commit 1feb69eb63e6739ff5db255ad529e84adf941a10
Author: Luc Verhaegen <libv@skynet.be>
Date:   Wed Oct 8 14:55:29 2008 +0200

    DGA: Fix ProcXF86DGASetViewPort for missing support in driver.
    
    Fixes a segfault when trying to activate a DGA mode without checking
    whether DGA modesetting is at all possible.

diff --git a/hw/xfree86/dixmods/extmod/xf86dga.c b/hw/xfree86/dixmods/extmod/xf86dga.c
index 0736167..c66bca2 100644
--- a/hw/xfree86/dixmods/extmod/xf86dga.c
+++ b/hw/xfree86/dixmods/extmod/xf86dga.c
@@ -93,7 +93,7 @@ ProcXF86DGADirectVideo(ClientPtr client)
 
     REQUEST_SIZE_MATCH(xXF86DGADirectVideoReq);
 
-    if (!DGAAvailable(stuff->screen)) 
+    if (!DGAAvailable(stuff->screen))
 	return DGAErrorBase + XF86DGANoDirectVideoMode;
 
     if (stuff->enable & XF86DGADirectGraphics) {
@@ -128,7 +128,7 @@ ProcXF86DGAGetViewPortSize(ClientPtr client)
     rep.length = 0;
     rep.sequenceNumber = client->sequence;
 
-    if (!DGAAvailable(stuff->screen)) 
+    if (!DGAAvailable(stuff->screen))
 	return (DGAErrorBase + XF86DGANoDirectVideoMode);
 
     if(!(num = DGAGetOldDGAMode(stuff->screen)))
@@ -153,6 +153,9 @@ ProcXF86DGASetViewPort(ClientPtr client)
 
     REQUEST_SIZE_MATCH(xXF86DGASetViewPortReq);
 
+    if (!DGAAvailable(stuff->screen))
+	return (DGAErrorBase + XF86DGANoDirectVideoMode);
+
     if (!DGAActive(stuff->screen))
     {
 	int num;