Created attachment 141725 [details]
log for dce_mi_free_dmif line:636

If my machine with a Vega 64 idles for long enough for the GPU to be "put to sleep" to save power, it won't wake up. If given inputs, The monitors get wake up, but only show black, indicating that something is happening.

Looking at kernel logs, this always starts with:
[drm:generic_reg_wait [amdgpu]] *ERROR* REG_WAIT timeout 10us * 3500 tries - dce_mi_free_dmif line:636
(full log attached separately)

While trying to "wake up" and/or if I try to switch to a different TTY, another error pops up for every attempt, but the opening line is now:
[drm:generic_reg_wait [amdgpu]] *ERROR* REG_WAIT timeout 10us * 6000 tries - dce_mi_allocate_dmif line:599
(full log also attached separately)

I experience this problem with every kernel version I tried from 4.16.x to and including 4.18.7
Haven't tried earlier versions and not sure which kernel to try to build in order to test the *latest* amdgpu code. Could test the latest amdgpu code if I could get pointed to it.

As a workaround, I have a tiny video on mpv running on infinite loop in the background using an opengl output, to prevent the GPU from trying to sleep.