I'm trying to connect small HDMI display 800x480, which not provide EDID information to RX480 card.
Status on HDMI port is "disconnected". I need force HDMI port "on' and force resolution.
With NVIDIA it's easy: (xorg.conf)
In monitor section just add
Option "ConnectedMonitor" "DFP-1"
Option "UseEDID" "false"
Is there similar option for AMD?