Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752959Ab0BEQlI (ORCPT ); Fri, 5 Feb 2010 11:41:08 -0500 Received: from fg-out-1718.google.com ([72.14.220.157]:3179 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752123Ab0BEQlF (ORCPT ); Fri, 5 Feb 2010 11:41:05 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=CAhZjfJrMuJVztutmf1n2+tMkBHQOIvSbNg9iwaOzRFnRmYOnEz7iw9C5aSLQBvB5p 6IYOXo44iOZCWr9Jw97XdrlEpz5y3SwPLl6RIn0TrVMEY9/FIflKWlDkq4GMr732F1pa u/IjNwv7YuH53OaUKspf9sYsQx7+3vxf8x+BQ= Subject: RE: [PATCH] MMC: fix hang if card was removed during suspend and unsafe resume was enabled From: Maxim Levitsky To: Madhusudhan Cc: "'Andrew Morton'" , linux-mmc@vger.kernel.org, "'Philip Langdale'" , "'linux-kernel'" , "'Jorg Schummer'" , "'linux-pm'" In-Reply-To: <002501caa67f$0d8ef310$544ff780@am.dhcp.ti.com> References: <1265219241.12549.8.camel@maxim-laptop> <1265325495-4220-1-git-send-email-maximlevitsky@gmail.com> <20100204160957.1c51cc1b.akpm@linux-foundation.org> <1265358702.3424.8.camel@maxim-laptop> <20100205061335.b664aa20.akpm@linux-foundation.org> <1265379560.14522.2.camel@maxim-laptop> <20100205063911.05eca1c6.akpm@linux-foundation.org> <1265385120.16817.6.camel@maxim-laptop> <002501caa67f$0d8ef310$544ff780@am.dhcp.ti.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 05 Feb 2010 18:32:43 +0200 Message-ID: <1265387563.17464.3.camel@maxim-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4403 Lines: 93 On Fri, 2010-02-05 at 10:19 -0600, Madhusudhan wrote: > > > -----Original Message----- > > From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc- > > owner@vger.kernel.org] On Behalf Of Maxim Levitsky > > Sent: Friday, February 05, 2010 9:52 AM > > To: Andrew Morton > > Cc: linux-mmc@vger.kernel.org; Philip Langdale; linux-kernel; Jorg > > Schummer; linux-pm > > Subject: Re: [PATCH] MMC: fix hang if card was removed during suspend and > > unsafe resume was enabled > > > > On Fri, 2010-02-05 at 06:39 -0800, Andrew Morton wrote: > > > On Fri, 05 Feb 2010 16:19:20 +0200 Maxim Levitsky > > wrote: > > > > > > > > > > > > > There is no del_disk in the kernel. Let's be more specific (and > > > > > accurate!) about the hang. I assume it's > > > > > mmc_remove_card->device_del->kobject_uevent? > > > > Sorry! > > > > I was referring to del_gendisk. > > > > > > > > <4>[15241.042047] [] ? prepare_to_wait+0x2a/0x90 > > > > <4>[15241.042159] [] ? trace_hardirqs_on+0xd/0x10 > > > > <4>[15241.042271] [] ? > > _raw_spin_unlock_irqrestore+0x42/0x80 > > > > <4>[15241.042386] [] ? bdi_sched_wait+0x0/0x20 > > > > <4>[15241.042496] [] bdi_sched_wait+0xe/0x20 > > > > <4>[15241.042606] [] __wait_on_bit+0x5f/0x90 > > > > <4>[15241.042714] [] ? bdi_sched_wait+0x0/0x20 > > > > <4>[15241.042824] [] > > out_of_line_wait_on_bit+0x78/0x90 > > > > <4>[15241.042935] [] ? wake_bit_function+0x0/0x40 > > > > <4>[15241.043045] [] ? bdi_queue_work+0xa3/0xe0 > > > > <4>[15241.043155] [] bdi_sync_writeback+0x6f/0x80 > > > > <4>[15241.043265] [] sync_inodes_sb+0x22/0x120 > > > > <4>[15241.043375] [] __sync_filesystem+0x82/0x90 > > > > <4>[15241.043485] [] sync_filesystem+0x4b/0x70 > > > > <4>[15241.043594] [] fsync_bdev+0x2e/0x60 > > > > <4>[15241.043704] [] invalidate_partition+0x2e/0x50 > > > > <4>[15241.043816] [] del_gendisk+0x3f/0x140 > > > > <4>[15241.043926] [] mmc_blk_remove+0x33/0x60 > > [mmc_block] > > > > <4>[15241.044043] [] mmc_bus_remove+0x17/0x20 > > > > <4>[15241.044152] [] > > __device_release_driver+0x66/0xc0 > > > > <4>[15241.044264] [] > > device_release_driver+0x2d/0x40 > > > > <4>[15241.044375] [] bus_remove_device+0xb5/0x120 > > > > <4>[15241.044486] [] device_del+0x12f/0x1a0 > > > > <4>[15241.044593] [] mmc_remove_card+0x5b/0x90 > > > > <4>[15241.044702] [] mmc_sd_remove+0x27/0x50 > > > > <4>[15241.044811] [] mmc_resume_host+0x10c/0x140 > > > > <4>[15241.044929] [] sdhci_resume_host+0x69/0xa0 > > [sdhci] > > > > <4>[15241.045044] [] sdhci_pci_resume+0x8e/0xb0 > > [sdhci_pci] > > > > > > So what's the hang? del_gendisk is doing IO? I'd assumed that it was > > > because it was calling kobject_uevent, but userspace is frozen. > > > > This is a backtrace of a hang. > > > > The patch I sent tries not to remove the card during suspend, by letting > > card presence logic to run after system is fully resumed. > > > > The assumption with CONFIG_MMC_UNSAFE_RESUME is that the card remains in the > slot during suspend. The controller driver can simply ignore a card removal > event if received in the suspended state. Wouldn't that solve your problem? The assumption is that user doesn't play games with the card while system is in low power state. Why should my computer hang if I remove the card and then resume the system? > > The system would resume because of the event and reinsertion of the card > would enumerate it again. Don't know about resume on removal, bacause its not supported by most controllers, and it very very dangerous (Think about closing the lid, removing the card, and putting the system in a bag.... Best regards, Maxim Levitsky -- 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/