Pulseaudio not starting and no audio devices.

@DCleri said:
If you followed the instruction from our wiki and installed the UP Kernel from our PPA, then make sure you also do the following steps to fix the broken audio setup on Ubuntu and Cherry Trail SoC included in our UP Board:

https://wiki.up-community.org/Ubuntu#Fixing_HDMI_Audio_not_working_on_UP_Board_and_UP_Core_on_Ubuntu_18.04

The wiki page you have referenced is misleading. Not all UP boards have their audio sinks at:

load-module module-alsa-sink device=hw:0,2

I am using a UPXtreme Edge, and after following the suggestions here:
https://forum.up-community.org/discussion/2453/ubuntu-17-10-working-hdmi-sound

and therefore indirectly here:
https://linuxiumcomau.blogspot.com/2017/10/fixing-broken-hdmi-audio.html

It seems my UP board had its sink at:

load-module module-alsa-sink device=hw:0,3

The wiki-page does get it right in that /etc/pulse/default.pa needed modification, explicitly when loading the module-alsa-sink device.