[linux-audio-user] usb midi

[R Parker]

Clemens,

Disreguard the previous message. I had a cable problem
and the system is now working.

Gotta run, session just walked in,

ron

--- Clemens Ladisch <clemens at ladisch.de> wrote:
> R Parker wrote:
> > --- Clemens Ladisch <clemens at ladisch.de> wrote:
> > > R Parker wrote:
> > > > I still don't understand where the usb-midi
> i/o
> > > device is.
> > > > ...
> > > > There's no messages passing through
> > > /dev/snd/midiC1D0
> > >
> > > This file handles all nine ports. The ALSA
> library
> > > uses a magic IOCTL to
> > > select the desired port; when you access the
> file
> > > directly, you get the
> > > first port only.
> >
> > After examining things a little closer, your reply
> > confirms my conclusion.
> >
> > I think there's something wrong because no data is
> > making it to the /dev/snd/midiC1D0 file.
> >
> > For demonstration, I've connected everything:
> > ...
> > With this scenario anything that comes in port_N,8
> > should be seen in the file /dev/snd/midiC1D0. Am I
> > right?
> 
> Well, what I said earlier isn't entirely correct,
> accessing
> /dev/snd/midiC1D0 will open the first free port.
> Connecting ports will
> open them, so the first free port in your case was
> probably Port 8.
> 
> And when you connect port x to port 0, data from the
> device at port x will
> be written to port 0, but you won't be able to read
> it from port 0 because
> MIDI Out 1 and MIDI In 1 are different ports.
> 
> 
> I think you really need virmidi to do what you want.
> Please add the following lines (or modify them) in
> your modules.conf:
> 
> 	options snd cards_limit=3
> 	alias snd-card-2 snd-virmidi
> 	alias snd-slot-2 snd-card-2
> 	options snd-virmidi index=2
> 
> then connect the desired ports of the 8x8 to port
> 80:0, and then the
> incoming data should be available at /dev/midi02.
> 
> > > If possible, you should use a program that can
> > > access MIDI ports via the
> > > ALSA library (the 8x8's ports would be named
> > > "hw:1,x", x = 0..8).
> >
> > I've always used dd to see check for incoming mmc
> > messages. It's always worked. Is this what you're
> > referring to?
> 
> No, dd doesn't use the ALSA library.
> 
> The ALSA library hides the device files behind
> device names. Instead of
> accessing the ALSA device files directly, you are
> supposed to use some
> program which uses the ALSA library.
> 
> There is an ugly test program which can display the
> data from an ALSA
> rawmidi port in the alsa-lib/test directory. Please
> go there, run "make
> rawmidi", and start it with
> 	./rawmidi -v -i hw:1,x
> 
> 
> HTH
> Clemens
> 
> 


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