Re: cpufreq and kernel >2.6.15.6 is limited

From: Robert Hancock
Date: Tue May 30 2006 - 23:59:27 EST


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
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Home Page: http://www.roberthancock.com/

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