With amdgpu.dc=1, when I turn off the monitor or the monitor enters power-save
state, the screen resolution changes to 1368x768, which messes up the desktop
elements arrangement. Opening the settings, it is the highest offered
resolution, and the original resolution can only be restored by killing X or
rebooting.

This effectively means that I have to keep my monitor running till logout.

It happens on three different systems, all using amdgpu (RX480, RX580, RX460).

Does not happen with amdgpu.dc=0.