Audio distortion in Windows KVM machine

Operating Systems & Open Source Linux
1

I’m trying to run Windows Server 2012 R2 in a Proxmox/KVM virtual machine, but am experiencing a lot of audio distortion. I know Windows Server is an odd choice for a gaming machine, but it was convenient and I’ve had a lot of problems with “Code 43” errors with the NVidia drivers in Windows 10 guests, The Nvidia drivers just seem to work without any hacks in Windows Server.

But back to the problem at hand. Most audio devices, whether using PCIe or USB passthrough, seem to cause audio distortion to lesser or greater degrees. Games themselves seem to run fine, but audio will occasionally skip or distort. Music can be listened too, but you’ve got to expect major hiccups every 10 minutes or so.

Currently I’m using HDMI audio from my GTX 1050 Ti in the Windows guest. I’ve also enabled Message Signaled Interrupts on the HDMI audio device, which helped, but still doesn’t completely eliminate the distortion.

Host specs:
Dell Precision T5500
Xeon X5670
24GB DDR3-1066 ECC RAM
Geforce Quadro FX 3800 1GB (host)
Gigabyte GTX 1050 Ti 4GB (guest)
Samsung EVO 950 512GB SSD

Anyone here have any hints on how to fix this persistent audio distortion?

2

What have you done to diagnose the problem so far?

You are going to want to check some of the basic settings.
Try this guide. http://www.thewindowsclub.com/sound-distortion-issue-windows-10

Also have you updated all your audio drivers in the windows VM?

Hope this helps.

3

So far I’ve tried a few things that have helped but not eliminated the problem. Enabling disk image caching in Proxmox helped, as did an option called “I/O thread” which I assume dedicates a whole thread to I/O. I also put the VM on an SSD to help eliminate I/O bottlenecks. On the guest side, I’m using the most recent Nvidia driver package, which I assume contains the most recent audio driver. I’ve also enabled something called Message Signaling Interrupts, which is supposed to reduce CPU usage by the audio device.

Because I’ve had audio problems with Windows Server even when it’s running on bare metal, I’m going to try installing Windows 10 and hope that I don’t get a Code 43 error in Device Manager.

4

Unfortunately, Windows 10 will exhibit the Code 43 issue. It’s a consumer OS, so Nvidia will not like you running that kind of virtualization.

If it’s happening in bare metal, you should do a DPC latency check. Sometimes conflicting PCI peripherals (especially wireless cards) can cause DPC latency spikes causing this audio distortion.

5

I thought some form members had with a lot of difulty fond a workaround for code 43 issues Nividia gpu generate in a guest VMware,or did I misunderstand something.

6

Actually I’ve got it working just fine with ESXi. There’s a specific parameter you have to put in the VM config file to fool the Nvidia driver. I wanted to migrate to Linux so I could use it as a daily driver. I’m having to use Linux more often at work, and wanted to get more familiar with it.

My situation with audio isn’t ideal, but I can make it work since I can still use the host OS (Debian/Proxmox) for A/V playback. The only catch is that the Nvidia driver won’t compile with the headers provided by Proxmox, so I’m stuck with Nouveau.