usbip: error: already used bus id #-#

[e-t-l]

I'm trying to attach a USB game controller but I'm receiving the error in the title. Output below:

> usbip list -r 100.72.247.44
Intel Corp.
Exportable USB devices
======================
 - 100.72.247.44
        1-2: Microsoft Corp. : Xbox One Controller (Firmware 2015) (045e:02dd)
           : USB\VID_045E&PID_02DD\7EED850A438F
           : Vendor Specific Class / unknown subclass / unknown protocol (ff/47/d0)
           :  0 - Vendor Specific Class / unknown subclass / unknown protocol (ff/47/d0)
           :  1 - Vendor Specific Class / unknown subclass / unknown protocol (ff/47/d0)
           :  2 - Vendor Specific Class / unknown subclass / unknown protocol (ff/47/d0)

> usbip attach -r 100.72.247.44 -b 1-2 -t
usbip: error: already used bus id: 1-2

> usbip port
Imported USB devices
====================

> usbip detach -p 1-2
usbip: error: failed to detach

I have no idea what "already used bus id" could mean in this case. To my knowledge I don't have any local USB buses with that id (running usbip list -l does not show any busid of 1-2, and running the attach command with the -s arg produces the same error). As you can see from usbip port there do not appear to be any currently attached devices.

Anyone know what's going on here?

[e-t-l]

Unbinding the device, then force-binding on the server PC using usbipd bind -f -b 1-2 solved this.