diff --git a/include/hardware/hwcomposer_defs.h b/include/hardware/hwcomposer_defs.h
index 3823765..c4d8a44 100644
--- a/include/hardware/hwcomposer_defs.h
+++ b/include/hardware/hwcomposer_defs.h
@@ -299,10 +299,19 @@
 enum {
     HWC_DISPLAY_PRIMARY     = 0,
     HWC_DISPLAY_EXTERNAL    = 1,    // HDMI, DP, etc.
-    HWC_DISPLAY_VIRTUAL     = 2,
 
-    HWC_NUM_PHYSICAL_DISPLAY_TYPES = 2,
-    HWC_NUM_DISPLAY_TYPES          = 3,
+    HWC_DISPLAY_EXTERNAL_2  = 2,
+    HWC_DISPLAY_EXTERNAL_3  = 3,
+    HWC_DISPLAY_EXTERNAL_4  = 4,
+
+    HWC_DISPLAY_BUILTIN_2   = 5,
+    HWC_DISPLAY_BUILTIN_3   = 6,
+    HWC_DISPLAY_BUILTIN_4   = 7,
+
+    HWC_DISPLAY_VIRTUAL     = 8,
+
+    HWC_NUM_PHYSICAL_DISPLAY_TYPES = 8,
+    HWC_NUM_DISPLAY_TYPES          = 9,
 };
 
 enum {