Power OFF and ON USB device in linux (ubuntu)

Posted on Feb 20, 2014

There are two methods of doing this. So first method is for kernels after 2.6.32, and second for older ones.

To view kernel version, simply enter:

> uname -r 
3.8.0-29-generic

find Your USB device, no mather what it is USB flash drive, Yubikey, USB disk drive:

> lsusb 
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 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 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 005: ID 12d1:14db Huawei Technologies Co., Ltd. 
Bus 002 Device 006: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub

> lsusb -t
/:  Bus 02.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 1: Dev 5, If 0, Class=comm., Driver=cdc_ether, 480M
        |__ Port 1: Dev 5, If 1, Class=data, Driver=cdc_ether, 480M
        |__ Port 5: Dev 6, If 0, Class=hub, Driver=hub/4p, 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

Our target is:

Bus 002 Device 005: ID 12d1:14db Huawei Technologies Co., Ltd.

Which is located at 2-1.1 (tree part where device 5 is located)
First method (newer kernel)

To turn it off simply echo address:

echo '2-1.1' > /sys/bus/usb/drivers/usb/unbind

here is result from syslog:

Feb 20 12:03:27 vgsms6 kernel: [ 1734.993667] cdc_ether 2-1.1:1.0 eth2: unregister 'cdc_ether' usb-0000:00:1d.0-1.1, CDC Ethernet Device

Unfortunately this device was still visible in lsusb, so I turned off whole usb hub there (2-1), and voila, usb device gone.

To enable it, echo same address to ‘bind’ part, for example:

echo '2-1.1' > /sys/bus/usb/drivers/usb/bind

Second method (older kernel)
You need to go to devices:

cd /sys/bus/usb/devices

Addressess will be listed similar:

/sys/bus/usb/devices# ls -alh
total 0
drwxr-xr-x 2 root root 0 Feb 20 11:34 .
drwxr-xr-x 4 root root 0 Feb 20 11:34 ..
lrwxrwxrwx 1 root root 0 Feb 20 11:34 1-0:1.0 -> ../../../devices/pci0000:00/0000:00:1a.0/usb1/1-0:1.0
lrwxrwxrwx 1 root root 0 Feb 20 11:34 1-1 -> ../../../devices/pci0000:00/0000:00:1a.0/usb1/1-1
lrwxrwxrwx 1 root root 0 Feb 20 11:34 1-1:1.0 -> ../../../devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1:1.0
lrwxrwxrwx 1 root root 0 Feb 20 11:34 2-0:1.0 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-0:1.0
lrwxrwxrwx 1 root root 0 Feb 20 11:34 2-1 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-1
lrwxrwxrwx 1 root root 0 Feb 20 12:34 2-1.1 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.1
lrwxrwxrwx 1 root root 0 Feb 20 12:34 2-1:1.0 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1:1.0
lrwxrwxrwx 1 root root 0 Feb 20 12:34 2-1.1:1.0 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.1/2-1.1:1.0
lrwxrwxrwx 1 root root 0 Feb 20 12:34 2-1.1:1.1 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.1/2-1.1:1.1
lrwxrwxrwx 1 root root 0 Feb 20 12:34 2-1.5 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5
lrwxrwxrwx 1 root root 0 Feb 20 12:34 2-1.5:1.0 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5/2-1.5:1.0
lrwxrwxrwx 1 root root 0 Feb 20 11:34 usb1 -> ../../../devices/pci0000:00/0000:00:1a.0/usb1
lrwxrwxrwx 1 root root 0 Feb 20 11:34 usb2 -> ../../../devices/pci0000:00/0000:00:1d.0/usb2

So go to in our example 2-1.1/power (full path /sys/bus/usb/devices2-1.1/power)

cd /sys/bus/usb/devices2-1.1/power

to turn off device:

echo suspend > level

to turn on:

echo on > level