From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763635AbXGYTIh (ORCPT ); Wed, 25 Jul 2007 15:08:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753763AbXGYTIa (ORCPT ); Wed, 25 Jul 2007 15:08:30 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:3957 "EHLO spitz.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753884AbXGYTI3 (ORCPT ); Wed, 25 Jul 2007 15:08:29 -0400 Date: Wed, 25 Jul 2007 19:01:15 +0000 From: Pavel Machek To: Richard Purdie Cc: Pierre Ossman , kernel list Subject: Re: MMC/SD Root filesystem suspend/resume problems Message-ID: <20070725190115.GB10208@ucw.cz> References: <1184860419.29634.10.camel@localhost.localdomain> <20070719190309.28708be8@poseidon.drzeus.cx> <1185110313.6819.8.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1185110313.6819.8.camel@localhost.localdomain> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > Lots of Linux handhelds use MMC/SD devices as the root file system. > > > This has worked quite reliably for many kernel versions. In 2.6.22, > > > it seems that if you suspend such a system then resume it, the device > > > locks up. Trying to execute anything on the filesystem results in a > > > "Permission Denied" message. I did see a message from the MMC > > > subsystem saying it had redetected the card. There are also messages > > > on the console like "MMC: killing requests for dead queue" each time > > > you suspend/resume. > > > > The card is removed when you suspend and readded when you resume. > > That's the only safe thing we can do until we get suspend support in > > the filesystems. > > > > If you really want to shoot yourself in the foot, there is a Kconfig > > option that keeps the card around across the suspend. > > I enabled the MMC_UNSAFE_RESUME option and the problems I was seeing was > "fixed". I think having this option is a bad idea (in its current form) > as it doesn't actually stop filesystem corruption. > > With the option disabled, if a filesystem is mounted when you suspend my > tests show the filesystem is corrupted. At least if the option is > enabled, the filesystem is only corrupted if you remove the card whilst > suspended which is more preferable. Are we talking _corruption_ here, or are we talking 'the kind of corruption recoverable by fsck that happens on powerfail'? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html