I'm pretty sure I know the answer to the question, but I just want to run it past people here.

 

My unraid server is running a i7-4770 and a pretty basic motherboard (HP branded mATX Q87).

 

I have ACS enabled and it shows three different USB controllers in their own IOMMU groups with different IDs, but if I plug in USB devices, they always appear in the same USB bus regardless of which port (USB3, USB2, front panel, back panel) plugged in to.  I seem to remember somewhere that the USB controller is either on-die or on-board, but the same physical controller handles all USB traffic.  If that's so, it would explain why all USB devices show as attaching to the same bus, and my presumption is therefore that its not possible to actually passthrough one of the three controllers to a VM and get that functionality.

 

I have an add-in card that does work, so its not a huge deal.

 

Any thoughts?

Edited November 30, 20187 yr by toastman
clarification

It may not change anything, but if there are options in the BIOS for USB configuration, try changing those around. I seem to remember discussions about changing seemingly meaningless USB settings accomplishing what you want for some boards.

Yeah, USB hand-off and the like.  I did try that