[Intel-gfx] i915 / 3.15 intermittently boots into blank screeen

[Daniel Vetter]

On Fri, Jul 18, 2014 at 4:49 PM, Jan Niggemann <jn at hz6.de> wrote:
>
> Am 18.07.2014 15:27, schrieb Daniel Vetter:
>>
>> On Thu, Jul 17, 2014 at 10:31:30PM +0200, Jan Niggemann wrote:
>>>
>>> I'm experiencing an issue with 3.15.5 on my Lenovo T400:
>>> Since 3.15 (or 3.14, can't say for sure), the boot starts normally, but
>>> the
>>> first mode change doesn't occur, resulting in a black screen with
>>> backlight
>>> on. The system is entirely unresponsive and I can only press the power
>>> button until to switch it off.
>>
>> I think the only way to move forward here is to double-check that 3.14
>>
>> works and 3.15 is broken by recompiling with the same .config
>> (occasionally config changes cause regressions). And then do a full git
>> bisect to find the offending commit.
>
> thank you for the feedback.
> I still have all my custom built kernels, I will test 3.14.0 through 3.14.8
> to make sure those were OK and report back.

You only need to test 3.14.0, since the backported fixes only contain
a very small subset of all patches for 3.15. So it's more efficient to
then switch to git bisect between 3.14 and 3.15 directly (after you've
confirmed that 3.15.0 is indeed busted).
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch