> 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
>
> please try the patch at
>
>
http://lkml.org/lkml/2008/4/28/52
>
> with mtrr_chunk_size=1g