diff --git a/include/gui/SurfaceControl.h b/include/gui/SurfaceControl.h
index 84fb9f9..9f62f7c 100644
--- a/include/gui/SurfaceControl.h
+++ b/include/gui/SurfaceControl.h
@@ -57,8 +57,8 @@
     // release surface data from java
     void        clear();
 
-    status_t    setLayerStack(int32_t layerStack);
-    status_t    setLayer(int32_t layer);
+    status_t    setLayerStack(uint32_t layerStack);
+    status_t    setLayer(uint32_t layer);
     status_t    setPosition(float x, float y);
     status_t    setSize(uint32_t w, uint32_t h);
     status_t    hide();