https://bugs.freedesktop.org/show_bug.cgi?id=91880
--- Comment #121 from emilio.moretti@gmail.com --- Finally working: I just upgraded to ubuntu 16.10 (kernel 4.8.0-22-generic) and I've been using the pc all day long without problems (this was impossible before). I had to use the kernel parameter radeon.dpm=0 in grub in order to get a stable desktop, and I can confirm I don't need it any more.