Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750734AbWHPAhe (ORCPT ); Tue, 15 Aug 2006 20:37:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750736AbWHPAhe (ORCPT ); Tue, 15 Aug 2006 20:37:34 -0400 Received: from mx1.redhat.com ([66.187.233.31]:2710 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S1750734AbWHPAhd (ORCPT ); Tue, 15 Aug 2006 20:37:33 -0400 Date: Tue, 15 Aug 2006 20:37:28 -0400 From: Dave Jones To: Nigel Cunningham Cc: Linux Kernel Subject: Re: peculiar suspend/resume bug. Message-ID: <20060816003728.GA3605@redhat.com> Mail-Followup-To: Dave Jones , Nigel Cunningham , Linux Kernel References: <20060815221035.GX7612@redhat.com> <1155687599.3193.12.camel@nigel.suspend2.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1155687599.3193.12.camel@nigel.suspend2.net> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1421 Lines: 39 On Wed, Aug 16, 2006 at 10:19:59AM +1000, Nigel Cunningham wrote: > Hi Dave. > > On Tue, 2006-08-15 at 18:10 -0400, Dave Jones wrote: > > Here's a fun one. > > - Get a dual core cpufreq aware laptop (Like say, a core-duo) > > - Add a cpufreq monitor to gnome-panel. Configure it > > to watch the 2nd core. > > - Suspend. > > - Resume. > > > > Watch the cpufreq monitor die horribly. > > > > I believe this is because we take down the 2nd core at suspend > > time with cpu hotplug, and for some reason we're scheduling > > userspace before we bring that second core back up. > > > > Anyone have any clues why this is happening? > > If you hotunplug and replug the cpu using the sysfs interface, rather > than suspending and resuming, does the same thing happen? cpufreq-applet crashes as soon as the cpu goes offline. Now, the applet should be written to deal with this scenario more gracefully, but I'm questioning whether or not userspace should *see* the unplug/replug that suspend does at all. IMO, when we shouldn't schedule userspace until the system is in the exact state it was before we suspended. Dave -- http://www.codemonkey.org.uk - 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/