Date: Wed, 19 Jul 1995 01:58:27 -0700 (PDT) From: "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com> To: davidg@Root.COM Cc: CVS-commiters@freefall.cdrom.com, cvs-sys@freefall.cdrom.com Subject: Re: cvs commit: src/sys/i386/include pmap.h Message-ID: <199507190858.BAA06594@gndrsh.aac.dev.com> In-Reply-To: <199507190713.AAA00404@corbin.Root.COM> from "David Greenman" at Jul 19, 95 00:13:01 am
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> > >> > >> davidg 95/07/18 23:37:13 > >> > >> Modified: sys/i386/i386 machdep.c > >> sys/i386/include pmap.h > >> Log: > >> Rewrote memory sizing code to generally deal with holes in extended memory. > >> This code change should allow certain Compaq machines with a 128K hole > >> at 16MB to work. > > > >And probably just fixed a problem for all PS/2 ABIOS class machines > >with a simliar ``hole'', but often larger (15->16MB is missing on > >a true blue PS/2 ABIOS machine.) > > Unfortunately, it doesn't yet have a mechanism that allows you to say "I > have a memory hole in this range of addresses, so please skip it". The code > tries to figure it out by itself and this will obviously fail if there are > some shared memory devices that are addressed in the hole. I'm sure you agree > that it would be bad to add that shared memory into the global page pool. :-) :-) yea, and the PS/2 has some really fun stuff in there! > I don't know how to deal with this problem. It almost needs to be a > userconfig'able sort of thing. Perhaps two configurable holes that can be > specified to map out a given area would be sufficient for most cases. For the PS/2 it would be detectable very early on, you simply need to look for a few magic tokens and find out if you have an ABIOS system, if you do 15M->16M is off limits to you. I'll agree that this should be configurable in some way, but I think your idea of 2 holes would cover 90% of what we are likely to ever run into, and the other 10% is going to be so bizzare we won't ever be able to easily deal with it. > Anyway, > my point is only that the mechanism doesn't yet exist. Well, okay, but at least a start has been made!!! -- Rod Grimes rgrimes@gndrsh.aac.dev.com Accurate Automation Company Reliable computers for FreeBSD
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