cpufreq/powernowd limiting CPU frequency on kernels >=2.6.16

cpufreq/powernowd limiting CPU frequency on kernels >=2.6.16

[Inter filmati]

Most recent kernel where this bug did not occur:2.6.15
Distribution:Ubuntu64bit
Hardware Environment: X2 3800+, DFI NF4 Ultra-D, X800GT
Software Environment:
Problem Description: I overclocked via bios my cpu (factory: 200x10) to 
2565mhz
(285x9), and I haven't any problems 'til 2.6.15, it goes down to 285x5 in 
idle
and up to 285x9 in full load. If I upgrade to a newer kernel, it says 1ghz 
in
idle and 1,8ghz in full load (I wonder it takes the fsb value, that is 
200mhz,
directly form cpu and not from the bios, so it assumes 200x5 in idle and 
200x9
in full load)
flapane@a64:~$ cpufreq-info
cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006
Report errors and bugs to linux@brodo.de, please.
analyzing CPU 0:
  driver: powernow-k8
  CPUs which need to switch frequency at the same time: 0 1
  hardware limits: 1000 MHz - 1.80 GHz
  available frequency steps: 1.80 GHz, 1000 MHz
  available cpufreq governors: userspace, powersave, ondemand, conservative,
performance
  current policy: frequency should be within 1000 MHz and 1.80 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1000 MHz.
analyzing CPU 1:
  driver: powernow-k8
  CPUs which need to switch frequency at the same time: 0 1
  hardware limits: 1000 MHz - 1.80 GHz
  available frequency steps: 1.80 GHz, 1000 MHz
  available cpufreq governors: userspace, powersave, ondemand, conservative,
performance
  current policy: frequency should be within 1000 MHz and 1.80 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1000 MHz.


Steps to reproduce:
simply compile a kernel >=2.6.16 and try to overclock your cpu from the bios
raising the FSB (or HT)

Flavio
www.flapane.com 

Re: cpufreq/powernowd limiting CPU frequency on kernels >=2.6.16

[thunder7]

From: Inter filmati <interfc@jumpy.it>
Date: Thu, Oct 26, 2006 at 07:08:20PM +0200
> Most recent kernel where this bug did not occur:2.6.15
> Distribution:Ubuntu64bit
> Hardware Environment: X2 3800+, DFI NF4 Ultra-D, X800GT
> Software Environment:
> Problem Description: I overclocked via bios my cpu (factory: 200x10) to 
> 2565mhz

this ugly quoting would be prevented if you used a line length of 72.

> (285x9), and I haven't any problems 'til 2.6.15, it goes down to 285x5 in 
> idle
> and up to 285x9 in full load. If I upgrade to a newer kernel, it says 1ghz 
> in
> idle and 1,8ghz in full load (I wonder it takes the fsb value, that is 
> 200mhz,
> directly form cpu and not from the bios, so it assumes 200x5 in idle and 
> 200x9
> in full load)
> 
> Steps to reproduce:
> simply compile a kernel >=2.6.16 and try to overclock your cpu from the bios
> raising the FSB (or HT)
> 
No so simple: I mildly overclocked my FSB, from 2400 to 2520 MHz and I
see:

cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006
Report errors and bugs to linux@brodo.de, please.
analyzing CPU 0:
  driver: powernow-k8
  CPUs which need to switch frequency at the same time: 0 1
  hardware limits: 1000 MHz - 2.40 GHz
  available frequency steps: 2.40 GHz, 2.20 GHz, 2.00 GHz, 1.80 GHz, 1000 MHz
  available cpufreq governors: ondemand, powersave, performance
  current policy: frequency should be within 1000 MHz and 2.40 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1000 MHz.
analyzing CPU 1:
[the same]

from demsg:
time.c: Detected 2520.575 MHz processor.

Which means that my X2 4600+ works just fine, but after overclocking
cpufreq restores it to the FSB that it should run on.

If you care about that changed, try to find out what patch caused this,
but in general, there's no support for overclocking in the kernel, and
bugreports from overclocked systems are frowned upon.

Kind regards,
Jurriaan
-- 
"What sort of timeframe did you have in mind?"
"An immediate one," I said. "The immediater the better."
	Jim Butcher - Blood Rites
Debian (Unstable) GNU/Linux 2.6.18-mm3 2x5042 bogomips load 0.91

Re: cpufreq/powernowd limiting CPU frequency on kernels >=2.6.16

[Inter filmati]

----- Original Message ----- 
From: <thunder7@xs4all.nl>
To: "Inter filmati" <interfc@jumpy.it>
Cc: <linux-kernel@vger.kernel.org>
Sent: Thursday, October 26, 2006 7:41 PM
Subject: Re: cpufreq/powernowd limiting CPU frequency on kernels >=2.6.16

> Which means that my X2 4600+ works just fine, but after overclocking
> cpufreq restores it to the FSB that it should run on.
>
> If you care about that changed, try to find out what patch caused this,
> but in general, there's no support for overclocking in the kernel, and
> bugreports from overclocked systems are frowned upon.
>
It would be kind to find out why the problem seems to show only from 2.6.16 
and not before, unfortunately I ain't so skilled to investigate into cpufreq 
source.

---
Flavio
www.flapane.com 

Re: cpufreq/powernowd limiting CPU frequency on kernels >=2.6.16

[thunder7]

From: Inter filmati <interfc@jumpy.it>
Date: Thu, Oct 26, 2006 at 07:59:41PM +0200
> >
> >If you care about that changed, try to find out what patch caused this,
> >but in general, there's no support for overclocking in the kernel, and
> >bugreports from overclocked systems are frowned upon.
> >
> It would be kind to find out why the problem seems to show only from 2.6.16 
> and not before, unfortunately I ain't so skilled to investigate into 
> cpufreq source.
> 
You could start by trying 2.6.16-rc1, -rc2, -rc3 and find out in which
kernel it changed. Then, read the changelog for that patch to find out
what changed in the cpufreq driver. So far, no great skill required.
Then, post here, mentioning which patch caused the different behaviour.

Jurriaan
-- 
Despite the best efforts of a quantum bigfoot drive (yes I know everyone
told me they suck, now I know they were right) 2.1.109ac1 is now available
	Alan Cox announcing Linux 2.1.109ac1
Debian (Unstable) GNU/Linux 2.6.18-mm3 2x5042 bogomips load 0.91