[Intel-gfx] [Acer Aspire V5-573G] Black screen on boot due to low brightness setting

[Mario Kleinsasser]

On Thu, Nov 14, 2013 at 8:29 AM, Aaron Lu <aaron.lu at intel.com> wrote:
> On 11/14/2013 02:24 PM, Jani Nikula wrote:
>>
>> Hi Mario -
>>
>> On Wed, 13 Nov 2013, Mario Kleinsasser <mario.kleinsasser+linux-kernel at gmail.com> wrote:
>>> In the last three weeks I've narrowed down the bug described in the
>>> subject through Ubuntu launchpad. My new Laptop (Acer Aspire V5-573G)
>>> with new Haswell CPU shows a black screen on reboot because the
>>> brightness is on zero level. I verified this behaviour with the latest
>>> mainline kernel from
>>> http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.12-trusty/
>>
>> Thanks for the report. I'll have to ask you to try some kernels, and
>> logs running them, etc. that IMHO are better suited attached to a bug
>> report than cluttered on the mailing list. Please file a bug on
>> DRM/Intel at [1]. Reference your mail. There it will also pop up in our
>> bug team's searches, and has a better chance of not falling under the
>> radar. :)
>>
>>> I have done the bisect process and tracked the bug down to the
>>> following commit.
>>>
>>> For explanation:
>>> good commit means: The laptop starts with display brightness on full
>>> power, but low(er) resolution and the Fn+ keys are not working
>>> bad commit means: The laptop starts with black display (0 brightness),
>>> Fn+ keys are working and you can level up the brightness trough the
>>> Fn+ keys. The resolution is the native LCD hardware display resolution
>>>
>>> Bisect output:
>>>
>>> 70b12bb415463c1bd146b67c5fbf6784fd046ad9 is the first bad commit
>>> commit 70b12bb415463c1bd146b67c5fbf6784fd046ad9
>>> Author: Paulo Zanoni <paulo.r.zanoni at intel.com>
>>> Date: Tue Nov 20 13:32:30 2012 -0200
>>>
>>>     drm/i915: promote Haswell to full support
>>>
>>>     Since it should be working a little bit better now.
>>>
>>>     Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
>>>     Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>>>
>>> :040000 040000 f93a7761de2157a8be61f20ca9a5499264bb5c55
>>> 1fed098470278830f06b0bca1706f61ba231d38d M drivers
>>>
>>> For the full bug report and the additional hardware information please
>>> see https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1239183
>>>
>>> I've also searched the LKML and maybe this bug could be in conjunction
>>> with http://marc.info/?t=137837786100005&r=1&w=2
>>
>> You only start using our driver for Haswell from the first "bad" commit,
>> and then we actually serve the ACPI opregion backlight requests. This
>> explains the backlight Fn keys in your good/bad commit explanations. If
>> this is a known bug in ACPI, it also explains the zero backlight.
>
> It's actually a bug in firmware and we try to work around it in ACPI
> video module :-)
>
> From the description it indeed seems to be the firmware initial zero
> brightness level bug to me.
>
> Thanks,
> Aaron

Bug filed as https://bugs.freedesktop.org/show_bug.cgi?id=71596

I will try the given branches and post my results in the filed bug.

Thanks for information!

Mario


>
>>
>> There's two branches I'd like you to try:
>>
>> 1) linux-next branch of [2]. This should contain a fix for some ACPI
>>    initial backlight issues. (CC Aaron for this.)
>>
>> 2) backlight-rework branch of [3]. What the branch name says.
>>
>> Please add drm.debug=0xe module parameter and attach full dmesg to the
>> bug.
>>
>>
>> Thanks,
>> Jani.
>>
>>
>> [1] https://bugs.freedesktop.org/enter_bug.cgi?product=DRI
>> [2] http://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git
>> [3] git://gitorious.org/jani/drm.git
>>
>>
>>
>