fix(wayland): acknowledge the KDE decoration mode a client requests

Answering server-side to every request_mode made Firefox, which asks for
client-side, request again in a tight loop: 40% CPU with Firefox idle.
The requested mode is now echoed as the protocol describes; undefined
modes are ignored. The server default still removes GTK4 title bars.

commit: 02045ff9bb87c3d31bb3835f683d60c1b4bbf777
author: brice · 28d ago · 2026-09-25 08:24 UTC
parent: cc04d40
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

2 files · +67 -3

M internal/adapters/wayland/decoration.go +10 -3


@@ -41,9 +41,16 @@ type kdeDecoration struct{}
41	41
42	42		func (kdeDecoration) Release(*kdedecoration.OrgKdeKwinServerDecoration) {}
43	43
44		-	// Any requested mode is answered with server-side, like xdg-decoration.
45		-	func (kdeDecoration) RequestMode(r *kdedecoration.OrgKdeKwinServerDecoration, _ uint32) {
46		-	r.SendMode(uint32(kdedecoration.OrgKdeKwinServerDecorationModeServer))
	44	+	// A requested mode is acknowledged as is: the protocol has no way to
	45	+	// refuse, and answering server to a client that insists on client-side
	46	+	// (Firefox) makes it ask again forever. The server default already makes
	47	+	// GTK drop its title bar.
	48	+	// Unknown modes are ignored: replacing them would restart the loop.
	49	+	func (kdeDecoration) RequestMode(r *kdedecoration.OrgKdeKwinServerDecoration, mode uint32) {
	50	+	if mode > uint32(kdedecoration.OrgKdeKwinServerDecorationModeServer) {
	51	+	return
	52	+	}
	53	+	r.SendMode(mode)
47	54		}
48	55
49	56		func (decorationManager) Destroy(*xdgdecoration.ZxdgDecorationManagerV1) {}

 func (kdeDecoration) Release(*kdedecoration.OrgKdeKwinServerDecoration) {}
-// Any requested mode is answered with server-side, like xdg-decoration.
+// A requested mode is acknowledged as is: the protocol has no way to
-func (kdeDecoration) RequestMode(r *kdedecoration.OrgKdeKwinServerDecoration, _ uint32) {
+// refuse, and answering server to a client that insists on client-side
-	r.SendMode(uint32(kdedecoration.OrgKdeKwinServerDecorationModeServer))
+// (Firefox) makes it ask again forever. The server default already makes
+// GTK drop its title bar.
+// Unknown modes are ignored: replacing them would restart the loop.
+func (kdeDecoration) RequestMode(r *kdedecoration.OrgKdeKwinServerDecoration, mode uint32) {
+	if mode > uint32(kdedecoration.OrgKdeKwinServerDecorationModeServer) {
+		return
+	}
+	r.SendMode(mode)
 }
 func (decorationManager) Destroy(*xdgdecoration.ZxdgDecorationManagerV1) {}

A internal/adapters/wayland/decoration_test.go +57 -0

@@ -0,0 +1,57 @@
	1	+	package wayland
	2	+
	3	+	import (
	4	+	"testing"
	5	+	"time"
	6	+
	7	+	"github.com/bnema/nefertty/internal/ports"
	8	+	"github.com/bnema/purego-libwayland/protocol/kdedecoration"
	9	+	"github.com/bnema/purego-libwayland/protocol/wayland"
	10	+	"github.com/bnema/wlturbo"
	11	+	)
	12	+
	13	+	type kdeModeProxy struct {
	14	+	wlturbo.BaseProxy
	15	+	modes chan uint32
	16	+	}
	17	+
	18	+	func (p kdeModeProxy) Dispatch(e wlturbo.Event) { p.modes <- e.Uint32() }
	19	+
	20	+	// KDE decoration defaults to server-side and acknowledges the mode a client
	21	+	// asks for: answering server to Firefox's client request made it ask again
	22	+	// in a tight loop.
	23	+	func TestKDEDecorationAcknowledgesMode(t *testing.T) {
	24	+	s, _, _, dir := dmabufServer(t, ports.DMABufSupport{})
	25	+	c := protocolClient(t, s, dir)
	26	+	comp := bindProtocol(t, c, "wl_compositor")
	27	+	mgr := bindProtocol(t, c, "org_kde_kwin_server_decoration_manager")
	28	+	registerProtocol(t, c, mgr)
	29	+	surf := c.AllocateID()
	30	+	requestProtocol(t, c, comp, wayland.CompositorRequestCreateSurface, surf)
	31	+	deco := c.AllocateID()
	32	+	proxy := &kdeModeProxy{modes: make(chan uint32, 8)}
	33	+	proxy.SetID(deco)
	34	+	c.Context().Register(proxy)
	35	+	requestProtocol(t, c, mgr, kdedecoration.OrgKdeKwinServerDecorationManagerRequestCreate, deco, surf)
	36	+	requestProtocol(t, c, deco, kdedecoration.OrgKdeKwinServerDecorationRequestRequestMode, uint32(kdedecoration.OrgKdeKwinServerDecorationModeClient))
	37	+	// An undefined mode gets no answer.
	38	+	requestProtocol(t, c, deco, kdedecoration.OrgKdeKwinServerDecorationRequestRequestMode, uint32(3))
	39	+	if err := c.Roundtrip(); err != nil {
	40	+	t.Fatal(err)
	41	+	}
	42	+	for _, want := range []kdedecoration.OrgKdeKwinServerDecorationMode{kdedecoration.OrgKdeKwinServerDecorationModeServer, kdedecoration.OrgKdeKwinServerDecorationModeClient} {
	43	+	select {
	44	+	case got := <-proxy.modes:
	45	+	if got != uint32(want) {
	46	+	t.Fatalf("mode %d want %d", got, want)
	47	+	}
	48	+	case <-time.After(2 * time.Second):
	49	+	t.Fatalf("no mode %d", want)
	50	+	}
	51	+	}
	52	+	select {
	53	+	case got := <-proxy.modes:
	54	+	t.Fatalf("extra mode %d", got)
	55	+	default:
	56	+	}
	57	+	}

@@ -0,0 +1,57 @@
	1	+	package wayland
	2	+
	3	+	import (
	4	+	"testing"
	5	+	"time"
	6	+
	7	+	"github.com/bnema/nefertty/internal/ports"
	8	+	"github.com/bnema/purego-libwayland/protocol/kdedecoration"
	9	+	"github.com/bnema/purego-libwayland/protocol/wayland"
	10	+	"github.com/bnema/wlturbo"
	11	+	)
	12	+
	13	+	type kdeModeProxy struct {
	14	+	wlturbo.BaseProxy
	15	+	modes chan uint32
	16	+	}
	17	+
	18	+	func (p kdeModeProxy) Dispatch(e wlturbo.Event) { p.modes <- e.Uint32() }
	19	+
	20	+	// KDE decoration defaults to server-side and acknowledges the mode a client
	21	+	// asks for: answering server to Firefox's client request made it ask again
	22	+	// in a tight loop.
	23	+	func TestKDEDecorationAcknowledgesMode(t *testing.T) {
	24	+	s, _, _, dir := dmabufServer(t, ports.DMABufSupport{})
	25	+	c := protocolClient(t, s, dir)
	26	+	comp := bindProtocol(t, c, "wl_compositor")
	27	+	mgr := bindProtocol(t, c, "org_kde_kwin_server_decoration_manager")
	28	+	registerProtocol(t, c, mgr)
	29	+	surf := c.AllocateID()
	30	+	requestProtocol(t, c, comp, wayland.CompositorRequestCreateSurface, surf)
	31	+	deco := c.AllocateID()
	32	+	proxy := &kdeModeProxy{modes: make(chan uint32, 8)}
	33	+	proxy.SetID(deco)
	34	+	c.Context().Register(proxy)
	35	+	requestProtocol(t, c, mgr, kdedecoration.OrgKdeKwinServerDecorationManagerRequestCreate, deco, surf)
	36	+	requestProtocol(t, c, deco, kdedecoration.OrgKdeKwinServerDecorationRequestRequestMode, uint32(kdedecoration.OrgKdeKwinServerDecorationModeClient))
	37	+	// An undefined mode gets no answer.
	38	+	requestProtocol(t, c, deco, kdedecoration.OrgKdeKwinServerDecorationRequestRequestMode, uint32(3))
	39	+	if err := c.Roundtrip(); err != nil {
	40	+	t.Fatal(err)
	41	+	}
	42	+	for _, want := range []kdedecoration.OrgKdeKwinServerDecorationMode{kdedecoration.OrgKdeKwinServerDecorationModeServer, kdedecoration.OrgKdeKwinServerDecorationModeClient} {
	43	+	select {
	44	+	case got := <-proxy.modes:
	45	+	if got != uint32(want) {
	46	+	t.Fatalf("mode %d want %d", got, want)
	47	+	}
	48	+	case <-time.After(2 * time.Second):
	49	+	t.Fatalf("no mode %d", want)
	50	+	}
	51	+	}
	52	+	select {
	53	+	case got := <-proxy.modes:
	54	+	t.Fatalf("extra mode %d", got)
	55	+	default:
	56	+	}
	57	+	}