https://bugs.freedesktop.org/show_bug.cgi?id=65963

--- Comment #14 from Maciej gutigen@outlook.com --- @Damian Nowak

Before I've seen your answer I did full, fresh system reinstallation (cause hangs started happening after few minutes). Ubuntu was running fine for few hours, so I added Oibaf PPA and kernel 3.16-RC7 - so far no hang. I'll report if it happens again and add some logs.