From owner-freebsd-usb@FreeBSD.ORG Thu Feb 19 05:25:31 2009 Return-Path: Delivered-To: freebsd-usb@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B2E97106566C; Thu, 19 Feb 2009 05:25:31 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from harmony.bsdimp.com (bsdimp.com [199.45.160.85]) by mx1.freebsd.org (Postfix) with ESMTP id 53ADC8FC13; Thu, 19 Feb 2009 05:25:31 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from localhost (localhost [127.0.0.1]) by harmony.bsdimp.com (8.14.2/8.14.1) with ESMTP id n1J5Mqii066338; Wed, 18 Feb 2009 22:22:52 -0700 (MST) (envelope-from imp@bsdimp.com) Date: Wed, 18 Feb 2009 22:23:01 -0700 (MST) Message-Id: <20090218.222301.1655042223.imp@bsdimp.com> To: thompsa@FreeBSD.org From: "M. Warner Losh" In-Reply-To: <20090219050200.GA84647@citylink.fud.org.nz> References: <200902170856.11631.hselasky@c2i.net> <20090217.085424.775975548.imp@bsdimp.com> <20090219050200.GA84647@citylink.fud.org.nz> X-Mailer: Mew version 5.2 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: freebsd-usb@FreeBSD.org Subject: Re: USB2+umass: root mount fails X-BeenThere: freebsd-usb@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: FreeBSD support for USB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 19 Feb 2009 05:25:31 -0000 In message: <20090219050200.GA84647@citylink.fud.org.nz> Andrew Thompson writes: : On Tue, Feb 17, 2009 at 08:54:24AM -0700, M. Warner Losh wrote: : > In message: <200902170856.11631.hselasky@c2i.net> : > Hans Petter Selasky writes: : > : On Tuesday 17 February 2009, Marcel Moolenaar wrote: : > : > > But it looks like the old usb code didn't call it either... I think : > : > > old code enumerated right away during boot, while the new code defers : > : > > the enumeration until events can be processed... : > : > : > : > Yes, you're right. USB1 used the following: : > : > : > : > SYSINIT(usb_cold_explore, SI_SUB_CONFIGURE, SI_ORDER_MIDDLE, : > : > usb_cold_explore, NULL); : > : > : > : > SI_SUB_CONFIGURE didn't complete before all USB busses : > : > were enumerated. : > : : > : I would really prefer that first time USB enumeration is not synchronous. This : > : has to do with startup timing. It simply wastes a lot of time to wait for all : > : the busses to be probed in serial. Sure it works nice with a USB keyboard and : > : a USB mouse, but when you have a couple of USB HUBs and +8 devices connected, : > : it simply speeds up the boot time so that you reach the root prompt by the : > : time you would else have done the mount root mfs. : > : : > : If the mountroot code cannot find the disk, it should sleep and loop. : > : > I think this is a weak argument. I'm strongly in favor of the usb1 : > behavior here. : : I think its slightly more complex that adding a cold explore task. Most : of the USB2 periperhel drivers defer a portion of their attach to a : thread task, a change which needs to be reverted first. As others have : said both the probe and attach must be synchronous. That's true too. The point I was trying to make wasn't that we needed a cold explore task, but more that usb should know when it is done with the probe phase and then do what other hot-plug busses have started doing. See my recent changes to dev/pccbb for one example. Warner