[arch-general] Fn-F{5, 6} keys for backlight - how to disable native handling?

[Oon-Ee Ng]

On Thu, Jun 27, 2013 at 1:35 PM, Martín Cigorraga <msx at archlinux.us> wrote:
> On Wed, Jun 26, 2013 at 2:22 PM, Leonardo Dagnino <leodag.sch at gmail.com>wrote:
>
>> 2013/6/25 Oon-Ee Ng <ngoonee.talk at gmail.com>
>>
>> > I have an ASUS N56V where the Fn-F{5,6} keys do not work natively (no
>> > output in xev when pressed). This is very easily worked-around using
>> > acpi_os="!Windows 2012".
>> >
>> > The resulting control is something along the 3-10 range (10 being
>> > brightest and 0 being off, these are not the actual numerical values),
>> > which means I can't dim my backlight beyond a certain value.
>> > Similarly, using xbacklight and setting to 0 actually gives a "3"
>> > backlight, not totally blank. Setting
>> > /sys/class/backlight/intel_backlight/brightness to 0 does turn the
>> > screen off though.
>> >
>> > The problem is that if I write a simple script to adjust brightness
>> > and bind that using xbindkeys, the native handler still works for a
>> > fraction of a second before the value I calculate takes effect. This
>> > results in a brief flicker everytime I press the keys.
>> >
>> > Conclusion - I want to disable this native handling of Fn-F{5,6}, is
>> > this possible or is this not software-controlled?
>> >
>>
>>
> Before giving up the native handling please try adding the kernel flag
> "acpi_backlight=vendor".

Hi Martin, I tried that before in conjunction with the requisite
acpi_osi="!Windows 2012" (for my laptop). If just acpi_osi is set, at
least I can recognize the keys and get the slightly buggy behaviour
I'm mentioning. With acpi_backlight=vendor the keys don't respond at
all.