https://bugzilla.kernel.org/show_bug.cgi?id=199139
--- Comment #18 from Eduard (wirch.eduard@gmail.com) --- Even after updating to 4.19 release did not solve the problem.
I was able to work around it by disabling monitor power management in Xorg settings:
Section "Monitor" Identifier "Monitor0" Option "DPMS" "false" EndSection
I sill get this error:
kernel: [drm:dce110_vblank_set [amdgpu]] *ERROR* Failed to get VBLANK!
But it does not repeat every 10s any more, and also my system does not freeze. So I can finally upgrade from 4.14.