Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758139AbZGHTzO (ORCPT ); Wed, 8 Jul 2009 15:55:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755910AbZGHTzD (ORCPT ); Wed, 8 Jul 2009 15:55:03 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:53390 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755355AbZGHTzA (ORCPT ); Wed, 8 Jul 2009 15:55:00 -0400 Date: Wed, 8 Jul 2009 15:54:57 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: "Michael S. Zick" cc: Oliver Neukum , Jiri Kosina , , Subject: Re: Null Pointer BUG in uhci_hcd In-Reply-To: <200907071624.37176.lkml@morethan.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: 2200 Lines: 43 On Tue, 7 Jul 2009, Michael S. Zick wrote: > Here is an example of the message paths taken - I have another 27Mbytes of the same > if this snippet isn't enough. > Jun 30 10:38:00 cb01 kernel: hub 2-0:1.0: over-current change on port 1 > Jun 30 10:38:02 cb01 kernel: hub 2-0:1.0: connect-debounce failed, port 1 disabled > Jun 30 10:38:02 cb01 kernel: hub 2-0:1.0: over-current change on port 2 > Jun 30 10:38:02 cb01 kernel: hub 2-0:1.0: over-current change on port 1 > Jun 30 10:38:04 cb01 kernel: hub 2-0:1.0: connect-debounce failed, port 1 disabled > Jun 30 10:38:04 cb01 kernel: hub 2-0:1.0: over-current change on port 2 This is typical of the errors on bus 2. ehci-hcd receives status-change interrupts because of the over-current-change flag. The hub driver tries to debounce port 1 (presumably because a device is connected there) but gives up after two seconds. Then the cycle repeats. > Jun 30 10:38:34 cb01 kernel: hub 1-0:1.0: over-current change on port 1 > Jun 30 10:38:34 cb01 kernel: ehci_hcd 0000:00:10.4: port 1 resume error -19 > Jun 30 10:38:34 cb01 kernel: hub 1-0:1.0: hub_port_status failed (err = -32) > Jun 30 10:38:34 cb01 kernel: hub 1-0:1.0: connect-debounce failed, port 1 disabled > Jun 30 10:38:34 cb01 kernel: hub 1-0:1.0: over-current change on port 2 > Jun 30 10:38:34 cb01 kernel: ehci_hcd 0000:00:10.4: port 2 resume error -19 > Jun 30 10:38:34 cb01 kernel: hub 1-0:1.0: hub_port_status failed (err = -32) > Jun 30 10:38:34 cb01 kernel: hub 1-0:1.0: connect-debounce failed, port 2 disabled This is typical of the problems on bus 1. Again we see over-current-change flags, and this time there's the "resume error -19". The only reason that code can appear is if a read returns 0xffffffff, i.e., ~(u32)0. See handshake() in ehci-hcd.c, and see the call to handshake in ehci-hub.c shortly before the line containing "resume error". It's like I said, your hardware really isn't working properly. 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/