Excerpts from netbsd: 27-Jul-98 ps2 mouse in GENERIC kernel.
rvb@sicily.odyssey.cs.cm (1189)

> As you can see from the code change below this was a major
> typo.
> [...]
> 72c72
> < #define       PMS_INT_DISABLE 0x65    /* disable controller interrupts */
> ---
> > #define       PMS_INT_DISABLE 0x45    /* disable controller interrupts */

Can you give some more details?
This doesn't really look like a typo - the 0x65 makes some
sense as well. (The 0x65 disables the port and the interrupt,
while 0x45 disables only the interrupt.)
I'd like to understand what went wrong here. Did the hang only
happen to machines without a PS/2 mouse port?

best regards
Matthias