Power OFF and ON USB device in linux (ubuntu)

http://loginroot.com/power-off-and-on-usb-device-in-linux-ubuntu/

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:

Shell

1 2	> uname -r 3.8.0-29-generic

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

Shell

> 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:

Shell

1	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:

Shell

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

here is result from syslog:

Shell

1	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:

Shell

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

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

Shell

1	cd /sys/bus/usb/devices

Addressess will be listed similar:

Shell

/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)

Shell

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

to turn off device:

Shell

1	echo suspend > level

to turn on:

Shell

1	echo on > level

Like this:

AnonymousSeptember 28, 2014 at 4:01 pm

~ $ sudo echo ‘1-1.2’ > /sys/bus/usb/drivers/usb/unbind
-bash: /sys/bus/usb/drivers/usb/unbind: Permission denied

Reply ↓
NiekoNovember 4, 2014 at 11:59 am

Thanks, finally got it working! :)

Anonymous: your command executes “echo ‘1-1.2′” under sudo, and then tries to write that to /sys/bus/usb/drivers/usb/unbind as the normal user again. Try this: echo ‘1-1.2″ | sudo tee /sys/bus/usb/drivers/usb/unbind

Reply ↓
SantosNovember 8, 2014 at 2:25 am

You could also use a switchable USB hub.

Something like this https://www.yepkit.com/products/ykush

but it’s more expensive :)

Reply ↓
1. nsc(Post author)November 8, 2014 at 9:47 am
  
  Smart way of leaving a backlink.
  I encourage doing opensource projects :)
  
  Usually the budget depends on what are the requirements. For a simple “faulty” usb emergency device reset I would use my way (I wouldn’t expect something to break, would I?).
  
  But for day to day planned switch off/on I’d consider such device.
  Thanks for sharing Your product.
  That’s pretty useful thing, it should have more reliable switching capability and it’s more powerful than a server usb port.
  
  You should consider making a bigger hub, as it seems to be possible to use it as a powersource for usb devices (2Amps of current).
  For example external usb 2.5 hdd would already take 2 ports, leaving only one free.
  Or make an usb controlled power source switcher with relays, it would perfectly go as a combo with this usb hub device :)
  
  Reply ↓
  1. SantosNovember 8, 2014 at 1:58 pm
    
    Fully agree with you, the best approach depends of the requirements.
    
    Those are cool ideas for improving the product.
    
    Cheers
    
    Reply ↓
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