Comment # 55 on bug 105760 from Thomas Martitz

Created attachment 140845 [details]
dmesg + Karols hack

No, unfortunately, the GPU is unusable after resume, but the dmesg output is
different now.

FWIW, in this case I have booted with pcie_port_pm=off which I feel improves
things on my system (but it's nowhere a solution), since I think the GPU is
behind a PCIe bridge to which the TB3 port is also connected, and I found in
the source that bridge pm should be disabled if there are TB3 ports behind due
to hotplug.

Without pcie_port_pm the behavior is almost the same, except that dmesg shows
lots of powerplay error messages that don't occur in the attached output
(again, made with pcie_port_pm=off).

Karol's patch didn't apply cleanly onto drm-next-4.19-wip, so I made some
changes, perhaps you may check if it's still equivalent (will attach with the
next comment.