No sound through hdmi/GPU passthrough

I'm new at this and went with UNRAID after trying to setup passthrough with proxmox and failed.

I've setup GPU passthrough to a windows 10 vm for gaming in my living room/tv and its working great! My only problem is that 90% of the times I boot the vm the sound device is either missing or sometimes not working. Using the device manager trying to reinstall the driver allways fails with an error. I have tried both with the default windows driver and the nvidia hd audio driver and it doesn't seem to mather as it has worked with both a few times but as soon as I shutdown the vm and start it again the sound is gone. Trying to install a driver (if there is any?) from the virtio didn't work either as it says "The device already have the best driver installed" or something alike.

The Nvidia virtual audio device (wave extensible)(WDM) is always present and the High Definition Audio Device is the one that sometimes don't work or is missing.

Sometimes it helped to edit the vm settings and switch from nvidia to vnc / no audio or the Realtek and then back to nvidia and boot the vm.

If I change the soundcard to the Realtek on the motherboard it always works.

I'm using i5 6400 skylake CPU and GTX 750 Ti GPU with seaBios settings.

I guess it has something to do with the passthrough but I would appreciate some help as I can't solve it my self

Thanks!

Try with OVMF and the issue may be removed.

Some cards prefer this, and OVMF/UEFI allows for device initialization after POST where SeaBios does not.

This will unfortunately involve reinstalling Windows.

Also, you may want to make sure that the MSI fix has been applied. Search the forum for this, all my Nvidia cards require this (this is not directly your issue, but it can lead to "demonic" audio if not set correctly).

I'll try OVMF together with the Msi fix tomorrow, thanks.

Try with OVMF and the issue may be removed.

Some cards prefer this, and OVMF/UEFI allows for device initialization after POST where SeaBios does not.

This will unfortunately involve reinstalling Windows.

 

Also, you may want to make sure that the MSI fix has been applied. Search the forum for this, all my Nvidia cards require this (this is not directly your issue, but it can lead to "demonic" audio if not set correctly).

Sadly though OVMF didn't solve it for me. With SeaBios i had no playback devices present and sometimes after either server reboot or just vm reboot the sound worked again, but with OVMF I had 3 Nvidia HD output but they all said not connected/unplugged. Tried both windows default driver and nvidia's.

Made the Msi tweak to the GPU and rebooted, no change. And as a last thing I did the Msi fix on the Nvidia sound device too and then windows wouldn't boot. It just loops the "memory test ok" thingie. It doesn't mather since I havn't put any data on the vm yet.

Any other tweak that could solve it? I want to put in another small gpu and run kodi/xmbc displayed on another hdmi port on the tv so I really want this to work.

If i would just run one vm to the tv i could have used the motherboard sound to the gaming vm but that would leave the xmbc with no sound.

Could this be something with the specifik gpu model I have and another nvidia model could work? Or is it more of a cpu/iommu group problem?

Please tell me if there is any dump/info that would help troubleshoot this.

I found a solution that seems to be working!! I remade the vm again.. and used SeaBios (might work with OVMF too) and Q35-2.3 instead of i440fx.

And now I understand what you mean with demonic sound. I had to enable the Msi fix on both gpu and gpu-soundcard to get rid of the choppy sound.

Now I have rebooted windows a few times and the sound is there every time. Even with having the server wake from S3 sleep and wol for both server and vm works great.

Hope this can help someone else in the future.

For anyone having problem finding the "Msi fix" here it is: http://lime-technology.com/wiki/index.php/UnRAID_6/VM_Guest_Support#Enable_MSI_for_Interrupts_to_Fix_HDMI_Audio_Support

Glad you figured it out!

The only other thing that can help is passing the rom of the card to the VM.

This can solve a variety of issues for difficult cards.

As for the MSI fix, there is also a utility that makes this 100 times easier in Windows, linked here in my post https://lime-technology.com/forum/index.php?topic=46264.msg442915#msg442915

I have noticed that updates to the Nvidia Windows driver will revert the MSI setting, so this utility makes it stupid easy to fix that, just make sure to run as administrator.

Thanks, I'll save that file for later use.

Rom?(what is the gpu rom?) That option isn't visable from the menu when creating the vm right?

Thanks, I'll save that file for later use.

Rom?(what is the gpu rom?) That option isn't visable from the menu when creating the vm right?

Has to be done in the Edit XML option, instructions here http://lime-technology.com/wiki/index.php/UnRAID_6/VM_Management#Edit_XML_for_VM_to_supply_GPU_ROM_manually

More info and how to extract it yourself in this thread https://lime-technology.com/forum/index.php?topic=43644.0.

Thanks, I'll save that file for later use.

Rom?(what is the gpu rom?) That option isn't visable from the menu when creating the vm right?

You could try to use the rom source from the unraid wiki (Techpowerup), but I have not had any success with them, so the best thing is to extract it yourself by following this guide.