	b, failed, ok := p.build(width, height, format, flags)
	239	+	if !ok {
	240	+	return
	241	+	}
	242	+	if failed {
	243	+	r.SendFailed()
	244	+	return
	245	+	}
	246	+	// A server-side wl_buffer: id 0 asks libwayland to allocate one.
	247	+	res, err := wayland.NewBuffer(r.Client(), 1, 0, b)
	248	+	if err != nil {
	249	+	b.close()
	250	+	r.SendFailed()
	251	+	return
	252	+	}
	253	+	p.global.server.addBuffer(res, b)
	254	+	r.SendCreated(res)
	255	+	}
	256	+
	257	+	func (p params) CreateImmed(r linuxdmabuf.ZwpLinuxBufferParamsV1, id uint32, width, height int32, format, flags uint32) {
	258	+	b, failed, ok := p.build(width, height, format, flags)
	259	+	if !ok {
	260	+	return
	261	+	}
	262	+	if failed {
	263	+	// Immediate creation has no failure event: the protocol says to
	264	+	// raise invalid_wl_buffer.
	265	+	r.PostError(uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorInvalidWlBuffer), "unsupported buffer")
	266	+	return
	267	+	}
	268	+	res, err := wayland.NewBuffer(r.Client(), 1, id, b)
	269	+	if err != nil {
	270	+	b.close()
	271	+	return
	272	+	}
	273	+	p.global.server.addBuffer(res, b)
	274	+	}
	275	+
	276	+	func (params) SetSamplingDevice(linuxdmabuf.ZwpLinuxBufferParamsV1, []byte) {}
	277	+
	278	+	// dmabufBuffer is a wl_buffer backed by client GPU memory.
	279	+	type dmabufBuffer struct{ buf *ports.DMABuf }
	280	+
	281	+	func (dmabufBuffer) Destroy(wayland.Buffer) {}
	282	+
	283	+	func (b *dmabufBuffer) close() {
	284	+	for _, pl := range b.buf.Planes {
	285	+	pl.File.Close()
	286	+	}
	287	+	}
	288	+
	289	+	func (b *dmabufBuffer) size() (int, int) { return b.buf.Width, b.buf.Height }
	290	+
	291	+	// content hands the renderer the buffer itself: nothing is copied.
	292	+	func (b *dmabufBuffer) content(id ports.WindowID) (ports.SurfaceContent, bool) {
	293	+	opaque := b.buf.Format == fourccXRGB \|\| b.buf.Format == fourccXBGR
	294	+	return ports.SurfaceContent{ID: id, Width: b.buf.Width, Height: b.buf.Height, Opaque: opaque, DMABuf: b.buf}, true
	295	+	}
	296	+
	297	+	const (
	298	+	fourccXRGB = 'X' \| 'R'<<8 \| '2'<<16 \| '4'<<24
	299	+	fourccXBGR = 'X' \| 'B'<<8 \| '2'<<16 \| '4'<<24
	300	+	)

A internal/adapters/wayland/dmabuf_test.go +174 -0

@@ -0,0 +1,174 @@
	1	+	package wayland
	2	+
	3	+	import (
	4	+	"context"
	5	+	"os/exec"
	6	+	"testing"
	7	+	"time"
	8	+
	9	+	"github.com/bnema/nefertty/internal/logging"
	10	+	"github.com/bnema/nefertty/internal/ports"
	11	+	"github.com/bnema/purego-libwayland/protocol/linuxdmabuf"
	12	+	"github.com/bnema/wlturbo"
	13	+	"golang.org/x/sys/unix"
	14	+	)
	15	+
	16	+	var linearARGB = ports.DMABufFormat{Format: 'A' \| 'R'<<8 \| '2'<<16 \| '4'<<24}
	17	+
	18	+	func dmabufServer(t testing.T, sup ports.DMABufSupport) (Server, chan ports.ClientEvent, chan ports.SurfaceContent, string) {
	19	+	t.Helper()
	20	+	dir := t.TempDir()
	21	+	events := make(chan ports.ClientEvent, 16)
	22	+	contents := make(chan ports.SurfaceContent, 16)
	23	+	s, err := New(Options{RuntimeDir: dir, Outputs: testOutputs, DMABuf: sup}, Channels{Events: events, Contents: contents}, logging.For(context.Background(), "wayland"))
	24	+	if err != nil {
	25	+	t.Fatal(err)
	26	+	}
	27	+	ctx, cancel := context.WithCancel(context.Background())
	28	+	done := make(chan error, 1)
	29	+	go func() { done <- s.Run(ctx) }()
	30	+	t.Cleanup(func() {
	31	+	cancel()
	32	+	select {
	33	+	case err := <-done:
	34	+	if err != nil {
	35	+	t.Errorf("Run: %v", err)
	36	+	}
	37	+	case <-time.After(2 * time.Second):
	38	+	t.Error("Run hung")
	39	+	}
	40	+	})
	41	+	return s, events, contents, dir
	42	+	}
	43	+
	44	+	// Without renderer formats there is no linux-dmabuf global.
	45	+	func TestNoDMABufWithoutFormats(t *testing.T) {
	46	+	s, _, _, dir := dmabufServer(t, ports.DMABufSupport{})
	47	+	c := protocolClient(t, s, dir)
	48	+	if _, ok := c.Registry().FindGlobal("zwp_linux_dmabuf_v1"); ok {
	49	+	t.Fatal("zwp_linux_dmabuf_v1 advertised")
	50	+	}
	51	+	}
	52	+
	53	+	type paramsProxy struct {
	54	+	wlturbo.BaseProxy
	55	+	result chan uint16
	56	+	}
	57	+
	58	+	func (p paramsProxy) Dispatch(e wlturbo.Event) { p.result <- e.Opcode }
	59	+
	60	+	// A format the renderer did not list fails; a plane past the end of its
	61	+	// file is a protocol error.
	62	+	func TestDMABufParams(t *testing.T) {
	63	+	s, _, _, dir := dmabufServer(t, ports.DMABufSupport{Formats: []ports.DMABufFormat{linearARGB}})
	64	+	c := protocolClient(t, s, dir)
	65	+	g, ok := c.Registry().FindGlobal("zwp_linux_dmabuf_v1")
	66	+	if !ok \|\| g.Version != dmabufVersion {
	67	+	t.Fatalf("global %+v", g)
	68	+	}
	69	+	dm, err := c.Registry().BindID(g.Name, g.Interface, dmabufVersion)
	70	+	if err != nil {
	71	+	t.Fatal(err)
	72	+	}
	73	+	fd, err := unix.MemfdCreate("fake-dmabuf", 0)
	74	+	if err != nil {
	75	+	t.Fatal(err)
	76	+	}
	77	+	defer unix.Close(fd)
	78	+	if err := unix.Ftruncate(fd, 256*16); err != nil {
	79	+	t.Fatal(err)
	80	+	}
	81	+	create := func(format uint32, height int32) (uint32, chan uint16) {
	82	+	p := c.AllocateID()
	83	+	requestProtocol(t, c, dm, linuxdmabuf.ZwpLinuxDmabufV1RequestCreateParams, p)
	84	+	proxy := &paramsProxy{result: make(chan uint16, 2)}
	85	+	proxy.SetID(p)
	86	+	c.Context().Register(proxy)
	87	+	if err := c.SendRequestWithFDs(p, uint16(linuxdmabuf.ZwpLinuxBufferParamsV1RequestAdd), []int{fd}, uint32(0), uint32(0), uint32(256), uint32(0), uint32(0)); err != nil {
	88	+	t.Fatal(err)
	89	+	}
	90	+	requestProtocol(t, c, p, linuxdmabuf.ZwpLinuxBufferParamsV1RequestCreate, int32(64), height, format, uint32(0))
	91	+	if err := c.Roundtrip(); err != nil {
	92	+	t.Fatal(err)
	93	+	}
	94	+	return p, proxy.result
	95	+	}
	96	+	// NV12 is not in the list: failed, not a protocol error.
	97	+	_, result := create('N'\|'V'<<8\|'1'<<16\|'2'<<24, 16)
	98	+	if op := <-result; op != uint16(linuxdmabuf.ZwpLinuxBufferParamsV1EventFailed) {
	99	+	t.Fatalf("event %d", op)
	100	+	}
	101	+	// Supported: created (import errors surface in the renderer).
	102	+	_, result = create(linearARGB.Format, 16)
	103	+	if op := <-result; op != uint16(linuxdmabuf.ZwpLinuxBufferParamsV1EventCreated) {
	104	+	t.Fatalf("event %d", op)
	105	+	}
	106	+	// Taller than the file: out of bounds.
	107	+	big := c.AllocateID()
	108	+	requestProtocol(t, c, dm, linuxdmabuf.ZwpLinuxDmabufV1RequestCreateParams, big)
	109	+	if err := c.SendRequestWithFDs(big, uint16(linuxdmabuf.ZwpLinuxBufferParamsV1RequestAdd), []int{fd}, uint32(0), uint32(0), uint32(256), uint32(0), uint32(0)); err != nil {
	110	+	t.Fatal(err)
	111	+	}
	112	+	requestProtocol(t, c, big, linuxdmabuf.ZwpLinuxBufferParamsV1RequestCreate, int32(64), int32(17), linearARGB.Format, uint32(0))
	113	+	expectProtocolError(t, c, big, uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorOutOfBounds))
	114	+	}
	115	+
	116	+	// A reused params object is a protocol error.
	117	+	func TestDMABufParamsReuse(t *testing.T) {
	118	+	s, _, _, dir := dmabufServer(t, ports.DMABufSupport{Formats: []ports.DMABufFormat{linearARGB}})
	119	+	c := protocolClient(t, s, dir)
	120	+	g, _ := c.Registry().FindGlobal("zwp_linux_dmabuf_v1")
	121	+	dm, err := c.Registry().BindID(g.Name, g.Interface, dmabufVersion)
	122	+	if err != nil {
	123	+	t.Fatal(err)
	124	+	}
	125	+	fd, err := unix.MemfdCreate("fake-dmabuf", 0)
	126	+	if err != nil {
	127	+	t.Fatal(err)
	128	+	}
	129	+	defer unix.Close(fd)
	130	+	if err := unix.Ftruncate(fd, 256*16); err != nil {
	131	+	t.Fatal(err)
	132	+	}
	133	+	p := c.AllocateID()
	134	+	requestProtocol(t, c, dm, linuxdmabuf.ZwpLinuxDmabufV1RequestCreateParams, p)
	135	+	proxy := &paramsProxy{result: make(chan uint16, 2)}
	136	+	proxy.SetID(p)
	137	+	c.Context().Register(proxy)
	138	+	if err := c.SendRequestWithFDs(p, uint16(linuxdmabuf.ZwpLinuxBufferParamsV1RequestAdd), []int{fd}, uint32(0), uint32(0), uint32(256), uint32(0), uint32(0)); err != nil {
	139	+	t.Fatal(err)
	140	+	}
	141	+	requestProtocol(t, c, p, linuxdmabuf.ZwpLinuxBufferParamsV1RequestCreate, int32(64), int32(16), linearARGB.Format, uint32(0))
	142	+	if err := c.Roundtrip(); err != nil {
	143	+	t.Fatal(err)
	144	+	}
	145	+	requestProtocol(t, c, p, linuxdmabuf.ZwpLinuxBufferParamsV1RequestCreate, int32(64), int32(16), linearARGB.Format, uint32(0))
	146	+	expectProtocolError(t, c, p, uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorAlreadyUsed))
	147	+	}
	148	+
	149	+	// weston-simple-dmabuf-egl renders on the GPU and sends dmabufs: its
	150	+	// contents reach the renderer as DMABuf, never as pixels.
	151	+	func TestWestonDMABuf(t *testing.T) {
	152	+	tool, err := exec.LookPath("weston-simple-dmabuf-egl")
	153	+	if err != nil {
	154	+	t.Skip("weston-simple-dmabuf-egl not installed")
	155	+	}
	156	+	// Linear buffers: every GPU allocates them, and the client picks from
	157	+	// what it is offered.
	158	+	xrgb := ports.DMABufFormat{Format: fourccXRGB}
	159	+	s, events, contents, dir := dmabufServer(t, ports.DMABufSupport{Formats: []ports.DMABufFormat{linearARGB, xrgb}})
	160	+	_, _, output := lifecycleClient(t, tool, s, dir, nil)
	161	+	w := mapped(t, events, 5*time.Second)
	162	+	deadline := time.After(5 * time.Second)
	163	+	for {
	164	+	select {
	165	+	case c := <-contents:
	166	+	if c.ID != w.ID \|\| c.DMABuf == nil \|\| c.Pixels != nil \|\| len(c.DMABuf.Planes) == 0 \|\| c.DMABuf.Planes[0].File == nil {
	167	+	t.Fatalf("content %+v", c)
	168	+	}
	169	+	return
	170	+	case <-deadline:
	171	+	t.Fatalf("no dmabuf content: %s", output.String())
	172	+	}
	173	+	}
	174	+	}

@@ -0,0 +1,174 @@
	1	+	package wayland
	2	+
	3	+	import (
	4	+	"context"
	5	+	"os/exec"
	6	+	"testing"
	7	+	"time"
	8	+
	9	+	"github.com/bnema/nefertty/internal/logging"
	10	+	"github.com/bnema/nefertty/internal/ports"
	11	+	"github.com/bnema/purego-libwayland/protocol/linuxdmabuf"
	12	+	"github.com/bnema/wlturbo"
	13	+	"golang.org/x/sys/unix"
	14	+	)
	15	+
	16	+	var linearARGB = ports.DMABufFormat{Format: 'A' \| 'R'<<8 \| '2'<<16 \| '4'<<24}
	17	+
	18	+	func dmabufServer(t testing.T, sup ports.DMABufSupport) (Server, chan ports.ClientEvent, chan ports.SurfaceContent, string) {
	19	+	t.Helper()
	20	+	dir := t.TempDir()
	21	+	events := make(chan ports.ClientEvent, 16)
	22	+	contents := make(chan ports.SurfaceContent, 16)
	23	+	s, err := New(Options{RuntimeDir: dir, Outputs: testOutputs, DMABuf: sup}, Channels{Events: events, Contents: contents}, logging.For(context.Background(), "wayland"))
	24	+	if err != nil {
	25	+	t.Fatal(err)
	26	+	}
	27	+	ctx, cancel := context.WithCancel(context.Background())
	28	+	done := make(chan error, 1)
	29	+	go func() { done <- s.Run(ctx) }()
	30	+	t.Cleanup(func() {
	31	+	cancel()
	32	+	select {
	33	+	case err := <-done:
	34	+	if err != nil {
	35	+	t.Errorf("Run: %v", err)
	36	+	}
	37	+	case <-time.After(2 * time.Second):
	38	+	t.Error("Run hung")
	39	+	}
	40	+	})
	41	+	return s, events, contents, dir
	42	+	}
	43	+
	44	+	// Without renderer formats there is no linux-dmabuf global.
	45	+	func TestNoDMABufWithoutFormats(t *testing.T) {
	46	+	s, _, _, dir := dmabufServer(t, ports.DMABufSupport{})
	47	+	c := protocolClient(t, s, dir)
	48	+	if _, ok := c.Registry().FindGlobal("zwp_linux_dmabuf_v1"); ok {
	49	+	t.Fatal("zwp_linux_dmabuf_v1 advertised")
	50	+	}
	51	+	}
	52	+
	53	+	type paramsProxy struct {
	54	+	wlturbo.BaseProxy
	55	+	result chan uint16
	56	+	}
	57	+
	58	+	func (p paramsProxy) Dispatch(e wlturbo.Event) { p.result <- e.Opcode }
	59	+
	60	+	// A format the renderer did not list fails; a plane past the end of its
	61	+	// file is a protocol error.
	62	+	func TestDMABufParams(t *testing.T) {
	63	+	s, _, _, dir := dmabufServer(t, ports.DMABufSupport{Formats: []ports.DMABufFormat{linearARGB}})
	64	+	c := protocolClient(t, s, dir)
	65	+	g, ok := c.Registry().FindGlobal("zwp_linux_dmabuf_v1")
	66	+	if !ok \|\| g.Version != dmabufVersion {
	67	+	t.Fatalf("global %+v", g)
	68	+	}
	69	+	dm, err := c.Registry().BindID(g.Name, g.Interface, dmabufVersion)
	70	+	if err != nil {
	71	+	t.Fatal(err)
	72	+	}
	73	+	fd, err := unix.MemfdCreate("fake-dmabuf", 0)
	74	+	if err != nil {
	75	+	t.Fatal(err)
	76	+	}
	77	+	defer unix.Close(fd)
	78	+	if err := unix.Ftruncate(fd, 256*16); err != nil {
	79	+	t.Fatal(err)
	80	+	}
	81	+	create := func(format uint32, height int32) (uint32, chan uint16) {
	82	+	p := c.AllocateID()
	83	+	requestProtocol(t, c, dm, linuxdmabuf.ZwpLinuxDmabufV1RequestCreateParams, p)
	84	+	proxy := &paramsProxy{result: make(chan uint16, 2)}
	85	+	proxy.SetID(p)
	86	+	c.Context().Register(proxy)
	87	+	if err := c.SendRequestWithFDs(p, uint16(linuxdmabuf.ZwpLinuxBufferParamsV1RequestAdd), []int{fd}, uint32(0), uint32(0), uint32(256), uint32(0), uint32(0)); err != nil {
	88	+	t.Fatal(err)
	89	+	}
	90	+	requestProtocol(t, c, p, linuxdmabuf.ZwpLinuxBufferParamsV1RequestCreate, int32(64), height, format, uint32(0))
	91	+	if err := c.Roundtrip(); err != nil {
	92	+	t.Fatal(err)
	93	+	}
	94	+	return p, proxy.result
	95	+	}
	96	+	// NV12 is not in the list: failed, not a protocol error.
	97	+	_, result := create('N'\|'V'<<8\|'1'<<16\|'2'<<24, 16)
	98	+	if op := <-result; op != uint16(linuxdmabuf.ZwpLinuxBufferParamsV1EventFailed) {
	99	+	t.Fatalf("event %d", op)
	100	+	}
	101	+	// Supported: created (import errors surface in the renderer).
	102	+	_, result = create(linearARGB.Format, 16)
	103	+	if op := <-result; op != uint16(linuxdmabuf.ZwpLinuxBufferParamsV1EventCreated) {
	104	+	t.Fatalf("event %d", op)
	105	+	}
	106	+	// Taller than the file: out of bounds.
	107	+	big := c.AllocateID()
	108	+	requestProtocol(t, c, dm, linuxdmabuf.ZwpLinuxDmabufV1RequestCreateParams, big)
	109	+	if err := c.SendRequestWithFDs(big, uint16(linuxdmabuf.ZwpLinuxBufferParamsV1RequestAdd), []int{fd}, uint32(0), uint32(0), uint32(256), uint32(0), uint32(0)); err != nil {
	110	+	t.Fatal(err)
	111	+	}
	112	+	requestProtocol(t, c, big, linuxdmabuf.ZwpLinuxBufferParamsV1RequestCreate, int32(64), int32(17), linearARGB.Format, uint32(0))
	113	+	expectProtocolError(t, c, big, uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorOutOfBounds))
	114	+	}
	115	+
	116	+	// A reused params object is a protocol error.
	117	+	func TestDMABufParamsReuse(t *testing.T) {
	118	+	s, _, _, dir := dmabufServer(t, ports.DMABufSupport{Formats: []ports.DMABufFormat{linearARGB}})
	119	+	c := protocolClient(t, s, dir)
	120	+	g, _ := c.Registry().FindGlobal("zwp_linux_dmabuf_v1")
	121	+	dm, err := c.Registry().BindID(g.Name, g.Interface, dmabufVersion)
	122	+	if err != nil {
	123	+	t.Fatal(err)
	124	+	}
	125	+	fd, err := unix.MemfdCreate("fake-dmabuf", 0)
	126	+	if err != nil {
	127	+	t.Fatal(err)
	128	+	}
	129	+	defer unix.Close(fd)
	130	+	if err := unix.Ftruncate(fd, 256*16); err != nil {
	131	+	t.Fatal(err)
	132	+	}
	133	+	p := c.AllocateID()
	134	+	requestProtocol(t, c, dm, linuxdmabuf.ZwpLinuxDmabufV1RequestCreateParams, p)
	135	+	proxy := &paramsProxy{result: make(chan uint16, 2)}
	136	+	proxy.SetID(p)
	137	+	c.Context().Register(proxy)
	138	+	if err := c.SendRequestWithFDs(p, uint16(linuxdmabuf.ZwpLinuxBufferParamsV1RequestAdd), []int{fd}, uint32(0), uint32(0), uint32(256), uint32(0), uint32(0)); err != nil {
	139	+	t.Fatal(err)
	140	+	}
	141	+	requestProtocol(t, c, p, linuxdmabuf.ZwpLinuxBufferParamsV1RequestCreate, int32(64), int32(16), linearARGB.Format, uint32(0))
	142	+	if err := c.Roundtrip(); err != nil {
	143	+	t.Fatal(err)
	144	+	}
	145	+	requestProtocol(t, c, p, linuxdmabuf.ZwpLinuxBufferParamsV1RequestCreate, int32(64), int32(16), linearARGB.Format, uint32(0))
	146	+	expectProtocolError(t, c, p, uint32(linuxdmabuf.ZwpLinuxBufferParamsV1ErrorAlreadyUsed))
	147	+	}
	148	+
	149	+	// weston-simple-dmabuf-egl renders on the GPU and sends dmabufs: its
	150	+	// contents reach the renderer as DMABuf, never as pixels.
	151	+	func TestWestonDMABuf(t *testing.T) {
	152	+	tool, err := exec.LookPath("weston-simple-dmabuf-egl")
	153	+	if err != nil {
	154	+	t.Skip("weston-simple-dmabuf-egl not installed")
	155	+	}
	156	+	// Linear buffers: every GPU allocates them, and the client picks from
	157	+	// what it is offered.
	158	+	xrgb := ports.DMABufFormat{Format: fourccXRGB}
	159	+	s, events, contents, dir := dmabufServer(t, ports.DMABufSupport{Formats: []ports.DMABufFormat{linearARGB, xrgb}})
	160	+	_, _, output := lifecycleClient(t, tool, s, dir, nil)
	161	+	w := mapped(t, events, 5*time.Second)
	162	+	deadline := time.After(5 * time.Second)
	163	+	for {
	164	+	select {
	165	+	case c := <-contents:
	166	+	if c.ID != w.ID \|\| c.DMABuf == nil \|\| c.Pixels != nil \|\| len(c.DMABuf.Planes) == 0 \|\| c.DMABuf.Planes[0].File == nil {
	167	+	t.Fatalf("content %+v", c)
	168	+	}
	169	+	return
	170	+	case <-deadline:
	171	+	t.Fatalf("no dmabuf content: %s", output.String())
	172	+	}
	173	+	}
	174	+	}

M internal/adapters/wayland/globals.go +20 -0


@@ -15,6 +15,7 @@ func registerGlobals(d server.Display, o Options, s Server) error {
15	15		func() error { return registerXDGOutput(d, s) },
16	16		func() error { return registerDecoration(d, s) },
17	17		func() error { return registerScale(d, s) },
	18	+	func() error { return registerDMABuf(d, s, o.DMABuf) },
18	19		func() error {
19	20		return wayland.NewCompositorGlobal(d, 6, func(c server.Client, v, id uint32) { wayland.NewCompositor(c, int32(v), id, compositor{s}) })
20	21		},

@@ -204,6 +205,25 @@ type buffer struct {
204	205
205	206		func (buffer) Destroy(wayland.Buffer) {}
206	207
	208	+	func (b *buffer) size() (int, int) { return b.width, b.height }
	209	+
	210	+	// clientBuffer is a wl_buffer's content source: wl_shm or linux-dmabuf.
	211	+	type clientBuffer interface {
	212	+	// content returns what the renderer draws; false means the client
	213	+	// broke its buffer (a truncated shm file).
	214	+	content(ports.WindowID) (ports.SurfaceContent, bool)
	215	+	size() (int, int)
	216	+	}
	217	+
	218	+	// addBuffer tracks a buffer until the client destroys it.
	219	+	func (s Server) addBuffer(r wayland.Buffer, b *dmabufBuffer) {
	220	+	s.buffers[r.Resource] = b
	221	+	r.OnDestroy = func() {
	222	+	delete(s.buffers, r.Resource)
	223	+	b.close()
	224	+	}
	225	+	}
	226	+
207	227		// A malicious client may truncate its fd after mmap; SetPanicOnFault converts
208	228		// the resulting SIGBUS on this goroutine to a recoverable panic.
209	229		func (b *buffer) content(id ports.WindowID) (content ports.SurfaceContent, ok bool) {


@@ -15,6 +15,7 @@ func registerGlobals(d server.Display, o Options, s Server) error {
15	func() error { return registerXDGOutput(d, s) },	15		func() error { return registerXDGOutput(d, s) },
16	func() error { return registerDecoration(d, s) },	16		func() error { return registerDecoration(d, s) },
17	func() error { return registerScale(d, s) },	17		func() error { return registerScale(d, s) },
		18	+	func() error { return registerDMABuf(d, s, o.DMABuf) },
18	func() error {	19		func() error {
19	return wayland.NewCompositorGlobal(d, 6, func(c server.Client, v, id uint32) { wayland.NewCompositor(c, int32(v), id, compositor{s}) })	20		return wayland.NewCompositorGlobal(d, 6, func(c server.Client, v, id uint32) { wayland.NewCompositor(c, int32(v), id, compositor{s}) })
20	},	21		},

@@ -204,6 +205,25 @@ type buffer struct {
204		205
205	func (buffer) Destroy(wayland.Buffer) {}	206		func (buffer) Destroy(wayland.Buffer) {}
206		207
		208	+	func (b *buffer) size() (int, int) { return b.width, b.height }
		209	+
		210	+	// clientBuffer is a wl_buffer's content source: wl_shm or linux-dmabuf.
		211	+	type clientBuffer interface {
		212	+	// content returns what the renderer draws; false means the client
		213	+	// broke its buffer (a truncated shm file).
		214	+	content(ports.WindowID) (ports.SurfaceContent, bool)
		215	+	size() (int, int)
		216	+	}
		217	+
		218	+	// addBuffer tracks a buffer until the client destroys it.
		219	+	func (s Server) addBuffer(r wayland.Buffer, b *dmabufBuffer) {
		220	+	s.buffers[r.Resource] = b
		221	+	r.OnDestroy = func() {
		222	+	delete(s.buffers, r.Resource)
		223	+	b.close()
		224	+	}
		225	+	}
		226	+
207	// A malicious client may truncate its fd after mmap; SetPanicOnFault converts	227		// A malicious client may truncate its fd after mmap; SetPanicOnFault converts
208	// the resulting SIGBUS on this goroutine to a recoverable panic.	228		// the resulting SIGBUS on this goroutine to a recoverable panic.
209	func (b *buffer) content(id ports.WindowID) (content ports.SurfaceContent, ok bool) {	229		func (b *buffer) content(id ports.WindowID) (content ports.SurfaceContent, ok bool) {

M internal/adapters/wayland/layer.go +1 -1


@@ -166,7 +166,7 @@ func (s *Server) layerChanged() {
166	166		}
167	167		if l.surface.current != nil {
168	168		if b := s.buffers[l.surface.current.Resource]; b != nil {
169		-	v.Width, v.Height = l.surface.logicalSize(b.width, b.height)
	169	+	v.Width, v.Height = l.surface.logicalSize(b.size())
170	170		}
171	171		}
172	172		list = append(list, v)


@@ -166,7 +166,7 @@ func (s *Server) layerChanged() {
166		}	166		}
167		if l.surface.current != nil {	167		if l.surface.current != nil {
168		if b := s.buffers[l.surface.current.Resource]; b != nil {	168		if b := s.buffers[l.surface.current.Resource]; b != nil {
169	-	v.Width, v.Height = l.surface.logicalSize(b.width, b.height)	169	+	v.Width, v.Height = l.surface.logicalSize(b.size())
170		}	170		}
171		}	171		}
172		list = append(list, v)	172		list = append(list, v)

M internal/adapters/wayland/server.go +8 -4


@@ -19,8 +19,10 @@ import (
19	19		// Options configures the server. Outputs is the initial layout; core
20	20		// replaces it with ports.SetOutputs.
21	21		type Options struct {
22		-	RuntimeDir string
23		-	Outputs ports.Layout
	22	+	RuntimeDir string
	23	+	Outputs ports.Layout
	24	+	// DMABuf is what the renderer imports; empty disables linux-dmabuf.
	25	+	DMABuf ports.DMABufSupport
24	26		Keymap string
25	27		RepeatRate, RepeatDelay int
26	28		}

@@ -43,7 +45,8 @@ type Server struct {
43	45		frames uint64
44	46		started time.Time
45	47		surfaces map[server.Resource]surface
46		-	buffers map[server.Resource]buffer
	48	+	buffers map[*server.Resource]clientBuffer
	49	+	dmabuf *dmabufGlobal
47	50		serial uint32
48	51		ctx context.Context
49	52		windows map[ports.WindowID]*window

@@ -108,7 +111,7 @@ func New(opts Options, ch Channels, log zerowrap.Logger) (*Server, error) {
108	111		d.Close()
109	112		return nil, err
110	113		}
111		-	s := &Server{display: d, env: linuxProcEnv{}, name: name, cleanup: cleanup, log: log, channels: ch, surfaces: make(map[server.Resource]surface), buffers: make(map[server.Resource]buffer), windows: make(map[ports.WindowID]window), layers: make(map[ports.WindowID]layerSurface), nextWindow: 1, eventReady: make(chan struct{}, 1), contents: make(map[ports.WindowID]ports.SurfaceContent), contentSeq: make(map[ports.WindowID]uint64), contentReady: make(chan struct{}, 1), contentNotify: make(chan struct{}), keymapFD: -1, keyboards: make(map[server.Client][]wayland.Keyboard), pointers: make(map[server.Client][]wayland.Pointer), repeatRate: opts.RepeatRate, repeatDelay: opts.RepeatDelay}
	114	+	s := &Server{display: d, env: linuxProcEnv{}, name: name, cleanup: cleanup, log: log, channels: ch, surfaces: make(map[server.Resource]surface), buffers: make(map[server.Resource]clientBuffer), windows: make(map[ports.WindowID]window), layers: make(map[ports.WindowID]layerSurface), nextWindow: 1, eventReady: make(chan struct{}, 1), contents: make(map[ports.WindowID]ports.SurfaceContent), contentSeq: make(map[ports.WindowID]uint64), contentReady: make(chan struct{}, 1), contentNotify: make(chan struct{}), keymapFD: -1, keyboards: make(map[server.Client][]wayland.Keyboard), pointers: make(map[server.Client][]*wayland.Pointer), repeatRate: opts.RepeatRate, repeatDelay: opts.RepeatDelay}
112	115		s.fractions = map[surface]fractionalscale.WpFractionalScaleV1{}
113	116		if opts.Keymap != "" {
114	117		fd, size, e := keymapFile(opts.Keymap)

@@ -123,6 +126,7 @@ func New(opts Options, ch Channels, log zerowrap.Logger) (*Server, error) {
123	126		if s.keymapFD >= 0 {
124	127		unix.Close(s.keymapFD)
125	128		}
	129	+	s.dmabuf.close()
126	130		cleanup()
127	131		}
128	132		if err = registerGlobals(d, opts, s); err != nil {

 // Options configures the server. Outputs is the initial layout; core
 // replaces it with ports.SetOutputs.
 type Options struct {
-	RuntimeDir              string
+	RuntimeDir string
-	Outputs                 ports.Layout
+	Outputs    ports.Layout
+	// DMABuf is what the renderer imports; empty disables linux-dmabuf.
+	DMABuf                  ports.DMABufSupport
 	Keymap                  string
 	RepeatRate, RepeatDelay int
 }
 	frames                  uint64
 	started                 time.Time
 	surfaces                map[*server.Resource]*surface
-	buffers                 map[*server.Resource]*buffer
+	buffers                 map[*server.Resource]clientBuffer
+	dmabuf                  *dmabufGlobal
 	serial                  uint32
 	ctx                     context.Context
 	windows                 map[ports.WindowID]*window
 		d.Close()
 		return nil, err
 	}
-	s := &Server{display: d, env: linuxProcEnv{}, name: name, cleanup: cleanup, log: log, channels: ch, surfaces: make(map[*server.Resource]*surface), buffers: make(map[*server.Resource]*buffer), windows: make(map[ports.WindowID]*window), layers: make(map[ports.WindowID]*layerSurface), nextWindow: 1, eventReady: make(chan struct{}, 1), contents: make(map[ports.WindowID]ports.SurfaceContent), contentSeq: make(map[ports.WindowID]uint64), contentReady: make(chan struct{}, 1), contentNotify: make(chan struct{}), keymapFD: -1, keyboards: make(map[server.Client][]*wayland.Keyboard), pointers: make(map[server.Client][]*wayland.Pointer), repeatRate: opts.RepeatRate, repeatDelay: opts.RepeatDelay}
+	s := &Server{display: d, env: linuxProcEnv{}, name: name, cleanup: cleanup, log: log, channels: ch, surfaces: make(map[*server.Resource]*surface), buffers: make(map[*server.Resource]clientBuffer), windows: make(map[ports.WindowID]*window), layers: make(map[ports.WindowID]*layerSurface), nextWindow: 1, eventReady: make(chan struct{}, 1), contents: make(map[ports.WindowID]ports.SurfaceContent), contentSeq: make(map[ports.WindowID]uint64), contentReady: make(chan struct{}, 1), contentNotify: make(chan struct{}), keymapFD: -1, keyboards: make(map[server.Client][]*wayland.Keyboard), pointers: make(map[server.Client][]*wayland.Pointer), repeatRate: opts.RepeatRate, repeatDelay: opts.RepeatDelay}
 	s.fractions = map[*surface]*fractionalscale.WpFractionalScaleV1{}
 	if opts.Keymap != "" {
 		fd, size, e := keymapFile(opts.Keymap)
 		if s.keymapFD >= 0 {
 			unix.Close(s.keymapFD)
 		}
+		s.dmabuf.close()
 		cleanup()
 	}
 	if err = registerGlobals(d, opts, s); err != nil {

M internal/adapters/wayland/surface.go +9 -5


@@ -107,13 +107,17 @@ func (s surface) Commit(wayland.Surface) {
107	107		s.server.log.Info().Uint64("id", uint64(id)).Int("w", c.Width).Int("h", c.Height).Msg("buffer size")
108	108		}
109	109		s.server.emitContent(c)
110		-	} else {
111		-	state.pool.shm.PostError(uint32(wayland.ShmErrorInvalidFd), "SHM backing file truncated")
	110	+	} else if shm, ok := state.(*buffer); ok {
	111	+	shm.pool.shm.PostError(uint32(wayland.ShmErrorInvalidFd), "SHM backing file truncated")
112	112		}
113		-	if b.Resource.Alive() {
114		-	b.SendRelease()
	113	+	// wl_shm pixels were copied: the client may reuse the buffer.
	114	+	// A dmabuf is read in place until the next buffer replaces it.
	115	+	if _, gpu := state.(*dmabufBuffer); !gpu {
	116	+	if b.Resource.Alive() {
	117	+	b.SendRelease()
	118	+	}
	119	+	s.released = true
115	120		}
116		-	s.released = true
117	121		}
118	122		}
119	123		}

 					s.server.log.Info().Uint64("id", uint64(id)).Int("w", c.Width).Int("h", c.Height).Msg("buffer size")
 				}
 				s.server.emitContent(c)
-			} else {
+			} else if shm, ok := state.(*buffer); ok {
-				state.pool.shm.PostError(uint32(wayland.ShmErrorInvalidFd), "SHM backing file truncated")
+				shm.pool.shm.PostError(uint32(wayland.ShmErrorInvalidFd), "SHM backing file truncated")
 			}
-			if b.Resource.Alive() {
+			// wl_shm pixels were copied: the client may reuse the buffer.
-				b.SendRelease()
+			// A dmabuf is read in place until the next buffer replaces it.
+			if _, gpu := state.(*dmabufBuffer); !gpu {
+				if b.Resource.Alive() {
+					b.SendRelease()
+				}
+				s.released = true
 			}
-			s.released = true
 		}
 	}
 }

M internal/app/app.go +4 -1


@@ -89,7 +89,10 @@ func run(ctx context.Context, opts Options, inject func(chan<- ports.InputEvent)
89	89		}
90	90		keymap := km.String()
91	91		runtimeDir := os.Getenv("XDG_RUNTIME_DIR")
92		-	server, err := wayland.New(wayland.Options{RuntimeDir: runtimeDir, Keymap: keymap, RepeatRate: opts.Config.Keyboard.RepeatRate, RepeatDelay: opts.Config.Keyboard.RepeatDelay}, wayland.Channels{Events: client, Commands: commands, Contents: contents}, logging.For(ctx, "wayland"))
	92	+	// Every output renders on the same GPU: its formats are the clients'.
	93	+	dmabuf := vulkan.Probe()
	94	+	log.Info().Int("formats", len(dmabuf.Formats)).Msg("dmabuf")
	95	+	server, err := wayland.New(wayland.Options{RuntimeDir: runtimeDir, DMABuf: dmabuf, Keymap: keymap, RepeatRate: opts.Config.Keyboard.RepeatRate, RepeatDelay: opts.Config.Keyboard.RepeatDelay}, wayland.Channels{Events: client, Commands: commands, Contents: contents}, logging.For(ctx, "wayland"))
93	96		if err != nil {
94	97		km.Close()
95	98		return err

 	}
 	keymap := km.String()
 	runtimeDir := os.Getenv("XDG_RUNTIME_DIR")
-	server, err := wayland.New(wayland.Options{RuntimeDir: runtimeDir, Keymap: keymap, RepeatRate: opts.Config.Keyboard.RepeatRate, RepeatDelay: opts.Config.Keyboard.RepeatDelay}, wayland.Channels{Events: client, Commands: commands, Contents: contents}, logging.For(ctx, "wayland"))
+	// Every output renders on the same GPU: its formats are the clients'.
+	dmabuf := vulkan.Probe()
+	log.Info().Int("formats", len(dmabuf.Formats)).Msg("dmabuf")
+	server, err := wayland.New(wayland.Options{RuntimeDir: runtimeDir, DMABuf: dmabuf, Keymap: keymap, RepeatRate: opts.Config.Keyboard.RepeatRate, RepeatDelay: opts.Config.Keyboard.RepeatDelay}, wayland.Channels{Events: client, Commands: commands, Contents: contents}, logging.For(ctx, "wayland"))
 	if err != nil {
 		km.Close()
 		return err

M internal/app/outputs.go +1 -1


@@ -77,7 +77,7 @@ func (s *outputSet) scenes(set []ports.Scene) {
77	77		}
78	78
79	79		func (s *outputSet) content(c ports.SurfaceContent) {
80		-	if c.Pixels == nil {
	80	+	if c.Empty() {
81	81		delete(s.latest, c.ID)
82	82		} else {
83	83		s.latest[c.ID] = c


@@ -77,7 +77,7 @@ func (s *outputSet) scenes(set []ports.Scene) {
77		}	77		}
78			78
79		func (s *outputSet) content(c ports.SurfaceContent) {	79		func (s *outputSet) content(c ports.SurfaceContent) {
80	-	if c.Pixels == nil {	80	+	if c.Empty() {
81		delete(s.latest, c.ID)	81		delete(s.latest, c.ID)
82		} else {	82		} else {
83		s.latest[c.ID] = c	83		s.latest[c.ID] = c

M internal/ports/messages.go +45 -6

@@ -1,5 +1,7 @@
1	1		package ports
2	2
	3	+	import "os"
	4	+
3	5		// ClientEvent carries wayland → core notifications.
4	6		type ClientEvent interface{ clientEvent() }
5	7

@@ -338,18 +340,55 @@ type SceneLayer struct {
338	340		Rect Rect
339	341		}
340	342
341		-	// SurfaceContent carries wayland → output the latest committed pixels of a
342		-	// window. Pixels is a private copy in B8G8R8A8 (wl_shm argb8888/xrgb8888
343		-	// little-endian) with Stride bytes per row; receivers never modify it.
344		-	// Pixels == nil means the window has no content. LogicalW and LogicalH are
345		-	// the surface size in logical pixels (buffer scale and viewport applied).
	343	+	// SurfaceContent carries wayland → output the latest committed content of a
	344	+	// window: either Pixels, a private copy in B8G8R8A8 (wl_shm
	345	+	// argb8888/xrgb8888 little-endian) with Stride bytes per row, or DMABuf, a
	346	+	// GPU buffer the renderer reads in place. Receivers never modify either.
	347	+	// Empty means the window has no content. LogicalW and LogicalH are the
	348	+	// surface size in logical pixels (buffer scale and viewport applied).
346	349		type SurfaceContent struct {
347	350		ID WindowID
348	351		Width, Height int
349	352		LogicalW, LogicalH int
350	353		Stride int
351		-	Opaque bool // xrgb8888: ignore the alpha byte
	354	+	Opaque bool // x formats: ignore the alpha byte
352	355		Pixels []byte
	356	+	DMABuf *DMABuf
	357	+	}
	358	+
	359	+	// Empty reports whether the content has nothing to draw.
	360	+	func (c SurfaceContent) Empty() bool { return c.Pixels == nil && c.DMABuf == nil }
	361	+
	362	+	// DMABuf is a client GPU buffer (linux-dmabuf). Its files stay open while
	363	+	// the client's buffer exists; a renderer that keeps it must duplicate the
	364	+	// descriptors under File.SyscallConn so a concurrent close cannot hand it a
	365	+	// reused one. ID is unique per buffer for the whole session: renderers key
	366	+	// their imports on it.
	367	+	type DMABuf struct {
	368	+	ID uint64
	369	+	Width, Height int
	370	+	Format uint32 // DRM fourcc
	371	+	Modifier uint64
	372	+	Planes []DMABufPlane
	373	+	}
	374	+
	375	+	// DMABufPlane is one plane of a DMABuf.
	376	+	type DMABufPlane struct {
	377	+	File *os.File
	378	+	Offset, Stride uint32
	379	+	}
	380	+
	381	+	// DMABufFormat is a DRM fourcc with a modifier the renderer can import.
	382	+	type DMABufFormat struct {
	383	+	Format uint32
	384	+	Modifier uint64
	385	+	}
	386	+
	387	+	// DMABufSupport is what the renderer imports: the render device (a dev_t,
	388	+	// 0 when unknown) and the formats. No formats means no dmabuf.
	389	+	type DMABufSupport struct {
	390	+	Device uint64
	391	+	Formats []DMABufFormat
353	392		}
354	393
355	394		// SceneWindow carries core → renderer window placement.

@@ -1,5 +1,7 @@
1		package ports	1		package ports
2			2
			3	+	import "os"
			4	+
3		// ClientEvent carries wayland → core notifications.	5		// ClientEvent carries wayland → core notifications.
4		type ClientEvent interface{ clientEvent() }	6		type ClientEvent interface{ clientEvent() }
5			7

@@ -338,18 +340,55 @@ type SceneLayer struct {
338		Rect Rect	340		Rect Rect
339		}	341		}
340			342
341	-	// SurfaceContent carries wayland → output the latest committed pixels of a	343	+	// SurfaceContent carries wayland → output the latest committed content of a
342	-	// window. Pixels is a private copy in B8G8R8A8 (wl_shm argb8888/xrgb8888	344	+	// window: either Pixels, a private copy in B8G8R8A8 (wl_shm
343	-	// little-endian) with Stride bytes per row; receivers never modify it.	345	+	// argb8888/xrgb8888 little-endian) with Stride bytes per row, or DMABuf, a
344	-	// Pixels == nil means the window has no content. LogicalW and LogicalH are	346	+	// GPU buffer the renderer reads in place. Receivers never modify either.
345	-	// the surface size in logical pixels (buffer scale and viewport applied).	347	+	// Empty means the window has no content. LogicalW and LogicalH are the
			348	+	// surface size in logical pixels (buffer scale and viewport applied).
346		type SurfaceContent struct {	349		type SurfaceContent struct {
347		ID WindowID	350		ID WindowID
348		Width, Height int	351		Width, Height int
349		LogicalW, LogicalH int	352		LogicalW, LogicalH int
350		Stride int	353		Stride int
351	-	Opaque bool // xrgb8888: ignore the alpha byte	354	+	Opaque bool // x formats: ignore the alpha byte
352		Pixels []byte	355		Pixels []byte
			356	+	DMABuf *DMABuf
			357	+	}
			358	+
			359	+	// Empty reports whether the content has nothing to draw.
			360	+	func (c SurfaceContent) Empty() bool { return c.Pixels == nil && c.DMABuf == nil }
			361	+
			362	+	// DMABuf is a client GPU buffer (linux-dmabuf). Its files stay open while
			363	+	// the client's buffer exists; a renderer that keeps it must duplicate the
			364	+	// descriptors under File.SyscallConn so a concurrent close cannot hand it a
			365	+	// reused one. ID is unique per buffer for the whole session: renderers key
			366	+	// their imports on it.
			367	+	type DMABuf struct {
			368	+	ID uint64
			369	+	Width, Height int
			370	+	Format uint32 // DRM fourcc
			371	+	Modifier uint64
			372	+	Planes []DMABufPlane
			373	+	}
			374	+
			375	+	// DMABufPlane is one plane of a DMABuf.
			376	+	type DMABufPlane struct {
			377	+	File *os.File
			378	+	Offset, Stride uint32
			379	+	}
			380	+
			381	+	// DMABufFormat is a DRM fourcc with a modifier the renderer can import.
			382	+	type DMABufFormat struct {
			383	+	Format uint32
			384	+	Modifier uint64
			385	+	}
			386	+
			387	+	// DMABufSupport is what the renderer imports: the render device (a dev_t,
			388	+	// 0 when unknown) and the formats. No formats means no dmabuf.
			389	+	type DMABufSupport struct {
			390	+	Device uint64
			391	+	Formats []DMABufFormat
353		}	392		}
354			393
355		// SceneWindow carries core → renderer window placement.	394		// SceneWindow carries core → renderer window placement.