https://bugs.freedesktop.org/show_bug.cgi?id=66963
--- Comment #8 from John electrobs@gmail.com --- Same issue, with 3.11 RC2 and radeon.dpm=1 on a Lenovo T500 with a AMD 3650. Though my screen goes black and then gradually goes white when enabled. Without the option pc boots normally.
Graphics: Switchable (disabled) between AMD 3650 and Intel 4500 Linux: 3.11 rc2 OS: Kubuntu 13.04 KDE: 4.11 beta 2 xorg: xorg-edgers ppa enabled