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

[Ingo]

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.





> -----Ursprüngliche Nachricht-----
> Von: Py Fave [mailto:pyfave at gmail.com]
> Gesendet: Mittwoch, 16. Oktober 2013 22:46
> An: Ingo
> Betreff: Re: [PD] USB power off from [shell] for eliminating MIDI
> interfaceproblems
> 
>  get a relay , transistor and a arduino,
>  or perhaps this card is easy to use :
> and talks hid ,
> 
> http://www.1010.co.uk/org/byron.html
> 
> usb resets if overloaded too.... not a suggestion
> 
> 2013/10/16 Ingo <ingo at miamiwave.com>:
> > I have tried
> >
> > echo on > /sys/bus/usb/devices/usb1/power/level       # turn on
> > echo suspend > /sys/bus/usb/devices/usb1/power/level  # turn off
> >
> > with different devices (like 4-2 which is the MIDI interface) and I'm
> always
> > getting "invalid argument" when I try to use "suspend".
> >
> > Any ideas?
> >
> > Ingo
> >
> >
> >
> >> A while ago a MIDI interface problem came up here that nobody seemed to
> >> really know about:
> >>
> >> All the sudden huge delays in the range of one or more seconds started
> to
> >> happen and then the interface sometimes possibly started playing notes,
> >> etc.
> >> on its own.
> >> I had experienced this quite a few times with Pd on Windows and Linux
> and
> >> already way back (about 25 years ago) with my Akai MPC60 drum
> sequencer.
> >>
> >> I finally found out what causes it.
> >> When starting the computer the interface gets powered up as well before
> >> the
> >> system is ready to receive any information coming from the interface.
> >> Therefor the interface keeps every input on the MIDI side in a buffer
> >> until
> >> it can transmit it to the USB port.
> >>
> >> From time to time the buffer gets completely overloaded during startup
> >> when
> >> receiving too much MIDI what in return makes the interface go nuts! The
> >> only
> >> way to reset it is to disconnect it from power.
> >>
> >>
> >> Now here is my question:
> >>
> >> Does anybody know how I can power off a USB port (probably using
> [shell])
> >> to
> >> do a reset (USB power off - USB power on) while or after loading the
> >> patch?
> >>
> >> I'm on Ubuntu Natty.
> >>
> >> Thanks
> >> Ingo
> >>
> >>
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