not sure about this MSI motherboard, but i recall that B450 motherboards had issues
and i do not think a solution found on old forum
search on bugzilla found this open bug report
Bug 195303 - AMD HD-audio controller: Sound capture is crackled / distorted
it appears that problems with this audio codec have not been resolved yet
I downgraded to kernel 4.19 and sound is working
if audio is working ok, suggest getting ALSA data with alsa-info.sh which could then be compared data from a non-working ALSA
but the ALSA data posted for kernel v5.4 is not showing any problems that i can see
suggest check for any error messages
sudo dmesg | grep snd
and
pacmd dump
to check pulseaudio
pulseaudio -k may appear to restart pulseaudio ok, but it will break some pulseaudio functions
- the systemd pulseaudio.service may fail
- some of the pulseaudio modules will not get re-loaded correctly
- GUI controls in KDE may not work (because pulseaudio does not have module-device-manger loaded)
- network audio device may not work (because two X11 modules are not loaded)
- audio devices may get muted or suspended
suggest use this command to check if pulseaudio is ok
systemctl --user --full --no-pager status pulseaudio.{socket,service}
and this to restart pulseaudio
systemctl --user restart pulseaudio