Fix T93649: Blender freezes when saving with active VR session

Dead-lock when VR viewport drawing and depsgraph updates would fight for
the draw-manager GL lock. This didn't usually cause issues because the
depsgraph would be evaluated at this point already, except in rare
exceptions like after file writing.

Fix this by ensuring the XR surface gets its depsgraph updated after
handling notifiers, which is where regular windows also do the depsgraph
updating.

2 files changed, 15 insertions, 0 deletions

diff --git a/source/blender/windowmanager/intern/wm_event_system.c b/source/blender/windowmanager/intern/wm_event_system.c
index 3e9bf413c9f..1b6df9fb0db 100644
--- a/source/blender/windowmanager/intern/wm_event_system.c
+++ b/source/blender/windowmanager/intern/wm_event_system.c
@@ -84,6 +84,7 @@
 #include "wm.h"
 #include "wm_event_system.h"
 #include "wm_event_types.h"
+#include "wm_surface.h"
 #include "wm_window.h"
 
 #include "DEG_depsgraph.h"
@@ -382,6 +383,8 @@ void wm_event_do_depsgraph(bContext *C, bool is_after_open_file)
     DEG_make_active(depsgraph);
     BKE_scene_graph_update_tagged(depsgraph, bmain);
   }
+
+  wm_surfaces_do_depsgraph(C);
 }
 
 void wm_event_do_refresh_wm_and_depsgraph(bContext *C)
diff --git a/source/blender/windowmanager/intern/wm_surface.c b/source/blender/windowmanager/intern/wm_surface.c
index 715f72d70cf..72b68788e79 100644
--- a/source/blender/windowmanager/intern/wm_surface.c
+++ b/source/blender/windowmanager/intern/wm_surface.c
@@ -50,6 +50,18 @@ void wm_surfaces_iter(bContext *C, void (*cb)(bContext *C, wmSurface *))
   }
 }
 
+static void wm_surface_do_depsgraph_fn(bContext *C, wmSurface *surface)
+{
+  if (surface->do_depsgraph) {
+    surface->do_depsgraph(C);
+  }
+}
+
+void wm_surfaces_do_depsgraph(bContext *C)
+{
+  wm_surfaces_iter(C, wm_surface_do_depsgraph_fn);
+}
+
 void wm_surface_clear_drawable(void)
 {
   if (g_drawable) {