Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758828Ab0FBWGT (ORCPT ); Wed, 2 Jun 2010 18:06:19 -0400 Received: from cantor.suse.de ([195.135.220.2]:52371 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758777Ab0FBWGR (ORCPT ); Wed, 2 Jun 2010 18:06:17 -0400 Date: Thu, 3 Jun 2010 08:05:56 +1000 From: Neil Brown To: "Rafael J. Wysocki" Cc: Thomas Gleixner , Alan Stern , Felipe Balbi , Arve =?UTF-8?B?SGrDuG5uZXbDpWc=?= , Peter Zijlstra , "Paul@smtp1.linux-foundation.org" , LKML , Florian Mickler , Linux OMAP Mailing List , Linux PM , Alan Cox , James Bottomley Subject: Re: [PATCH] - race-free suspend. Was: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) Message-ID: <20100603080556.46d2d671@notabene.brown> In-Reply-To: <201006022241.14152.rjw@sisk.pl> References: <20100602153235.340a7852@notabene.brown> <201006022241.14152.rjw@sisk.pl> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1236 Lines: 31 On Wed, 2 Jun 2010 22:41:14 +0200 "Rafael J. Wysocki" wrote: > On Wednesday 02 June 2010, Neil Brown wrote: > > - Would this fix the "bug"?? > > - and address the issues that suspend-blockers was created to address? > > - or are the requirements on user-space too onerous? > > In theory wakeup events can also happen after wait_for_blockers() has returned > 0 and I guess we should rollback the suspend in such cases. > I naively assumed this was already the case, but on a slightly closer look at the code it seems not. Presumably there is some point deep in the suspend code, probably after the call to sysdev_suspend, where interrupts are disabled and we are about to actually suspend. At that point a simple "is a roll-back required" test could abort the suspend. Then any driver that handles wake-up events, if it gets and event that (would normally cause a wakeup) PM_SUSPEND_PREPARE and PM_POST_SUSPEND, could set the "roll-back is required" flag. ?? NeilBrown -- 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/