linux-kernel - Re: [PATCH] e_powersaver: Underclock checks

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Message-ID: <20110713164529.GA1652@redhat.com>
Date:	Wed, 13 Jul 2011 12:45:30 -0400
From:	Dave Jones <davej@...hat.com>
To:	Rafał Bilski <rafalbilski@...eria.pl>
Cc:	Axel Lin <axel.lin@...il.com>, linux-kernel@...r.kernel.org,
	cpufreq@...r.kernel.org
Subject: Re: [PATCH] e_powersaver: Underclock checks

On Wed, Jul 13, 2011 at 05:40:22PM +0100, Rafał Bilski wrote:
 > 
 > >Some systems are using 1.2GHz@...mV processors running at 600MHz@...mV.
 > OK. That's strange. It is 1,2GHz system. Can both ACPI p-states and "e_powersaver"
 > drivers be running at the same time? 

no

 > Can BIOS change processor frequencies without
 > Linux knowing and without p-states driver loaded?

yes. Usually via SMI. some laptops do this when switching between power/battery,
and/or when overheating.

cpufreq usually detects when this happens and logs messages.

	Dave

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