[vfio-users] Weird experience with audio

[Janusz]

Hi,
I have some weird experience with audio on VM with windows with gpu
passthrough. I was using windows 10 with emulated hda sound drivers and
pulseaudio, and because I have some problems with sound distortions
(sound is cracking), I attached Geek Out v2  to VM, but this didn't
solved any problems, and interference in sound was even bigger. So I
decided to try win8.1 and to my surprise the sound didn't have any
problems. The difference between VM with win10 and win8.1 was that I
didn't used virtio drivers - virtio-scsi-pci and virtio for network. I
even used the same uefi vars. So I started VM with win10 again and now I
didn't have any sound problems. Then, I restarted VM with win10, and
sound problems came back, and everytime I started VM with win8 and after
that VM with win10 - problem was gone for one boot. So I decided to
install win8.1 in place of win10 on my ssd and using virtio drivers. It
was working correctly few times. Usually I start my VM once, stop VM,
put host to sleep and next day start again. But, one day I started VM
second time, and then on win8.1 I got the same sound problems, and
nothing is helping since then - I didn't do any changes to VM and host.
I have one more VM with ubuntu 15.10, and I don't have any problems on
it with sound. Does anyone know why this sound distortions happens, and
why running win8 VM is fixing sound in win10 VM for one boot?

my hw:
i7 6700k
MSI Z170a m7
Sapphire R9 290

Host: Gentoo, kernel 4.4, Qemu 2.5

windows10 VM script: https://bpaste.net/show/ad50f0a14d8b
windows8 VM script: https://bpaste.net/show/340ea632be4c

Thanks