From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [PATCH] Enable bit 11 in _PDC to advertise hw coord Date: Wed, 4 Feb 2009 12:40:36 -0800 Message-ID: <20090204204036.GB10680@suse.de> References: <20090202195717.GA24510@linux-os.sc.intel.com> <20090204085712.GF30821@kernel.dk> <20090204195331.GA905@khazad-dum.debian.net> <1233778002.4286.61.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from ns.suse.de ([195.135.220.2]:44514 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755415AbZBDUm0 (ORCPT ); Wed, 4 Feb 2009 15:42:26 -0500 Content-Disposition: inline In-Reply-To: <1233778002.4286.61.camel@localhost.localdomain> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Pallipadi, Venkatesh" Cc: Henrique de Moraes Holschuh , Jens Axboe , Len Brown , "linux-acpi@vger.kernel.org" , Chris Mason , stable kernel On Wed, Feb 04, 2009 at 12:06:42PM -0800, Pallipadi, Venkatesh wrote: > On Wed, 2009-02-04 at 11:53 -0800, Henrique de Moraes Holschuh wrote: > > On Wed, 04 Feb 2009, Jens Axboe wrote: > > > On Mon, Feb 02 2009, Pallipadi, Venkatesh wrote: > > > > > > > > Bit 11 in intel PDC definitions is meant for OS capability to handle > > > > hardware coordination of P-states. In Linux we have always supported > > > > hwardware coordination of P-states. Just let the BIOSes know that we > > > > support it, by setting this bit. > > > > > > > > Some BIOSes use this bit to choose between hardware or software coordination > > > > and without this change below, BIOSes switch to software coordination, which > > > > is not very optimal in terms of power consumption and extra wakeups from idle. > > > > > > I can confirm that this fixes the excessive reschedule ipi count on an > > > x60 with the ondemand governor. Can we please get this into 2.6.29? > > > > And, after that, -stable? > > > > Agreed. This should also go to -stable once it gets into mainline. Can someone send stable@kernel.org the git commit id when it goes into Linus's tree? thanks, greg k-h