From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762020AbYDYPga (ORCPT ); Fri, 25 Apr 2008 11:36:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753770AbYDYPgV (ORCPT ); Fri, 25 Apr 2008 11:36:21 -0400 Received: from adsl-67-113-118-6.dsl.sndg02.pacbell.net ([67.113.118.6]:51199 "EHLO multivac.one-eyed-alien.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753350AbYDYPgT (ORCPT ); Fri, 25 Apr 2008 11:36:19 -0400 Date: Fri, 25 Apr 2008 08:35:52 -0700 From: Matthew Dharm To: Pekka J Enberg Cc: Greg KH , Alan Stern , linux-kernel@vger.kernel.org, dsd@gentoo.org, linux-usb@vger.kernel.org, vegardno@ifi.uio.no, James.Bottomley@HansenPartnership.com, linux-scsi@vger.kernel.org Subject: Re: [RFC/PATCH] usb-storage: wait for device scanning before mounting root Message-ID: <20080425153552.GA20918@one-eyed-alien.net> Mail-Followup-To: Pekka J Enberg , Greg KH , Alan Stern , linux-kernel@vger.kernel.org, dsd@gentoo.org, linux-usb@vger.kernel.org, vegardno@ifi.uio.no, James.Bottomley@HansenPartnership.com, linux-scsi@vger.kernel.org References: <20080424225604.GA18737@kroah.com> <20080424233048.GQ16272@one-eyed-alien.net> <20080425070439.GA18915@one-eyed-alien.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="KsGdsel6WgEHnImy" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i Organization: One Eyed Alien Networks X-Copyright: (C) 2008 Matthew Dharm, all rights reserved. X-Message-Flag: Get a real e-mail client. http://www.mutt.org/ X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.1.12 (multivac.one-eyed-alien.net [127.0.0.1]); Fri, 25 Apr 2008 08:35:56 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --KsGdsel6WgEHnImy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Apr 25, 2008 at 11:19:02AM +0300, Pekka J Enberg wrote: > Hi Matthew, >=20 > On Thu, 24 Apr 2008, Matthew Dharm wrote: > > > > This also has all sorts of races between do_mounts 'waiting' and th= e actual > > > > USB device enumeration. It's entirely possible that the kernel loa= ds via > > > > BIOS, the USB drivers are loaded, that forces devices to disconnect= /reset, > > > > and they take a while to re-enumerate. During that delay, the kern= el gets > > > > to do_mount; now, no devices show in this "waiting for scan" count. >=20 > On Fri, Apr 25, 2008 at 09:30:52AM +0300, Pekka J Enberg wrote: > > > So how does that happen? ->storage_probe fails and driver core calls = it=20 > > > later at some point? >=20 > On Fri, 25 Apr 2008, Matthew Dharm wrote: > > There's no guarantee that storage_probe is going to get called in a tim= ely > > manner. >=20 > How can we add such a guarantee? Don't we have this problem with any othe= r=20 > storage devices? I doubt it. It all depends on exactly when the USB controller initializes, all relevant hubs get initialized, and the device finally discovered. Matt --=20 Matthew Dharm Home: mdharm-usb@one-eyed-alien.= net=20 Maintainer, Linux USB Mass Storage Driver I don't have a left mouse button. I only have one mouse and it's on my rig= ht. -- Customer User Friendly, 2/13/1999 --KsGdsel6WgEHnImy Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) iD8DBQFIEfpYHL9iwnUZqnkRAtbxAJ97o1foUv6LdPPcqOW8uHG6LTTAcQCfWDhu k5eZkJVM2mP0Vr/JCYTFpQI= =9eLJ -----END PGP SIGNATURE----- --KsGdsel6WgEHnImy--