Problems passing GPU through to Linux

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Hi Folks,


New to the unraid world, I'm trying to set up a box with a windows gaming VM and a linux dev VM. Threadripper 3970, Gigabyte Aorus TRX40 extreme motherboard. GTX1080 as the gaming GPU, AMD RX550 for the linux VM. I've been fighting with Hyper-V, then Xen for the last couple of weeks before stumbling across Unraid and it's so close to working but not quite!


So the windows VM is good, the 1080 gets passed through and performance seems fine.


With the Linux VM though, it fails early on in the install (tried Ubuntu 18.04 and 19.10 so far) . I get the GRUB boot menu, but as soon as I select an option and it tries to switch to a better resolution the screen either goes back or gets weird dots and lines painted at random places. The behavior is the same whether I pass through the AMD card, or stop the windows VM and pass through the nvida GPU. It works fine if I use a VNC display. I tried passing a video ROM that I found online but that didn't make any difference. I'm using the UEFI virtual BIOS, I wanted to try using legacy mode but there doesn't seem to be an option to switch in the VM config. I've googled endlessly and am running out of ideas, so any help would be appreciated; I am more than happy to pay for Unraid if I can make this work!


All the best,



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Try installing Ubuntu via VNC first and once done then change the VM template to pass through the GPU.


Also it's well known that recent generations of AMD GPUs suffer from reset issues (including the RX500 series) so you might not even be able to pass through an AMD GPU just because of that.

Even if passed through successfully, you may not be able to restart the VM without needing to restart the whole server.



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Thanks Testdasi, I'll try that and report back.. That's annoying about the GPU, I actually bought that one just for this job after failing to get things to work on an ancient HD5570 I found in cupboard at work :). I don't think that is my only problem here though as I get the same issue with the 1080, which I can pass through to windows fine.

Annoyingly my BIOS has a setting for choosing the PCIE port for the initial display but it seems to ignore me and always pick the AMD card to show the startup screen..


Is there a recommended card? It doesn't have to be super powerful, it's just for linux desktop use (though I'd like to be able to turn on the various bits of eye candy, much about with Wayland etc..)

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Hello again,


Thanks for your reply. I managed to install Ubuntu via VNC fine, but as soon as I enable passthrough I get the same problem - I get the TianoCore logo, then a bit of boot text from ubuntu but as soon as it switches to a graphical mode the screen goes black. I'm sticking to trying to pass the 1080 through as that works with a windows VM. I tried installing the official nvidia drivers (I just ran apt-get install nvidia-340, not sure if there's anything else i need to do?) but no cigar. It's annoying because I feel it's so close to working!


I'm attaching my diagnostics incase any kind soul fancies taking a look.

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Thanks jpowell, i'll give that a go. After some faffing around in recovery mode I finally got ubuntu to work, hurrah (at least with the 1080 passed through)!! The trick was installing the right nvidia driver installed properly with 'ubuntu-drivers autoinstall'..


Now if I can just figure out how to get the AMD card working I'll be good to go :)

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7 hours ago, Philip Scott said:

Holy cow... it works!! Stopping unraid from using my AMD GPU with video=efifb:off was the key to success..


Behold the glory! Now I just need to figure out the best way to share a keyboard/mouse



Very cool! 


If you need a keyboard and mouse for each you will need two of each, and either pass through usb controllers to each VM, or just the usb devices. Best way to go would be passing through a usb controller to each VM, as that gives you the ability to hot swap USB devices.

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