Individual USB passthrough in Windows 7 qubes

I have a sys-usb qube that is functional, and a Windows 7 HVM with Qubes Windows Tools and updated Xen PV drivers (version 8.2.2), and when I try to attach an USB device to the qube (in this case, a drawing tablet) using qvm-usb it gives me the following output:

$ qvm-usb -v win7 sys-usb:2-2
Device attach failed:

All possible solutions point to using PCI passthrough to give the qube an USB controller to use, but my computer (ThinkCentre m720q) only has one. What could I do to try to troubleshoot this further?

At the moment I don’t think you have any options. Under R4.0 with QWT USPIP-via-qrexec is not supported. I have seen recent forum posts indicating that rudimentary USB support is in the works for R4.1 / QWT.

However, depending what kind of device you want to attach it might not work. So having more than one USB controller really is the way to go. Unfortunately it looks like your computer is one of those compact ones that cannot be extended neither via PCI card nor via express card.