While VT-switched, FB access is disabled and should remain so. Trying to switch
modes in that state would re-enable it, potentially causing crashes if trying
to access it before the driver has recovered from the mode switch.

Thanks,
 - Pierre-Loup
>From 4d526e470faeaa658cd2cb362d3132384baa478b Mon Sep 17 00:00:00 2001
From: Pierre-Loup A. Griffais <[email protected]>
Date: Wed, 21 Apr 2010 17:59:42 -0700
Subject: [PATCH] xf86: Don't crash when switching modes through RandR without owning the VT.

While VT-switched, FB access is disabled and should remain so. Trying to switch
modes in that state would re-enable it, potentially causing crashes if trying
to access it before the driver has recovered from the mode switch.

Signed-off-by: Pierre-Loup A. Griffais <[email protected]>
---
 hw/xfree86/common/xf86RandR.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/xfree86/common/xf86RandR.c b/hw/xfree86/common/xf86RandR.c
index 02dcc34..d4beb2c 100644
--- a/hw/xfree86/common/xf86RandR.c
+++ b/hw/xfree86/common/xf86RandR.c
@@ -163,7 +163,7 @@ xf86RandRSetMode (ScreenPtr	    pScreen,
     WindowPtr		pRoot = WindowTable[pScreen->myNum];
     Bool		ret = TRUE;
 
-    if (pRoot)
+    if (pRoot && scrp->vtSema)
 	(*scrp->EnableDisableFBAccess) (pScreen->myNum, FALSE);
     if (useVirtual)
     {
@@ -229,7 +229,7 @@ xf86RandRSetMode (ScreenPtr	    pScreen,
      */
     xf86SetViewport (pScreen, pScreen->width, pScreen->height);
     xf86SetViewport (pScreen, 0, 0);
-    if (pRoot)
+    if (pRoot && scrp->vtSema)
 	(*scrp->EnableDisableFBAccess) (pScreen->myNum, TRUE);
     return ret;
 }
-- 
1.7.0.4

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