From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-gx0-f21.google.com (mail-gx0-f21.google.com [209.85.217.21]) by ozlabs.org (Postfix) with ESMTP id 4204BDDE00 for ; Thu, 25 Sep 2008 21:52:23 +1000 (EST) Received: by gxk14 with SMTP id 14so6619569gxk.9 for ; Thu, 25 Sep 2008 04:52:22 -0700 (PDT) Date: Thu, 25 Sep 2008 07:51:18 -0400 From: Josh Boyer To: seokin Hong Subject: Re: Tickless and CPU Idle framework for PPC405 Message-ID: <20080925115118.GA2243@yoda.jdub.homelinux.org> References: <001301c91e90$7e0090e0$7a01b2a0$@com> <20080925001323.GA26152@yoda.jdub.homelinux.org> <002a01c91ede$d3fdd310$7bf97930$@com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <002a01c91ede$d3fdd310$7bf97930$@com> Cc: linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Sep 25, 2008 at 04:17:54PM +0900, seokin Hong wrote: >Generic processor idle management framework >http://ols.108.redhat.com/2007/Reprints/pallipadi-Reprint.pdf > >The interface and machine independent interface is in following directory.. >/drivers/cpuidle > >So, I wonder that the linux kernel ported for PPC405 use this framework to >save power. No. PPC4xx doesn't have multiple hardware idle states, so having a govenor to manage that doesn't really make sense. There was work done to support putting the CPU in wait state on idle for PowerPC 440 chips. That could probably be ported over. Beyond that, the cpuidle framework just seems like overkill for these CPUs. >And Is the tickless feature is added to that kernel? Tickless was added to all of PowerPC around 2.6.21 or 2.6.22 I think. I don't recall anything explicitly added for 405, but it should make use of the generic support. josh