[linux-audio-dev] USB-MIDI Transfer rate

[Jens M Andreasen]

On Mon, 2005-09-19 at 10:03 +0200, Clemens Ladisch wrote: 
> Jens M Andreasen wrote:
> > On Fri, 2005-09-16 at 17:10 +0200, Clemens Ladisch wrote:
> > > Jens M Andreasen wrote:
> > > > Are you absolutely sure that it is not possible to increase the thruput?
> > >
> > > Try changing the line:
> > >
> > > 	ep->max_transfer = usb_maxpacket(umidi->chip->dev, pipe, 1);
> > >
> > > in the snd_usbmidi_out_endpoint_create function in usbmidi.c to:
> > >
> > > 	ep->max_transfer = 512;
> >
> > This will change all ports, no? Both internal as well as external?
> 
> Yes.  The MIDI data for all ports is multiplexed through the two
> (output+input) endpoints.
> 

I am running into troubles here. After reboot, the usb-midi goes
haywire!? And I have not even done any changes to the system yet ...

At first, I reboot with the usb device off and then have a peek:

$ ls /dev/midi*
/dev/midi1

$ amidi -l
Device    Name
hw:1,0    MPU-401 MIDI 1-0

.. which looks as expected. But then turning the device on gets weired:

$ amidi -l
Device    Name
hw:1,0    MPU-401 MIDI 1-0

ls /dev/midi*
/dev/midi  /dev/midi1  /dev/midi2  /dev/midi3


.. which is no good. The /dev/midi* devices are too many and not
working. Turning the usb device off again leaves me with:

$ ls /dev/midi*
/dev/midi1  /dev/midi3


I experience that at random times, the system actually wakes up in a
working state. I am still to figure out what that pattern is?


mvh // Jens M Andreasen

(going down for reboot)





> 
> Regards,
> Clemens
> 
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