You should see something in your logs, this is what I get for a usb 3.1 device:
kernel: usb 2-1.2: new SuperSpeed Gen 1 USB device number 5 using xhci_hcd USB 2 is only "high-speed": kernel: usb 1-1.3: new high-speed USB device number 12 using xhci_hcd Regards, Geoff
