Date: Tue, 30 May 2006 21:51:47 -0600
From: Robert Hancock <hancockr@shaw.ca>
Subject: Re: cpufreq and kernel >2.6.15.6 is limited
In-reply-to: <6in4s-44o-13@gated-at.bofh.it>
To: Dave Jones <davej@redhat.com>, Eric Sandall <eric@sandall.us>,
       linux-kernel@vger.kernel.org, Mattia Dongili <malattia@linux.it>
Message-id: <447D12D3.9050306@shaw.ca>
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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/

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