[PATCH] DDX/Randr: Avoid server crash when xrandr SetConfig is called while switched away

[Egbert Eich]

A call to Xrandr SetScreenConfig (for randr 1.1) causes the Xserver to
crash when xf86SetViewport() which does not check if the hardware is
accessible.
Wrap accesses to xf86SetViewport() with if (vtSema) { ... } to avoid that.

Signed-off-by: Egbert Eich <eich at freedesktop.org>
---
 hw/xfree86/common/xf86RandR.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/hw/xfree86/common/xf86RandR.c b/hw/xfree86/common/xf86RandR.c
index 5606bee..2418731 100644
--- a/hw/xfree86/common/xf86RandR.c
+++ b/hw/xfree86/common/xf86RandR.c
@@ -214,13 +214,15 @@ xf86RandRSetMode(ScreenPtr pScreen,
      */
     xf86ReconfigureLayout();
 
-    /*
-     * Make sure the whole screen is visible
-     */
-    xf86SetViewport(pScreen, pScreen->width, pScreen->height);
-    xf86SetViewport(pScreen, 0, 0);
-    if (pRoot && scrp->vtSema)
-        (*scrp->EnableDisableFBAccess) (scrp, TRUE);
+    if (scrp->vtSema) {
+        /*
+         * Make sure the whole screen is visible
+         */
+        xf86SetViewport (pScreen, pScreen->width, pScreen->height);
+        xf86SetViewport (pScreen, 0, 0);
+        if (pRoot)
+            (*scrp->EnableDisableFBAccess) (scrp, TRUE);
+    }
     return ret;
 }
 
-- 
1.8.1.4