1 files changed, 5 insertions, 0 deletions
diff --git a/video/out/vo.h b/video/out/vo.h
index 3c00bb988e..848f71e472 100644
--- a/video/out/vo.h
+++ b/video/out/vo.h
@@ -374,6 +374,11 @@ struct vo_driver {
      */
     void (*flip_page)(struct vo *vo);
 
+    /*
+     * See struct ra_swapchain. Optional.
+     */
+    double (*get_latency)(struct vo *vo);
+
     /* These optional callbacks can be provided if the GUI framework used by
      * the VO requires entering a message loop for receiving events and does
      * not call vo_wakeup() from a separate thread when there are new events.