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