From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965767AbXCIH4V (ORCPT ); Fri, 9 Mar 2007 02:56:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965771AbXCIH4V (ORCPT ); Fri, 9 Mar 2007 02:56:21 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:58667 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965767AbXCIH4U (ORCPT ); Fri, 9 Mar 2007 02:56:20 -0500 From: "Rafael J. Wysocki" To: Pavel Machek Subject: Re: [PATCH] swsusp: Disable nonboot CPUs before entering platform suspend Date: Fri, 9 Mar 2007 08:58:55 +0100 User-Agent: KMail/1.9.5 Cc: Andrew Morton , LKML References: <200703072044.12021.rjw@sisk.pl> <20070307210716.GA4913@ucw.cz> In-Reply-To: <20070307210716.GA4913@ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200703090858.55632.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, 7 March 2007 22:07, Pavel Machek wrote: > Hi! > > > Prevent the WARN_ON() in arch/x86_64/kernel/acpi/sleep.c:init_low_mapping() > > from triggering by disabling nonboot CPUs before we finally enter the platform > > suspend. > > > > Signed-off-by: Rafael J. Wysocki > > --- > > kernel/power/disk.c | 1 + > > kernel/power/user.c | 2 +- > > 2 files changed, 2 insertions(+), 1 deletion(-) > > > > Index: linux-2.6.21-rc2-mm2/kernel/power/disk.c > > =================================================================== > > --- linux-2.6.21-rc2-mm2.orig/kernel/power/disk.c > > +++ linux-2.6.21-rc2-mm2/kernel/power/disk.c > > @@ -61,6 +61,7 @@ static void power_down(suspend_disk_meth > > switch(mode) { > > case PM_DISK_PLATFORM: > > if (pm_ops && pm_ops->enter) { > > + disable_nonboot_cpus(); > > kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK); > > pm_ops->enter(PM_SUSPEND_DISK); > > break; > > ...so, if pm_ops is non-null, power_down does nonboot cpu disabling, > otherwise we proceed with cpus enabled? > > That looks ugly. > > Is the warning bogus? Well, maybe. I'm not sure. > Or maybe we should *always* disable nonboot cpus in powerdown path? I think we should do that. > > Index: linux-2.6.21-rc2-mm2/kernel/power/user.c > > =================================================================== > > --- linux-2.6.21-rc2-mm2.orig/kernel/power/user.c > > +++ linux-2.6.21-rc2-mm2/kernel/power/user.c > > @@ -398,9 +398,9 @@ static int snapshot_ioctl(struct inode * > > > > case PMOPS_ENTER: > > if (data->platform_suspend) { > > + disable_nonboot_cpus(); > > kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK); > > error = pm_ops->enter(PM_SUSPEND_DISK); > > - error = 0; > > } > > break; > > Foe an userland application, disabling cpus during pmops_enter is at > least surprising....... Yes, but this is not a usual ioctl(). OTOH, we can call enable_nonboot_cpus() if pm_ops->enter(PM_SUSPEND_DISK) returns an error (otherwise it souldn't return at all, no?). Rafael