[client] scheduler: qualify presentation feedback

Track cadence, interruption, and calibration wake reasons independently
across X11 and Wayland. Feed phase correction back only when a pure
cadence wake renders the exact frame that was queued at that wake.

Propagate EGL swap results through the display-server boundary. Reject
failed presentations and keep pending Wayland HDR descriptions inactive
until the preceding surface commit succeeds.

client/displayservers/Wayland/gl.c

@@ -228,8 +228,11 @@ static const struct wp_image_description_v1_listener hdrImageDescListener =
   .ready2 = hdrImageDescReadyV2,
 };
 
-void waylandEGLSwapBuffers(EGLDisplay display, EGLSurface surface, const struct Rect * damage, int count)
+bool waylandEGLSwapBuffers(EGLDisplay display, EGLSurface surface,
+    const struct Rect * damage, int count)
 {
+  bool result = false;
+
   // EGL presentation sends a batch of Wayland requests ending in a surface
   // commit. A concurrent commit would apply a partial batch and, when explicit
   // sync is active, omit one of the required acquire/release timeline points.
@@ -248,8 +251,10 @@ void waylandEGLSwapBuffers(EGLDisplay display, EGLSurface surface, const struct
 
     waylandPresentationFrame();
     applyHDRPending();
-    swapWithDamage(&wlWm.swapWithDamage, display, surface, damage, count);
-    activateReadyHDRImageDesc();
+    result = swapWithDamage(
+        &wlWm.swapWithDamage, display, surface, damage, count);
+    if (result)
+      activateReadyHDRImageDesc();
   });
 
   if (wlWm.needsResize)
@@ -305,6 +310,7 @@ void waylandEGLSwapBuffers(EGLDisplay display, EGLSurface surface, const struct
   }
 
   wlWm.desktop->shellAckConfigureIfNeeded();
+  return result;
 }
 #endif
 
@@ -750,6 +756,6 @@ void waylandGLSetSwapInterval(int interval)
 
 void waylandGLSwapBuffers(void)
 {
-  waylandEGLSwapBuffers(wlWm.glDisplay, wlWm.glSurface, NULL, 0);
+  (void)waylandEGLSwapBuffers(wlWm.glDisplay, wlWm.glSurface, NULL, 0);
 }
 #endif

client/displayservers/Wayland/wayland.h

@@ -267,7 +267,8 @@ struct WaylandDSState
   enum WaylandHDRPendingAction pendingHDRAction;
   struct WaylandHDRParameters  pendingHDR;
 
-  LGEvent * frameEvent;
+  _Atomic(unsigned) frameEventFlags;
+  LGEvent *         frameEvent;
 
   struct wl_list poll; // WaylandPoll::link
   struct wl_list pollFree; // WaylandPoll::link
@@ -333,7 +334,8 @@ void waylandCursorScaleChange(void);
 #if defined(ENABLE_EGL) || defined(ENABLE_OPENGL)
 bool waylandEGLInit(int w, int h);
 EGLDisplay waylandGetEGLDisplay(void);
-void waylandEGLSwapBuffers(EGLDisplay display, EGLSurface surface, const struct Rect * damage, int count);
+bool waylandEGLSwapBuffers(EGLDisplay display, EGLSurface surface,
+    const struct Rect * damage, int count);
 #endif
 
 #ifdef ENABLE_EGL
@@ -421,7 +423,7 @@ void waylandWindowFree(void);
 void waylandWindowUpdateScale(void);
 void waylandSetWindowSize(int x, int y);
 bool waylandIsValidPointerPos(int x, int y);
-bool waylandWaitFrame(void);
+LG_DSWaitFrameResult waylandWaitFrame(void);
 void waylandSkipFrame(void);
 void waylandStopWaitFrame(void);
 void waylandNeedsResize(void);

client/displayservers/Wayland/window.c

@@ -113,6 +113,13 @@ static const struct wl_surface_listener wlSurfaceListener = {
   .leave = wlSurfaceLeaveHandler,
 };
 
+static void waylandSignalFrame(LG_DSWaitFrameResult result)
+{
+  atomic_fetch_or_explicit(
+      &wlWm.frameEventFlags, result, memory_order_release);
+  lgSignalEvent(wlWm.frameEvent);
+}
+
 static void fractionalScalePreferredScale(void * data,
     struct wp_fractional_scale_v1 * fractionalScale, uint32_t scale)
 {
@@ -133,7 +140,7 @@ bool waylandWindowInit(const char * title, const char * appId, bool fullscreen,
     DEBUG_ERROR("Failed to initialize event for waitFrame");
     return false;
   }
-  lgSignalEvent(wlWm.frameEvent);
+  waylandSignalFrame(LG_DS_WAIT_FRAME_INTERRUPTED);
 
   if (!wlWm.compositor)
   {
@@ -220,7 +227,7 @@ bool waylandIsValidPointerPos(int x, int y)
 
 static void frameHandler(void * opaque, struct wl_callback * callback, unsigned int data)
 {
-  lgSignalEvent(wlWm.frameEvent);
+  waylandSignalFrame(LG_DS_WAIT_FRAME_CADENCE);
   wl_callback_destroy(callback);
 }
 
@@ -228,9 +235,11 @@ static const struct wl_callback_listener frame_listener = {
    .done = frameHandler,
 };
 
-bool waylandWaitFrame(void)
+LG_DSWaitFrameResult waylandWaitFrame(void)
 {
   lgWaitEvent(wlWm.frameEvent, TIMEOUT_INFINITE);
+  const LG_DSWaitFrameResult result = atomic_exchange_explicit(
+      &wlWm.frameEventFlags, LG_DS_WAIT_FRAME_NONE, memory_order_acquire);
 
   INTERLOCKED_SECTION(wlWm.surfaceLock,
   {
@@ -239,7 +248,7 @@ bool waylandWaitFrame(void)
       wl_callback_add_listener(callback, &frame_listener, NULL);
   });
 
-  return false;
+  return result;
 }
 
 void waylandSkipFrame(void)
@@ -253,5 +262,5 @@ void waylandSkipFrame(void)
 
 void waylandStopWaitFrame(void)
 {
-  lgSignalEvent(wlWm.frameEvent);
+  waylandSignalFrame(LG_DS_WAIT_FRAME_INTERRUPTED);
 }

client/displayservers/X11/x11.c

@@ -95,6 +95,13 @@ static void x11XPresentEvent(XGenericEventCookie *cookie);
 static void x11UpdateKeyboardGroup(void);
 static void x11GrabPointer(void);
 
+static void x11SignalFrame(LG_DSWaitFrameResult result)
+{
+  atomic_fetch_or_explicit(
+      &x11.frameEventFlags, result, memory_order_release);
+  lgSignalEvent(x11.frameEvent);
+}
+
 static uint64_t x11ModePeriod(
     const XRRScreenResources * resources, RRMode modeID)
 {
@@ -849,7 +856,7 @@ static void x11Startup(void)
 static void x11Shutdown(void)
 {
   if (x11.jitRender)
-    lgSignalEvent(x11.frameEvent);
+    x11SignalFrame(LG_DS_WAIT_FRAME_INTERRUPTED);
 }
 
 static void x11Free(void)
@@ -1595,7 +1602,7 @@ static void x11XPresentEvent(XGenericEventCookie *cookie)
       x11DoPresent(e->msc);
       atomic_store(&x11.presentMsc, e->msc);
       atomic_store(&x11.presentUst, e->ust);
-      lgSignalEvent(x11.frameEvent);
+      x11SignalFrame(LG_DS_WAIT_FRAME_CADENCE);
       break;
     }
   }
@@ -1645,14 +1652,14 @@ static EGLNativeWindowType x11GetEGLNativeWindow(void)
   return (EGLNativeWindowType)x11.window;
 }
 
-static void x11EGLSwapBuffers(EGLDisplay display, EGLSurface surface,
+static bool x11EGLSwapBuffers(EGLDisplay display, EGLSurface surface,
     const struct Rect * damage, int count)
 {
   static struct SwapWithDamageData data = {0};
   if (!data.init)
     swapWithDamageInit(&data, display);
 
-  swapWithDamage(&data, display, surface, damage, count);
+  return swapWithDamage(&data, display, surface, damage, count);
 }
 #endif
 
@@ -1692,10 +1699,17 @@ static void x11GLSwapBuffers(void)
 }
 #endif
 
-static bool x11WaitFrame(void)
+static LG_DSWaitFrameResult x11WaitFrame(void)
 {
   /* wait until we are woken up by the present event */
   lgWaitEvent(x11.frameEvent, TIMEOUT_INFINITE);
+  LG_DSWaitFrameResult result = atomic_exchange_explicit(
+      &x11.frameEventFlags, LG_DS_WAIT_FRAME_NONE, memory_order_acquire);
+
+  /* Interrupts carry no new presentation timestamp and must not perturb the
+   * calibration state. */
+  if (!(result & LG_DS_WAIT_FRAME_CADENCE))
+    return result;
 
 #define WARMUP_TIME 3000000 //2s
 #define CALIBRATION_COUNT 400
@@ -1713,7 +1727,7 @@ static bool x11WaitFrame(void)
     }
 
     if (ust < expire)
-      return false;
+      return result;
 
     warmup = false;
     DEBUG_INFO("Warmup done, doing calibration...");
@@ -1831,14 +1845,14 @@ static bool x11WaitFrame(void)
   /* force rendering until we have finished calibration so we can take into
    * account how long it takes for the scene to render */
   if (calibrate < CALIBRATION_COUNT)
-    return true;
+    result |= LG_DS_WAIT_FRAME_FORCE_RENDER;
 
-  return false;
+  return result;
 }
 
 static void x11StopWaitFrame(void)
 {
-  lgSignalEvent(x11.frameEvent);
+  x11SignalFrame(LG_DS_WAIT_FRAME_INTERRUPTED);
 }
 
 static void x11GuestPointerUpdated(double x, double y, double localX, double localY)

client/displayservers/X11/x11.h

@@ -81,6 +81,7 @@ struct X11DSState
   uint32_t          presentSerial;
   Pixmap            presentPixmap;
   XserverRegion     presentRegion;
+  _Atomic(unsigned) frameEventFlags;
   LGEvent *         frameEvent;
 
   bool xrandrSupported;