https://bugs.freedesktop.org/show_bug.cgi?id=107978
--- Comment #28 from Shmerl shtetldik@gmail.com --- Not sure if it's related, but with 4.20.0-rc6 the regression when monitor goes to sleep before reaching sddm is back. It's erratic, i.e. doesn't happen on every boot. And I do see this REG_WAIT in dmesg when it does.
Turning monitor off and on, then going to tty and restarting sddm works around it.
Similar bug was fixed in the previous kernels, so I wonder if the fix for this one somehow brought that issue back.
GPU: Sapphire Pulse Vega 56.