[Musix-users] [BUG] USB-MIDI not working with realtime-kernels

Thu Nov 9 18:11:50 CET 2006

Hello

> BTW: is the 2.6.16-beyond4.1 good enough for MIDI work for you?

unfortunately not in my case, but I think this is not a fault of Musix. I'm running it on an old 
notebook which has no hard disk any more. Most Linux live-cds with a 2.6-kernel do not boot on that 
computer at all, the kernel usually gets stuck right after loading without outputting a single 
message. I was very happy to see that this does not happen with the realtime-2.6-kernels of Musix, 
until I discovered the USB-MIDI problem...

However, the non-realtime kernel of Musix 0.39 (not yet "beyond4.1") also boots fine, which finally 
allows me to use Musix with a working MIDI interface. I like Musix very much, especially since I 
managed to manually compile and install SuperCollider3 from a memory stick. Together with 
SuperCollider, Musix now appears to be a complete playground me.

Thanks for your work,
Jens

Marcos Guglielmetti schrieb:
> El Vie 03 Nov 2006 19:58, Jens Gulden escribió:
> 
>>Hello everybody, especially Marcos,
>>
>>can you confirm this bug?: Realtime-patches confuse ALSA's USB-MIDI
>>functionality.
>>
>>Using Musix's realtime-kernels, MIDI-events from and to USB-MIDI devices
>>get not passed between clients when the device is connected inside ALSA's
>>sequencer API. E.g. using "'device' -> timidity" (connected via aconnect if
>>available, or qjackctl's midi-connections-tab), the MIDI events seem to get
>>stuck in an internal buffer:
>>cat /proc/asound/card2/midi0 ->
>>
>>MidiSport 2x2
>>
>>Output 0
>>   Tx bytes     : 0
>>Output 1
>>   Tx bytes     : 0
>>Input 0
>>   Rx bytes     : 1186
>>   Buffer size  : 4096
>>   Avail        : 1186  <--- ### SHOULD BE ZERO, NOT =RX BYTES! ###
>>   Overruns     : 0
>>Input 1
>>   Rx bytes     : 0
>>
>>Instead of passing the data further to the connected timidity in this
>>example, it remains in some kind of receive-buffer. When 4096 is reached,
>>overruns start to count up. Connections have been set up using qjackctl,
>>vkeybd->timidity works.
>>
>>When outputting MIDI-events, the same behaviour applies to an
>>output-buffer.
>>
>>See also
>>http://lists.ourproject.org/pipermail/musix-users/2006-October/000366.html.
>>
>>However, using the "amidi" tool from the alsa-utils package (can be
>>compiled from source on Musix), MIDI events show up correctly. The problem
>>thus might not originate from a device-driver, but probably somewhere in
>>ALSA's sequencer API. I'm not an ALSA expert, however. Thanks to Clemens
>>Ladisch for the hint about amidi.
>>
>>Booting the non-realtime kernels of the different Musix versions,
>>everything related to MIDI works fine.
>>
>>Tested Musix versions: 0.39, 0.49, 0.50, 0.59 (from cd-rom only, no
>>hd-install). Tested USB-Hardware:
>>- M-Audio Midisport 2x2 (on 0.49, 0.50 with added firmware)
>>- Edirol UM-1 (no firmware needed)
>>both devices get properly recognized by the system with both types of
>>kernels (otherwise they couldn't get connected via the midi-connect-tab),
>>but on realtime-kernels the above problem occurs Tested Computer-Hardware:
>>- 800 MHz Pentium desktop-PC
>>- 500 MHz Celeron old notebook
>>- 1,4 GHz Pentium-M new notebook
>>
>>Marcos, can you please add this at
>>https://www.musix.org.ar/drupal/?q=forum/16 if it confirms to be a bug? (I
>>don't know if the bug list is actually in use...)
>>
>>Thanks for the work on Musix,
>>Jens
> 
> 
> Thanks you, Bug reported into the forum.
> 
> Hey: maybve that's a problem with the 2.6.15.x kernels, so, we will have to 
> wait our kernel hacker to build anotherone.
> 
> BTW: is the 2.6.16-beyond4.1 good enough for MIDI work for you?
> 
> Regards
> 
> 
>>_______________________________________________
>>Musix GNU+Linux - www.musix.org.ar
>>Musix-users mailing list
>>Musix-users at lists.ourproject.org
>>https://lists.ourproject.org/cgi-bin/mailman/listinfo/musix-users
> 
> 