https://bugs.freedesktop.org/show_bug.cgi?id=65377
--- Comment #6 from Bastian Triller bastian.triller@gmail.com --- Booting a dd'ed image did not work. I'll have to find a disc to test it.
Looking into the xbacklight I saw that xbacklight tries to find a Backlught property on the output. xrandr lists this property on the intel output, but not on the radeon output.