From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759441AbYFTPbu (ORCPT ); Fri, 20 Jun 2008 11:31:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758480AbYFTPbk (ORCPT ); Fri, 20 Jun 2008 11:31:40 -0400 Received: from palinux.external.hp.com ([192.25.206.14]:45248 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757043AbYFTPbj (ORCPT ); Fri, 20 Jun 2008 11:31:39 -0400 Date: Fri, 20 Jun 2008 09:31:37 -0600 From: Matthew Wilcox To: Vegard Nossum Cc: Alan Stern , Pekka J Enberg , Stefan Richter , linux-kernel@vger.kernel.org, dsd@gentoo.org, mdharm-usb@one-eyed-alien.net, linux-usb@vger.kernel.org, vegardno@ifi.uio.no, James.Bottomley@hansenpartnership.com, linux-scsi@vger.kernel.org, Greg KH Subject: Re: [RFC/PATCH] usb-storage: wait for device scanning before mounting root Message-ID: <20080620153137.GT4392@parisc-linux.org> References: <20080619182310.GA30833@parisc-linux.org> <19f34abd0806200815t49b59df9sd9567b52482eaee3@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <19f34abd0806200815t49b59df9sd9567b52482eaee3@mail.gmail.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 20, 2008 at 05:15:43PM +0200, Vegard Nossum wrote: > On Thu, Jun 19, 2008 at 11:39 PM, Alan Stern wrote: > > As I recall, it died because the whole notion was very poorly defined > > to begin with. The idea was to stop waiting when all the SCSI buses > > had been scanned -- but there's no way to know when that occurs because > > new buses can be added at any time. > > Can you please explain why this is? The USB spec doesn't mandate a minimum time before devices come available. There's no way for the device to say "I'm here, I will be providing USB Storage, but I'm not ready yet". So we can't know when we've enumerated all the USB devices on the system. -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."