RE: warning in arch/x86/kernel/cpu/mtrr/generic.c:400 with 2.6.29-rc3 on IBM x3400

[Morten P.D. Stevens]

Hi,

> so there is some problem with your BIOS, please ask the vendor to
> provide one to make
> 2.6.24 happy.

I'll report the issue to the IBM support.

on our IBM x3400 servers running RHEL the same output:

2.6.18-92.1.10.el5 #

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=0xbff80000 (3071MB), size=196608MB: uncachable, count=1

and in dmesg:

mtrr: type mismatch for d0000000,1000000 old: uncachable new:
write-combining


Is this a big problem for direct usage? The performance on these servers
is still fine...?

Thanks for your assistance.

-

Morten

-----Original Message-----
From: yhlu.kernel@xxxxxxxxx [mailto:yhlu.kernel@xxxxxxxxx] On Behalf Of
Yinghai Lu
Sent: Wednesday, February 11, 2009 6:07 AM
To: Morten P.D. Stevens
Cc: Ingo Molnar; Thomas Gleixner; H. Peter Anvin; Arjan van de Ven;
linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: warning in arch/x86/kernel/cpu/mtrr/generic.c:400 with
2.6.29-rc3 on IBM x3400

On Tue, Feb 10, 2009 at 1:19 PM, Morten P.D. Stevens
<mstevens@xxxxxxxxxxxxxxxxxxxx> wrote:
> Hi,
>
>> can you post /proc/mtrr in 2.6.29-rc3 and old kernel without
> warn_on..?
>
> okay... affected are 2.6.26, 2.6.27, 2.6.28 and 2.6.29-rc3. (previous
> kernels are not tested)
> a small update: debian 2.6.26 lenny default kernel should be also
> affected.
>
> here /proc/mtrr from 2.6.28.4:
>
> ibm-x3400:~# cat /proc/mtrr
> reg00: base=0x0c0000000 ( 3072MB), size= 1024MB, count=1: uncachable
> reg01: base=0x000000000 (    0MB), size= 4096MB, count=1: write-back
> reg02: base=0x100000000 ( 4096MB), size= 1024MB, count=1: write-back
> reg03: base=0x0bff80000 ( 3071MB), size=  512KB, count=1: uncachable
>
> /proc/mtrr linux 2.6.24 (from gentoo 2008.0 amd64 livecd) no errors in
> dmesg
>
> 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=0xbff80000 (3071MB), size=196608MB: uncachable, count=1

so there is some problem with your BIOS, please ask the vendor to
provide one to make
2.6.24 happy.

YH
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