Re: [PATCH] drm/i915: Fix crash when failing to parse MIPI VBT

Kumar, Shobhit
2014-07-25T09:41:20Z

On 7/25/2014 1:20 PM, Daniel Vetter wrote:
> On Fri, Jul 25, 2014 at 09:47:06AM +0200, Daniel Vetter wrote:
>> On Thu, Jul 24, 2014 at 03:16:12PM +0100, rafael.barbalho@intel.com wrote:
>>> From: Rafael Barbalho <rafael.barbalho@intel.com>
>>>
>>> This particular nasty presented itself while trying to register the
>>> intelfb device (intel_fbdev.c). During the process of registering the device
>>> the driver will disable the crtc via i9xx_crtc_disable. These will
>>> also disable the panel using the generic mipi panel functions in
>>> dsi_mod_vbt_generic.c. The stale MIPI generic data sequence pointers would
>>> cause a crash within those functions. However, all of this is happening
>>> while console_lock is held from do_register_framebuffer inside fbcon.c. Which
>>> means that you got kernel log and just the device appearing to reboot/hang for
>>> no apparent reason.
>>
>> CONFIG_I915_FBDEV=n for when the console_lock gets in the way.
>>
>>> The fault started from the FB_EVENT_FB_REGISTERED event using the
>>> fb_notifier_call_chain call in fbcon.c.
>>>
>>> Cc: Shobhit Kumar <shobhit.kumar@intel.com>
>>> Signed-off-by: Rafael Barbalho <rafael.barbalho@intel.com>
>>
>> Queued for -next, thanks for the patch.
>
> Actually this is for fixes since 3.16 has dsi support. Also for
> regressions please cite the commit that introduced the offending
> behaviour. I've added that.

Also this reminds me that there is still a WARN dump in 3.16 which will
be fixed by -
[v2] drm/i915: Add correct hw/sw config check for DSI encoder

Assuming this can go in -fixes if it okay, this is waiting for review

Regards
Shobhit