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

Sat Nov 4 01:38:40 CET 2006

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

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-- 
Marcos Guglielmetti  
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