[client] wayland: serialize surface commits with EGL swaps

NVIDIA's Wayland EGL implementation sets explicit-sync acquire and
release points while presenting a frame. The requests emitted by
eglSwapBuffers and its final surface commit must be treated as one
logical transaction.

The pointer-warp path can commit the main surface from the input
thread while the render thread is inside eglSwapBuffers. If this
occurs between the explicit-sync requests, the cursor commit applies
incomplete pending state and the compositor disconnects the client
with:

  explicit sync is used, but no release point is set

Add a surface lock and hold it across EGL presentation. Use the same
lock for direct commits, frame callback registration, and
pointer-constraint updates, replacing the narrower confinement lock.
This prevents another thread from splitting the EGL transaction and
removes the need for __NV_DISABLE_EXPLICIT_SYNC=1.

client/displayservers/Wayland/gl.c

@@ -230,6 +230,11 @@ static const struct wp_image_description_v1_listener hdrImageDescListener =
 
 void waylandEGLSwapBuffers(EGLDisplay display, EGLSurface surface, const struct Rect * damage, int count)
 {
+  // 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.
+  INTERLOCKED_SECTION(wlWm.surfaceLock,
+  {
     if (!wlWm.swapWithDamage.init)
     {
       if (wl_proxy_get_version((struct wl_proxy *) wlWm.surface) < 4)
@@ -245,6 +250,7 @@ void waylandEGLSwapBuffers(EGLDisplay display, EGLSurface surface, const struct
     applyHDRPending();
     swapWithDamage(&wlWm.swapWithDamage, display, surface, damage, count);
     activateReadyHDRImageDesc();
+  });
 
   if (wlWm.needsResize)
   {

client/displayservers/Wayland/input.c

@@ -322,7 +322,8 @@ static const struct wl_keyboard_listener keyboardListener = {
 
 static void waylandCleanUpPointer(void)
 {
-  INTERLOCKED_SECTION(wlWm.confineLock, {
+  INTERLOCKED_SECTION(wlWm.surfaceLock,
+  {
     if (wlWm.lockedPointer)
     {
       zwp_locked_pointer_v1_destroy(wlWm.lockedPointer);
@@ -438,15 +439,12 @@ bool waylandInputInit(void)
   wl_seat_add_listener(wlWm.seat, &seatListener, NULL);
   wl_display_roundtrip(wlWm.display);
 
-  LG_LOCK_INIT(wlWm.confineLock);
-
   return true;
 }
 
 void waylandInputFree(void)
 {
   waylandUngrabPointer();
-  LG_LOCK_FREE(wlWm.confineLock);
 
   if (wlWm.pointer)
     waylandCleanUpPointer();
@@ -482,7 +480,7 @@ void waylandGrabPointer(void)
       &relativePointerListener, NULL);
   }
 
-  INTERLOCKED_SECTION(wlWm.confineLock,
+  INTERLOCKED_SECTION(wlWm.surfaceLock,
   {
     if (!wlWm.confinedPointer && !wlWm.lockedPointer)
     {
@@ -496,7 +494,7 @@ void waylandGrabPointer(void)
 inline static void internalUngrabPointer(bool lock)
 {
   if (lock)
-    LG_LOCK(wlWm.confineLock);
+    LG_LOCK(wlWm.surfaceLock);
 
   if (wlWm.confinedPointer)
   {
@@ -505,7 +503,7 @@ inline static void internalUngrabPointer(bool lock)
   }
 
   if (lock)
-    LG_UNLOCK(wlWm.confineLock);
+    LG_UNLOCK(wlWm.surfaceLock);
 
   if (!wlWm.warpSupport)
   {
@@ -536,7 +534,7 @@ void waylandCapturePointer(void)
     return;
   }
 
-  INTERLOCKED_SECTION(wlWm.confineLock,
+  INTERLOCKED_SECTION(wlWm.surfaceLock,
   {
     if (wlWm.confinedPointer)
     {
@@ -552,7 +550,7 @@ void waylandCapturePointer(void)
 
 void waylandUncapturePointer(void)
 {
-  INTERLOCKED_SECTION(wlWm.confineLock,
+  INTERLOCKED_SECTION(wlWm.surfaceLock,
   {
     if (wlWm.lockedPointer)
     {
@@ -601,11 +599,10 @@ void waylandWarpPointer(int x, int y, bool exiting)
   if (!wlWm.pointerInSurface || wlWm.lockedPointer)
     return;
 
-  INTERLOCKED_SECTION(wlWm.confineLock,
+  LG_LOCK(wlWm.surfaceLock);
-  {
   if (wlWm.lockedPointer)
   {
-      LG_UNLOCK(wlWm.confineLock);
+    LG_UNLOCK(wlWm.surfaceLock);
     return;
   }
 
@@ -638,7 +635,7 @@ void waylandWarpPointer(int x, int y, bool exiting)
 
   wl_surface_commit(wlWm.surface);
   wl_region_destroy(region);
-  });
+  LG_UNLOCK(wlWm.surfaceLock);
 }
 
 void waylandRealignPointer(void)

client/displayservers/Wayland/wayland.c

@@ -108,6 +108,7 @@ static bool getCompositor(char * dst, size_t size)
 static bool waylandInit(const LG_DSInitParams params)
 {
   memset(&wlWm, 0, sizeof(wlWm));
+  LG_LOCK_INIT(wlWm.surfaceLock);
   LG_LOCK_INIT(wlWm.pendingHDRLock);
   LG_LOCK_INIT(wlWm.hdrLock);
   wlWm.desktop        = WL_Desktops[0];
@@ -214,6 +215,7 @@ static void waylandFree(void)
   wl_display_disconnect(wlWm.display);
   LG_LOCK_FREE(wlWm.hdrLock);
   LG_LOCK_FREE(wlWm.pendingHDRLock);
+  LG_LOCK_FREE(wlWm.surfaceLock);
 }
 
 static bool waylandGetProp(LG_DSProperty prop, void * ret)

client/displayservers/Wayland/wayland.h

@@ -134,6 +134,7 @@ struct WaylandDSState
   struct wl_seat * seat;
   struct wl_shm * shm;
   struct wl_compositor * compositor;
+  LG_Lock surfaceLock;
 
   struct WaylandScale scale;
   bool fractionalScale;
@@ -192,7 +193,6 @@ struct WaylandDSState
   struct zwp_locked_pointer_v1 * lockedPointer;
   bool showPointer;
   uint32_t pointerEnterSerial;
-  LG_Lock confineLock;
 
   struct zwp_idle_inhibit_manager_v1 * idleInhibitManager;
   struct zwp_idle_inhibitor_v1 * idleInhibitor;

client/displayservers/Wayland/window.c

@@ -154,7 +154,10 @@ bool waylandWindowInit(const char * title, const char * appId, bool fullscreen,
         title, appId, fullscreen, maximize, borderless, resizable))
     return false;
 
+  INTERLOCKED_SECTION(wlWm.surfaceLock,
+  {
     wl_surface_commit(wlWm.surface);
+  });
 
   // The initial configure supplies the compositor-selected size for states
   // such as fullscreen. It must be received before the first buffer is made.
@@ -214,9 +217,12 @@ bool waylandWaitFrame(void)
 {
   lgWaitEvent(wlWm.frameEvent, TIMEOUT_INFINITE);
 
+  INTERLOCKED_SECTION(wlWm.surfaceLock,
+  {
     struct wl_callback * callback = wl_surface_frame(wlWm.surface);
     if (callback)
       wl_callback_add_listener(callback, &frame_listener, NULL);
+  });
 
   return false;
 }
@@ -224,7 +230,10 @@ bool waylandWaitFrame(void)
 void waylandSkipFrame(void)
 {
   // If we decided to not render, we must commit the surface so that the callback is registered.
+  INTERLOCKED_SECTION(wlWm.surfaceLock,
+  {
     wl_surface_commit(wlWm.surface);
+  });
 }
 
 void waylandStopWaitFrame(void)