Audio issue when passthrough onboard audio to VM

[Javen]

There is a very strange issue when I passthrough onboard sound card to my Win 11 VM. After some certain time(maybe hours or days),  I will lose the sound from SPDIF interface. Only restart/shutdown the VM will not recover, the solution is to reboot the phycical machine entirely. One more thing, when the sound from SPDIF interface is lost, other sound interfaces from other devices(e.g. GPU, bluetooth) are still working. E.g. If the monitor will play sound if I switch the output to HDMI.

 

 What could be the reason for the issue?

 

Here is my VM setting regarding the USB passthrough part. (My onboard sound card is detected as USB device in the 'USB devices' list)  I haven

't passthrough any PCIe devices related to sound to the VM. (I do have passthrough a GPU/2 nvme SSD/a USB card to the VM)

    <hostdev mode='subsystem' type='usb' managed='no'>
      <source>
        <vendor id='0x0db0'/>
        <product id='0x8af7'/>
        <address bus='1' device='3'/>
      </source>
      <alias name='hostdev5'/>
      <address type='usb' bus='0' port='1'/>
    </hostdev>
    <hostdev mode='subsystem' type='usb' managed='no'>
      <source>
        <vendor id='0x1b1c'/>
        <product id='0x0c07'/>
        <address bus='1' device='8'/>
      </source>
      <alias name='hostdev6'/>
      <address type='usb' bus='0' port='2'/>
    </hostdev>

 

My hardware:

Mainboard: MSI MPG Z590 GAMING FORCE (MS-7D06)

CPU: Intel i7 11700k oc

RAM: 4*8G oc DDR4 3600

[ghost82]

7 hours ago, Javen said:

Here is my VM setting regarding the USB passthrough part.

That's new for me that an onboard audio is attached to usb..

I can see two possible issues here:

1. the cause could be the emulated usb controllers you are attaching the audio devices to: by passing vendor/product ids you are attaching that devices to an emulated controller, defined in the xml (UHCI/EHCI probably). These emulated controllers sometimes don't play well with some hardware.

If you can, you should passthrough the whole usb controller as a pci device (the controller to which your audio is attached) and remove the vendor/product ids.

2. crappy audio drivers: check if you have installed the latest realtek alc4080 drivers.

Edited October 23, 2022 by ghost82