egl/wayland: Use roundtrips when awaiting buffer release
In get_back_bo, we use wl_display_dispatch_queue() to block and wait for
a buffer release event. However, not all Wayland compositors flush the
client socket on posting a buffer-release event, so by only blocking
client-side, we may block indefinitely, or at least need to wait for an
input event / frame completion to arrive for the compositor to flush.
We now use dispatch_queue as a first pass, but if our entire buffer pool
is exhausted, use a roundtrip (an immediately-triggered wl_callback) to
ensure that the compositor flushes out our release event immediately.
[daniels: Modified comment and commit message.]
Signed-off-by: Kai Chen <kai.chen@intel.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
CC: <mesa-stable@lists.freedesktop.org>
diff --git a/src/egl/drivers/dri2/platform_wayland.c b/src/egl/drivers/dri2/platform_wayland.c
index 15dc939..0b6cd1d 100644
--- a/src/egl/drivers/dri2/platform_wayland.c
+++ b/src/egl/drivers/dri2/platform_wayland.c
@@ -383,8 +383,13 @@
break;
/* If we don't have a buffer, then block on the server to release one for
- * us, and try again. */
- if (wl_display_dispatch_queue(dri2_dpy->wl_dpy, dri2_surf->wl_queue) < 0)
+ * us, and try again. wl_display_dispatch_queue will process any pending
+ * events, however not all servers flush on issuing a buffer release
+ * event. So, we spam the server with roundtrips as they always cause a
+ * client flush.
+ */
+ if (wl_display_roundtrip_queue(dri2_dpy->wl_dpy,
+ dri2_surf->wl_queue) < 0)
return -1;
}