Mailinglist Archive: opensuse-kernel (69 mails)

< Previous Next >
Re: [opensuse-kernel] kernel & BIOS report (incorrectly?) different current/available speeds for overclocked CPU
  • From: Jeff Mahoney <jeffm@xxxxxxxx>
  • Date: Mon, 03 Aug 2009 10:33:26 -0400
  • Message-id: <4A76F536.6080305@xxxxxxxx>
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Jan Beulich wrote:
PGNet Dev <pgnet.dev+oskrn@xxxxxxxxx> 02.08.09 20:27 >>>
i've built up a new openSUSE server on a

mobo: ASUS M3A78-CM, BIOS r1903
cpu: AMD 2.8GHz Phenom II X4 920 (Black)

@ BIOS, i've overclocked the CPU by 33% from 2.8Hz -> 1.33 x 2.*8 = 3.7GHz.

booting to OS, the reported(/available) CPU freq is NOT that which the
BIOS reports.

questions:

(1) is this a bug, or expected behavior for OC'ing?
(2) if a bug, is it in kernel, or BIOS?

BIOS: Both this

available frequency steps: 2.80 GHz, 2.10 GHz, 1.60 GHz, 800 MHz

and (presumably, as you didn't show it) /var/log/messages would confirm
this. The identifiers for the corresponding frequencies are stored in ACPI
tables and/or MSRs, so if the BIOS "supported" overclocking, it would have
to update these tables/registers (the actual frequencies get calculated
from these identifiers).

The value /proc/cpuinfo reports is simply one of the frequencies reported
as available.

The thing is that the non-CnQ mode is reported as 3.7 GHz. I don't know
enough about CnQ to know why that is - but values outside of the
original tables are getting reported if we're seeing the 3.7 GHz there.

- -Jeff

- --
Jeff Mahoney
SUSE Labs
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.9 (GNU/Linux)
Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org

iEYEARECAAYFAkp29TYACgkQLPWxlyuTD7L0JQCfWOK86nMY2u4o+FGIxi7oWudq
Qf8An2AVfnTC1IvVWwXrPDY6/04+H3Dt
=qTYr
-----END PGP SIGNATURE-----
--
To unsubscribe, e-mail: opensuse-kernel+unsubscribe@xxxxxxxxxxxx
For additional commands, e-mail: opensuse-kernel+help@xxxxxxxxxxxx

< Previous Next >
List Navigation
Follow Ups
References