AMD GPU Passthrough won't work as only card?

[xanvincent]

Hey guys. I've installed the latest unraid trial and I'm trying to get GPU pass through working. HVM and IOMMU is enabled and the GPU is in it's own group. However, when I passthrough the GPU to the windows 10 VM, Seabios is displayed followed by only a black screen with two blinking underscores.

I've tried: a "vanilla" config

Q35

Seabios and OVMF

Stubbing and not stubbing the GPU and it's HDMI audio

None of these seem to work. 

 

I get output if I use OVMF, stub the card, and specify the vbios rom for it. However, when it comes to booting the OS, it just sits at the TianoCore screen.

 

Everything works fine if I use VNC as the graphics card instead... From what I understand, AMD cards should "just work" even as the only GPU. What am I missing?

 

Config:

https://pastebin.com/gvCZZgfG

unRAID version 6.5.1-rc3 (also tried on 6.5 stable)

AMD Ryzen 1700X

MSI AMD RX580

[david279]

Every time I see threads like this the common denominator is the AMD GPU. I have a R5 1600x and have a GT 1030 passed thru and it works no problem. The AMD cards seem to be random if they even work or not. With Nvidia card i have to pass the card thru using abios file but with AMD cards you shouldn't need that.


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[thomas]

Sometimes the AMD gets "stuck" and the only way to recover is by powering down the unraid server and starting fresh. This is the case with my R9 370. This usually happens if I force close any VMs. Lately I'm passing through the GPU with the vbios file so I can use OVMF and I'm more careful with my VMs and it's working fine.

Edited April 6, 2018 by thomas

[tjb_altf4]

Have a look here and see if this solution listed in here helps (if applicable)