Troubleshooting Airtop3 Symptom: Audio Problem in Linux
Symptom: No front/rear sound problems under Linux OS
"Fix PCI/internal sound card not detected (dummy output) with Ubuntu kernel 5.3.0-41 and -42 in Ubuntu 19.10 / 18.04"
The solution for this "dummy output" regression is to:
1. Edit /etc/modprobe.d/alsa-base.conf as root and add options snd-hda-intel dmic_detect=0 at the end of this file. You can do this with a single command, by using (run this command only once):
echo "options snd-hda-intel dmic_detect=0" | sudo tee -a /etc/modprobe.d/alsa-base.conf
2. Edit /etc/modprobe.d/blacklist.conf as root and add blacklist snd_soc_skl at the end of the file. You can do this with a single command, by using (run this command only once):
echo "blacklist snd_soc_skl" | sudo tee -a /etc/modprobe.d/blacklist.conf
3. After making these changes, reboot your system.
In addition there was another recommendation, that solved this problem in another similar case: