[Intel-gfx] 2.6.36-rc5 i915 regression

[Seblu]

On Sat, Oct 9, 2010 at 11:40 AM, Seblu <seblu at seblu.net> wrote:
> On Fri, Oct 8, 2010 at 1:24 AM, Seblu <seblu at seblu.net> wrote:
>> On Sat, Oct 2, 2010 at 11:07 AM, Zhenyu Wang <zhenyuw at linux.intel.com> wrote:
>>> On 2010.10.01 22:27:45 +0200, Seblu wrote:
>>>> On Fri, Oct 1, 2010 at 3:22 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
>>>> > On Fri, 1 Oct 2010 12:55:56 +0000 (UTC), Seblu <seblu at seblu.net> wrote:
>>> I sent mail before to ask if ajax's eDP connector type change for PCH/eDP
>>> has caused regression for that, but one e6410 owner replied no effect by
>>> revert that patch. You may help by bisect drm/i915.
>> Ok i can try (first time). To understand correclty what you want, i
>> have to download linux 2.6.36-rc6 git, bisect, compile an run kernel
>> until i found the commit cause the issue?
>>
>> I will test new rc7 in near time to show if my display come back.
>>
> Nothing better with rc7, il will start bisecting this weekend.
>
Bug is introduced between 2.6.36-rc1 and 2.6.36-rc2. I have bisected
(all the night)  to find the following introducting commit

913d8d110078788c14812dce8bb62c37946821d2 is the first bad commit
commit 913d8d110078788c14812dce8bb62c37946821d2
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Sat Aug 7 11:01:35 2010 +0100

    drm/i915: Ensure that while(INREG()) are bounded (v2)

    Add a new macro, wait_for, to simplify the act of waiting on a register
    to change state. wait_for() takes three arguments, the condition to
    inspect on every loop, the maximum amount of time to wait and whether to
    yield the cpu for a length of time after each check.

    v2: Upgrade failure messages to DRM_ERROR on the suggestion of
    Eric Anholt. We do not expect to hit these conditions as they reflect
    programming errors, so if we do we want to be notified.

    Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
    Signed-off-by: Eric Anholt <eric at anholt.net>

:040000 040000 6002481a823acda95b2d1891c81d83cb8702af54
dc78f280e056469f9e46f02feae4607a4bbd5023 M      drivers

Regards,

-- 
Sébastien Luttringer
www.seblu.net