kernel-bug-exists-upstream-3.18-rc3 -- the aforementioned /usr/share/X11/xorg.conf.d/80-backlight.conf
with the contents:
Section "Device"
Identifier "Intel Graphics"
Driver "intel"
Option "AccelMethod" "sna"
Option "Backlight" "intel_backlight" # use your backlight that works here
BusID "PCI:0:2:0"
EndSection
kernel- bug-exists- upstream- 3.18-rc3 -- the aforementioned /usr/share/ X11/xorg. conf.d/ 80-backlight. conf
with the contents:
Section "Device"
Identifier "Intel Graphics"
Driver "intel"
Option "AccelMethod" "sna"
Option "Backlight" "intel_backlight" # use your backlight that works here
BusID "PCI:0:2:0"
EndSection
continues to work to workaround it.