From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932651AbWF1BFM (ORCPT ); Tue, 27 Jun 2006 21:05:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932656AbWF1BFM (ORCPT ); Tue, 27 Jun 2006 21:05:12 -0400 Received: from rwcrmhc11.comcast.net ([216.148.227.151]:11670 "EHLO rwcrmhc11.comcast.net") by vger.kernel.org with ESMTP id S932651AbWF1BFK (ORCPT ); Tue, 27 Jun 2006 21:05:10 -0400 Message-ID: <44A1D5E5.3020903@acm.org> Date: Tue, 27 Jun 2006 20:05:41 -0500 From: Corey Minyard User-Agent: Thunderbird 1.5.0.2 (X11/20060517) MIME-Version: 1.0 To: Alan Cox CC: Linux Kernel , Andrew Morton , OpenIPMI Developers , Wim Van Sebroeck Subject: Re: [PATCH] watchdog: add pretimeout ioctl References: <20060627182225.GD10805@localdomain> <1151434785.32186.56.camel@localhost.localdomain> In-Reply-To: <1151434785.32186.56.camel@localhost.localdomain> X-Enigmail-Version: 0.94.0.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Alan Cox wrote: > Ar Maw, 2006-06-27 am 13:22 -0500, ysgrifennodd minyard@acm.org: > >> Some watchdog timers support the concept of a "pretimeout" which >> occurs some time before the real timeout. The pretimeout can >> be delivered via an interrupt or NMI and can be used to panic >> the system when it occurs (so you get useful information instead >> of a blind reboot). >> > > All watchdogs can do pre-timeouts in software so possibly this should > use a software fallback as well if you want good coverage ? > I hadn't thought of that, but a software emulator could be used with this interface, but it doesn't really help with hard lockups. This is primarily intended to set up watchdogs that can delver an NMI, since even if the machine is hard-locked the NMI will come through. Of course, there's all kinds of problems with getting the NMI to a useful handler, but that's another story. -Corey