Mixxx crashes after reloading controller script

[Tristan Young]

Hello.

I've been working on a Pioneer DDJ-SX3 controller script, based on a different similar script.

I'm running Mixxx official release v2.3.0.8292 64bit on Windows 10 v10.0.19043 Build 19043

When I save my changes to the script, Mixxx reloads the script.

When reloading, sometimes things will go well, and sometimes they don't. It appears the Pioneer DDJ-SX3 doesn't receive its keep-alive message on-time, and exits Serato mode. When it does this, I hear the Windows 10 USB device disconnect notification sound. Mixxx has crashed by this point.

I am not using the DDJ-SX3 as a soundcard; all my Mixxx audio settings route through my Focusrite Saffire Pro 40 for now.

My repository for the script is located here:
    https://github.com/TristanYoung/mixxx

My call trace is attached to this report.

[Be (be.ing)]

Interesting... it looks like PortMidi is trying to dereference a pointer to an address which is no longer valid. I suppose the DDJ-SX3 (or the driver?) is resetting the USB connection or something. Unfortunately PortMidi does not support hotplug although we have been talking about implementing hotplug support in Mixxx for a long time.

I just forked the unmaintained PortMidi library to our GitHub organization and rewrote the build system yesterday: https://github.com/mixxxdj/portmidi
Feel free to dig in and get to the root of this.

[Tristan Young (tristan-young)]

Thank you for taking the time to look.

I wish I knew more about programming. I can't really offer much help.

Hotplugging definitely seems like a good idea, especially considering the round of random disconnect issues that used to plague the USB on my motherboard (which have since been fixed with a BIOS update).

I'm going to try to keep the controller alive by firing off one more keep-alive upon script termination - assuming of course that the shutdown function is called before the script is reloaded.

What's weird is I found another script that someone had started that doesn't exhibit this behaviour - the controller is able to remain in Serato every time the script reloads. It doesn't appear to be anything special, so perhaps it's due to the time it takes to reload, and compile the script.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/10474