[Intel-gfx] [PATCH v3 0/4] Fix Win8 backlight issue

[Jörg Otte]

2013/9/25 Jani Nikula <jani.nikula at linux.intel.com>:
> On Wed, 25 Sep 2013, Jörg Otte <jrg.otte at gmail.com> wrote:
>> 2013/9/25 Jani Nikula <jani.nikula at linux.intel.com>:
>>> On Wed, 25 Sep 2013, Aaron Lu <aaron.lu at intel.com> wrote:
>>>> On Wed, Sep 25, 2013 at 10:29:37AM +0200, Jörg Otte wrote:
>>>>> Backlight can't be modified with this patch set - neither with
>>>>> function keys nor with the gui. It is a step backward to v3.11-rc1
>>>
>>> So both hotkeys and GUI work in v3.11-rc1? And v3.12-rc2?
>>
>> In  v3.11-rc1 it didn't work.
>> Since a later rc (I don't remember exactly which) it did work.
>> In v3.12-rc1/2 it does work.
>> In v3.12-rc2 + Aaron's patch set it again doesn't work.
>>
>>>
>>>> Thanks for the test.
>>>>
>>>> Please check /sys/class/backlight, is there only one link file
>>>> intel_backlight?
>>>
>>> Indeed, are there others? fujitsu-laptop perhaps? If yes, try
>>> CONFIG_FUJITSU_LAPTOP=n or an appropriate module blacklist.
>>>
>>> Just checking, you do have CONFIG_BACKLIGHT_CLASS_DEVICE=y?
>>
>> There is only one intel_backlight link.
>> Yes, I have CONFIG_BACKLIGHT_CLASS_DEVICE=y
>>
>>> Embarrassingly there was a bug in i915 fixed just recently where the
>>> backlight device wasn't registered for
>>> CONFIG_BACKLIGHT_CLASS_DEVICE=m...
>>>
>>>> If so, please cd inside and try modify the brightness file using echo
>>>> with some values in the range of 0 - max_brightness, does the
>>>> backlight level change when you echo a new value? I guess it doesn't,
>>>> or you wouldn't notice problem. If indeed so, perhaps file a bug at
>>>> http://bugzilla.kernel.org, Drivers/Video(DRI-Intel)? I suppose Jani
>>>> and Daniel can help fix your problem.
>>>
>>> Yup, please check the above, and report back.
>>
>> - echo 0..max_brightness > brightness does not work.
>
> Thanks for the info.
>
> How about v3.12-rc2 without Aaron's patches? Does intel_backlight also
> not work there? How about the acpi_video0 (which I presume is present)
> sysfs interface?
>

Without Aaron's patches intel_backlight also does not work.
But acpi_video0 does (and takes precedence I think).

>>>>> Video driver: i915
>>>>> FUJITSU LIFEBOOK AH532/FJNBB1C, BIOS Version 1.09 05/22/2012
>>
>> Jörg