[Intel-gfx] Trouble with dell latitude E6420

[Georg Grabler]

ahm, of takeshi .. mixing up things here.

On Sat, Jun 30, 2012 at 5:49 PM, Georg Grabler <ggrabler at gmail.com> wrote:
> It's fixed in 3.5rc4.
> And I patched my 3.4 kernel with the commit of keith. The problem was
> gone afterwards as well.
>
> Kind regards,
> Georg
>
> On Thu, Jun 28, 2012 at 8:23 PM, Giacomo Comes <comes at naic.edu> wrote:
>> On Thu, Jun 28, 2012 at 07:52:18AM +0200, Takashi Iwai wrote:
>>> At Tue, 26 Jun 2012 15:08:32 -0400,
>>> Giacomo Comes wrote:
>>> >
>>> > I have a dell latitude E6420 with Sandybridge Mobile (GT2).
>>> > Since I got it (about one year ago), it has been a nightmare to run linux on it.
>>> > At the beginning I installed openSUSE 11.4 (kernel 2.6.37.6) and the laptop
>>> > would freeze almost immediately. After that I waited for newer kernels in order to
>>> > see if things would improve. They did improve indeed and finally with kernel 3.0
>>> > I was able to run linux (openSUSE 11.4) without laptop freeze or screen issue.
>>> > Unfortunately, the only kernel that works with my laptop is 3.0. Newer kernel
>>> > (3.1, 3.2, 3.3 and 3.4) do not work.
>>> > This is what happen if I run kernel 2.6.39, 3.1, 3.2, 3.3 and 3.4:
>>> > The laptop boot and does the boot process fine. At the end of the boot process X
>>> > starts and here the problem appears (about 50% of the times):
>>> > the screen goes black on the left side (about 2/3 of the whole screen) with white
>>> > stripes to the right side (the remaining 1/3).
>>> > The laptop is not dead: I can remotely login or I can perform a clean shutdown
>>> > if I press the power button, but the screen is totally dead.
>>> > Another strange issue is that after a bad boot (with the black screen) at the
>>> > next reboot the screen will start to flicker. The flickering will last some time
>>> > and it will become less intense as the time goes until it will disappear completely.
>>> > The funny thing is that the intensity of flicker depends on how long I keep the
>>> > black screen. If, after the boot process, the black screen appears and I reboot
>>> > the laptop immediately, then the flicked is moderate and it disappear after
>>> > 1 or 2 minutes. If I keep the black screen for 1 minute or more, then after the
>>> > reboot the flicker is very intense and it takes much more to fade.
>>>
>>> This reminds me of a similar bug I've seen on HP laptops with HD+
>>> (1600x900) monitors.  Could you check whether the patch below helps?
>>>
>>> Note that it just avoids entering to the wrong mode.  If your laptop
>>> already starts flickering, at first recover from the flickering state,
>>> apply the patch, and reboot/test.
>>>
>>>
>>> Takashi
>>>
>>> ---
>>> diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
>>> index 08eb04c..3f61bba 100644
>>> --- a/drivers/gpu/drm/i915/intel_lvds.c
>>> +++ b/drivers/gpu/drm/i915/intel_lvds.c
>>> @@ -413,7 +413,7 @@ static void intel_lvds_prepare(struct drm_encoder *encoder)
>>>        * the panel fitter. However at all other times we can just reset
>>>        * the registers regardless.
>>>        */
>>> -     if (!HAS_PCH_SPLIT(encoder->dev) && intel_lvds->pfit_dirty)
>>> +     /*if (!HAS_PCH_SPLIT(encoder->dev) && intel_lvds->pfit_dirty)*/
>>>               intel_lvds_disable(intel_lvds);
>>>  }
>>>
>>
>> This patch seems to fix the problem. I will regularly run a kernel with
>> this patch and report if I see any other issue.
>>
>> Giacomo
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