https://bugs.freedesktop.org/show_bug.cgi?id=106175
--- Comment #48 from tempel.julian@gmail.com --- With amdgpu.dc=0, TearFree works as expected for me (no tearing without compositor, scrolling in Firefox windowed is free of stutter, no issues with compositor vsync either).
I think we should leave TearFree out of this as it's entirely unrelated, apart from the fact that it forces pageflipping.
Regarding the original issue with amdgpu.dc=1: Still totally unchanged for me with latest stable versions and also 4.21-wip, llvm-svn, mesa-git, libdrm-git, xorg-server 1.20.3 and modesetting / xf86-video-amdgpu-git on Arch.
I'm getting an Asus Vega 56 Strix card tomorrow, which I will try instead of my current MSI Aero RX 560 card. But since there were already reports for Vega, I'm not hopeful.