[git pull] drm merge for 3.9-rc1

[Alex Deucher]

On Wed, Feb 27, 2013 at 8:14 PM, Josh Boyer <jwboyer at gmail.com> wrote:
> On Wed, Feb 27, 2013 at 7:01 PM, Josh Boyer <jwboyer at gmail.com> wrote:
>> On Wed, Feb 27, 2013 at 3:20 PM, Josh Boyer <jwboyer at gmail.com> wrote:
>>> On Wed, Feb 27, 2013 at 11:34 AM, Josh Boyer <jwboyer at gmail.com> wrote:
>>>> On Mon, Feb 25, 2013 at 7:05 PM, Dave Airlie <airlied at linux.ie> wrote:
>>>>> Alex Deucher (29):
>>>>>       drm/radeon: halt engines before disabling MC (6xx/7xx)
>>>>>       drm/radeon: halt engines before disabling MC (evergreen)
>>>>>       drm/radeon: halt engines before disabling MC (cayman/TN)
>>>>>       drm/radeon: halt engines before disabling MC (si)
>>>>>       drm/radeon: use the reset mask to determine if rings are hung
>>>>
>>>> Something in this series of commits is causing the GPU to hang on reboot
>>>> on my Dell XPS 8300 machine.  That has a:
>>>>
>>>> 01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee
>>>> ATI Caicos [Radeon HD 6450]
>>>>
>>>> card in it.  After reboots, I get a screen that looks like this:
>>>>
>>>> http://t.co/tPnT6xQZUK
>>>>
>>>> I can hit it fairly consistently after a few reboots, so I tried doing a
>>>> git bisect on the radeon driver and it came down to:
>>>>
>>>> ca57802e521de54341efc8a56f70571f79ffac72 is the first bad commit
>>>
>>> So I don't think that's actually the cause of the problem.  Or at least
>>> not that alone.  I reverted it on top of Linus' latest tree and I still
>>> get the lockups.
>>
>> Actually, git bisect does seem to have gotten it correct.  Once I
>> actually tested the revert of just that on top of Linus' tree (commit
>> d895cb1af1), things seem to be working much better.  I've rebooted a
>> dozen times without a lockup.  The most I've seen it take on a kernel
>> with that commit included is 3 reboots, so that's definitely at least an
>> improvement.
>
> I give up.  GPU issues are not my thing.  2 reboots after I sent that it
> gave me pretty rainbow static again.  So it might have been an
> improvement, but revert it is not a solution.
>
> Looking at there rest of the commits, the whole GPU rework might be
> suspect, but I clearly have no clue.

GPUs are tricky beasts :)

ca57802e521de54341efc8a56f70571f79ffac72 mostly likely wasn't the
problem anyway since it only affects 6xx/7xx and your card is handled
by the evergreen code.  I'll put together some patches to help narrow
down the problem.

Alex