From owner-freebsd-arch@FreeBSD.ORG Tue Jul 29 14:06:27 2003 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E943237B401 for ; Tue, 29 Jul 2003 14:06:27 -0700 (PDT) Received: from area51.slashnet.org (area51.slashnet.org [209.150.101.138]) by mx1.FreeBSD.org (Postfix) with ESMTP id 577B143FA3 for ; Tue, 29 Jul 2003 14:06:27 -0700 (PDT) (envelope-from smkelly@freebsd.org) Received: from edgemaster.zombie.org (ip68-13-71-251.om.om.cox.net [68.13.71.251]) by area51.slashnet.org (Postfix) with ESMTP id 6623849F2A; Tue, 29 Jul 2003 17:06:23 -0400 (EDT) Received: by edgemaster.zombie.org (Postfix, from userid 1001) id D7D6C3983A; Tue, 29 Jul 2003 16:06:24 -0500 (CDT) Date: Tue, 29 Jul 2003 16:06:24 -0500 From: Sean Kelly To: Doug Ambrisko Message-ID: <20030729210624.GA45102@edgemaster.zombie.org> References: <200307292043.h6TKhBIh078195@www.ambrisko.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200307292043.h6TKhBIh078195@www.ambrisko.com> User-Agent: Mutt/1.5.4i cc: arch@freebsd.org cc: Julian Elischer Subject: Re: Remove "options HW_WDOG"? X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 29 Jul 2003 21:06:28 -0000 First, I apologize for the original crosspost between -current and -arch. On Tue, Jul 29, 2003 at 01:43:11PM -0700, Doug Ambrisko wrote: > Julian Elischer writes: > | this code WAS used in the interjet. > | We had modules that linked in and just needed somewhere to hook into.. > | the hardware watchdog was held off by our software, but we needed to add > | code to the core-dump routines to routinely call the watchdog hold-off > | or we could never get a coredump because the watchdog would always go > | off before the dump was completed. > | > | I doubt it is used by anyone any more but It's good that you asked.. > | I did notice some people were working on the watchdog support for the > | chipsets that have a watchdog in them so I guess they wil have all their > | own entrypoints. My basic point is that nothing in the 5.x tree uses the HW_WDOG knob anymore. As Bruce Evans kindly pointed out, the only use of HW_WDOG is in FreeBSD 4.x in i386/isa/wd.c, pc98/pc98/wd.c, and kern/kern_shutdown.c to "tickle" the watchdog in the middle of a crashdump. The 'wd' driver has since died and gone on to a better place, and kern_shutdown.c doesn't use HW_WDOG to call a 'tickle' function anymore. Why have an option if nothing in our tree actually uses it beyond defining a tickle function type (watchdog_tickle_fn) which is never used? If somebody is actually porting a watchdog patch from 4.x to 5.x, they have enough code to change that needing to implement their own tickle option and function should be no big deal. Is there really a reason to keep this around? Can't it be purged for a better (and complete) implementation by hardware watchdog developers? > Most sane watchdogs let you disable them. The ones I've implemented > allow this. I then added code to the panic/debugger code to disable > consmute and disable the watchdog. The old HW_WDOG code also assumed that tickling was necessary during a crashdump, though it only worked for ATA disks. There was no framework for traits such as whether a watchdog can be disabled and reenabled. I just see the current HW_WDOG bits that are still hanging around as debris that needs cleaned up since it is no longer working or used by anything in the source tree. -- Sean Kelly | PGP KeyID: D2E5E296 smkelly@FreeBSD.org | http://www.sean-kelly.org/