thanx, I thought jack midi was only used by soundcards with midi support, like some firewire cards for example..?
... and several midi applications ... and you can bridge the two different systems if you need to pass midi on to an app that does not support jack-midi.
I am not sure how reasonable it would be for your usb connection to use jack-midi rather than alsa-midi (perhaps jack-midi is mainly for midi between applications rather than with hardware?), but it would be worth looking into as it would help with the timing issues you have, especially as you say you are trying to use midi much faster than the original protocol allowed for ... which is obviously much more possible over usb than serial.
Simon
thanx for your response Simon, I've been tweeking with the usb endpoints on my device and have already gotten a faster and steadier performance with alsa-midi via jack. but it is a balance of how many bytes you can send at the same time and at what speed, as usb midi also support a bulk mode..you can send up to 64bytes of midi messages at a single call but without a speed request.
but for my purpose right now it works best with 4bytes at 1ms interrupt...as usbmidi is 4bytes i can send 1 message at the time if wanted to use 8 so i can always send the platter info and another midi-message at the same time but then i need to adjust the speed already for it to work properly
though connecting Pd directly to /dev/midi1 has no problem with all this.....i believe jack alsa-midi does a tme sync for midi with the audio. i'm going to see if i can write a simple jackd wrapper for oss /dev/midi from one of the jack simple midi examples, or perhaps someone already did.. it seems a bit useless as the oss usb device is probably an emulation of alsa who is really driving the device, but maybe it works
best, Rob