Struggling with GPU Passthrough - stuck at Tianocore


J89eu

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33 minutes ago, J89eu said:

I use UEFI for booting, I was having some issues with legacy so switch to UEFI and haven't looked back. Can't do much for a few hours as I'm not at home!

I posted this on another topic also about being stuck at Tiano core. With cards that don't like being passed through, the following seem to help:

  • Boot Unraid in legacy mode - I purposely disabled UEFI when building my USB stick to ensure if it boots, it 100% boots in legacy mode.
  • Set primary GPU as something other than the to-be-passed-through card in the motherboard BIOS
  • Use Q35 machine type (I recommend starting a new template from scratch AND use Unraid 6.8, save you the trouble of needing the root port patch)
  • Dump your own vbios and use it
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32 minutes ago, J89eu said:

I didn't think the VBIOS was required for AMD GPU's? I only have the Vega in the system, no onboard graphics either since the Ryzen's don't have it on most CPUs

vbios is never a "required" thing. It's a "fix" thing i.e. if you have problems passing through a GPU (regardless of brand), that is a fix that you can attempt. It is particularly relevant to passing through a primary GPU.

 

In fact, my general recommendation is, where possible, dump your own vbios regardless. It can only help with stability.

Edited by testdasi
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OK, my issue then is that I don't have another GPU to use... I'll look into borrowing one for now. 

 

Still not home yet to look at why the server has gone down but hopefully I can get that working and with the properly stubbed soundcard I will hopefully get some sound!

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43 minutes ago, J89eu said:

OK, my issue then is that I don't have another GPU to use... I'll look into borrowing one for now. 

 

Still not home yet to look at why the server has gone down but hopefully I can get that working and with the properly stubbed soundcard I will hopefully get some sound!

It's just one of the potential fixes you can try. Personally, I have found vbios is less useful without booting Unraid in Legacy mode. There's something about UEFI that prevents a GPU from resetting properly.

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5 hours ago, testdasi said:

It's just one of the potential fixes you can try. Personally, I have found vbios is less useful without booting Unraid in Legacy mode. There's something about UEFI that prevents a GPU from resetting properly.

I'm also using Legacy Mode, because with the UEFI it never worked properly. Also the vbios is required for me to actually show the image before fully loading the OS...

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Not had chance to do this yet but hopefully tonight, I started to mess around with another VM as a test to rule out any OS issues from the previous hardware but it locked up and I had to fat finger the server which then resulted in my cache pool sh*tting the bed so I've been rebuilding that today!

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OK now booting up in legacy mode.

Cannot attach a second GPU to my system without removing the RAID card so I ran through the steps from Spaceinvaderone's video and managed to dump the VBIOS but when I use that file I just get a black screen or nothing at all on the VM, using one I grabbed from Techpowerup ages ago and have been using until I dumped the VBIOS for this test works fine but still no sound passing through from either the GPU or the dedicated... I then moved the dedicated sound card to another PCIe port and still the same, I cannot seem to get any sound at all to work..

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OK I though I'd wrap this up as I'm now all working. Essentially I ended up having to create a whole new VM. It had the same settings yet the XML was totally different. This then got my soundcard working, for other parts I needed to switch to Q35 and also enable both on the ACS Override. 

 

Thanks everyone for your help

Edited by J89eu
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  • 1 year later...
17 hours ago, oh-tomo said:

I can stub a toe.  Or a cigarette.  But stub a card?

Means attaching a device to a dummy driver.

You "stub" a device with boot args in your syslinux:

pci-stub.ids=aaaa:xxxx

where aaaa:xxxx are vendor/product ids.

Similar to:

vfio-pci.ids=aaaa:xxxx

 

For difference between the two have a read here:

https://unix.stackexchange.com/questions/328422/pci-stub-vs-vfio-pci

 

In my opinion, better vfio-pci.ids

Edited by ghost82
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