@kill if you have matching controllers or encoders you never have to configure player 2. Both players share the same config file. After you setup player one if you want player two working immediately in emulationstation just restart emulationstation. Retroarch emulators dont need a restart to have player 2 already working in it. You can create problems trying to find an issue with encoders wiring between both players if you setup player 2 as it overwrites any configuration you setup with player one.