Crippling performance regressions in combination with xf86-video-amdgpu and TearFree (meson build)

Link to original bug (Arch Linux Bugtracker FS#58782)

I noticed a considerable regression in performance, causing window drags and damage repaints to lag more than a second behind.

Steps to reproduce:

open an X server as user with TearFree enabled (but no compositing window manager) on xf86-video-amdgpu
open two windows
move one window over the other

Temporary solution: xorg-server built by autotools
Tested with:
xorg-server-git 1.20.0.r227.g709c65629-1
xf86-video-amdgpu-git 18.1.0.r42.g9045fb3-1
openbox 3.6.1-4

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