cdcafdb fix(drm): keep VRR across lost master and short compositions, remember refused async flips · neferwl

M examples/config +4 -0


@@ -63,6 +63,10 @@ layout.presets = 1/3, 1/2, 2/3, 1
63	63		# output.DP-2.scale = 4/3
64	64
65	65		render.direct-scanout = on
	66	+	# Games asking for tearing flip without waiting for vblank, and variable
	67	+	# refresh runs; both only while a fullscreen window is scanned out directly.
	68	+	render.tearing = on
	69	+	render.vrr = on
66	70
67	71		# log.level: debug, info, warn or error. log.debug: components or all.
68	72		log.level = info


@@ -63,6 +63,10 @@ layout.presets = 1/3, 1/2, 2/3, 1
63	# output.DP-2.scale = 4/3	63		# output.DP-2.scale = 4/3
64		64
65	render.direct-scanout = on	65		render.direct-scanout = on
		66	+	# Games asking for tearing flip without waiting for vblank, and variable
		67	+	# refresh runs; both only while a fullscreen window is scanned out directly.
		68	+	render.tearing = on
		69	+	render.vrr = on
66		70
67	# log.level: debug, info, warn or error. log.debug: components or all.	71		# log.level: debug, info, warn or error. log.debug: components or all.
68	log.level = info	72		log.level = info

M internal/adapters/drm/output.go +33 -8


@@ -50,6 +50,8 @@ type Output struct {
50	50		tearing bool
51	51		vrrProp uint32
52	52		vrrOn, async bool
	53	+	// composedSince is when composition took over from scanout.
	54	+	composedSince time.Time
53	55		// kind is how the images were made; validated once a modeset took them.
54	56		kind imageKind
55	57		validated bool

@@ -115,7 +117,13 @@ func (o *Output) present(r ports.Renderer) error {
115	117		if b := o.bufs[o.back]; b != nil {
116	118		r.CopyBGRX(b.mem, int(b.pitch))
117	119		}
118		-	o.setVRR(false)
	120	+	// VRR goes off only after composing for vrrHold: each toggle is a
	121	+	// blocking commit and may flicker, so short compositions keep it.
	122	+	if o.composedSince.IsZero() {
	123	+	o.composedSince = time.Now()
	124	+	} else if time.Since(o.composedSince) > vrrHold {
	125	+	o.setVRR(false)
	126	+	}
119	127		o.setAsync(false)
120	128		if err := flip(o.fd, o.crtc, o.fbs[o.back], false); err != nil {
121	129		return err

@@ -149,23 +157,28 @@ func (o *Output) tryScanout(scene ports.Scene, surfaces map[ports.WindowID]ports
149	157		// Already on screen: nothing to flip.
150	158		return true, nil
151	159		}
152		-	o.setVRR(true)
153	160		// Drivers refuse async flips that change the format or modifier: the
154	161		// flip from the composed image into scanout waits for vblank.
155		-	async := c.Async && o.tearing && o.shown != 0
156		-	o.setAsync(async)
	162	+	cfb := o.clientFBs[c.DMABuf.ID]
	163	+	async := c.Async && o.tearing && o.shown != 0 && !cfb.noAsync
157	164		err := flip(o.fd, o.crtc, fb, async)
158	165		if err != nil && async && errors.Is(err, unix.EINVAL) {
159		-	// Refused anyway (e.g. the client changed buffer layout): flip
160		-	// at vblank this time.
	166	+	// Refused (e.g. a layout change, or not a fast update): this
	167	+	// buffer flips at vblank from now on.
161	168		o.log.Debug().Err(err).Str("connector", o.conn.name).Msg("async flip refused")
	169	+	cfb.noAsync, async = true, false
162	170		err = flip(o.fd, o.crtc, fb, false)
163	171		}
	172	+	if err == nil {
	173	+	o.setAsync(async)
	174	+	o.setVRR(true)
	175	+	o.composedSince = time.Time{}
	176	+	}
164	177		if err != nil {
165	178		if errors.Is(err, unix.EINVAL) \|\| errors.Is(err, unix.ERANGE) {
166	179		// KMS refuses this buffer on the plane: compose it instead.
167	180		o.log.Info().Err(err).Uint32("format", c.DMABuf.Format).Uint64("modifier", c.DMABuf.Modifier).Msg("scanout flip refused")
168		-	o.clientFBs[c.DMABuf.ID].failed = "flip_refused"
	181	+	cfb.failed = "flip_refused"
169	182		o.reason = "flip_refused"
170	183		o.log.Info().Bool("direct_scanout", false).Str("reason", o.reason).Str("connector", o.conn.name).Msg("scanout")
171	184		return false, nil

@@ -177,6 +190,9 @@ func (o *Output) tryScanout(scene ports.Scene, surfaces map[ports.WindowID]ports
177	190		return true, nil
178	191		}
179	192
	193	+	// vrrHold is how long composition runs before VRR turns off.
	194	+	const vrrHold = 500 * time.Millisecond
	195	+
180	196		// setVRR turns variable refresh on or off, when the output has it.
181	197		func (o *Output) setVRR(on bool) {
182	198		if o.vrrProp == 0 \|\| on == o.vrrOn {

@@ -186,13 +202,18 @@ func (o *Output) setVRR(on bool) {
186	202		if on {
187	203		v = 1
188	204		}
	205	+	// SETPROPERTY is a blocking atomic commit (about one refresh).
	206	+	start := time.Now()
189	207		if err := setProp(o.fd, o.crtc, objCrtc, o.vrrProp, v); err != nil {
	208	+	if lostMaster(err) {
	209	+	return // switched away: retried on the next change
	210	+	}
190	211		o.log.Warn().Err(err).Str("connector", o.conn.name).Msg("vrr; disabled")
191	212		o.vrrProp = 0
192	213		return
193	214		}
194	215		o.vrrOn = on
195		-	o.log.Info().Bool("vrr", on).Str("connector", o.conn.name).Msg("vrr")
	216	+	o.log.Info().Bool("vrr", on).Str("connector", o.conn.name).Dur("took", time.Since(start)).Msg("vrr")
196	217		}
197	218
198	219		// setAsync logs when the output starts or stops tearing.

@@ -344,6 +365,10 @@ func (o *Output) Run(ctx context.Context, newRenderer func(w, h int) (ports.Rend
344	365		dirty = dirty \|\| scene.Shows(c.ID)
345	366		case <-stats.C:
346	367		o.dropClientFBs(time.Now(), false)
	368	+	// A composed screen that stopped changing still drops VRR.
	369	+	if !o.composedSince.IsZero() && time.Since(o.composedSince) > vrrHold {
	370	+	o.setVRR(false)
	371	+	}
347	372		ev := o.log.Info().Int("frames", frame).Int("flips", o.flips)
348	373		if o.cursor != nil {
349	374		cs := o.cursor.TakeStats()

 	tearing      bool
 	vrrProp      uint32
 	vrrOn, async bool
+	// composedSince is when composition took over from scanout.
+	composedSince time.Time
 	// kind is how the images were made; validated once a modeset took them.
 	kind      imageKind
 	validated bool
 	if b := o.bufs[o.back]; b != nil {
 		r.CopyBGRX(b.mem, int(b.pitch))
 	}
-	o.setVRR(false)
+	// VRR goes off only after composing for vrrHold: each toggle is a
+	// blocking commit and may flicker, so short compositions keep it.
+	if o.composedSince.IsZero() {
+		o.composedSince = time.Now()
+	} else if time.Since(o.composedSince) > vrrHold {
+		o.setVRR(false)
+	}
 	o.setAsync(false)
 	if err := flip(o.fd, o.crtc, o.fbs[o.back], false); err != nil {
 		return err
 		// Already on screen: nothing to flip.
 		return true, nil
 	}
-	o.setVRR(true)
 	// Drivers refuse async flips that change the format or modifier: the
 	// flip from the composed image into scanout waits for vblank.
-	async := c.Async && o.tearing && o.shown != 0
+	cfb := o.clientFBs[c.DMABuf.ID]
-	o.setAsync(async)
+	async := c.Async && o.tearing && o.shown != 0 && !cfb.noAsync
 	err := flip(o.fd, o.crtc, fb, async)
 	if err != nil && async && errors.Is(err, unix.EINVAL) {
-		// Refused anyway (e.g. the client changed buffer layout): flip
+		// Refused (e.g. a layout change, or not a fast update): this
-		// at vblank this time.
+		// buffer flips at vblank from now on.
 		o.log.Debug().Err(err).Str("connector", o.conn.name).Msg("async flip refused")
+		cfb.noAsync, async = true, false
 		err = flip(o.fd, o.crtc, fb, false)
 	}
+	if err == nil {
+		o.setAsync(async)
+		o.setVRR(true)
+		o.composedSince = time.Time{}
+	}
 	if err != nil {
 		if errors.Is(err, unix.EINVAL) || errors.Is(err, unix.ERANGE) {
 			// KMS refuses this buffer on the plane: compose it instead.
 			o.log.Info().Err(err).Uint32("format", c.DMABuf.Format).Uint64("modifier", c.DMABuf.Modifier).Msg("scanout flip refused")
-			o.clientFBs[c.DMABuf.ID].failed = "flip_refused"
+			cfb.failed = "flip_refused"
 			o.reason = "flip_refused"
 			o.log.Info().Bool("direct_scanout", false).Str("reason", o.reason).Str("connector", o.conn.name).Msg("scanout")
 			return false, nil
 	return true, nil
 }
+// vrrHold is how long composition runs before VRR turns off.
+const vrrHold = 500 * time.Millisecond
 // setVRR turns variable refresh on or off, when the output has it.
 func (o *Output) setVRR(on bool) {
 	if o.vrrProp == 0 || on == o.vrrOn {
 	if on {
 		v = 1
 	}
+	// SETPROPERTY is a blocking atomic commit (about one refresh).
+	start := time.Now()
 	if err := setProp(o.fd, o.crtc, objCrtc, o.vrrProp, v); err != nil {
+		if lostMaster(err) {
+			return // switched away: retried on the next change
+		}
 		o.log.Warn().Err(err).Str("connector", o.conn.name).Msg("vrr; disabled")
 		o.vrrProp = 0
 		return
 	}
 	o.vrrOn = on
-	o.log.Info().Bool("vrr", on).Str("connector", o.conn.name).Msg("vrr")
+	o.log.Info().Bool("vrr", on).Str("connector", o.conn.name).Dur("took", time.Since(start)).Msg("vrr")
 }
 // setAsync logs when the output starts or stops tearing.
 			dirty = dirty || scene.Shows(c.ID)
 		case <-stats.C:
 			o.dropClientFBs(time.Now(), false)
+			// A composed screen that stopped changing still drops VRR.
+			if !o.composedSince.IsZero() && time.Since(o.composedSince) > vrrHold {
+				o.setVRR(false)
+			}
 			ev := o.log.Info().Int("frames", frame).Int("flips", o.flips)
 			if o.cursor != nil {
 				cs := o.cursor.TakeStats()

M internal/adapters/drm/scanout.go +2 -0


@@ -90,6 +90,8 @@ type clientFB struct {
90	90		last time.Time // when last wanted on screen
91	91		// failed is the reason KMS refused the buffer; it is not retried.
92	92		failed string
	93	+	// noAsync: KMS refused an async flip to it; it flips at vblank.
	94	+	noAsync bool
93	95		}
94	96
95	97		// scanoutFB returns the framebuffer of a client buffer, importing it on


@@ -90,6 +90,8 @@ type clientFB struct {
90	last time.Time // when last wanted on screen	90		last time.Time // when last wanted on screen
91	// failed is the reason KMS refused the buffer; it is not retried.	91		// failed is the reason KMS refused the buffer; it is not retried.
92	failed string	92		failed string
		93	+	// noAsync: KMS refused an async flip to it; it flips at vblank.
		94	+	noAsync bool
93	}	95		}
94		96
95	// scanoutFB returns the framebuffer of a client buffer, importing it on	97		// scanoutFB returns the framebuffer of a client buffer, importing it on

M internal/adapters/wayland/surface.go +1 -0


@@ -140,6 +140,7 @@ func (s *surface) detach() {
140	140
141	141		func (s surface) Destroy(wayland.Surface) {
142	142		s.destroyed = true
	143	+	s.tearing = nil // the control becomes inert
143	144		if s.server.cursorSurface == s {
144	145		// The pointer keeps no cursor until the client sets another.
145	146		s.server.cursorSurface = nil


@@ -140,6 +140,7 @@ func (s *surface) detach() {
140		140
141	func (s surface) Destroy(wayland.Surface) {	141		func (s surface) Destroy(wayland.Surface) {
142	s.destroyed = true	142		s.destroyed = true
		143	+	s.tearing = nil // the control becomes inert
143	if s.server.cursorSurface == s {	144		if s.server.cursorSurface == s {
144	// The pointer keeps no cursor until the client sets another.	145		// The pointer keeps no cursor until the client sets another.
145	s.server.cursorSurface = nil	146		s.server.cursorSurface = nil

M internal/adapters/wayland/tearing_test.go +25 -2


@@ -34,6 +34,17 @@ func TestTearingHintAppliesOnCommit(t *testing.T) {
34	34		registerProtocol(t, c, control)
35	35		requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, control, surf)
36	36		requestProtocol(t, c, control, tearingcontrol.WpTearingControlV1RequestSetPresentationHint, uint32(tearingcontrol.WpTearingControlV1PresentationHintAsync))
	37	+	if err := c.Roundtrip(); err != nil {
	38	+	t.Fatal(err)
	39	+	}
	40	+	// Double-buffered: nothing changes before the commit.
	41	+	select {
	42	+	case got := <-contents:
	43	+	if got.Async {
	44	+	t.Fatal("hint applied before commit")
	45	+	}
	46	+	case <-time.After(50 * time.Millisecond):
	47	+	}
37	48		requestProtocol(t, c, surf, wayland.SurfaceRequestCommit)
38	49		if err := c.Roundtrip(); err != nil {
39	50		t.Fatal(err)

@@ -48,11 +59,23 @@ func TestTearingHintAppliesOnCommit(t *testing.T) {
48	59		}
49	60		asyncContent(t, contents, w.ID, false)
50	61
	62	+	// A control outliving its surface is inert.
	63	+	inert := c.AllocateID()
	64	+	registerProtocol(t, c, inert)
	65	+	requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, inert, surf)
	66	+	requestProtocol(t, c, surf, wayland.SurfaceRequestDestroy)
	67	+	requestProtocol(t, c, inert, tearingcontrol.WpTearingControlV1RequestSetPresentationHint, uint32(tearingcontrol.WpTearingControlV1PresentationHintAsync))
	68	+	if err := c.Roundtrip(); err != nil {
	69	+	t.Fatal(err)
	70	+	}
	71	+	unmapped(t, events, w.ID)
	72	+
51	73		// A surface has at most one control.
	74	+	_, other, _ := surfaceMapper(t, c, events)()
52	75		first, second := c.AllocateID(), c.AllocateID()
53	76		registerProtocol(t, c, first)
54	77		registerProtocol(t, c, second)
55		-	requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, first, surf)
56		-	requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, second, surf)
	78	+	requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, first, other)
	79	+	requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, second, other)
57	80		expectProtocolError(t, c, manager, uint32(tearingcontrol.WpTearingControlManagerV1ErrorTearingControlExists))
58	81		}


@@ -34,6 +34,17 @@ func TestTearingHintAppliesOnCommit(t *testing.T) {
34		registerProtocol(t, c, control)	34		registerProtocol(t, c, control)
35		requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, control, surf)	35		requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, control, surf)
36		requestProtocol(t, c, control, tearingcontrol.WpTearingControlV1RequestSetPresentationHint, uint32(tearingcontrol.WpTearingControlV1PresentationHintAsync))	36		requestProtocol(t, c, control, tearingcontrol.WpTearingControlV1RequestSetPresentationHint, uint32(tearingcontrol.WpTearingControlV1PresentationHintAsync))
			37	+	if err := c.Roundtrip(); err != nil {
			38	+	t.Fatal(err)
			39	+	}
			40	+	// Double-buffered: nothing changes before the commit.
			41	+	select {
			42	+	case got := <-contents:
			43	+	if got.Async {
			44	+	t.Fatal("hint applied before commit")
			45	+	}
			46	+	case <-time.After(50 * time.Millisecond):
			47	+	}
37		requestProtocol(t, c, surf, wayland.SurfaceRequestCommit)	48		requestProtocol(t, c, surf, wayland.SurfaceRequestCommit)
38		if err := c.Roundtrip(); err != nil {	49		if err := c.Roundtrip(); err != nil {
39		t.Fatal(err)	50		t.Fatal(err)

@@ -48,11 +59,23 @@ func TestTearingHintAppliesOnCommit(t *testing.T) {
48		}	59		}
49		asyncContent(t, contents, w.ID, false)	60		asyncContent(t, contents, w.ID, false)
50			61
			62	+	// A control outliving its surface is inert.
			63	+	inert := c.AllocateID()
			64	+	registerProtocol(t, c, inert)
			65	+	requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, inert, surf)
			66	+	requestProtocol(t, c, surf, wayland.SurfaceRequestDestroy)
			67	+	requestProtocol(t, c, inert, tearingcontrol.WpTearingControlV1RequestSetPresentationHint, uint32(tearingcontrol.WpTearingControlV1PresentationHintAsync))
			68	+	if err := c.Roundtrip(); err != nil {
			69	+	t.Fatal(err)
			70	+	}
			71	+	unmapped(t, events, w.ID)
			72	+
51		// A surface has at most one control.	73		// A surface has at most one control.
			74	+	_, other, _ := surfaceMapper(t, c, events)()
52		first, second := c.AllocateID(), c.AllocateID()	75		first, second := c.AllocateID(), c.AllocateID()
53		registerProtocol(t, c, first)	76		registerProtocol(t, c, first)
54		registerProtocol(t, c, second)	77		registerProtocol(t, c, second)
55	-	requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, first, surf)	78	+	requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, first, other)
56	-	requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, second, surf)	79	+	requestProtocol(t, c, manager, tearingcontrol.WpTearingControlManagerV1RequestGetTearingControl, second, other)
57		expectProtocolError(t, c, manager, uint32(tearingcontrol.WpTearingControlManagerV1ErrorTearingControlExists))	80		expectProtocolError(t, c, manager, uint32(tearingcontrol.WpTearingControlManagerV1ErrorTearingControlExists))
58		}	81		}