Distributor ID:    Ubuntu
Description:    Ubuntu 12.04.1 LTS
Release:    12.04
Codename:    precise

$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 174f:6a31 Syntek Web Cam - Asus A8J, F3S, F5R, VX2S, V1S
Bus 005 Device 006: ID 046d:c019 Logitech, Inc. Optical Tilt Wheel Mouse
Bus 007 Device 002: ID 0b05:1712 ASUSTek Computer, Inc. BT-183 Bluetooth 2.0+EDR adapter

$ dmesg|tail
[ 6478.524075] usb 6-2: device descriptor read/64, error -71
[ 6478.804064] usb 6-2: device descriptor read/64, error -71
[ 6479.076061] usb 6-2: new full-speed USB device number 15 using uhci_hcd
[ 6479.256062] usb 6-2: device descriptor read/64, error -71
[ 6479.480065] usb 6-2: device descriptor read/64, error -71
[ 6479.696065] usb 6-2: new full-speed USB device number 16 using uhci_hcd
[ 6480.108058] usb 6-2: device not accepting address 16, error -71
[ 6480.220066] usb 6-2: new full-speed USB device number 17 using uhci_hcd
[ 6480.632056] usb 6-2: device not accepting address 17, error -71
[ 6480.632090] hub 6-0:1.0: unable to enumerate USB device on port 2