From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [linux-pm] [RFC PATCH 0/4] save and restore ACPI NVS memory during hibernation Date: Fri, 11 Jul 2008 20:51:39 +0200 Message-ID: <20080711185139.GA6843@elf.ucw.cz> References: <1215051868.5628.32.camel@rzhang-dt.sh.intel.com> <20080708193752.GD8694@ucw.cz> <200807092137.18966.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from gprs189-60.eurotel.cz ([160.218.189.60]:33278 "EHLO gprs189-60.eurotel.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754917AbYGKSu6 (ORCPT ); Fri, 11 Jul 2008 14:50:58 -0400 Content-Disposition: inline In-Reply-To: <200807092137.18966.rjw@sisk.pl> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Rafael J. Wysocki" Cc: Zhang Rui , linux-pm , linux-acpi , linux-kernel On Wed 2008-07-09 21:37:18, Rafael J. Wysocki wrote: > On Tuesday, 8 of July 2008, Pavel Machek wrote: > > Hi! > > > > > According to the ACPI spec, ACPI NVS memory region is required to > > > be saved/restored by OS during hibernation. > > > > > > Section 15.3.2 ACPI Spec 3.0b, > > > "OSPM will call the _PTS control method some time before entering > > > a sleeping state, to allow the platform???s AML code to update > > > this memory image before entering the sleeping state. > > > After the system awakes from an S4 state, OSPM will restore this > > > memory area and call the _WAK control method to enable the BIOS > > > to reclaim its memory image." > > > > > > This patch set add the mechanism to save/restore ACPI NVS memory > > > during hibernation. > > > > > > Patch 01: call platform_begin before swsusp_shrink_memory. > > > So that we can allocate enough pages for ACPI NVS memory > > > before shrink the memory. > > > > Why is it neccessary to allocate memory for a copy? We should be able > > to save ACPI NVS area same way we are saving kernel pages, no? > > Because we want to restore it from the hibernated kernel (when it gets control > back again). Why is that important? So we can run some ACPI methods from hibernated kernel before restoring it? -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html