Mine
public text v1 · immutableru@mythicness:~$ DISPLAY=:0.1 dgen -f -G 800x600 -j /usr/emulators/megadrive/roms/Sonic\ and\ Knuckles\ \(JUE\)\ \[\!\].bin
sdl: Couldn't init SDL: No I/O port permissions!
main: Couldn't initialize graphics!
ru@mythicness:~$ DISPLAY=:0.1 dgen -f -G 800x600 -j /usr/emulators/megadrive/roms/Sonic\ and\ Knuckles\ \(JUE\)\ \[\!\].bin
sdl: Couldn't init SDL: No I/O port permissions!
main: Couldn't initialize graphics!