Debug info
$ lsusb
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate
Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 005: ID 04a9:1073 Canon, Inc. I550 Printer
Bus 001 Device 004: ID 093a:2510 Pixart Imaging, Inc. Optical
Mouse
Bus 001 Device 003: ID 046d:089d Logitech, Inc. QuickCam E2500
series
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate
Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 002: ID 04a9:190f Canon, Inc.
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
$ lsusb -t
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p,
5000M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M
|__ Port 3: Dev 2, If 0, Class=Vendor Specific Class, Driver=,
480M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
|__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
|__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
|__ Port 3: Dev 3, If 0, Class=Vendor Specific Class,
Driver=gspca_zc3xx, 12M
|__ Port 3: Dev 3, If 1, Class=Audio,
Driver=snd-usb-audio, 12M
|__ Port 3: Dev 3, If 2, Class=Audio,
Driver=snd-usb-audio, 12M
|__ Port 4: Dev 4, If 0, Class=Human Interface Device,
Driver=usbhid, 1.5M
|__ Port 6: Dev 5, If 0, Class=Printer, Driver=usblp, 12M