From: Denis Vlasenko <vda@ilport.com.ua>
To: Christian Parpart <trapni@gentoo.org>, linux-kernel@vger.kernel.org
Subject: Re: I'm having 4GB RAM, but Linux sees just 3GB???
Date: Tue, 17 May 2005 09:34:26 +0300 [thread overview]
Message-ID: <200505170934.26701.vda@ilport.com.ua> (raw)
In-Reply-To: <200505161959.04440.trapni@gentoo.org>
On Monday 16 May 2005 20:59, Christian Parpart wrote:
> (oops)
>
> On Monday 16 May 2005 7:48 pm, Brian Gerst wrote:
> > > BIOS-e820: 0000000000000000 - 0000000000094800 (usable)
> > > BIOS-e820: 0000000000094800 - 00000000000a0000 (reserved)
> > > BIOS-e820: 00000000000c2000 - 0000000000100000 (reserved)
> > > BIOS-e820: 0000000000100000 - 00000000bff20000 (usable)
> > > BIOS-e820: 00000000bff20000 - 00000000bff2e000 (ACPI data)
> > > BIOS-e820: 00000000bff2e000 - 00000000bff80000 (ACPI NVS)
> > > BIOS-e820: 00000000bff80000 - 00000000c0000000 (reserved)
> > > BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
> > > BIOS-e820: 00000000fec00000 - 00000000fec00400 (reserved)
> > > BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
> > > BIOS-e820: 00000000fff80000 - 0000000100000000 (reserved)
> > >
> > > hmm... what does this mean?
> >
> > It means that there is a hole at 00000000c0000000 - 0000000100000000
> > (3GB-4GB) for PCI memory-mapped devices. The 4th GB of RAM should be
> > remapped by the BIOS to 4GB-5GB, but isn't. Your BIOS is either buggy
> > or misconfigured.
>
> Aiiii, that's good news.
>
> I found a "Memhole" area. But I never used to change these items.
> Unfortunately, my TYAN board reference guide isn't telling me what to change
> there for good - so - can you tell me where to find more information about
> there?
>
> If I remember correctly, it provided me the options ("Automatic"/"Manual") and
> a value list with the following items:
> 64MB 128MB, 256MB, 512MB, 1024MB 2048MB, 3G, 3.5G.
>
> and another list I can't remember by now.
>
> but *playing* around with these values didn't help much (I just reduced my
> memory in linux down to 2GB once but didn't find the right values for getting
> 4GB).
>
> So, what should I do then?
You should boot with different BIOS options and examine e820 map after
each boot, looking for setup where there is 1 Gig of RAM at 4G mark.
Also google for 'e820' to get some info on this stuff.
--
vda
next prev parent reply other threads:[~2005-05-17 6:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-16 14:04 I'm having 4GB RAM, but Linux sees just 3GB??? Christian Parpart
2005-05-16 14:44 ` Brian Gerst
2005-05-16 15:01 ` Christian Parpart
2005-05-16 17:48 ` Brian Gerst
2005-05-16 17:59 ` Christian Parpart
2005-05-17 6:34 ` Denis Vlasenko [this message]
2005-05-16 17:15 ` Peter Buckingham
2005-05-16 18:01 ` Christian Parpart
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