Status: open
Group: v0.47
Created: Sun Oct 16, 2016 05:17 PM UTC by Albert Graef
Last Updated: Sun Oct 16, 2016 05:17 PM UTC
Owner: Miller Puckette
This has been there forever, and affects all Linux systems when using ALSA MIDI devices.
sys_alsa_putmidibyte() in s_midi_alsa.c outputs individual bytes instead of complete MIDI messages. You can clearly see this, e.g., when sending a sysex message from Pd to an ALSA MIDI output and looking at the results in kmidimon. Instead of a proper sysex message you'll get a sequence of (malformed) single-byte messages.
You can't just output single bytes of a multi-byte MIDI message with snd_seq_event_output_direct(), this only works with single-byte (such as system realtime) messages. The proper way to do this, so that it works with any MIDI message, is to use snd_midi_event_encode_byte() and output the message when it's complete. The following fix is from the pd-l2ork repo, but it should apply cleanly on the current pure-data master branch:
https://github.com/pd-l2ork/pd/commit/9f5a265