[PATCH v3 0/4] Fix Win8 backlight issue

[Jani Nikula]

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?

BR,
Jani.



>
>>>>
>>>> Video driver: i915
>>>> FUJITSU LIFEBOOK AH532/FJNBB1C, BIOS Version 1.09 05/22/2012
>>>>
>>>> acpi_backlight=video works.
>
> Jörg