With 78e35df52aa2f7d770f929a0866a0faa89c261a9 I see hangs on  [AMD/ATI] Baffin
[Radeon RX 560D  / Pro 450/455/460/555/560] (rev e5). 

Specifically, when I run "Outlast" through a virgl/vtest setup with this
hardware on the host, the whole X-session hangs after the very first loading
screen. I can still log into the machine but even a reboot hangs and a reboot
can only be forced by ctrl-alt-sysrq-B (or turning the laptop on and off). 


I'll try to get a host trace to add a bit more info here.