https://bugzilla.kernel.org/show_bug.cgi?id=91371
--- Comment #5 from Adis Hamzić adis@hamzadis.com ---
I just tested the kernels 3.14.27 and 3.16.7.3 and they both display the issue.
Now, I had used the 3.14.27 kernel for at least 10 days and I never noticed this issue. In that time I was doing some kernel debugging which involved a great number of cold and hard reboots so I think I would have noticed the issue if it had been there. I'll test some older kernels soon.
What I found out during my testing was: * Setting radeon.dpm=0 fixes the issue. * Doing a hard reboot / poweroff has a very high chance of triggering the problem, in fact I managed to reproduce it 10 consecutive times. * Doing a soft reboot has very little chance of triggering the problem. With this I managed to have 10 consecutive successful boots.