I dug out my old SNES controller and USB adapter to play some classic games, and I can't seem to get it to work. Nestopia and SNES9X act like I'm not pressing any buttons when trying to configure the controller.
I tested the controller on Windows, and it works fine. The controller shows up fine on the Mac's System Profiler. Mednafen recognizes it as a controller (I think it uses SDL for input anyways), I just haven't configured it yet.
Isn't there some framework you have to have in order to use controllers with these emulators? Not sure, just throwing ideas out there.
This sounds similar to what happens to me if I start up my WoW and exit before I realize that my gamepad is connected. You see, for some reason, when initially connecting gamepads, especially those with analog axes, you need to start up a game that recognizes the pad (in my case WoW), and on the dpad do a circular motion a few times, and press all other buttons a few times, and then the system finally sees the x-y "range" for each button press and voila, no more stuck button.
Until you do so, you'll end up with a gamepad connected whose buttons are sensed as being at one extreme or the other of the x-y button press range values and thus is "stuck".