https://bugs.freedesktop.org/show_bug.cgi?id=79980
--- Comment #154 from Jacob jacobsvenningsen15@hotmail.com --- (In reply to agapito from comment #152)
IMPORTANT
This was my first message in this bug report:
I have the same problem with my HD 7950; using hangouts, playing Left for Dead 2, or watching a flash video my screen goes crazy with vertical lines or grey fog. Started when i upgraded to testing repo (Archlinux) and downloaded the newest linux-firmware package, who includes TAHITI_mc2.bin. I suffered this bug on kernels 3.14 and 3.15.
In Archlinux i was stable with kernel 3.14, and the problem started when i was using the new firmware. I thought that the new firmware was the cause of this bug, but NO, because i had the same bug using the old firmare, so this bug it was caused by one of this radeon commits backported to kernel 3.14.6 (the first kernel using newest firmware). I am 100% sure.
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/ ?id=refs/tags/v3.14.21&ofs=1300
I've just compared the git messages from your link and from http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.15-rc3-utopic/CHANGES and it seems like the commits made to drm/radeon, are the only commits these two kernel versions have in common. Only seven of them are part of 3.15-rc3, which crashed on me yesterday, so it would seem like the crashes are caused by one of those commits