Created attachment 121745 [details]
journal output

Sometimes Xorg freezes when the screens are turned off (from idle or manually
with xset dpms off). The rest of the machine keeps working. The X server no
longer accepts input and does not turn on the screens.

Hardware: 5650M + Intel 460M (muxed)
Software:
- Linux 4.3+ (not happening on 4.2.4 and older)
- xorg-server 1.18.1
- xf86-video-ati 7.6.1
- xf86-video-intel 2.99.917+519+g8229390

I could try to bisect but reproducing for every version would be very time
consuming, since the bu does not happen every time.

I think it only happens if the screens are off for a long time (15 min+?).