Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757956AbYFTQkZ (ORCPT ); Fri, 20 Jun 2008 12:40:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752984AbYFTQkJ (ORCPT ); Fri, 20 Jun 2008 12:40:09 -0400 Received: from hp3.statik.tu-cottbus.de ([141.43.120.68]:48994 "EHLO hp3.statik.tu-cottbus.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752150AbYFTQkI (ORCPT ); Fri, 20 Jun 2008 12:40:08 -0400 Message-ID: <485BDCE4.2010303@s5r6.in-berlin.de> Date: Fri, 20 Jun 2008 18:37:56 +0200 From: Stefan Richter User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8.1.13) Gecko/20080313 SeaMonkey/1.1.9 MIME-Version: 1.0 To: Alan Stern CC: Vegard Nossum , Matthew Wilcox , Pekka J Enberg , 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 References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1235 Lines: 27 Alan Stern wrote: > New USB devices can appear at any time. None are present when the > system is started; they are all detected dynamically by the khubd > thread. > > While I'm not familiar with the details of any other hotpluggable > buses (like Firewire), I imagine much the same is true for them. It's very similar with FireWire. FireWire devices announce SBP-2 target capability (if they have it) after they became ready. The ieee1394 or firewire core then scans or re-scans them in a process context. Then upper layer drivers like the SBP-2 driver are matched, bound, probed. If SBP-2 targets went through a power state change, they typically first power everything up (spin up media etc.) before they announce their protocol capabilities, and this may of course take a while. Before that they just are inaccessible, and it is unknown whether they could become candidates for access by upper layer drivers. -- Stefan Richter -=====-==--- -==- =-=-- http://arcgraph.de/sr/ -- 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/