Comment # 3 on bug 100289 from Michel Dänzer

(In reply to OmegaPhil from comment #2)
> confirmed 7.9 is loaded, the problem is still present.

Does radeon_scanout_flip still spit out both "Invalid argument" and "Device or
resource busy" errors?


> Hmm, so XFCE4 Display could be responsible for blacking out the other
> monitors momentarily too?

Yes, that could be a side effect of XFCE changing the virtual desktop
resolution.

All of this could be triggered by the DisplayPort connection appearing
disconnected while the monitor is off, which I understand can happen at least
with some monitors.