Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753342Ab3JBXck (ORCPT ); Wed, 2 Oct 2013 19:32:40 -0400 Received: from mail-pd0-f176.google.com ([209.85.192.176]:41657 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753089Ab3JBXci (ORCPT ); Wed, 2 Oct 2013 19:32:38 -0400 Date: Wed, 2 Oct 2013 16:32:32 -0700 From: Guenter Roeck To: Chris Murphy Cc: Henrik Rydberg , Josh Boyer , khali@linux-fr.org, lm-sensors@lm-sensors.org, "Linux-Kernel@Vger. Kernel. Org" Subject: Re: applesmc oops in 3.10/3.11 Message-ID: <20131002233232.GA32438@roeck-us.net> References: <20131002035156.GA566@roeck-us.net> <20131002095339.GA2716@polaris.bitmath.org> <524C1FE1.4050207@roeck-us.net> <20131002163418.GA4557@polaris.bitmath.org> <20131002164718.GA7392@roeck-us.net> <20131002172410.GA381@polaris.bitmath.org> <20131002180206.GB4811@roeck-us.net> <20131002205931.GA18939@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2943 Lines: 54 On Wed, Oct 02, 2013 at 03:34:41PM -0600, Chris Murphy wrote: > > On Oct 2, 2013, at 2:59 PM, Guenter Roeck wrote: > > > On Wed, Oct 02, 2013 at 12:33:00PM -0600, Chris Murphy wrote: > >> > >> On Oct 2, 2013, at 12:02 PM, Guenter Roeck wrote: > >> > >>> On Wed, Oct 02, 2013 at 07:24:10PM +0200, Henrik Rydberg wrote: > >>>> On Wed, Oct 02, 2013 at 09:47:18AM -0700, Guenter Roeck wrote: > >>>>> On Wed, Oct 02, 2013 at 06:34:18PM +0200, Henrik Rydberg wrote: > >>>>>>>>> One thing I have seen in all logs is the earlier "send_byte fail" message, so > >>>>>>>>> I think that is a pre-requisite. > >>>>>>>> > >>>>>>>> Not necessarily - it could be that the patch actually fixes the root > >>>>>>>> cause. One possible scenario is that on recent SMCs, some of the > >>>>>>>> commands produce more data than we actually read. This would > >>>>>>>> eventually lead to both data corruption and overflow somwhere in the > >>>>>>>> SMC internals. If the original SMC error is interpreted as a read > >>>>>>>> buffer overflow, then that problem should be fixed with this patch. > >>>>>>>> > >>>>>>> > >>>>>>> Good point. > >>>>>>> > >>>>>>> But shouldn't we at least get the "flushed %d bytes" warning message in this case ? > >>>>>> > >>>>>> The explanation I have there is that the (newer) SMC needs the > >>>>>> application to read the 'no more bytes' or it will get confused. It > >>>>>> makes sense, if the number of bytes to read is no longer specified. > >>>>>> > >>>>> You mean that just reading from APPLESMC_CMD_PORT would solve the problem ? > >>>>> That might make sense. > >>>> > >>>> It also points at the possibility of a smaller patch to test, but I > >>>> have not had the time to check this very deeply myself: > >>>> > >>> I like this patch much more than the previous patch. Chris, can you test it ? > >> > >> Yes. Building now. What kernel message should I be looking for? At least on 2011 and 2012 laptops I have yet to see an Oops related to smc. The kernel with previous patch at least is not causing problems on them so far, which works well as I can test more on the 2008 model. > >> > > None, if I understand correctly and if the patch really fixes the root cause > > of the problem. > > A vast majority of the Ooops I've had are when booting from flash media, testing Fedora installs. Is it possible the much slower kernel load and boot time is a trigger? If so, I'll look into modifying the media to accept the custom kernel and requisite fat initramfs. > Yes, that could be a possible trigger. I thought it might be triggered by faster boot (as one gets with 3.10 and 3.11), but slow boot is just as likely. Guenter -- 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/