I've got a Windows 10 PC with an RX 480 8GB (running 17.1.1 drivers) connected via HDMI to my primary monitor and via HDMI to a Yamaha AVR/Hisense TV in an adjacent room. Until a few months ago, I used to be able to use either display independently (i.e. I could turn off either TV/monitor and just use one of them). Now the TV screen won't maintain a display unless the primary monitor is also on. I've got it set to duplicate the screens and haven't changed any settings, so I think a driver update may have stopped this working.
Does anyone have suggestions for fixing this? Seems a shame to be wasting electricity running two monitors!