diff --git a/glx/glxdri2.c b/glx/glxdri2.c
index 8d21c937b..c4b7ba4c6 100644
--- a/glx/glxdri2.c
+++ b/glx/glxdri2.c
@@ -184,6 +184,7 @@ __glXdriSwapEvent(ClientPtr client, void *data, int type, CARD64 ust,
 	break;
     default:
 	/* unknown swap completion type */
+	wire.event_type = 0;
 	break;
     }
     wire.drawable = drawable->drawId;