linux USB power control

Hellow there,

I have a USB fan connected to my computer. The box is a NISE-3110 industrial PC.
The fan only takes 5 Volts voltage from the port. no drivers, no keys , etc…

The question is, to control the power of the fan. We are satisfied by only turning off and on.

Any comments??

my uname -a is:

Linux vinocamera 2.6.34.7-0.7-desktop #1 SMP PREEMPT 2010-12-13 11:13:53 +0100 x86_64 x86_64 x86_64 GNU/Linux

On 02/04/2011 10:36 AM, anooshr wrote:

> The question is, to control the power of the fan. We are satisfied by
> only turning off and on.

when you write “control the power of the fan” are you wanting to
change the electrical power flowing to the fan, or change the speed at
which the fan turns?

the documentation which came with the fan: did it lead you to believe
the fan speed could be controlled by using in computer software to
adjust the voltage supplied to it via the USB port ??

did the documention mention the software you should use to do that?


DenverD
CAVEAT: http://is.gd/bpoMD
[NNTP posted w/openSUSE 11.3, KDE4.5.5, Thunderbird3.0.11, nVidia
173.14.28 3D, Athlon 64 3000+]
“It is far easier to read, understand and follow the instructions than
to undo the problems caused by not.” DD 23 Jan 11

There is no documentation with the Fan. The question is how to power off the USB port completely ( e.g. , no electricity flows through the port ) . The fan is just an example. we want to shut down the port completely then turn it on again.

Thanks for your reply !!

i don’t know how to do that…i think that is because it can’t be
done…

ok i did a little google and found several things like this:

"You can’t simply toggle pins on a USB port. Period. USB is a serial
protocol. The connector contains

  1. Power. The Host can control the power lines as it can cut the
    power in case of overload. This is something done by the USB host
    driver, which means the driver of the host adapter in the PC. This
    does not mean any custom device driver you might need for hardware
    that doesn’t use any of the device classes the OS already ships drivers.
  2. Data. The data is sent via a serial protocol, so there is no way
    to control those pins if you’re using USB."

check around, google is your friend!


DenverD
CAVEAT: http://is.gd/bpoMD
[NNTP posted w/openSUSE 11.3, KDE4.5.5, Thunderbird3.0.11, nVidia
173.14.28 3D, Athlon 64 3000+]
“It is far easier to read, understand and follow the instructions than
to undo the problems caused by not.” DD 23 Jan 11

Some possibilities here: turn-off-power-usb-port

However my impression is that the actual usb power management have to be implemented by the device.