On Mon, 17 Apr 2006 rasmit.ranjan@xxxxxxxxx wrote: > Hi all, > I can suspend a port from the user space manualy by doing > > echo -n 3 > /sys/bus/usb....../power/state > > Similarlly can I enable/power off a port from the user space manually ? It depends on where the port is. For ports built into the computer, the answer is generally No. The USB controller hardware in computers does not have per-port power control. On some systems you might be able to turn off power to _all_ the ports attached to a particular USB host controller by turning off power to the controller itself (put it in a D3cold state). But this would affect more than one port, and most systems won't allow you to do it anyway. If the port is part of an external hub instead of build into the computer, you may be able to do it. Many hubs do not support per-port power control, but some of them do. You can get more information and a userspace program here: http://www.gniibe.org/ac-power-by-usb/ac-power-control.html Alan Stern
