Subject: Re: [v6 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER.

From: Arjan van de Ven <[email-masked]>
Date: Thu, 24 Sep 2009 14:22:28 +0200

On Thu, 24 Sep 2009 10:42:41 +0530
Arun R Bharadwaj <[email-masked]> wrote:

> * Arun R Bharadwaj <[email-masked]> [2009-09-22 16:55:27]:
> 
> Hi Len, (or other acpi folks),
> 
> I had a question regarding ACPI-cpuidle interaction in the current
> implementation.
> 
> Currently, every cpu (i.e. acpi_processor) registers to cpuidle as
> a cpuidle_device. So every cpu has to go through the process of
> setting up the idle states and then registering as a cpuidle device.
> 
> What exactly is the reason behind this?
> 

technically a BIOS can opt to give you C states via ACPI on some cpus,
but not on others.

in practice when this happens it tends to be a bug.. but it's
technically a valid configuration

-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org