xwayland/glamor: Add return status to post_damage

If the glamor backend failed to post damage, the caller should do the
same to avoid a failure to attach the buffer to the Wayland surface.

Change the API of Xwayland's glamor backend post_damage() to return a
status so that xwl_window_post_damage() can tell whether the callee
failed.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
https://gitlab.freedesktop.org/xorg/xserver/-/issues/1156

hw/xwayland/xwayland-glamor-eglstream.c

@@ -605,7 +605,7 @@ xwl_glamor_eglstream_allow_commits(struct xwl_window *xwl_window)
     return FALSE;
 }
 
-static void
+static Bool
 xwl_glamor_eglstream_post_damage(struct xwl_window *xwl_window,
                                  PixmapPtr pixmap, RegionPtr region)
 {
@@ -625,7 +625,7 @@ xwl_glamor_eglstream_post_damage(struct xwl_window *xwl_window,
          * flipping OpenGL or Vulkan window. In that case, we don't
          * need to do the copy below.
          */
-        return;
+        return TRUE;
 
     /* Unbind the framebuffer BEFORE binding the EGLSurface, otherwise we
      * won't actually draw to it
@@ -668,6 +668,8 @@ xwl_glamor_eglstream_post_damage(struct xwl_window *xwl_window,
 
     /* hang onto the pixmap until the compositor has released it */
     pixmap->refcnt++;
+
+    return TRUE;
 }
 
 static Bool

hw/xwayland/xwayland-glamor.c

@@ -304,14 +304,16 @@ xwl_glamor_pixmap_get_wl_buffer(PixmapPtr pixmap)
     return NULL;
 }
 
-void
+Bool
 xwl_glamor_post_damage(struct xwl_window *xwl_window,
                        PixmapPtr pixmap, RegionPtr region)
 {
     struct xwl_screen *xwl_screen = xwl_window->xwl_screen;
 
     if (xwl_screen->egl_backend->post_damage)
-        xwl_screen->egl_backend->post_damage(xwl_window, pixmap, region);
+        return xwl_screen->egl_backend->post_damage(xwl_window, pixmap, region);
+
+    return TRUE;
 }
 
 Bool

hw/xwayland/xwayland-glamor.h

@@ -83,7 +83,7 @@ struct xwl_egl_backend {
      * you should implement blitting from the glamor pixmap to the wayland
      * pixmap here. Otherwise, this callback is optional.
      */
-    void (*post_damage)(struct xwl_window *xwl_window,
+    Bool (*post_damage)(struct xwl_window *xwl_window,
                         PixmapPtr pixmap, RegionPtr region);
 
     /* Called by Xwayland to confirm with the egl backend that the given
@@ -117,7 +117,7 @@ void xwl_glamor_init_wl_registry(struct xwl_screen *xwl_screen,
                                  uint32_t version);
 Bool xwl_glamor_has_wl_interfaces(struct xwl_screen *xwl_screen,
                                  struct xwl_egl_backend *xwl_egl_backend);
-void xwl_glamor_post_damage(struct xwl_window *xwl_window,
+Bool xwl_glamor_post_damage(struct xwl_window *xwl_window,
                             PixmapPtr pixmap, RegionPtr region);
 Bool xwl_glamor_allow_commits(struct xwl_window *xwl_window);
 void xwl_glamor_egl_make_current(struct xwl_screen *xwl_screen);

hw/xwayland/xwayland-window.c

@@ -811,8 +811,12 @@ xwl_window_post_damage(struct xwl_window *xwl_window)
     }
 
 #ifdef XWL_HAS_GLAMOR
-    if (xwl_screen->glamor)
-        xwl_glamor_post_damage(xwl_window, pixmap, region);
+    if (xwl_screen->glamor) {
+        if (!xwl_glamor_post_damage(xwl_window, pixmap, region)) {
+            ErrorF("glamor: Failed to post damage\n");
+            return;
+        }
+    }
 #endif
 
     wl_surface_attach(xwl_window->surface, buffer, 0, 0);