From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755858AbZGUTEW (ORCPT ); Tue, 21 Jul 2009 15:04:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755808AbZGUTEU (ORCPT ); Tue, 21 Jul 2009 15:04:20 -0400 Received: from cs20.apochromatic.org ([204.152.189.161]:65152 "EHLO cs20.apochromatic.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755766AbZGUTER (ORCPT ); Tue, 21 Jul 2009 15:04:17 -0400 X-Greylist: delayed 523 seconds by postgrey-1.27 at vger.kernel.org; Tue, 21 Jul 2009 15:04:17 EDT Date: Tue, 21 Jul 2009 19:55:09 +0100 From: Matt Fleming To: "A, Raghu" Cc: "pierre@ossman.eu" , "dbrownell@users.sourceforge.net" , "linux-kernel@vger.kernel.org" , "Dasgupta, Romit" Subject: Re: Restoring back the system state from MMC after a successful hibernation Message-ID: <20090721185509.GA31923@console-pimps.org> References: <2A3DCF3DA181AD40BDE86A3150B27B6B02F1B9BF4C@dbde02.ent.ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2A3DCF3DA181AD40BDE86A3150B27B6B02F1B9BF4C@dbde02.ent.ti.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 21, 2009 at 07:35:55PM +0530, A, Raghu wrote: > Hi, > > I am trying a hibernate-restore procedure on my system, wherein I store the context image on a swap partition on a MMC device (/dev/mmcblk0). The hibernation process happens smoothly. However, when I try to restore back, after including "resume = /dev/mmcblk0" in the bootargs, I find that the MMC card does not get detected by the time late_initcall(software_resume) is called, as a result of which the restore does not happen. > > To resolve the problem, I have included a mmc_flush_scheduled_work() call immediately after the mmc_detect_change(host, 0) call in mmc_start_host(struct mmc_host *host) function defined in linux/drivers/mmc/core/core.c, so that instead of mmc_rescan happening sometime later, it now happens right away, and the MMC card gets detected at the end of the host's .probe() callback itself. > > /***** > > void mmc_start_host(struct mmc_host *host) > > { > mmc_power_off(host); > mmc_detect_change(host, 0); > mmc_flush_scheduled_work(); > } > > The host's probe() routine calls mmc_add_host , which in turn calls mmc_start_host. > > *****/ > > Is this approach correct? Or is there any other way I can get the MMC card detected before late_initcall(software_resume) happens? > I think this is a good idea. Based on the comment for mmc_add_host(), by the time we've exited mmc_add_host() the host should be ready to start servicing requests, so mmc_start_host() really needs to have the detected the card by the time it returns. Perhaps it would be a good idea for mmc_detect_change() to grow another argument that allows the detection to be synchronous?