[Intel-gfx] [PATCH 3/3] xf86-video-intel: Add a helper for setting backlight without root rights

[Chris Wilson]

On Sat, Feb 15, 2014 at 12:02:37AM +0100, Hans de Goede wrote:
> Once the xserver stops running as root on kms capabable systems, we will need
> some other way to access the backlight.
> 
> The approach taken in this patch leaves most of the heavy lifting (wrt
> doing everything suid root safe) to pkexec, as is done in ie
> gnome-settings-daemon, which controls the backlight directly on ati and
> nouveau cards.
> 
> This commit adds src/backlight.h and src/backlight.c as a place to share common
> backlight code, in the future most of the duplicate backlight code inside
> src/sna/sna_display.c and src/uxa/intel_display.c should be moved there.

Right, I agree and think we can make that transition now. It should not
result in much more code than motion than introducing the helper.
Importantly, I think it will also clarify the tests we require before
declaring the backlight functional.

Is there a reason why the standalone helper is not kept alive? We could
just connect the pipe to the helper's stdin and launch it as a daemon
rather than keeping a child around who's only task is to spawn the
standalone helper everytime?

Otherwise the only other tweak I can see would be to replace the #ifdef
__linux__ with something like #ifdef USE_BACKLIGHT_HELPER
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre