I am trying to get Debian 9 working on my friend's computer. I've got everything working except for sound through the DisplayPort. I've checked pavucontrol and alsamixer, and it simply doesn't appear as an audio device at all, only the analog sound card does.
The GPU is an AMD Radeon 4200. I've been researching for ages, but I can't find any recent information on this problem.
He is using a DP to HDMI cable, if that's important.
Has anyone had a similar problem, with the HDMI/DP audio card simply missing?
Update: There are no meaningful audio settings in the BIOS, unfortunately.
