Because my RetroPie doesn't switch inputs when I turn on my controller
Read more in the Retropie Forum Thread
This has now took the form of some udev rules that trigger CEC commands whenever another joystick is added.
Thanks to @Sano and @psyke83 on the Retropie forum for 1upping my solution!
PR's are accepted!
You can unoffiically quasi-add and install my package like this...
curl https://raw.githubusercontent.com/superterran/SupaCEC/master/RetroPie-Setup/scriptmodules/supplementary/supacec.sh > /home/pi/RetroPie-Setup/scriptmodules/supplementary/supacec.sh
Once added, you can install using RetroPie Setup using the GUI or via the CLI with...
sudo /home/pi/RetroPie-Setup/retropie_packages.sh supacec
And SupaCEC should install and begin to run. It should also show up as an Experimental Package you can manage.