Re: i915_do_wait_request BUG: unable to handle kernel NULL pointer dereference at (null)

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Fri, 23 Apr 2010 12:24:25 +0200
Zdenek Kabelac <zdenek.kabelac@gmail.com> wrote:

> Hi
> 
> Just tried to boot current vanilla upstream kernel - and got pretty ugly  oops.
> Here is serial console catch after X-startup:
> 
> 
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: [<ffffffffa035de81>] i915_do_wait_request+0x101/0x4f0 [i915]
> PGD 139649067 PUD 133b5a067 PMD 0
> Oops: 0000 [#1] PREEMPT SMP
> last sysfs file: /sys/devices/virtual/backlight/acpi_video0/actual_brightness
> CPU 0
> Modules linked in: xt_tcpudp bridge stp llc autofs4 sunrpc ipv6
> ipt_REJECT xt_physdev xt_state ]
> 

Here's the fix I'm testing now.

-- 
Jesse Barnes, Intel Open Source Technology Center

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7f52cc1..ef3d91d 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1793,7 +1793,7 @@ i915_get_gem_seqno(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 
-	if (IS_I965G(dev))
+	if (HAS_PIPE_CONTROL(dev))
 		return ((volatile u32 *)(dev_priv->seqno_page))[0];
 	else
 		return READ_HWSP(dev_priv, I915_GEM_HWS_INDEX);