Fix the keyboard lockup problem. There were two big clues: The first was a

Fix the keyboard lockup problem.  There were two big clues:  The first was a
report that it sometimes seemed to occur during heavy video operations.  The
second was a set of kernel dates from Jansen Gotis and Michael Powell that
focused me in on the right part of the code.

Simply put, there is a hack for AT keyboards that polls the keyboard for
data 10 times a second in order to catch lost interrupts.  Lost interrupts
can occur because unlike other interrupts the AT keyboard interrupt is
edge-triggered.  This means that latency in the system can cause the
keyboard interrupt to retrigger before it is reenabled after an earlier
event but not cause any further interrupts.

There is a big hack in the system that polls for keyboard data 10 times a
second in order to detect this 'lost' interrupt case.  However, that code
was broken by the timeout->callout work I did on September 19th.  An
incorrectly placed callout_reset() stopped the polling code in its tracks.

Reported-by: Jeroen Ruigrok/asmodai <asmodai@wxs.nl>,
		Chris Pressey <cpressey@catseye.mine.nu>,
		Michael Powell <nightrecon@hotmail.com>,
		Jansen Gotis <jtgotis@gmail.com>,
		And others.