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SubjectRe: [PATCH] x86_32: trim memory by updating e820 v3
On Sat, Apr 26, 2008 at 5:56 AM, Gabriel C <nix.or.die@googlemail.com> wrote:
>
> Andrew Morton wrote:
> > On Tue, 22 Jan 2008 16:23:20 -0800 Yinghai Lu <Yinghai.Lu@Sun.COM> wrote:
> >
> >> [PATCH] x86_32: trim memory by updating e820 v3
> >>
> >> when mtrr is not covering all e820 table, need to trim the ram, need to update e820
> >>
> >> reuse some code for x86_64
> >>
> >> here need to add early_get_cap and use it in early_cpu_detect, and move mtrr_bp_init early
> >>
> >> need Justine to test with his special system with bug bios.
> >>
> >> Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
> >
> > Speaking of mtrr and e820....
> >
> > Could someone please take a peek at
> > http://bugzilla.kernel.org/show_bug.cgi?id=10508 ?
> >
> > For some reason we seem to have turned this:
> >
> > [ 0.000000] BIOS-e820: 0000000000000000 - 000000000009f800 (usable)
> > [ 0.000000] BIOS-e820: 000000000009f800 - 00000000000a0000 (reserved)
> > [ 0.000000] BIOS-e820: 00000000000dc000 - 0000000000100000 (reserved)
> > [ 0.000000] BIOS-e820: 0000000000100000 - 00000000bf6d0000 (usable)
> > [ 0.000000] BIOS-e820: 00000000bf6d0000 - 00000000bf6e3000 (ACPI NVS)
> > [ 0.000000] BIOS-e820: 00000000bf6e3000 - 00000000c0000000 (reserved)
> > [ 0.000000] BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
> > [ 0.000000] BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
> > [ 0.000000] BIOS-e820: 00000000fed00000 - 00000000fed00400 (reserved)
> > [ 0.000000] BIOS-e820: 00000000fed14000 - 00000000fed1a000 (reserved)
> > [ 0.000000] BIOS-e820: 00000000fed1c000 - 00000000fed90000 (reserved)
> > [ 0.000000] BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
> > [ 0.000000] BIOS-e820: 00000000ff000000 - 0000000100000000 (reserved)
> > [ 0.000000] BIOS-e820: 0000000100000000 - 0000000140000000 (usable)
> >
> > into this:
> >
> > reg00: base=0xc0000000 (3072MB), size=1024MB: uncachable, count=1
> > reg01: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1
> > reg02: base=0x100000000 (4096MB), size=1024MB: write-back, count=1
> > reg03: base=0xbf700000 (3063MB), size= 1MB: uncachable, count=1
> > reg04: base=0xbf800000 (3064MB), size= 8MB: uncachable, count=1
> >
> > which screws up the X server's attempt to map the video memory at
> > 0xd0000000.
>
> I see that on my box with ASUS P5E-VM DO and 4G RAM.
> It has an Q35 intel chipset and the intel card is set to use 256MB in BIOS.
>
> I tested 2.6.{24*,25,25-next,25-latest-git} 32/64 bit.
>
> Also I get the mtrr type mismatch message on 32 and 64 bit kernels.
>
> ...
>
> [ 0.000000] BIOS-provided physical RAM map:
> [ 0.000000] BIOS-e820: 0000000000000000 - 000000000009ec00 (usable)
> [ 0.000000] BIOS-e820: 000000000009ec00 - 00000000000a0000 (reserved)
> [ 0.000000] BIOS-e820: 00000000000e4000 - 0000000000100000 (reserved)
> [ 0.000000] BIOS-e820: 0000000000100000 - 00000000cf550000 (usable)
> [ 0.000000] BIOS-e820: 00000000cf550000 - 00000000cf55e000 (ACPI data)
> [ 0.000000] BIOS-e820: 00000000cf55e000 - 00000000cf5e0000 (ACPI NVS)
> [ 0.000000] BIOS-e820: 00000000cf5e0000 - 00000000cf600000 (reserved)
>
> [ 0.000000] BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
> [ 0.000000] BIOS-e820: 00000000ffc00000 - 0000000100000000 (reserved)
> [ 0.000000] BIOS-e820: 0000000100000000 - 000000012c000000 (usable)
> ...
>
> cat /proc/mtrr :
>
> reg00: base=0xd0000000 (3328MB), size= 256MB: uncachable, count=1
> reg01: base=0xe0000000 (3584MB), size= 512MB: uncachable, count=1
> reg02: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1
> reg03: base=0x100000000 (4096MB), size= 512MB: write-back, count=1
> reg04: base=0x120000000 (4608MB), size= 128MB: write-back, count=1
> reg05: base=0x128000000 (4736MB), size= 64MB: write-back, count=1
> reg06: base=0xcf600000 (3318MB), size= 2MB: uncachable, count=1
>
>
> dmesg is saying :
>
> ..
>
> [ 24.012694] [drm] Initialized i915 1.6.0 20060119 on minor 0
> [ 24.175500] mtrr: type mismatch for d0000000,10000000 old: write-back new: write-combining
> [ 24.423740] set status page addr 0x00033000

another continuous MTRR mapping.

several months ago, we were talking about modifying MTRR. but Eric
said that is not safe because acpi and smi...

YH


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