Volume control works both ways. 861 display says PCM 44k 2 chan. I don’t have the problem, as others reported, of it vanishing. I can see it, I can change the volume, I just get no sound. I do get sound from other inputs (e.g. from roon via a hifiberry plugged into D4).
Roon is on Ubuntu 18.04, with an AMD 3400G, 32GB of RAM and an SSD (i.e. massive overkill).
ID40 is 1.3, b169.