diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 3c8f4e5..3284fdb 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -308,6 +308,9 @@
             void        composeSurfaces(const Region& dirty);
 
 
+            void        setInvalidateRegion(const Region& reg);
+            Region      getAndClearInvalidateRegion();
+
             ssize_t     addClientLayer(const sp<Client>& client,
                     const sp<LayerBaseClient>& lbc);
             status_t    addLayer_l(const sp<LayerBase>& layer);
@@ -367,6 +370,10 @@
                 bool                        mLayersRemoved;
                 DefaultKeyedVector< wp<IBinder>, wp<Layer> > mLayerMap;
 
+                // access must be protected by mInvalidateLock
+    mutable     Mutex                       mInvalidateLock;
+                Region                      mInvalidateRegion;
+
                 // constant members (no synchronization needed for access)
                 sp<IMemoryHeap>             mServerHeap;
                 surface_flinger_cblk_t*     mServerCblk;