Created attachment 136677 [details]
xorg log with the pageflip failures

RX 480, radv master and amdvlk, xf86-video-amdgpu master

This happens only with vkmark and only with kwin compositing enabled. With
compton compositing it does not happen.

When starting vkmark, X starts spamming these messages to the Xorg log:

[   128.815] (WW) AMDGPU(0): flip queue failed: Cannot allocate memory
[   128.815] (WW) AMDGPU(0): Page flip failed: Cannot allocate memory
[   128.815] (EE) AMDGPU(0): present flip failed

and there are some synchronization artifacts on the screen. As soon as vkmark
quits, everything is back to normal.

When switching vkmark's present mode to immediate or fifo with vkmark -p
immediate, this does not happen, only with the default (mailbox).

Filed for DRM since it happens with amdvlk too.