Wait for DRM presentation before releasing frame callbacks

Cancel callback-only timers when a frame is submitted and defer callback delivery until retirement. Cover a delayed timer and missed presentation deadline in the scheduler tests.

Clean up shader argument borrows and shell region decoding to pass Clippy.

compositor/src/backends/direct.rs

@@ -862,6 +862,10 @@ fn render_output(state: &mut Ferese, node: DrmNode, crtc: crtc::Handle, plan: cr
     let submitted = rendered.as_ref().is_ok_and(|submitted| *submitted);
     record_frame_schedule(&mut output, plan, render_started.elapsed(), submitted);
 
+    if submitted && let Some(token) = output.callback_timer.take() {
+        forecast.loop_handle.remove(token);
+    }
+
     match rendered {
         Ok(true) => tracing::trace!(?node, ?crtc, "queued DRM frame"),
         Ok(false) => (),
@@ -1262,12 +1266,15 @@ fn schedule_frame_callbacks(state: &mut Ferese, node: DrmNode, crtc: crtc::Handl
         return;
     };
 
-    if output.callback_timer.is_some() {
+    if output.callback_timer.is_some() || output.frame_pending {
         return;
     }
 
     let identity = output.output.clone();
-    let callback_at = output.scheduler.callback_deadline(timestamp, target);
+    let Some(callback_at) = output.scheduler.callback_deadline(timestamp, target) else {
+        return;
+    };
+
     if callback_at <= timestamp {
         deliver_frame_callbacks(state, node, crtc, &identity);
         return;
@@ -1313,12 +1320,15 @@ fn deliver_frame_callbacks(state: &mut Ferese, node: DrmNode, crtc: crtc::Handle
     };
 
     output.callback_timer = None;
-    if !backend.active || !device.drm.is_active() || state.session_lock.sleeping {
+    if !backend.active || !device.drm.is_active() || state.session_lock.sleeping || output.frame_pending {
         return;
     }
 
     let timestamp = monotonic_now();
-    let next = output.scheduler.callback_deadline(timestamp, timestamp);
+    let Some(next) = output.scheduler.callback_deadline(timestamp, timestamp) else {
+        return;
+    };
+
     if next > timestamp {
         schedule_frame_callbacks(state, node, crtc, next);
         return;

compositor/src/frame_scheduler.rs

@@ -192,14 +192,20 @@ impl FrameScheduler {
         })
     }
 
-    pub fn callback_deadline(&self, now: Duration, target: Duration) -> Duration {
+    pub fn callback_deadline(&self, now: Duration, target: Duration) -> Option<Duration> {
+        // A timer from a callback-only update must yield to a later submission.
+        // Its page flip will release callbacks using the observed refresh phase.
+        if self.submitted.is_some() {
+            return None;
+        }
+
         let tolerance = Duration::from_micros(500).min(self.interval / 8);
         if target <= now
             && self
                 .last_callback
                 .is_none_or(|last| last + self.interval <= now + tolerance)
         {
-            return now;
+            return Some(now);
         }
 
         let earliest = self
@@ -207,7 +213,7 @@ impl FrameScheduler {
             .map_or(now, |last| last + self.interval)
             .max(target)
             .max(now);
-        self.phase_at_or_after(earliest)
+        Some(self.phase_at_or_after(earliest))
     }
 
     pub fn callback_sent(&mut self, now: Duration) {
@@ -298,7 +304,35 @@ mod tests {
         scheduler.callback_sent(ms(110));
         scheduler.request(ms(108));
         assert_eq!(scheduler.plan(ms(108)).unwrap().present_at, ms(120));
-        assert_eq!(scheduler.callback_deadline(ms(111), ms(110)), ms(120));
+        assert_eq!(scheduler.callback_deadline(ms(111), ms(110)).unwrap(), ms(120));
+    }
+
+    #[test]
+    fn callback_only_timer_waits_for_a_later_submission_even_when_it_misses_its_target() {
+        let mut scheduler = FrameScheduler::new(ms(10));
+        scheduler.presented(ms(100));
+        scheduler.request(ms(101));
+        let unchanged = scheduler.plan(ms(101)).unwrap();
+        scheduler.begin();
+        scheduler.rendered(unchanged, ms(108), ms(1), false);
+        let callback_at = scheduler.callback_deadline(ms(108), unchanged.present_at).unwrap();
+        assert_eq!(callback_at, ms(110));
+
+        scheduler.request(ms(109));
+        let changed = scheduler.plan(ms(109)).unwrap();
+        scheduler.begin();
+        scheduler.rendered(changed, ms(118), ms(1), true);
+
+        // The old timer is dispatched late, after a new frame was queued.
+        // Neither that timer nor the predicted refresh can release callbacks.
+        assert_eq!(scheduler.callback_deadline(ms(118), callback_at), None);
+        assert_eq!(scheduler.callback_deadline(ms(120), changed.present_at), None);
+        assert_eq!(scheduler.callback_deadline(ms(129), callback_at), None);
+
+        scheduler.presented(ms(130));
+        assert_eq!(scheduler.callback_deadline(ms(130), ms(130)), Some(ms(130)));
+        scheduler.callback_sent(ms(130));
+        assert_eq!(scheduler.callback_deadline(ms(130), callback_at), Some(ms(140)));
     }
 
     #[test]
@@ -323,9 +357,9 @@ mod tests {
         scheduler.callback_sent(ms(100) + Duration::from_micros(80));
         scheduler.presented(ms(110));
         let now = ms(110) + Duration::from_micros(10);
-        assert_eq!(scheduler.callback_deadline(now, now), now);
+        assert_eq!(scheduler.callback_deadline(now, now).unwrap(), now);
         scheduler.callback_sent(now);
-        assert_eq!(scheduler.callback_deadline(now, now), ms(120));
+        assert_eq!(scheduler.callback_deadline(now, now).unwrap(), ms(120));
     }
 
     #[test]

compositor/src/presentation.rs

@@ -430,19 +430,21 @@ mod tests {
         let start = Duration::ZERO;
         let refresh = Duration::from_millis(16);
         let mut clock = crate::frame_scheduler::FrameScheduler::new(refresh);
-        assert_eq!(clock.callback_deadline(start, start), start);
+        assert_eq!(clock.callback_deadline(start, start).unwrap(), start);
         clock.callback_sent(start);
         for millisecond in 1..16 {
             assert_eq!(
-                clock.callback_deadline(start + Duration::from_millis(millisecond), start),
+                clock
+                    .callback_deadline(start + Duration::from_millis(millisecond), start)
+                    .unwrap(),
                 start + refresh
             );
         }
 
         let late = start + Duration::from_millis(50);
-        assert_eq!(clock.callback_deadline(late, late), late);
+        assert_eq!(clock.callback_deadline(late, late).unwrap(), late);
         clock.callback_sent(late);
-        assert_eq!(clock.callback_deadline(late, late), late + refresh);
+        assert_eq!(clock.callback_deadline(late, late).unwrap(), late + refresh);
     }
 
     #[test]
@@ -454,11 +456,11 @@ mod tests {
         fast.callback_sent(start);
         fast.callback_sent(start + Duration::from_millis(8));
         assert_eq!(
-            slow.callback_deadline(start + Duration::from_millis(8), start),
+            slow.callback_deadline(start + Duration::from_millis(8), start).unwrap(),
             start + Duration::from_millis(16)
         );
         assert_eq!(
-            fast.callback_deadline(start + Duration::from_millis(8), start),
+            fast.callback_deadline(start + Duration::from_millis(8), start).unwrap(),
             start + Duration::from_millis(16)
         );
     }

compositor/src/render/decorations.rs

@@ -29,11 +29,11 @@ pub(super) fn rounded_clip_program(state: &mut Ferese, renderer: &mut GlesRender
         UniformName::new("opacity", UniformType::_1f),
         UniformName::new("shadow_color", UniformType::_4f),
     ];
-    let texture = renderer.compile_custom_texture_shader(&corner_shader(ROUNDED_TEXTURE_SHADER), &texture_uniforms);
-    let border = renderer.compile_custom_pixel_shader(&corner_shader(ROUNDED_BORDER_SHADER), &border_uniforms);
-    let shadow = renderer.compile_custom_pixel_shader(&corner_shader(WINDOW_SHADOW_SHADER), &shadow_uniforms);
+    let texture = renderer.compile_custom_texture_shader(corner_shader(ROUNDED_TEXTURE_SHADER), &texture_uniforms);
+    let border = renderer.compile_custom_pixel_shader(corner_shader(ROUNDED_BORDER_SHADER), &border_uniforms);
+    let shadow = renderer.compile_custom_pixel_shader(corner_shader(WINDOW_SHADOW_SHADER), &shadow_uniforms);
     let solid = renderer.compile_custom_pixel_shader(
-        &corner_shader(ROUNDED_SOLID_SHADER),
+        corner_shader(ROUNDED_SOLID_SHADER),
         &[
             UniformName::new("clip_rect", UniformType::_4f),
             UniformName::new("radius", UniformType::_1f),

compositor/src/render/materials.rs

@@ -322,7 +322,7 @@ pub(super) fn blur_program(state: &mut Ferese, renderer: &mut GlesRenderer) -> O
     if let Some(program) = state.blur_programs.get(&context) {
         return Some(program.clone());
     }
-    match renderer.compile_custom_texture_shader(&corner_shader(BLUR_SHADER), &blur_uniform_names()) {
+    match renderer.compile_custom_texture_shader(corner_shader(BLUR_SHADER), &blur_uniform_names()) {
         Ok(program) => {
             let program = BlurProgram(program);
             state.blur_programs.insert(context, program.clone());
@@ -394,7 +394,7 @@ pub(super) fn material_program(state: &mut Ferese, renderer: &mut GlesRenderer)
         UniformName::new("shadow_rect", UniformType::_4f),
         UniformName::new("shadow_values", UniformType::_2f),
     ];
-    match renderer.compile_custom_pixel_shader(&corner_shader(MATERIAL_SHADER), &uniforms) {
+    match renderer.compile_custom_pixel_shader(corner_shader(MATERIAL_SHADER), &uniforms) {
         Ok(program) => {
             let program = MaterialProgram(program);
             state.material_programs.insert(context, program.clone());

compositor/src/render/mod.rs

@@ -542,7 +542,7 @@ mod tests {
         let mut renderer = unsafe { GlesRenderer::new(context).unwrap() };
         let program = renderer
             .compile_custom_pixel_shader(
-                &super::corner_shader(super::ROUNDED_SOLID_SHADER),
+                super::corner_shader(super::ROUNDED_SOLID_SHADER),
                 &[
                     UniformName::new("clip_rect", UniformType::_4f),
                     UniformName::new("radius", UniformType::_1f),
@@ -599,7 +599,7 @@ mod tests {
         let mut renderer = unsafe { GlesRenderer::new(context).unwrap() };
         for source in [super::ROUNDED_TEXTURE_SHADER, super::BLUR_SHADER] {
             renderer
-                .compile_custom_texture_shader(&super::corner_shader(source), &[])
+                .compile_custom_texture_shader(super::corner_shader(source), &[])
                 .unwrap();
         }
         for source in [
@@ -609,7 +609,7 @@ mod tests {
             super::MATERIAL_SHADER,
         ] {
             renderer
-                .compile_custom_pixel_shader(&super::corner_shader(source), &[])
+                .compile_custom_pixel_shader(super::corner_shader(source), &[])
                 .unwrap();
         }
     }
@@ -627,7 +627,7 @@ mod tests {
         let context = EGLContext::new(&display).unwrap();
         let mut renderer = unsafe { GlesRenderer::new(context).unwrap() };
         let program = renderer
-            .compile_custom_texture_shader(&super::corner_shader(super::BLUR_SHADER), &super::blur_uniform_names())
+            .compile_custom_texture_shader(super::corner_shader(super::BLUR_SHADER), &super::blur_uniform_names())
             .unwrap();
         let size = (32, 32).into();
         let mut pixels = vec![128u8; 32 * 32 * 4];