Re: [PATCH 3/3] acpi-video: change acpi-video brightness_switch_enabled default to 0

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 05/06/2014 04:01 AM, Aaron Lu wrote:
> On 05/05/2014 05:38 PM, Hans de Goede wrote:
>> acpi-video is unique in that it not only generates brightness up/down
>> keypresses, but also (sometimes) actively changes the brightness itself.
>>
>> This presents an inconsistent kernel interface to userspace, basically there
>> are 2 different scenarios, depending on the laptop model:
>>
>> 1) On some laptops a brightness up/down keypress means: show a brightness osd
>> with the current brightness, iow it is a brightness has changed notification.
>>
>> 2) Where as on (a lot of) other laptops it means a brightness up/down key was
>> pressed, deal with it.
>>
>> Most of the desktop environments interpret any press as in scenario 2, and
>> change the brightness up / down as a response to the key events, causing it
>> to be changed twice, once by acpi-video and once by the DE.
>>
>> With the new default for video.use_native_backlight we will be moving even
>> more laptops over to behaving as in scenario 2. Making the remaining laptops
>> even more of a weird exception. Also note that it is hard to detect scenario
>> 1 properly in userspace, and AFAIK none of the DE-s deals with it.
>>
>> Therefor this commit changes the default of brightness_switch_enabled to 0
>> making its behavior consistent with all the other backlight drivers.
>>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> 
> Reviewed-by: Aaron Lu <aaron.lu@intel.com>
> 
> Note that the Documentation/kernel-parameters.txt has to be modified
> accordingly to change the default value for video.brightness_switch_enabled
> to 0.

Good one, I'll send a v2 with this fixed.

Regards,

Hans