Messages in this thread |  | | Date | Wed, 10 Jan 2001 17:59:46 -0800 | From | "H. Peter Anvin" <> | Subject | Re: The latest instance in the A20 farce |
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"Dunlap, Randy" wrote: > > I'm not sure about this, but I'm wondering if the > Fixed (as in Static) ACPI Description Table (FADT) > can indicate that the platform is a legacy-free system. >
Parsing ACPI is a nightmare on steroids. That is just Not An Option[TM] in a < 10K bootstrap routine.
> > > Worse, they define that port 92h, bit 1, is no longer > > A20M#... but they > > don't forbid the system from using it for other things. > > I don't quite see it that way. Where do you see that? > Maybe it just needs to be more explicit. >
It probably was *intended*, but it isn't *specified*, and in fact some manufacturers have been known to abuse this bit.
> Ch. 3 (SYS-0047) says that port 92h:bit 1 doesn't toggle/affect A20M#. > Appendix A says that port 92h is (still?) "System Control Port A" > (not defined here AFAIK). > (I haven't checked all of the other chapters/appendices.) >
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