[PD] USB power off from [shell] for eliminating MIDI interfaceproblems

[IOhannes m zmoelnig]

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On 2013-10-17 10:27, Ingo wrote:
> Thanks for the suggestion!
> 
> I know this can be done with a relay but it's not doable in my
> particular case. I really need to find out how to do this in
> software.
> 
> Unbind and bind in /sys/bus/usb/drivers/...  won't work either,
> btw. I managed to turn the interface(s) off and on but not the
> power supply. So the problem persists.
> 
> There is a maximum power setting that allows to specify the number
> of mA but is tells me that I don't have permission (as root) to
> make changes.
> 
> It's also not possible to unplug and replug the interfaces as they
> are in a closed box.

there's a rather old post at stackoverflow [1], which seems to suggest
that the route to go would be a USB2 hub that allows power-switching.


oh, and i just tried to switch off my mouse, by doing:

# PROCPATH=$(lsusb \
           | grep -i mouse \
           | cut -f6 -d' ' \
           | sed -e 's|:| |' \
           | while read v p; do \
              for vf in /sys/bus/usb/devices/*/*/idVendor; do \
                 dev=${vf%idVendor}; grep -w "${v}" "${dev}/idVendor"
1>/dev/null  && grep -w "${p}" "${dev}/idProduct" 1>/dev/null && echo
${dev}; \
              done; \
             done)
# echo "0" > "${PROCPATH}/power/autosuspend"
# echo "auto" > "${PROCPATH}/power/level"


fmasdr
IOhannes

[1]
http://stackoverflow.com/questions/1163824/linux-usb-turning-the-power-on-and-off

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