Can't get HDMI audio to work with NVIDIA gpu on Ubuntu 20.04 LTS
After digging through the internet I was able to find that the error was due to ubuntu automatically applying power control on the sound card and so I was able to get it working by editing the nvidia rules file in ubuntu bios rules directory. In that file you just need to switch the "auto" setting in the last couple lines to "on". https://forums.developer.nvidia.com/t/no-option-for-audio-over-displayport-hdmi/175889/3