Rosegarden don't show any midi devices with OSSv4 but show them with ALSA. Timidity installed and work with OSSv4.
D. Michael McIntyre
OSS doesn't have support for MIDI devices. In 2007 they said "The MIDI programming section of this manual is currently under construction because there is no MIDI support in OSS 4.0. This section will be completed after MIDI support becomes available."
There wasn't any MIDI support in OSS back in 2001 either. I had to learn how to install ALSA to get MIDI working. It was one of the first technical challenges I had to overcome as a new Linux user. Twelve years later, no MIDI support in OSS.
Chances of implementing this request: 0