[PATCH] Fix oops in MGA DRM on root bus.

[David Woodhouse]

I think that if a PCI bus is a root bus, attached to a host bridge not a
PCI->PCI bridge, then bus->self is allowed to be NULL. Certainly that's
the case on my Pegasos, and it makes the MGA DRM driver oops...

Signed-off-by: David Woodhouse <dwmw2 at infradead.org>

diff --git a/drivers/char/drm/mga_drv.c b/drivers/char/drm/mga_drv.c
--- a/drivers/char/drm/mga_drv.c
+++ b/drivers/char/drm/mga_drv.c
@@ -161,7 +161,7 @@ static int mga_driver_device_is_agp(drm_
 	 * device.
 	 */
 
-	if ((pdev->device == 0x0525)
+	if ((pdev->device == 0x0525) && pdev->bus->self &&
 	    && (pdev->bus->self->vendor == 0x3388)
 	    && (pdev->bus->self->device == 0x0021)) {
 		return 0;

-- 
dwmw2