diff --git a/include/X11/extensions/xf86vmproto.h b/include/X11/extensions/xf86vmproto.h
index 7307284..efc48d4 100644
--- a/include/X11/extensions/xf86vmproto.h
+++ b/include/X11/extensions/xf86vmproto.h
@@ -165,7 +165,7 @@ typedef struct {
     CARD16	vsyncstart;
     CARD16	vsyncend;
     CARD16	vtotal;
-    CARD16	pad1;
+    CARD32	pad1;
     CARD32	flags;
     CARD32	reserved1;
     CARD32	reserved2;