1/ dmesg | grep usb

usb 2-1: USB disconnect, address 5
usb 2-1: usb_disable_device nuking all URBs
usb 2-1: unregistering interface 2-1:1.0
usb 2-1:1.0: uevent
usb 2-1: unregistering device
usb 2-1: uevent
usb 2-1: new full speed USB device using ohci_hcd and address 6
usb 2-1: ep0 maxpacket = 32
usb 2-1: default language 0x0409
usb 2-1: new device strings: Mfr=1, Product=2, SerialNumber=0
usb 2-1: Product: Canon Digital Camera
usb 2-1: Manufacturer: Canon Inc.
usb 2-1: uevent
usb 2-1: device is self-powered
usb 2-1: configuration #1 chosen from 1 choice
usb 2-1: adding 2-1:1.0 (config #1, interface 0)
usb 2-1:1.0: uevent
drivers/usb/core/inode.c: creating file '006'

2/tail -f /var/log/syslog
Oct 22 12:11:58 iDebian kernel: usb 3-1: configuration #1 chosen from 1 choice
Oct 22 12:11:58 iDebian kernel: usb 3-1: adding 3-1:1.0 (config #1, interface 0)
Oct 22 12:11:58 iDebian kernel: usb 3-1:1.0: uevent
Oct 22 12:11:58 iDebian kernel: usbhid 3-1:1.0: usb_probe_interface
Oct 22 12:11:58 iDebian kernel: usbhid 3-1:1.0: usb_probe_interface - got id
Oct 22 12:11:58 iDebian kernel: input: Logitech USB-PS/2 Optical Mouse as /class
/input/input9
Oct 22 12:11:58 iDebian kernel: input: USB HID v1.10 Mouse [Logitech USB-PS/2 Op
tical Mouse] on usb-0001:10:1b.1-1
Oct 22 12:11:58 iDebian kernel: drivers/usb/core/inode.c: creating file '008'
Oct 22 12:11:58 iDebian kernel: hub 3-0:1.0: state 7 ports 2 chg 0000 evt 0002
Oct 22 12:12:00 iDebian usb.agent[13884]:      usbhid: already loaded