Since
commit ee1452d7
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Fri Sep 20 15:05:30 2013 +0300

    drm/i915: assume all GM45 Acer laptops use inverted backlight PWM

failed and was later reverted in
commit be505f64
Author: Alexander van Heukelum <heukelum@fastmail.fm>
Date:   Sat Dec 28 21:00:39 2013 +0100

    Revert "drm/i915: assume all GM45 Acer laptops use inverted backlight PWM"

fix the individual broken machine instead.

Note to backporters:

http://patchwork.freedesktop.org/patch/17837/

is the patch you want for 3.13 and older.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=54171
Reference: http://mid.gmane.org/DUB115-W7628C7C710EA51AA110CD4A5000@phx.gbl
CC: stable@vger.kernel.org
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Patch mangling for 3.14 plus adding the link to the original
for 3.13.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>