Gamepad inputs ignored when using conveyor module

[panth77]

Any layout that uses the conveyor module seems to have an error when using gamepads (specifically tested using both a Xin-Mo 2-player gamepad encoder and 2 separate Zero-Delay USB gamepad encoders). If you hold "down" to cycle through the games list for a few seconds (perhaps long enough where scrolling acceleration would normally begin) and then release "down", the next gamepad directional input will be consistently ignored. Subsequent inputs, and repeated short inputs are not affected. It also does not appear to affect when scrolling in the "up" direction.

The problem appears to be limited specifically to gamepads, and affects all gamepads connected to the system. An x-arcade keyboard encoder attached to the same type of arcade joystick, and regular keyboards are not affected. Layouts that do not use the conveyor module appear to be unaffected.

All tests have been done in RetroPie running on a Raspberry Pi 3. AttractMode is the only software affected by these missed directional inputs. Jstest and all emulation software have no problems consistently recognizing all inputs.