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

[Jörg Otte]

2013/9/27 Rafael J. Wysocki <rjw at sisk.pl>:
> On Thursday, September 26, 2013 09:49:03 AM Jörg Otte wrote:
>> 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).
>
> So can you please open a bug entry at bugzilla.kernel.org against i915?
>
> The fact that ACPI video works for you doesn't mean that intel_backlight
> shouldn't, I suppose?
>
> Rafael
>
done. Bug-Id:62281

Jörg