power off 5V on USB port

[Hans Petter Selasky]

On 04/07/15 15:30, Matthias Apitz wrote:
>
>
> Hello,
>
> I'm using an Ubuntu smartphone connected on one of the USB ports to my
> netbook as a router to the Internet. I wanted to power-off the USB port to
> a) save energy in the netbook and
> b) not having the phone always charged for the memory effect in the battery.
>
> I tried:
>
> $ usbconfig
> ...
> ugen0.3: <AquarisE4.5 BQ> at usbus0, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=ON (500mA)
>
> # usbconfig -d ugen0.3 power_off
> # usbconfig -d ugen0.3
> ugen0.3: <AquarisE4.5 BQ> at usbus0, cfg=255 md=HOST spd=HIGH (480Mbps) pwr=OFF (500mA)
>
> as you can see the state is now pwr=OFF, but in this state the USB port
> is not longer usable. What is the correct way to shutdown the 5V
> provided via USB to the device?
>

Not all USB ports support power off.

--HPS