Re: Cut power to a USB port?

[Andrew Barr <andrew.james.barr@gmail.com>]

On Tue, 2007-01-02 at 08:36 -0800, Randy Dunlap wrote:
> On Tue, 02 Jan 2007 10:28:38 -0500 Andrew Barr wrote:
> 
> > On Tue, 2007-01-02 at 00:32 -0800, Greg KH wrote:
> > > On Mon, Jan 01, 2007 at 03:56:25PM -0500, Andrew Barr wrote:
> > > > I have a simple question perhaps someone can help me with here...
> > > > 
> > > > I have one of those simple LED keyboard lamps that get their power from
> > > > the USB port. Is there some way in Linux, using files under /sys I would
> > > > imagine, to cut power to the USB port into which this lamp is plugged? I
> > > > know I would have to manually figure out what port it's plugged into, as
> > > > it is not a "real" USB device...e.g. it just draws power. I would like
> > > > to be able to programmatically switch the lamp on and off.
> > > 
> > > Search the archives of the linux-usb-devel mailing list for a program
> > > that might do this for you (depending on your hardware.)
> > 
> > What search terms should I use? Searching on "power" and "port power" at
> > Gmane in the gmane.linux.usb.devel group doesn't readily give me
> > anything.
> 
> You can try:
> 
> usbpoweroff.c
> (http://www.informatik.uni-halle.de/~ladischc/usbpoweroff.c)
> or
> hub-ctrl-2.c (http://www.gniibe.org/log/linux)

Hm, my hardware must not support it. The hub-ctrl-2.c program fails with
a broken pipe and the usbpoweroff.c program silently does nothing,
exiting returning zero.

Thanks to you all anyway,
Andrew

> > For the record, my hardware:
> > 
> > 00:1d.0 USB Controller: Intel Corporation 82801DB/DBL/DBM
> > (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #1 (rev 01)
> > 00:1d.1 USB Controller: Intel Corporation 82801DB/DBL/DBM
> > (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #2 (rev 01)
> > 00:1d.2 USB Controller: Intel Corporation 82801DB/DBL/DBM
> > (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #3 (rev 01)
> > 00:1d.7 USB Controller: Intel Corporation 82801DB/DBM (ICH4/ICH4-M) USB2
> > EHCI Controller (rev 01)
> > 
> > IBM Thinkpad R51 2883-ELU.
> 
> 
> ---
> ~Randy