From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Buesch Subject: Re: [Bugme-new] [Bug 10473] New: Infinite loop "b44: eth0: powering down PHY" Date: Fri, 18 Apr 2008 21:19:15 +0200 Message-ID: <200804182119.16195.mb@bu3sch.de> References: <200804182018.52753.mb@bu3sch.de> <9bfa9ae0804181202o601e7e86p135547ce802db88d@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: "Andrew Morton" , netdev@vger.kernel.org, bugme-daemon@bugzilla.kernel.org, "Gary Zambrano" To: "Nelson A. de Oliveira" Return-path: Received: from vs166246.vserver.de ([62.75.166.246]:59951 "EHLO vs166246.vserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760760AbYDRTTk (ORCPT ); Fri, 18 Apr 2008 15:19:40 -0400 In-Reply-To: <9bfa9ae0804181202o601e7e86p135547ce802db88d@mail.gmail.com> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: On Friday 18 April 2008 21:02:37 Nelson A. de Oliveira wrote: > Hi! > > On Fri, Apr 18, 2008 at 3:18 PM, Michael Buesch wrote: > > On Friday 18 April 2008 20:09:36 Nelson A. de Oliveira wrote: > > > On Fri, Apr 18, 2008 at 2:59 PM, Michael Buesch wrote: > > > > > b44_poll: istat = 0x00000400 > > > > > > > > Hm, a descriptor error. Smells like my DMA fix actually broke this, damit. > > > > On which architecture are you running? > > > > > > i386 here. > > > > Hm, I tested my patch on i386. > > So I'm not sure what's going on, actually. And the patch was pretty > > trivial and I really can't find a bug in it. > > So you say 2.6.24 was still working? > > Strange... compiled 2.6.24.4, 2.6.24 and 2.6.23 here and they are all > stopping with this: > > b44: eth0: Link is up at 100 Mbps, full duplex. > b44: eth0: Flow control is off for TX and off for RX. > > And it seems to keep waiting for something. The system isn't freezed > (as CTRL+ALT+DEL kills the running processes and correctly reboots the > machine). Well. 2.6.24 didn't have this message. But it could still have the actual bug, of course. So can you try applying my printk patch to a broken 2.6.24 kernel and see whether it triggers the message or not? Under normal circumstances this codepath should never trigger. > With Debian's 2.6.24.4 it is working. > With vanilla 2.6.25 and my config it just enters an infinite loop of > "b44: eth0: powering down PHY". This message was added in 2.6.25. That doesn't mean the bug was also added in 2.6.25, of course. > Can different GCC versions cause this? Can a bad .config file cause > things like that? (I am using this .config for a long time and it has > always been working correctly, at least until now) Well, possible, although unlikely. Can you try bisecting the bug? Yeah, I know about the lwn article [1] that says bisecting is baaaaaad (tm), but my opinion is different. :) It's an excellent tool for efficiently finding patches that caused bugs. But take care to really check whether device _works_ or not. Just looking at the actual "powering down PHY" will _not_ be enough, as that was only recently added, as I said. [1] http://lwn.net/Articles/278137/ -- Greetings Michael.