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

[Damon Chaplin]

On Fri, 2007-08-10 at 16:55 +0200, Clemens Ladisch wrote:
> I wrote:
> > Damon Chaplin wrote:
> > > Is it possible to workaround the problem?
> > 
> > Only by changing the driver.  Please wait until tomorrow.
> 
> Well, the driver should now continue after receiving bad data.
> 
> To be able to convert the data sent by the CME UFx to a real master
> volume message, I need to know the data format at a lower level.
> Please change line 58 of sound/usb/usbmidi.c to
> 	#define DUMP_PACKETS
> and recompile the driver, then show the entries that are written to the
> (debug) system log when a master volume message is received.

Here they are. Only one byte changes as the slider moves,from 00 to 7f:

received packet: [ 0f f0 7f 7f 04 01 7f 00 f7 ]
received packet: [ 0f f0 7f 7f 04 01 7f 7f f7 ]
                                        ^^

Damon