Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755416AbYJQO6j (ORCPT ); Fri, 17 Oct 2008 10:58:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754212AbYJQO6a (ORCPT ); Fri, 17 Oct 2008 10:58:30 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:44412 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754045AbYJQO6a (ORCPT ); Fri, 17 Oct 2008 10:58:30 -0400 Date: Fri, 17 Oct 2008 10:58:28 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Jeremy Fitzhardinge cc: Linux Kernel Mailing List , linux-usb Subject: Re: Oops in UHCI when encountering "host controller process error" In-Reply-To: <48F7E3B8.2090106@goop.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1096 Lines: 26 On Thu, 16 Oct 2008, Jeremy Fitzhardinge wrote: > Looks like this is the relevent detail: "uhci->skelqh[1]->node.next is > NULL" for all the queues. Haven't looked into it yet. > ------------[ cut here ]------------ > WARNING: at /home/jeremy/hg/xen/paravirt/linux/drivers/usb/host/uhci-q.c:1744 uhci_scan_schedule+0xb7/0x9a3() > uhci->skelqh[1]->node.next is NULL Odd. Is skelqh[1] the only entry whose node.next is NULL? Not skelqh[2] or others? The node is initialized during uhci_start() in uhci-hcd.c -- there's a loop which initializes all the uhci->skelqh[i] entries by calling uhci_alloc_qh(). You should check inside that loop to see whether uhci->skelqh[i]->node.next is NULL to begin with. If it is then something about the DMA-coherent memory is funny; if not then the linked list pointer gets corrupted somewhere. Alan Stern -- 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/