Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761214AbXIVKV0 (ORCPT ); Sat, 22 Sep 2007 06:21:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752196AbXIVKVT (ORCPT ); Sat, 22 Sep 2007 06:21:19 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:45935 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752192AbXIVKVS (ORCPT ); Sat, 22 Sep 2007 06:21:18 -0400 From: "Rafael J. Wysocki" To: Kyle Moffett Subject: Re: [linux-pm] Re: [RFC][PATCH 1/2 -mm] kexec based hibernation -v3: kexec jump Date: Sat, 22 Sep 2007 12:34:17 +0200 User-Agent: KMail/1.9.5 Cc: Jeremy Maitin-Shepard , Alan Stern , Nigel Cunningham , nigel@suspend2.net, Kexec Mailing List , linux-kernel@vger.kernel.org, "Eric W. Biederman" , "Huang, Ying" , linux-pm@lists.linux-foundation.org, huang ying , Andrew Morton References: <878x6z67n8.fsf@jbms.ath.cx> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200709221234.18426.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1927 Lines: 39 On Saturday, 22 September 2007 01:19, Kyle Moffett wrote: > On Sep 21, 2007, at 17:16:59, Jeremy Maitin-Shepard wrote: > > "Rafael J. Wysocki" writes: > >> The ACPI platform firmware is allowed to preserve information > >> accross the hibernation-resume cycle, so this need not be the same. > > > > All of my comments related to the case where S4 is not being used > > (instead the system is just powered off normally), and a boot > > kernel that does not initialize ACPI is used. In that case, the > > ACPI platform firmware should not be able to distinguish a normal > > boot from a resume from hibernation. > > I think that in order for this to work, there would need to be some > ABI whereby the resume-ing kernel can pass its entire ACPI state and > a bunch of other ACPI-related device details to the resume-ed kernel, > which I believe it does not do at the moment. In fact we don't need to do this. The solution is not to touch ACPI in the boot kernel (ie. the one that loads the image) and pass control to the image kernel. This is how it's supposed to work according to the spec, more or less (well, there are some ugly details that need handling, like the restoration of the NVS area). > I believe that what causes problems is the ACPI state data that the kernel > stores is *different* between identical sequential boots, especially when > you add/remove/replace batteries, AC, etc. Rather the ACPI state data that the platform firmware stores may be different, depending on whether you enter S4 or S5 during "power off" and that determines the interactions between the kernel and the firmware after the next boot. Greetings, Rafael - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/