[kernel/f21] Make sure acpi brightness_switch is disabled (like forever in Fedora)

[Hans de Goede]

Hi,

On 29-07-15 17:17, Ranjan Maitra wrote:
>>
>> Oops.  The revert-revert patch was never actually dropped so long ago.
>> So we're still defaulting the ACPI brightness_switch_enabled parameter
>> off by default in Fedora.
>>
>> If you still believe we should drop it, I can do so with the 4.2
>> kernels.  Hopefully we've had enough time upstream to shake out any
>> issues.  I'd like confirmation before I do that though.
>
> Just to be clear, because I am hopelessly confused, what will the dropping do. Have the ACPI brightness_switch_enabled parameter enabled by default? If so, I would like that.

Yes dropping the Fedora specific cause will make it enabled by default,
relying on it is not a good idea though, as newer laptops use
a different backlight driver which does not do this, responding
to brightness keypresses should really be done by userspace.

If you rely on the brightness_switch_enabled=yes behavior, your
workflow will likely break when you replace your laptop.

Regards,

Hans