Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754152Ab3JBU7r (ORCPT ); Wed, 2 Oct 2013 16:59:47 -0400 Received: from mail-pa0-f51.google.com ([209.85.220.51]:38363 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754099Ab3JBU7h (ORCPT ); Wed, 2 Oct 2013 16:59:37 -0400 Date: Wed, 2 Oct 2013 13:59:31 -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: <20131002205931.GA18939@roeck-us.net> References: <4FFB3671-DDB4-40F7-BA5D-C9AA9391BDA9@colorremedies.com> <524A4384.4040403@roeck-us.net> <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> 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: 2286 Lines: 45 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. 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/