diff --git a/include/video/permedia2.h b/include/video/permedia2.h
index 144c81c..cf1d95b 100644
--- a/include/video/permedia2.h
+++ b/include/video/permedia2.h
@@ -153,6 +153,7 @@
 #define PM2VI_RD_CURSOR_Y_HIGH				0x00A
 #define PM2VI_RD_CURSOR_X_HOT				0x00B
 #define PM2VI_RD_CURSOR_Y_HOT				0x00C
+#define PM2VI_RD_OVERLAY_KEY				0x00D
 #define PM2VI_RD_CLK0_PRESCALE				0x201
 #define PM2VI_RD_CLK0_FEEDBACK				0x202
 #define PM2VI_RD_CLK0_POSTSCALE				0x203