Does anyone know what the differences are between macOS Mojave and macOS Catalina for their USB MIDI class host driver implementation?
I am developing a hardware product that includes a USB MIDI interface over Full Speed USB 2.0. It exposes two In Ports and two Out Ports to the host.
On macOS Mojave, the device works. I can see all of the ports in the Audio MIDI Setup's MIDI Studio page, and I can see message traffic in both directions in Wireshark and Pocket MIDI.
In Catalina, though, the device enumerates properly and it shows up in Audio MIDI Setup's MIDI Studio page. But none of the ports show up, so I can't send messages in either direction.
I did notice that on both operating systems, the Mac will send a two-byte SYSEX message F0 F7 immediately after it sends the SetConfiguration message.
What am I missing here? What are the differences between the OSes?