From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752992Ab1GGNxU (ORCPT ); Thu, 7 Jul 2011 09:53:20 -0400 Received: from mail1.slb.deg.dub.stisp.net ([84.203.253.98]:2419 "HELO mail1.slb.deg.dub.stisp.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751748Ab1GGNxQ (ORCPT ); Thu, 7 Jul 2011 09:53:16 -0400 Message-ID: <4E15B9FD.8080003@draigBrady.com> Date: Thu, 07 Jul 2011 14:51:57 +0100 From: =?UTF-8?B?UMOhZHJhaWcgQnJhZHk=?= User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: Bjorn Helgaas CC: Wim Van Sebroeck , linux-kernel@vger.kernel.org, linux-watchdog@vger.kernel.org Subject: Re: [PATCH 0/2] [RFC] watchdog reboot timeout References: <20110706160744.4002.94920.stgit@bhelgaas.mtv.corp.google.com> In-Reply-To: <20110706160744.4002.94920.stgit@bhelgaas.mtv.corp.google.com> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/07/11 17:09, Bjorn Helgaas wrote: > I'm looking for comments on these patches. I'm not really happy with > them because they add basically identical code in each driver. I also > don't like the fact that the parameter is not generic, so I have to know > which driver will be used on my machine. Hmm, so this is protecting the window between watchdog_stop and machine_reset. It would be nice to have this as generic code that did WDIOC_SETTIMEOUT immediately after (or instead of) shutdown. Leaving a watchdog enabled across boot does have issues on some systems. It was OK for winboond based watchdogs I tested, but for some IBM server systems, "weird stuff" happened if the watchdog was left enabled across boot. Just to mention the other watchdog boot scenario I often use (which does _not_ protect your window above), which is to enable the watchdog in the BIOS. This is more general protection for the boot _up_ process. On a netboot system for example this will mean that the system will keep rebooting until whatever switch is down etc. is restored. Many systems I've used had support for this in the BIOS and those that didn't were quickly updated by vendors to do so. A related issue I noticed with iTCO_wdt is that something else in the kernel disables the iTCO watchdog (which my BIOS had started). This is undesirable for obvious reasons. cheers, Pádraig.