diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index f77a828..5dad4a9 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -1024,6 +1024,7 @@
     // Can only be accessed with the SF state lock held.
     bool mChildrenChanged{false};
 
+    // Can only be accessed with the SF state lock held.
     std::optional<int64_t> mFrameTimelineVsyncId;
 
     // Window types from WindowManager.LayoutParams