[mutter] onscreen/native: Complete buffer swap also if we discarded

[Marge Bot <marge-bot src gnome org>]

commit c29f8c8b73dcb07eddb54400b34e7b08a7007455
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Apr 12 16:07:40 2021 +0200

    onscreen/native: Complete buffer swap also if we discarded
    
    We already swapped the front buffer, and even if it didn't get
    presented, we should still swap our representation of the state, to not
    get into a confused buffer tracking state.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1822>

 src/backends/native/meta-onscreen-native.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
index be150879ed..da75b03ec4 100644
--- a/src/backends/native/meta-onscreen-native.c
+++ b/src/backends/native/meta-onscreen-native.c
@@ -341,6 +341,7 @@ page_flip_feedback_discarded (MetaKmsCrtc  *kms_crtc,
   frame_info->flags |= COGL_FRAME_INFO_FLAG_SYMBOLIC;
 
   meta_onscreen_native_notify_frame_complete (onscreen);
+  meta_onscreen_native_swap_drm_fb (onscreen);
 }
 
 static const MetaKmsPageFlipListenerVtable page_flip_listener_vtable = {