GPU passthrough only working in slot 2?


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I have a Geforce GTX 950 in a Lenovo TS140 running unRAID 6.2

 

It has a PCIEx16 (slot 1) and a PICEx8 (slot 2)

 

Now I know each should run just as fast but slot 1 would be better as it would lead to better air flow. The fans are very close to the bottom of the case in slot 2. However in slot 1 the card doesn't show up in unRAID. It is not listed in the list of System Devices. Move it to slot 2 it appears and I can select it for passthrough to a VM.

 

Any ideas why? My processor is a Xeon E3-1225 v3, it has on-board graphics and that s selected as the default graphics adapter in the BIOS I can confirm that when I boot the output is through on-board graphics and not the Geforce.

 

 

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The best way to troubleshoot this would be, when in slot 1 do you see the device in your BIOS?

UnRAID should list what it sees, if it is not listed it is not UnRAID but something else going on.

Unfortunately not all BIOS's do a good job of showing devices that are initialized but some do (ASRock for instance has a display that shows what slots are used, and by what). I'd start there, however it also sounds like something is wrong with the device or MB as you've eluded to issues now in slot 2.

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FYI slot 2 for the computer you specified "Lenovo TS140" is only a 4X PCIe Gen 2 slot, from the manufacturer page.

1 x PCIe GEN3: HH/FL x16 mechanical, x16 electrical

1 x PCIe GEN2: HH/HL x1 mechanical, x1 electrical

1 x PCIe GEN2: HH/HL x16 mechanical, x4 electrical

1 x PCI 32-bit/33 MHz: FH/HL

http://shop.lenovo.com/us/en/systems/servers/towers/thinkserver/ts140/#tab-tech_specs

 

So you may want to investigate further or you may have some bottlenecking related to this.

 

Edit: Also in case you care (keep in mind this can be dependent on manufacturer GPU BIOS implementation) I recently upgraded to a GTX950, using it in OVMF, and it performs correctly. I'm certain many others use this card also, so you should be able to get OVMF to work as expected.

On my previous card (R260X) I would see an "invalid rom contents" in the VM log file that would lead to instability in OVMF. Passing the rom to the card with the "romfile=" in the XML to the VM solved this issue, and the message and related instability (mainly) disappeared.

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So I tried setting the primary GPU in the bIOS to PCI and now unRAID recognises the card in slot 1.

 

However starting the VMs leads to unRAID hanging. I had originally set the primary graphics to IGP as I had read I needed to do that.

 

Try dumping the gpu bios and passing through the bios to the card? But dont use a downloaded vbios from the internet download your own.

 

Read through this thread here http://lime-technology.com/forum/index.php?topic=43644.msg482110#msg482110

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Okay many thanks for that. Tried it and the crashing has stopped!

 

However I am still not getting output on the card. Within Windows it shows up with an exclamation mark in device manager saying it has been stopped "Windows has stopped this device because it has reported problems. (Code 43)"

 

This was with my older seabios one though. Will try now with OVMF...

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Mmm same thing. Not getting a video signal from the card. Not sure I trust the ROM. have tried extracting again in slot 2 but now getting input/output error. Tried starting/stopping a bound VM as some others have suggested to then do an unbind but it stops being bound once the VM is shutdown and I still get input/output after that...

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