[vfio-users] PCIe Sound Card VFIO Pass through Sounds Terrible (link to audio file)

[Hristo Iliev]

Have you tried enabling MSI for the passed-through sound device as 
described on Alex' blog here:

http://vfio.blogspot.de/2014/09/vfio-interrupts-and-how-to-coax-windows.html

This usually solves the problems with choppy audio.

Cheers,
Hristo

Am 30.09.2016 13:00, schrieb Jonathan Scruggs:

> Hi all,
> 
> I have a PCIe sound card that I wish to pass through to a Windows 10 
> guest using VFIO, but it sounds terrible.
> 
> Kernel: Linux Beast 4.7.5-gentoo #5 SMP PREEMPT Thu Sep 29 11:26:39 BST 
> 2016 x86_64 Intel(R) Core(TM) i7-5930K CPU @ 3.50GHz GenuineIntel 
> GNU/Linux
> 
> Qemu version: app-emulation/qemu-2.7.0-r4::gentoo
> 
> Libvirt version: app-emulation/libvirt-2.2.0
> 
> The sound card is:
> 09:00.0 Audio device: Creative Labs Sound Core3D [Sound Blaster Recon3D 
> / Z-Series] (rev 01)
> 
> The relevant part of the XML file is:
> 
> <hostdev mode='subsystem' type='pci' managed='yes'>
> <driver name='vfio'/>
> <source>
> <address domain='0x0000' bus='0x09' slot='0x00' function='0x0'/>
> </source>
> <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' 
> function='0x0'/>
> </hostdev>
> 
> The Audio I'm trying to play: 
> https://www.youtube.com/watch?v=jc8Mm5TtIhg
> 
> What it actually sounds like:
> https://drive.google.com/file/d/0B12vXeyT8c8HZ0RqMmpnWDZUdXM/view?usp=sharing
> 
> To record the Audio, I plugged the cable into a recorder instead of 
> going through speakers or line in on the host to see if it was any 
> other device, but it sounds the same on all.
> 
> I hope you can help.
> Jon