[PATCH] xfree86: if only one screen was found, disable Xinerama (#24627)

[Peter Hutterer]

Xorg +xinerama crashes immediately due to whacky dependency between Xinerama
and RandR12. The latter doesn't initialize if Xinerama is enabled, but if
only one screen is found, Xinerama is disabled again and RandR12 tries to
access data it never initialized.

Dependency chain is:
- ProcessCommandLine sets noPanoramiXExtension to FALSE
- xf86RandR12Init() is a noop
- PanoramiXExtensionInit sets noPanoramiXExtension to TRUE
- xf86RandR12CreateScreenResources tries to use the devPrivates key it never
  initialized.

This hack checks if there's only one screen at the time RandR12 is
initialized. If so, we expect Xinerama to fail anyhow so we disable it
ourselves and proceed as planned.

X.Org Bug 24627 <http://bugs.freedesktop.org/show_bug.cgi?id=24627>

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 hw/xfree86/modes/xf86RandR12.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/hw/xfree86/modes/xf86RandR12.c b/hw/xfree86/modes/xf86RandR12.c
index 6ea9d26..1fc63c4 100644
--- a/hw/xfree86/modes/xf86RandR12.c
+++ b/hw/xfree86/modes/xf86RandR12.c
@@ -871,7 +871,12 @@ xf86RandR12Init (ScreenPtr pScreen)
 #ifdef PANORAMIX
     /* XXX disable RandR when using Xinerama */
     if (!noPanoramiXExtension)
-	return TRUE;
+    {
+        if (xf86NumScreens == 1)
+            noPanoramiXExtension = TRUE;
+        else
+            return TRUE;
+    }
 #endif
 
     if (xf86RandR12Generation != serverGeneration)
-- 
1.6.5.2