I think this might be a hardware issue.. I've replaced the soundblaster
with an isapnp OPL3-SA card, and am not experiencing midi lockups.

Ben

On Fri, Nov 23, 2001 at 09:34:39AM -0800, collver@linuxfreemail.com wrote:
> I am using NetBSD 1.5.2 i386 with an isapnp SoundBlaster16, the MPU-401
> MIDI UART is on /dev/rmidi0.  I am tinkering with csound and midi.
> 
> Csound reads from /dev/rmidi0 and works great.  After about 10 or 15
> minutes, csound locks up.  I've reproduced this 4 times.  Every time
> there was more than one note playing, and csound locked up in the middle
> of the notes.  The csound program continues to run, it just doesn't
> receive the note-off's or any other midi events.
> 
> Using gdb, I jumped to a routine to explicitly close the file
> descriptor for /dev/rmidi0.  I built the kernel with DEBUG_AUDIO and
> DEBUG_MIDI options enabled, and the only message was when I killed
> csound, "audio_sleep: woke up st=-1".
> 
> After csound terminates, trying to open /dev/rmidi0 returns an error,
> errno == EIO.  After a few minutes, I am able to open /dev/rmidi0, but I
> don't receive any input.  However, at that point midiplay can play music
> through the MPU-401.  Can anyone give me advice for troubleshooting this?