--- drivers/gpu/drm/udl/udl_drv.c.orig	2015-03-09 22:10:14.292335527 -0700
+++ drivers/gpu/drm/udl/udl_drv.c	2015-03-09 22:22:14.148342842 -0700
@@ -41,6 +41,7 @@ static struct drm_driver driver = {
 	.load = udl_driver_load,
 	.unload = udl_driver_unload,
 	.set_busid = udl_driver_set_busid,
+	.get_vblank_counter = drm_vblank_count,
 
 	/* gem hooks */
 	.gem_free_object = udl_gem_free_object,