Re: problems with 1gb ddr memory sticks on linux
H. Peter Anvin (hpa@zytor.com)
8 Aug 2002 11:09:30 -0700
Followup to: <20020808163952.GJ16225@weccusa.org>
By author: "Bryan K. Walton" <thisisnotmyid@tds.net>
In newsgroup: linux.dev.kernel
>
> On Thu, Aug 08, 2002 at 06:47:20PM +0100, Alan Cox wrote:
> >
> > Almost certainly a BIOS problem. What typically happens when you see
> > this is that the BIOS misconfigured the MTRR registers. Linux starts
> > from top of ram windows seems to start from bottom so the effect shows
> > strongly in Linux.
> >
> > Can you post your /proc/mtrr file please
> >
> Here you go . . .
>
> Dimm slot 1 = 256MB DDR PC2100 and
> Dimm slot 2 = 1024MB DDR PC2100
>
> and the /proc/mtrr shows:
>
> casa:~# cat /proc/mtrr
> reg00: base=0x00000000 ( 0MB), size= 512MB: write-back, count=1
>
Your BIOS didn't mark the second memory chunk as cacheable, so you're
running it uncached. No wonder it sucks.
-hpa
--
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt <amsp@zytor.com>
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