Earlier quoted context omitted.
XBox wired controller works well with mac as well thanks to the open source driver ( http://tattiebogle.net/index.php/ProjectRoot/Xbox360Controll... ). I have never faced any issue using the controller to play steam games on my mac.
I have kernel panic with this driver unfortunately. Wired XBox 360 with iMac 2011 and MacBook Pro 2012. Not sure what caused the issue... Because of it, I installed Windows via BootCamp and play all games over there, a bit inconvenient.
Or you could try to debug the source if you're up for that. I would try but don't have the expertise to help without seeing it and tinkering with it.