From: Arjan van de Ven <arjan@infradead.org>
To: arun@linux.vnet.ibm.com
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Gautham R Shenoy <ego@in.ibm.com>,
Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>,
linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
Paul Mackerras <paulus@samba.org>,
Shaohua Li <shaohua.li@intel.com>, Ingo Molnar <mingo@elte.hu>,
linuxppc-dev@lists.ozlabs.org, Len Brown <lenb@kernel.org>
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.
Date: Thu, 24 Sep 2009 14:22:28 +0200 [thread overview]
Message-ID: <20090924142228.5a2ddf59@infradead.org> (raw)
In-Reply-To: <20090924051238.GA5963@linux.vnet.ibm.com>
On Thu, 24 Sep 2009 10:42:41 +0530
Arun R Bharadwaj <arun@linux.vnet.ibm.com> wrote:
> * Arun R Bharadwaj <arun@linux.vnet.ibm.com> [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
next prev parent reply other threads:[~2009-09-24 12:25 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-22 11:25 [v6 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER Arun R Bharadwaj
2009-09-22 11:27 ` [v6 PATCH 1/7]: cpuidle: cleanup drivers/cpuidle/cpuidle.c Arun R Bharadwaj
2009-09-22 11:28 ` [v6 PATCH 2/7]: cpuidle: implement a list based approach to register a set of idle routines Arun R Bharadwaj
2009-09-22 11:29 ` [v6 PATCH 3/7]: x86: refactor x86 idle power management code and remove all instances of pm_idle Arun R Bharadwaj
2009-09-22 11:30 ` [v6 PATCH 4/7]: POWER: enable cpuidle for POWER Arun R Bharadwaj
2009-09-22 11:31 ` [v6 PATCH 5/7]: pSeries/cpuidle: remove dedicate/shared idle loops, which will be moved to arch/powerpc/platforms/pseries/processor_idle.c Arun R Bharadwaj
2009-09-22 11:32 ` [v6 PATCH 6/7]: POWER: add a default_idle idle loop for POWER Arun R Bharadwaj
2009-09-22 11:33 ` [v6 PATCH 7/7]: pSeries: implement pSeries processor idle module Arun R Bharadwaj
2009-09-24 5:12 ` [v6 PATCH 0/7]: cpuidle/x86/POWER: Cleanup idle power management code in x86, cleanup drivers/cpuidle/cpuidle.c and introduce cpuidle to POWER Arun R Bharadwaj
2009-09-24 12:22 ` Arjan van de Ven [this message]
2009-09-25 7:06 ` Vaidyanathan Srinivasan
2009-09-25 8:54 ` Peter Zijlstra
2009-09-25 9:35 ` Arjan van de Ven
2009-09-25 7:20 ` Balbir Singh
2009-09-25 17:08 ` Arun R Bharadwaj
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