From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752693AbbCDXum (ORCPT ); Wed, 4 Mar 2015 18:50:42 -0500 Received: from mga11.intel.com ([192.55.52.93]:60220 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751602AbbCDXul (ORCPT ); Wed, 4 Mar 2015 18:50:41 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,343,1422950400"; d="scan'208";a="694097106" Message-ID: <54F79A42.9070801@linux.intel.com> Date: Thu, 05 Mar 2015 07:50:26 +0800 From: "Li, Aubrey" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: "Rafael J. Wysocki" , Peter Zijlstra CC: Thomas Gleixner , Alan Cox , LKML , Linux PM list , ACPI Devel Maling List , Kristen Carlson Accardi , John Stultz , Len Brown Subject: Re: [PATCH 5/6] intel_idle: Add ->enter_freeze callbacks References: <8292243.ibkmfVtXac@vostro.rjw.lan> <2407992.WHaFxrNaoa@vostro.rjw.lan> <20150212132643.GY23123@twins.programming.kicks-ass.net> <25445086.IBiaGBbm1j@vostro.rjw.lan> In-Reply-To: <25445086.IBiaGBbm1j@vostro.rjw.lan> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/2/13 0:24, Rafael J. Wysocki wrote: > On Thursday, February 12, 2015 02:26:43 PM Peter Zijlstra wrote: >> >> Why bother with enter_freeze() for any but the deepest state (C6 in this >> case)? > > User space may disable the deepest one (and any of them in general) via sysfs > and there's no good reason to ignore its choice in this particular case while > we're honoring it otherwise. > > So the logic is basically "find the deepest one which isn't disabled" and > setting the pointers costs us nothing really. > If the user has chance to disable C6 via /sys, that means c6 works? Shouldn't we ignore user space setting during freeze? Otherwise, we will lost S0ix? Thanks, -Aubrey