Help configuring hotplug gamepad controller override for arcade controllers

[Anders]

I just built a 2p retropi cabinet with the xin mo controller and everything works great. Now I'm trying to configure retropie to also be able to use a gamepad if one is plugged into the external USB port I also built into my cabinet. How do I go about configuring this? I have confirmed all controllers are detected OK in linux as /dev/input/js0 for the gamepad, and js1 & js2 for the arcade sticks. To clarify: I don't need to use all 3 controllers, and I don't want to switch in menus or hard code which games or emulators use the gamepad - I just want retropie to use the gamepad when it's plugged in. I wouldn't mind if the left arcade controls also control the player while the gamepad is used.

Currently the gamepad will be detected in linux and by the controller config menu but I can't make it be the controller used in games (and it behaves badly in the menus too for some reason - pressing "down" will register as a "right" and after navigating back in the games list with "left" it will start autofiring "down" until it reaches the end of the list. Odd.

I'm sure this question has come up before, and a search shows me these:
https://retropie.org.uk/forum/topic/1890/switching-player-1-controller-on-the-fly/2
Very similar - but the answer is going into menus to switch (every time?) which I'd rather avoid

This question is exactly my question - but the answer seems to suggest my config should already be working!
https://retropie.org.uk/forum/topic/2443/changeover-switch

all you need to do is plug in your usb controls in the correct usb ports to set the order. The usbs on the pi have a boot order so if you have all three controls plugged in you want the extra controller to be seen as the first controller so put that controller in whatever usb port makes it the first controller. Now if you dont have that controller plugged in your arcade stick will be seen as the first controller but once you plug the "extra" controller in to the correct usb port it then automatically becomes the first controller

Edit: a third question about the same thing (from which I still couldn't figure out how exactly controllers are chosen by RetroPie)...
https://retropie.org.uk/forum/topic/5542/retropie-arcade-buttons-and-controllers

The text in the bottom left corner when I plug controllers in/out suggest that my gamepad is "port #2" while the arcade controller is "port #1" - is that why it doesn't work?

Thanks for any pointers!

Pi: 3
RetroPi: 4.1
Power supply: big JAMMA arcade PS
Controllers: Xin Mo dual + one Cheapo SNES clone

[normanmsu96]

Did you ever succeed with this? Very soon I will be looking to have 2 arcade style controllers all the time in my cocktail cab and then I would like option of plugging in gamepads occassionally.