Hi,

I am sorry for the absence of activity on this. A couple of people very
close to me died, and I also got busy
with the linux kernel mentorship program for a while. It was a weird year.
But I am back on this now.

I have the basic functionality of the sound card working. I tested it on an
ubuntu vm and it plays audio just fine. I'd like to test
other things like changing stream parameters and channel maps. Also the
VIRTIO_SND_PCM_F_MSG_POLLING,
VIRTIO_SND_PCM_F_EVT_SHMEM_PERIODS, VIRTIO_SND_PCM_F_EVT_XRUNS features
aren't implemented yet.
Implementing VIRTIO_SND_PCM_F_EVT_SHMEM_PERIODS hopefully shouldn't be much
of a challenge. We can send a notification
when we have processed period bytes (if I correctly understand this).

I will send another rfc patch series once I have channel maps and jacks
ready. And one more when I have these PCM features
ready.