[SOLVED] Passthrough more than 5 USB ports to VM

drojas32

Member
Oct 21, 2020
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Hello,

I'm very new with Proxmox and VMs but had some questions regarding passing through more than 5 USB ports to my VM. im running PVE 6.2 and can't quite figure out how to increase the allowed number of USB ports from 5 to 6. Any help, documentation, or guides are greatly appreciated. I have read up on the topic but still can't wrap my head around what's being suggested to figure it out. Appreciate the help and explanation, thank you
 
Have a look at this post?
Hello avw,

I've attempted option 3 to no success. With option 2, proxmox doesn't recognize the USB hub although I have a mouse and keyboard connected on it that I was able to pass but still brought my limit of 5 USB ports. I'm currently trying to figure out option 1 still. I've used that to passthrough a GPU already but can't quite figure out how to use this for the USB ports
 
Update: I'm not completely sure why and definitely don't know why or can't speak further on it, however the combination of option 2 and 3 helped passthrough the 6 USB ports I wanted. I changed the limit to 6 USBs and had changed the conf file for the specific VM.

It was until i started testing by using the VM that i noticed all 6 USB ports were being passed to the VM. i'll be attempting to do more testing to confirm this before marking this as solved. However, the proxmox web client still only lets me add 5 USBs and I assumed that I couldn't get the 6th working since it wasn't showing up in GUI. Test and check your VM for the specific USB devices you're attempting to passthrough as option 2 and 3 appear to work.
 
Option 2 does not work like that, see the follow up posts,
Regarding option 3, it extends the configuration file options to 9 but the web GUI does indeed not support this.
If you wan to passthrough a USB-controller as in option 1, use the same steps as for a GPU: find a USB-controller that is in its own IOMMU group (use this command to show you the groups: for d in /sys/kernel/iommu_groups/*/devices/*; do n=${d#*/iommu_groups/*}; n=${n%%/*}; printf 'IOMMU group %s ' "$n"; lspci -nns "${d##*/}"; done;) and pass it to the VM using hostpci (remember that the host will lose access to the USB ports of that controller).
 
I forgot to mark this as solved. In general, the steps that I was directed to look at helped my issue. This is practically the same information I found on google when figuring out this problem.

It isn't noted but the 5 USB limit only applies to the web client GUI when you edit and attempt to passthrough new USB devices to the VM. The GUI edits the vm's config file which you can manually edit yourself to include USB devices well passed the 5 limit. I tested it with 9 devices and worked without problem.

Going back to your question, yes i've accomplished A LOT since asking this question. Very nice of you to ask :)
 

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