xwayland/eglstream: Do not commit without surface

The EGL surface for the xwl_pixmap is created once the stream is ready
and valid.

If the pixmap's EGL surface fails, for whatever reason, the xwl_pixmap
will be unusable and will end up as an invalid wl_buffer.

Make sure we do not allow commits in that case and recreate the
xwl_pixmap/stream.

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

@@ -670,7 +670,14 @@ xwl_glamor_eglstream_allow_commits(struct xwl_window *xwl_window)
 
             return FALSE;
         } else {
-            return TRUE;
+            if (xwl_pixmap->surface != EGL_NO_SURFACE)
+                return TRUE;
+
+            /* The pending stream got removed, we have a xwl_pixmap and
+             * yet we do not have a surface.
+             * So something went wrong with the surface creation, retry.
+             */
+            xwl_eglstream_destroy_pixmap_stream(xwl_pixmap);
         }
     }