pulseaudio agent not running when attempting qvm-device mic attach

[Dave C]

I'm running 4.2 and attempting to attach microphone to a debian appvm.

```

$ qvm-device mic attach untrusted dom0:mic

Failed to attach audio input from dom0 to untrusted: pulseaudio agent not running

```

I've searched for similar errors and found numerous threads.  I have to admit I'm having trouble following them.  Some point out that either pipewire should be running or pulseaudio, but not both.  I'm scratching my head about which should be running, and in which VMs.  I haven't found any big-picture documentation telling me how it is supposed to work. (I don't think https://www.qubes-os.org/doc/audio-virtualization/ is up-to-date for 4.2)

Can anyone help with either the big picture?  Or the specific error?  Is the pulseaudio agent a systemctl service, and is the error saying it is missing from the appvm or dom0?

Thanks for any help.