Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758888AbXFDVGY (ORCPT ); Mon, 4 Jun 2007 17:06:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761139AbXFDVGA (ORCPT ); Mon, 4 Jun 2007 17:06:00 -0400 Received: from hansmi.home.forkbomb.ch ([213.144.146.165]:7433 "EHLO hansmi.home.forkbomb.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761055AbXFDVF7 (ORCPT ); Mon, 4 Jun 2007 17:05:59 -0400 Date: Mon, 4 Jun 2007 23:05:55 +0200 From: Michael Hanselmann To: Alan Stern Cc: linux-kernel@vger.kernel.org, dbrownell@users.sourceforge.net, linux-usb-devel@lists.sourceforge.net, linux-kernel@killerfox.forkbomb.ch Subject: Re: [linux-usb-devel] [PATCH] Fix NEC OHCI chip silicon bug Message-ID: <20070604210555.GB12676@hansmi.ch> References: <20070602124009.GA6991@hansmi.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1901 Lines: 42 On Sat, Jun 02, 2007 at 10:49:44AM -0400, Alan Stern wrote: > Then later on, when the hub driver is resumed it will see the flag and > disconnect all the devices below the root hub. > For instance, you could force ohci-hcd to report connect-change events > on all the ports. Perhaps it does something like that anyway, in which > case you wouldn't have to worry about it. After studying the code for two evenings, I'm quite sure it does that already. A comment in ohci-hcd.c:ohci_restart reads: /* mark any devices gone, so they do nothing till khubd disconnects. * recycle any "live" eds/tds (and urbs) right away. * later, khubd disconnect processing will recycle the other state, * (either as disconnect/reconnect, or maybe someday as a reset). */ usb_root_hub_lost_power marks the ports as gone, khubd will disconnect them. After restarting the chip, khubd will cause them to be detected again. This is also what I can watch in the logs: ohci_hcd 0001:10:15.1: OHCI Unrecoverable Error, scheduling NEC chip restart usb usb2: root hub lost power or was reset usb 2-2: USB disconnect, address 2 input: appletouch disconnected usb 2-2: new full speed USB device using ohci_hcd and address 3 usb 2-2: configuration #1 chosen from 1 choice input: Apple Computer Apple Internal Keyboard / Trackpad as /class/input/input16 on usb-0001:10:15.1-2 input: appletouch as /class/input/input17 input: Apple Computer Apple Internal Keyboard / Trackpad as /class/input/input18 on usb-0001:10:15.1-2 (Actually, I added some code to trigger the error handling code, reliably reproducing it otherwise is impossible.) Thanks, Michael - 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/