This is new, I believe. At least, I've never encountered it before, and I'm sure I've hot-swapped in the past.

So: in PD 0.54.1, if I unplug the USB MIDI device (ie, tested both Korg nanoKontrol2 and nanoPad2), PD just up and quits. I don't need to be monitoring anything (like with [ctlin]) though the device needs to be one of my input/output devices.

I'm running up-to-date Arch Linux, kernel 6.7.1. Anyone else? Just me? Bug report, or is there a bug in my brain?

@Load074 No problems here, tried multiple devices and multiple ways and can not get hot swapping midi devices to kill pd on Slackware current (pretty much rolling release like arch) with a self compiled pd. I am going to guess it has something to do with how you manage your midi connections at the software level, what midi driver and what software do you use for the connections? Simple test would be to take as much out of the chain as possible, use alsa midi and make the connection in a terminal with aconnect assuming you are not already doing that.

@oid thanks for checking your system. It's probably an Arch-thing or, more likely, a me-thing then.

I haven't changed anything about my setup, and I've used this Arch & PD installation for at least two years now. I use Jack for audio and MIDI, and usually use PD itself to make the connections (although to be honest - and this is a question I've had for ages now - I'm confused about PD MIDI connections / ALSA MIDI / Jack MIDI, and how sometimes I can make all choices in PD, and sometimes (depending on the PD version?) I have to use Jack).

OK... one crash-during-performance later, I'm looking more closely into this.

If I have the USB device set to "Output Device" as well as "Input Device," and unplug it while PD is running, PD will crash. If, however, the device is only "Input Device" and not an "Output Device," unplugging it is no problem.

Also, if I have PD set to "MIDI Through-Port [0,1,2,3...]" (instead of looking directly to the device) and make the nanoKONTROL2 -> MIDI Through-Port in, ie, qjackctl, then I can unplug without a crash.

So! Maybe I should file a bug report? Or maybe someone else who has an input + output USB MIDI device and is running PD on Linux (or, who knows? any platform?) wants to try this out and see if it's just me?

I like to use a virtual port to connect my hardware (in windows or wine MIDI-OX), that way I can stop and start/close reopen it if I need to unplug it physically without having to interrupt any audio software running

@fishcrystals yeah, that's what I ended up doing as well. Mind you... AFTER learning the hard way on "stage" (ok, I don't usually get a literal stage to play on).

I'm still not sure why different PDs over the years have given me different options for MIDI connections (it's partially a Linux issue as well), but now I've been using the software Jack ports, then making the connections to the hardware in Jack, and everything has been predictable and reliable.

@Load074 PD uses different libraries for audio and midi based on how its compiled and what OS its talking to .. so in linux I bet there's a difference between alsa, jack, or legacy and id guess that over time thats changed when libraries either continue to get updated or not

back in the glory days of Windows XP if you unplugged a live usb midi it would not only crash out your software, possibly need a reboot, it could show up like an entirely different device and everything had to be set up all over again.. doubt anyone has tried it but vanilla is still being built for XP