Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755145AbYJXN5t (ORCPT ); Fri, 24 Oct 2008 09:57:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753044AbYJXN5j (ORCPT ); Fri, 24 Oct 2008 09:57:39 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:54194 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751307AbYJXN5i (ORCPT ); Fri, 24 Oct 2008 09:57:38 -0400 Date: Fri, 24 Oct 2008 09:57:37 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Larry Finger cc: Greg Kroah-Hartman , , LKML Subject: Re: [PATCH] usbcore: Limit number of 'unable to enumerate USB device' messages In-Reply-To: <49010A25.6020702@lwfinger.net> 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: 1554 Lines: 34 On Thu, 23 Oct 2008, Larry Finger wrote: > In my system, a number of messages that state "unable to enumerate USB device" > are logged. These are intermittent and likely due to some race condition > at bootup. > > Some of these happen when the EHCI driver is loaded after UHCI or OHCI, which > causes the device to be switched away from the other controller that's trying > to enumerate it, at least momentarily. This type of message is logged at most > once for each hub and occurs in about 70% of my reboots. This is normal; it is caused by userspace loading the drivers in the wrong order. ehci-hcd is supposed to be loaded before uhci-hcd or ohci-hcd, not after. There's no point trying to change the kernel to avoid it. > A more insidious form of the message occurs hundreds of times in about 10% of > reboots. They continue until the system is rebooted. This patch limits the > number of these messages to 20. Once the actual cause of this message is > located, this patch can be reverted. I would prefer to attack this problem directly rather than wallpaper over it. Can you provide more information? For example, a dmesg log with CONFIG_USB_DEBUG and CONFIG_PRINTK_TIME enabled would help. It might also help to know what the devices which can't be enumerated actually are. 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/