From mboxrd@z Thu Jan 1 00:00:00 1970 From: Len Brown Subject: Re: [PATCH] intel_idle: disable HW auto-demotion Date: Wed, 16 Feb 2011 01:19:18 -0500 (EST) Message-ID: References: <20110119144152.GA23020@srcf.ucam.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: Received: from vms173011pub.verizon.net ([206.46.173.11]:47522 "EHLO vms173011pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751330Ab1BPGTk (ORCPT ); Wed, 16 Feb 2011 01:19:40 -0500 Received: from localhost.localdomain ([unknown] [108.7.58.61]) by vms173011.mailsrvcs.net (Sun Java(tm) System Messaging Server 7u2-7.02 32bit (built Apr 16 2009)) with ESMTPA id <0LGP00M3J5KAGNT3@vms173011.mailsrvcs.net> for linux-acpi@vger.kernel.org; Wed, 16 Feb 2011 00:19:29 -0600 (CST) In-reply-to: <20110119144152.GA23020@srcf.ucam.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Matthew Garrett Cc: linux-pm@lists.linux-foundation.org, x86@kernel.org, linux-acpi@vger.kernel.org On Wed, 19 Jan 2011, Matthew Garrett wrote: > On Tue, Jan 18, 2011 at 09:52:26PM -0500, Len Brown wrote: > > + * Disable HW auto demotion on tick-less idle kernels > > + */ > > +static unsigned int has_nhm_snb_hw_auto_demotion; > > +#ifdef CONFIG_NO_HZ > > +static unsigned int auto_demotion; > > +#else > > +static unsigned int auto_demotion = 1; > > +#endif > > What if someone boots with nohz=off? The next version of this patch will disable auto-demotion independent of HZ, on the assumption that the governor is smart enough today to get what it asks for, HZ or NO_HZ. It is also now limits the change to NHM/WSM, as SNB has auto-un-demotion to address this scenario. > Just so I'm clear on this - this is unrelated to the auto-popup on DMA, > right? Right, C2 popup is a different feature, and that is smart enought to return to the power saving state after the DMA is done. cheers, Len Brown, Intel Open Source Technology Center