Re: cpufreq and kernel >2.6.15.6 is limited

Re: cpufreq and kernel >2.6.15.6 is limited

[Robert Hancock]

Dave Jones wrote:
> On Tue, May 30, 2006 at 05:25:26PM -0700, Eric Sandall wrote:
>  > -----BEGIN PGP SIGNED MESSAGE-----
>  > Hash: SHA1
>  > 
>  > It seems that any kernel on my Dell Inspiron 5100 after 2.6.15.6
>  > (including 2.6.17-rc5) 'breaks' my cpufreq in that up to and including
>  > 2.6.15.6 I can scale between 300MHz-2.4GHz, but after (starting with
>  > 2.6.16) I can only scale between 2.1GHz and 2.4GHz.
>  > 
>  > I've attached the files, sorted by kernel, I assume may be helpful. Let
>  > me know if you need any more.
> 
> It may have worked in the past, but the CPU has an errata which makes
> it an unsafe operation to scale below 2GHz.

There was some discussion about whether this was correct or not in this 
thread:

http://groups.google.ca/group/fa.linux.kernel/browse_thread/thread/d5b5905d7f1aa221/66c41ee3a26583b3

Did this ever get resolved? From my reading of the N60 erratum, 
disabling the 12.5% duty cycle sounds like this should be enough, 
disabling everything under 2GHz is not necessary..

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/

Re: cpufreq and kernel >2.6.15.6 is limited

[Eric Sandall]

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Robert Hancock wrote:
> Dave Jones wrote:
>> On Tue, May 30, 2006 at 05:25:26PM -0700, Eric Sandall wrote:
>>  >  > It seems that any kernel on my Dell Inspiron 5100 after 2.6.15.6
>>  > (including 2.6.17-rc5) 'breaks' my cpufreq in that up to and including
>>  > 2.6.15.6 I can scale between 300MHz-2.4GHz, but after (starting with
>>  > 2.6.16) I can only scale between 2.1GHz and 2.4GHz.
>>  >  > I've attached the files, sorted by kernel, I assume may be
>> helpful. Let
>>  > me know if you need any more.
>>
>> It may have worked in the past, but the CPU has an errata which makes
>> it an unsafe operation to scale below 2GHz.
> 
> There was some discussion about whether this was correct or not in this
> thread:
> 
> http://groups.google.ca/group/fa.linux.kernel/browse_thread/thread/d5b5905d7f1aa221/66c41ee3a26583b3
> 
> 
> Did this ever get resolved? From my reading of the N60 erratum,
> disabling the 12.5% duty cycle sounds like this should be enough,
> disabling everything under 2GHz is not necessary..

I would definitely prefer that approach of removing the problem
frequency rather than all 8.

- -sandalle

- --
Eric Sandall                     |  Source Mage GNU/Linux Developer
eric@sandall.us                  |  http://www.sourcemage.org/
http://eric.sandall.us/          |  SysAdmin @ Shock Physics @ WSU
http://counter.li.org/  #196285  |  http://www.shock.wsu.edu/
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Re: cpufreq and kernel >2.6.15.6 is limited

[Dave Jones]

On Tue, May 30, 2006 at 05:25:26PM -0700, Eric Sandall wrote:
 > -----BEGIN PGP SIGNED MESSAGE-----
 > Hash: SHA1
 > 
 > It seems that any kernel on my Dell Inspiron 5100 after 2.6.15.6
 > (including 2.6.17-rc5) 'breaks' my cpufreq in that up to and including
 > 2.6.15.6 I can scale between 300MHz-2.4GHz, but after (starting with
 > 2.6.16) I can only scale between 2.1GHz and 2.4GHz.
 > 
 > I've attached the files, sorted by kernel, I assume may be helpful. Let
 > me know if you need any more.

It may have worked in the past, but the CPU has an errata which makes
it an unsafe operation to scale below 2GHz.

		Dave

-- 
http://www.codemonkey.org.uk

cpufreq and kernel >2.6.15.6 is limited

[Eric Sandall]

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It seems that any kernel on my Dell Inspiron 5100 after 2.6.15.6
(including 2.6.17-rc5) 'breaks' my cpufreq in that up to and including
2.6.15.6 I can scale between 300MHz-2.4GHz, but after (starting with
2.6.16) I can only scale between 2.1GHz and 2.4GHz.

I've attached the files, sorted by kernel, I assume may be helpful. Let
me know if you need any more.

- -sandalle

- --
Eric Sandall                     |  Source Mage GNU/Linux Developer
eric@sandall.us                  |  http://www.sourcemage.org/
http://eric.sandall.us/          |  SysAdmin @ Shock Physics @ WSU
http://counter.li.org/  #196285  |  http://www.shock.wsu.edu/

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cpufrequtils 0.4: cpufreq-info (C) Dominik Brodowski 2004
Report errors and bugs to linux@brodo.de, please.
analyzing CPU 0:
  driver: p4-clockmod
  CPUs which need to switch frequency at the same time: 0
  hardware limits: 300 MHz - 2.40 GHz
  available frequency steps: 300 MHz, 600 MHz, 900 MHz, 1.20 GHz, 1.50 GHz, 1.80 GHz, 2.10 GHz, 2.40 GHz
  available cpufreq governors: conservative, ondemand, powersave, userspace, performance
  current policy: frequency should be within 900 MHz and 2.40 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 900 MHz.

[-- Attachment #4: 2.6.15.6.cpuinfo --]
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processor	: 0
vendor_id	: GenuineIntel
cpu family	: 15
model		: 2
model name	: Intel(R) Pentium(R) 4 CPU 2.40GHz
stepping	: 9
cpu MHz		: 1794.434
cache size	: 512 KB
fdiv_bug	: no
hlt_bug		: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 2
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid xtpr
bogomips	: 4786.98


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cpufrequtils 0.4: cpufreq-info (C) Dominik Brodowski 2004
Report errors and bugs to linux@brodo.de, please.
analyzing CPU 0:
  driver: p4-clockmod
  CPUs which need to switch frequency at the same time: 0
  hardware limits: 2.10 GHz - 2.40 GHz
  available frequency steps: 2.10 GHz, 2.40 GHz
  available cpufreq governors: conservative, ondemand, powersave, userspace, performance
  current policy: frequency should be within 2.10 GHz and 2.40 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 2.10 GHz.

[-- Attachment #10: 2.6.17-rc5.cpuinfo --]
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processor	: 0
vendor_id	: GenuineIntel
cpu family	: 15
model		: 2
model name	: Intel(R) Pentium(R) 4 CPU 2.40GHz
stepping	: 9
cpu MHz		: 2099.947
cache size	: 512 KB
fdiv_bug	: no
hlt_bug		: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 2
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe up cid xtpr
bogomips	: 4786.96


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