(In reply to tempel.julian from comment #8)
> Unfortunately, Linux 5.0.3 with
> 
> drm: Block fb changes for async plane updates
> commit 25dc194b34dd5919dd07b8873ee338182e15df9d
> 
> hasn't changed the situation, as far as I can tell. :(

That's the DRM level bugfix for use after free on async updates for plane
framebuffer swaps. It actually hurts performance rather than helps it.

There's a fix that allows framebuffer swaps again being developed right now
with some patches in dri-devel:

https://patchwork.freedesktop.org/series/57524/

You'd have to revert

"drm/amd/display: Skip fast cursor updates for fb changes"

as well though to actually allow this series to work.