[Intel-gfx] What to do with xf86-video-intel backlight control when running Xorg as non root

[Hans de Goede]

Hi All,

Currently xf86-video-intel is unique in that it is the only video driver
which does backlight control inside the driver rather then letting
something else (ie the desktop environment) deal with it.

This is a problem when running the xserver without root rights because
writing /sys/class/backlight/foo/brightness requires root rights.

There are 2 possible (short term) solutions for this:

1) Detect that the xserver is not running as root, and don't register the
backlight property on the connectors, let something else deal with it,
as is done or other xf86-video-* drivers already.

2) Add a little xf86-video-intel-brightness helper on Linux which the driver
execs (through pkexec) each time it needs to set the brightness.


1) of course is very KISS, so I like. 2) is not that hard either, and
1) might cause some regressions in cases where ie gsd-brightness-helper
does not do the right thing, where as the intel driver does. OTOH it seems
that the intel video code is mostly there to deal with older kernels, and
rootless xorg will be used with newer kernels only anyways.

So before I start writing a patch for this I would like to hear which
approach would be acceptable for inclusion into xf86-video-intel.

Regards,

Hans