[DESKTOP] Audio doesn't work with DP to mDP

[daihard]

Hi.

I have 18.04 running on a Dell box with two DisplayPort (DP) ports. I use one of them to connect to a Dell UltraSharp 2027 monitor using a DP to mDP cable.

I also have a Nintendo Switch connected to the same monitor using an HDMI to HDMI cable.

Finally, I have PC speakers connected to the monitor using its audio output jack.

Now, my problem:

The sound is played fine from Nintendo Switch, but not from Kubuntu. "Audio Volumes" under "System Settings" only shows "Built-in Audio Analog Stereo." I've read that it should also show a digital output that corresponds to DP audio, and I don't see that.

Are there any additional steps I need to take in order to get DP audio working with 18.04? I restarted pulseaudio, but to no avail.

Any help would be appreciated.

[daihard]

An update here. I've swapped the mDP-to-DP cable with a direct DP-to-DP cable, but with the same disappointing results.