When I run xrandr when the screen is off I can see the HDMI port "connected" with all the screen resolutions options fine.
However, when I turn the screen on, I just get a blank screen and when i run xrandr again the HDMI port shows as "disconnected" and I can't see any resolution or what so ever.
My video card is AMD 480 and trying to run Ubuntu 20.04 but have been having this issue with older versions of Ubuntu, actually its one of the main reasons I didnt switch to Ubuntu yet.
Note that my screen is working fine on Windows 10.
Edited:
LG Model as Requested: LG DM2780A
