Comment 21 for bug 1297464

No need to run any bisecting. You can see where the change was with cgit ( https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=919cf555c04e16dafb1fba56904eb23889a812c3 ). Technically, it's not fixed upstream. They just applied the aforementioned workaround of disabling DPM for Northern Islands until they figure out how to fix it. Another bug report on bugzilla related to the bug can be found here: https://bugzilla.kernel.org/show_bug.cgi?id=68571 which shows how even with kernel 3.14, manually enabling DPM, since it is disabled by default now, with radeon.dpm=1 still causes the problems. In kernel 3.12 and prior, DPM was disabled by default since it was buggy, but for some reason it was enabled by default with 3.13, leading to these problems.