[alsa-devel] Problem with CME UF5 MIDI keyboard master volume slider

[Clemens Ladisch]

Damon Chaplin wrote:
> On Mon, 2007-08-06 at 12:41 +0200, Clemens Ladisch wrote:
> > Damon Chaplin wrote:
> > > I have a CME UF5 MIDI keyboard (USB), which mostly works fine with ALSA.
> > > 
> > > However if I move the Master Volume slider I stop getting MIDI events -
> > > I have to disconnect the snd_seq port and reconnect it to get MIDI
> > > events working again.
> > 
> > Is there any error message in the system log when this happens?
> 
> No, I don't think so. You mean /var/log/messages?

Yes.

> > > Also, I wanted to try the rawmidi test app, but what would the device ID
> > > be?
> > 
> > Have a look at the output of "amidi -l".
> 
> Thanks. I've got rawmidi working, and it doesn't seem to have a problem
> with the master volume slider. So I guess it is an alsa-seq issue.
> 
> If I move the slider I get this in rawmidi (4 lines for each increment):
> 
> read f0
> read 01
> read 7f
> read 7e
> 
> read f0
> read 01
> read 7f
> read 7d
> 
> Are they valid MIDI messages?

No.  These look like the first four bytes of master volume sysex
messages, but anything after the first four bytes seems to be missing.
Sysex messages end with a F7 byte, so it's possible that the following
data gets misinterpreted.

Please show the output of "amidi --dump" with some key presses after
you've used the master volume slider.


Regards,
Clemens