With kernels 3.17 and 3.18 I have freezes when playing some games, those
freezes can happen somewhere between 10 minutes and 1 hour.
Freeze occur only in games.
With kernel 3.16 everything is normal and there are no freezes.
Latest patch (auto->high and radeon.dpm=1) is used in each of those kernels.
Everything else is exactly the same, just booting with different kernel makes a
difference.