Date: Tue, 16 Aug 2005 11:14:28 -0400 From: Martin Cracauer <cracauer@cons.org> To: Scott Long <scottl@samsco.org> Cc: Martin Cracauer <cracauer@cons.org>, freebsd-amd64@freebsd.org Subject: Re: 4 GB RAM showing up as 3, BIOS memory hole and all that Message-ID: <20050816111428.A24284@cons.org> In-Reply-To: <430173BE.4080802@samsco.org>; from scottl@samsco.org on Mon, Aug 15, 2005 at 11:03:58PM -0600 References: <20050815125657.A92343@cons.org> <20050815172250.GA32804@troutmask.apl.washington.edu> <20050815183846.A99145@cons.org> <430173BE.4080802@samsco.org>
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> You are definitely going to loose the address space from 3.75GB to 4GB > to normal PCI and APIC overhead. If you have PCI Express then you'll > likely also loose the space from 3.5 to 3.75GB. Any other space lost > beyond that would be possible but usual. And no, most AMD systems do > *NOT* remap the lost space. > > If you want a detailed analysis then please send a verbose boot message > along with a pointer to the specs on your motherboard. That will give > enough to information to say if FreeBSD is at fault or if your > motherboard is simply sub-standard. If you have time for explanations I would rather be interested to know how the above situation works in the case that you *don't* have 4 GB of RAM. Correct me if I'm wrong but: - the above 3.5 to 4.0 GB addresses are physical, not virtual - if you have less than 3.5 GB there is no physical memory at these addresses that PCI and APIC need - but if you have 4 GB there is physical memory at these addresses I don't understand how this can transparently work with and without physical RAM at 3.5-4.0 GB. I am not worrying too much about my particular board, and in any case I just fatfingered a BIOS update and it won't POST :-) It's a Arima Rioworks HDAMB http://www.rioworks.com/HDAMB.htm If people are interested I can send the boot -v afer I recover. Thanks Martin -- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Martin Cracauer <cracauer@cons.org> http://www.cons.org/cracauer/ No warranty. This email is probably produced by one of my cats stepping on the keys. No, I don't have an infinite number of cats.
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