[Intel-gfx] v3.14-rc7: Backlight control broken on Dell XPS13

[Romain Francoise]

Jani Nikula <jani.nikula at intel.com> writes:

> Here's two patches to try, separately, *without* the quirk: [...]

Okay, I've tried both and neither works. However, I've noticed that
while the backlight level never changes even though I'm changing it with
Fn+F4/Fn+F5, it *does* get registered somewhere because if I bring it
all the day down and reboot, the brightness is reduced in the next BIOS
POST (loading i915 gets it back to 100%).

Thanks,
-r