diff --git a/Xext/vidmode.c b/Xext/vidmode.c
index 0d6fc5a5b4..7d818900ab 100644
--- a/Xext/vidmode.c
+++ b/Xext/vidmode.c
@@ -332,8 +332,7 @@ static void fillModeInfoV2(x_rpcbuf_t *rpcbuf, int dotClock,
     x_rpcbuf_write_CARD16(rpcbuf, VidModeGetModeValue(mode, VIDMODE_V_SYNCSTART));
     x_rpcbuf_write_CARD16(rpcbuf, VidModeGetModeValue(mode, VIDMODE_V_SYNCEND));
     x_rpcbuf_write_CARD16(rpcbuf, VidModeGetModeValue(mode, VIDMODE_V_TOTAL));
-    x_rpcbuf_reserve0(rpcbuf, sizeof(CARD16)); /* pad1 */
-    x_rpcbuf_reserve0(rpcbuf, sizeof(CARD16)); /* XXX extra padding not explicitly defined in struct XXX */
+    x_rpcbuf_reserve0(rpcbuf, sizeof(CARD32)); /* pad1 */
     x_rpcbuf_write_CARD32(rpcbuf, VidModeGetModeValue(mode, VIDMODE_FLAGS));
     x_rpcbuf_reserve0(rpcbuf, sizeof(CARD32) * 4); /* reserved[1,2,3], privsize */
 }