Created attachment 134418 [details]
dmesg containing errors (see end of file)

I was playing visual novel Tsukihime with wine. I tried to switch to windowed
mode from fullscreen and my monitor went black, and after that I couldn't
recover picture using xrandr or arandr, or xfce's monitor utility. Only restart
helped. There are errors in log attached. 

Linux 4.12.13, AMD Radeon R9 200 Series (AMD TONGA / DRM 3.15.0 /
4.12.13-1-ARCH, LLVM 5.0.0) OpenGL version: 4.5 Mesa 17.2.0