Index: xorg-server-1.3.0.0/exa/exa.c
===================================================================
--- xorg-server-1.3.0.0.orig/exa/exa.c     2007-02-16 17:03:12.000000000 +0100
+++ xorg-server-1.3.0.0/exa/exa.c     2007-05-21 21:11:15.000000000 +0200
@@ -783,8 +783,10 @@
 {
     ExaScreenPriv(pScreen);
 
-    if (pExaScr->info->needsSync && !pExaScr->swappedOut) {
-        (*pExaScr->info->WaitMarker)(pScreen, pExaScr->info->lastMarker);
+    if (pExaScr->info->needsSync
+        && !pExaScr->swappedOut) {
+        if (pExaScr->info->WaitMarker)
+            (*pExaScr->info->WaitMarker)(pScreen, pExaScr->info->lastMarker);
         pExaScr->info->needsSync = FALSE;
     }
 }