>
> fwiw my X1 gen2 works fine with that snap.
>
> The hardware is quite different though and I'm on a considerably older
> bios...
>
Well, this is embarassing. I discovered that I had a quite large buffer
size:
sndiod_flags=-b 24000
in /etc/rc.conf.local. I don't recall why exactly or when I added it, I
believe it was issues with mpd and an online radio station.
Some playing around has revealed that setting a buffer size smaller than
16386 results in working audio, while greater than that doesn't.