Created attachment 138887 [details]
xorg.conf

Hi,

My Setup :
- AMD Ryzen 1600
- 16 Gb Memory RAM
- Host (Debian Stable, kernel 4.16.2) : AMD Rx560 4Gb
- Guest (Windows 10 / Archlinux Kernel 4.15.x-4.16.x) : AMD Rx580 - 8Gb

Years ago there was an issue on Windows virtual machine with Qemu/VFIO and AMD
GPU. It was impossible to reboot or use a 2nde time the Guest because the GPU
was not reinitialized when the Host was shutdown. The only solution to re-use
the VM was to reboot the Host OR use a Nvidia GPU.

Actually, the issue is fixed on Windows VM + AMD GPU passed through (i don't
know how), i can use more times my VM without reboot the Host. 

But if i use my Linux VM with my Rx580, the issue still exist. The first launch
works, i can use the Rx580 to play without problem. But if i shutdown/reboot
the guest, the Rx580 is "blocked". I need to hard reboot because the system
hangs after ~2-3 minutes.

Thanks for your help,
Maxime 

(Sorry for my English, i'm French)