#Usb ports powered when computer is off driver

The final line field contains the driver used ('usbhid' in our 1st example) If the field 'I:*' contains asterisk (like in our 1st example) then there is input, from or to the device, i am not sure, maybe both. If not ('C:') then the device is 'more or less' powered off meaning there is always a tiny current when a device is pluged, otherwise we wouldn't be able to read all this info. If there is an asterisk in 'C:' (like in our 1st example) then the device is powered. It contains info regarding the power (current) of the device. So the device you are looking for is the following string :Д«us-Rank (this is not a mathematical function, its a string, 1-2 in this example) Rank=Cnt+1 (this is a mathematical function, Rank=2 in this example) You will need to add '1' (arithmetic one) to 'Cnt' to get the rank They are located in the 'T:' line (first line of paragraph). (first paragraph with device powered on, second one with same device powered off but still pluged in) T: Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 4 Spd=1.5 MxCh= 0Д: Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1 Or 'Manufacturer' and 'Product' (all these values are constant per device). Read relevant paragraph of '/proc/bus/usb/devices' according to your devices 'Vendor' (vendor id) and 'ProdID' (product id) This is an example with a Logitech USB wireless mouse under linux. This is particularly useful for embedded devices, such as a UVC webcams, which never seem to function properly and would otherwise require a system reboot to reset. I'm guessing at a lower layer this is interacting with the EHCI host controller to actually shut power off on the port. I haven't hooked up a protocol analyzer to see what's actually happening on the bus, but I know my mouse light turns off when I unbind it. Finally, cycle the port power: echo '2-1.1.1'|sudo tee /sys/bus/usb/drivers/usb/unbindД®cho '2-1.1.1'|sudo tee /sys/bus/usb/drivers/usb/bind |_ Port 1: Dev 6, If 0, Class=HID, Driver=usbhid, 1.5M

|_ Port 1: Dev 3, If 0, Class=hub, Driver=hub/3p, 480M |_ Port 1: Dev 2, If 0, Class=hub, Driver=hub/6p, 480M The syntax seems to be '.port.' For example, my mouse is connected to an external hub which connects to my computer's hub which internally connects to a root hub: /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci_hcd/2p, 480M Locate the device in the bus / hub port hierarchy using the bus and device number: sudo lsusb -t|less Search for the bus and device number: sudo lsusb -v|less So, here's how I cycle hub port power on Ubuntu Oneiric Ocelot from a Bash shell. The usbfs interaction seems to have changed a number of times since this question was originally answered.

Usb ports powered when computer is off