From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: Regression in suspend to ram in 2.6.31-rc kernels Date: Mon, 14 Sep 2009 21:17:03 +0200 Message-ID: <200909142117.03726.rjw@sisk.pl> References: <20090903232317.GA6760@lst.de> <200909120036.41725.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from ogre.sisk.pl ([217.79.144.158]:54715 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751063AbZINTQM (ORCPT ); Mon, 14 Sep 2009 15:16:12 -0400 In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Zdenek Kabelac Cc: Chris Ball , Pavel Machek , OGAWA Hirofumi , Christoph Hellwig , Linux Kernel Mailing List , linux-mmc@vger.kernel.org, viro@zeniv.linux.org.uk On Monday 14 September 2009, Zdenek Kabelac wrote: > 2009/9/12 Rafael J. Wysocki : > > On Saturday 12 September 2009, Chris Ball wrote: > >> Hi, > >> > >> > Well system could check basic card ids if they match after resume > >> > >> No. That (arguably) guarantees that it's the same card, but not that > >> it wasn't modified in another machine during the suspend. > > > > Generally speaking, we'd also need to check superblocks for this to work. > > > >> > if some users wants to crash his card by randomly swapping it > >> > during suspend/resume - I'd have no problem with that.... > >> > >> You should have a problem with it. Taking a card from a suspended > >> machine and working on it with a different machine is not a bizarre > >> thing to want to do. > > > > Agreed. > > > Well - ok - so let me ask this question - if I'll replace local hard > drive during suspend - what will happen - is this prohibited by hw > (e.i. to switch SATA cables) ? That I'm unsure of, but if you replace some other major components, such as the CPU or memory, the hardware will detect that and the resume will fail. > IMHO filesystem should be able to detect corruption of its data > structures - (assuming fs is notified about suspend/resume operation) Well, the problem is that at the moment such a notification mechanism doesn't exist. > Also there could be one simple quick solution/hack No hacks, please. > - to require to have at least all remote drives unmounted - so suspend would Define "remote". It isn't that simple, even your root fs can be on USB, iSCSI, whatever. > be refused if it runs mounted card/usb drive - this would be 100% better > than current solution which effectively kills my laptop if I forget to > unmount card in mmc reader - especially if dmesg contains message with > the reason why my suspend fails. You can make the suspend scripts check for that, there's no reason for the kernel to do it IMO. Thanks, Rafael