https://bugzilla.kernel.org/show_bug.cgi?id=43441
--- Comment #4 from Adrian Knoth adi@drcomp.erfurt.thur.de --- I can report similar (same?) garbage with the following device:
01:05.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RS482M [Mobility Radeon Xpress 200]
Kernel version is 3.11.
While UMS always used to work, KMS is causing trouble.
Note that garbage goes away when I plug in the A/C power supply, in other words, it only happens when running on battery.
I've added two videos showing the corruption:
http://adi.loris.tv/radeon-kms1.mp4
http://adi.loris.tv/radeon-kms2.mp4
I guess it's PM related, since radeon with KMS sometimes fails to properly resume/suspend, but I haven't noticed a reproducible pattern. As a rough estimate, first suspend/resume cycle works, second almost always fails. If not, then the 3rd will.