what happens:
If you need to cycle off-on your USB MIDI controller during work-perform with Renoise, you might come across a problem that Renoise do not recognize that the controller is turned back on,or recogniye it after a loong time or you fiddling with MIDI setup trying to get it working.
In effect,you cannot work or perform anymore-you need to exit from Renoise to recognize the device(s) again. Frankly,it sucks a lot, and eliminate Renoise from live setup if you do live performance.
How to reproduce>
have your USB MIDI controller ready on and connected.
Start Renoise, and load your template song or whatever you like.
Check it is set up and recognized properly.
Play a few tones with your fav instrumentto be sure.
Disconnect controller from usb or cycle its off-on switch once.
See if renoise recognize it anymore.
My setup>
32 or 64 bit version of renoise (both have similar behaviour with this issue)
M-AUDIO (AVID) - X-session Pro USB MIDI controller DJ mixer
M-AUDIO (AVID) - Keystudio 49i USB MIDI controller keyboard
That is not a Renoise bug, that is a technical limitation of Windows.
For OS platforms like Mac and perhaps Linux, this might not be a big deal.
Windows is a different story, it passes on the audio system only once when the audio system is enumerated, it doesn´t update it if any changes occur.
The only solution i suspect that might work for these situations is that a side-process application is polling the audio system every 5 seconds and if any changes occur, then ordering Renoise to restart the audio system. At least it is the only way to do this in Windows. For Midi this will for sure work, i am not sure if audio devices are listed when they are already acquired by an application, specially ASIO drivers are in most cases dedicated drivers, so monitoring availability might not work in those situations.