https://bugs.freedesktop.org/show_bug.cgi?id=91880
--- Comment #163 from Thomas DEBESSE dev@illwieckz.net ---
It seems tied to a small subset of 390s.
Many precise models were listed. It's easy to get one of them. For example this one is known to be buggy: https://www.amazon.com/dp/B00ZGF158A/
It's weird if AMD developers can't put their hand on AMD hardware.