My Presonus (Firewire 400) works in El Capitan 10.11.1 on my 2008 Macbook Pro and Logic Pro 9 appears to be working OK, but my M-Audio Midiman 2x2 Anniversary Edition doesn't want to play nice. Their web site says it's fine for El Capitan but even before this point I always had to unplug it and plug it back in after starting Logic Pro 9 or there would be this absurd input delay from my Roland Piano. In El Capitan, it shows up OK on a full boot or reboot, but the delay is there once again when I start Logic Pro 9. If I unplug/plug now, I don't get the driver back period. It just stops the input sensor LED and my Roland says Communication Error and it's "ghosted" in the Midi Control Panel in El Capitan. Rescanning, etc. doesn't work. I have to reboot to get it to come back and then it has the unusable delay problem again. Just lovely. I guess I may have to go back to Mavericks, after all. Actually, Logic Pro 9 worked best in Snow Leopard (i.e. less overhead meant more tracks before CPU ran out, but that was the only difference. Otherwise, Mountain Lion and Mavericks worked fine.)
Edit: OK, I found out some strange things by experimenting. First, I found that if I rebooted the computer but left the MIDI cables unplugged until it booted and THEN plugged them in, I got no delay the first time I ran Logic Pro. Exiting Logic Pro and restarting it resulted in the delay again, though. Nothing I did would get rid of it using those ports (B).
Then I tried something I've NEVER tried before. I used Ports A instead of Ports B. I never used Ports A for a very simple reason. The input plug is on the FRONT of the unit while the output port is on the back. Ports B have both in and out on the back. Thus, it looked so much better sitting on the piano with the MIDI cables coming out the back of the unit. Whatever is going on, though is apparently related to only the B ports. Using the A ports, there is no input delay period regardless if I exit or restart the Mac or Logic Pro 9. It survived waking from sleep too, but if I unplug the USB cable, I have to reboot to get it back. It will not recognize the device hot plugged for some insane reason. I think there's something wrong with the MIDI utility. If you even close the window or minimize it, you lose the window until you quit and restart. Something isn't right.
Edit 2: Yeah, it doesn't matter which ports are used. The problem is booting with the MIDI cables plugged in. It will delay on whatever ports are plugged in during a boot (only Midi IN matters to output to the computer for Logic synth control, though). Switching to the other set of ports afterwards cures the problem (but unlike previous OS X versions, I cannot unplug/plug. MIDI dies if I do that until I reboot. The latter is definitely some kind of bug. The Midiman is recognized by OS X in the USB port, but whatever controls MIDI won't pick it up except on a boot. Pretty frustrating, but I suppose it can at least be made to work. I'm going to send Apple feedback (for all the good it will do).
