Created attachment 143701 [details]
Logs with drm.debug=4. Looks like some DC validation failure.

It seems when I power cycle the monitor, I get some "failed DC validation"
errors. As for link training failure... yeah, just looked at the log and it did
mention something like that.

I just upgraded my Linux systems to 5.0 kernel, and the problem persists there.
The log is also done with 5.0 kernel on one of the systems.

The problem seems to be amdgpu/DC related as my Linux systems have AMD cards of
different generations and are all affected by the issue (and 100%
reproducible).