Power OFF and ON USB device in linux (ubuntu)

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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

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

> 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

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

/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

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Comments (7)

• 
  
  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 ↓
  
  
  • 
    
    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 ↓
    
    
    • 
      
      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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