diff --git a/drmdisplaycompositor.h b/drmdisplaycompositor.h
index bc19f35..975de63 100644
--- a/drmdisplaycompositor.h
+++ b/drmdisplaycompositor.h
@@ -143,6 +143,7 @@
   int ApplyPreComposite(DrmDisplayComposition *display_comp);
   int PrepareFrame(DrmDisplayComposition *display_comp);
   int CommitFrame(DrmDisplayComposition *display_comp, bool test_only);
+  int SquashFrame(DrmDisplayComposition *src, DrmDisplayComposition *dst);
   int ApplyDpms(DrmDisplayComposition *display_comp);
   int DisablePlanes(DrmDisplayComposition *display_comp);