When I have USB keyboard emulation enabled on an i440fx IBM Aptiva system I get pauses and jitters in the system. They're minor (a couple milliseconds here and there) and I don't generally care except for it seems to cause issues with the gameport. From the behavior I assume the gameport is trying to fill a cap until it reaches a certain voltage and track the duration of that to determine the ohms of the pot inputs (axis value) and the timer is thrown off by the USB keyboard code causing frequent delays.

I'll get jitters and instability in the gamepad input. Just sitting there it'll bounce all over the place.

Example of jittery input: https://www.youtube.com/watch?v=SzYhve9yCwM

Disabling keyboard emulation or using [this driver](https://bretjohnson.us/) fixes the issue but I would really like it to just work.

Example of non-jittery input with USB kb emulation disabled: https://www.youtube.com/watch?v=uYdOU9TqmJ8

Example of non-jittery input with USB kb emulation enabled and the USBDOS driver loaded: https://www.youtube.com/watch?v=YCyywG19ILY

I suspect the issue is due to IBM's USB emulation handler. I _think_ flashing a different i440fx BIOS might solve this issue if it has a better implementation (if it fails I can desolder the BIOS eeprom and reflash it but would rather not), but I don't know what BIOSes might have this issue or if that's actually a valid approach on this platform.

Anyone have any knowledge of any i440fx BIOSes that don't have this issue? Does my read of the situation seem correct?