Comment # 57 on bug 1028575 from Mircea Kitsune

I randomly decided to google parts of my dmesg output. I was surprised to
discover that someone else has reported a very similar issue, which looks like
it might have the same root as mine!

https://bugs.freedesktop.org/show_bug.cgi?id=101325

The dmesg output their provided almost perfectly matches my last log, and they
also have a RadeonSI card which further narrows down the problem. The main
difference is that they experience this with Unreal Engine 4 Editor, whereas
for me the trigger is the Plasma desktop.

That report seems to contain a fair amount of logs, so hopefully bringing it
and this together can help produce a solution at long last.