Force kill Xorg on shutdown

[Khumarahn]

Hello folks

I have a problem on shutdown - Xorg doesn't properly exit and I have to wait a long time before filesystems can be unmounted. I use multiseat, and roots of the problem are likely to be in the ati-drivers.

The issue has a history already, I have submitted a bug 370053 with details some time ago. The issue didn't bother me for some time, but with new updates it is back.

My question here is: is there any way to force-kill that Xorg process before unmounting filesystems?