From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933688AbcIUNYX (ORCPT ); Wed, 21 Sep 2016 09:24:23 -0400 Received: from out2-smtp.messagingengine.com ([66.111.4.26]:58532 "EHLO out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932964AbcIUNYV (ORCPT ); Wed, 21 Sep 2016 09:24:21 -0400 X-Sasl-enc: 4P5fjENRLfDgiUTKsjQUtz9JGsaG35iJAIexH60chk3Z 1474464260 Date: Wed, 21 Sep 2016 10:24:16 -0300 From: Henrique de Moraes Holschuh To: David Madore Cc: Mika Westerberg , Linux Kernel mailing-list Subject: Re: iTCO_wdt watchdog on Asus P10S-WS motherboard FREEZES MOTHERBOARD COMPLETELY Message-ID: <20160921132416.GA5574@khazad-dum.debian.net> References: <20160908170109.GA927@achernar.madore.org> <20160920125009.GQ1811@lahna.fi.intel.com> <20160921121041.GA20766@achernar.madore.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160921121041.GA20766@achernar.madore.org> X-GPG-Fingerprint1: 4096R/39CB4807 C467 A717 507B BAFE D3C1 6092 0BD9 E811 39CB 4807 User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 21 Sep 2016, David Madore wrote: > On Tue, Sep 20, 2016 at 03:50:09PM +0300, Mika Westerberg wrote: > > Does the machine have WDAT ACPI table (see /sys/firmware/acpi/tables/*)? > > If it does, you can try the new WDAT watchdog driver instead [1]. It > > still uses the same hardware, though but via set of instructions > > provided by the BIOS that should work (given the vendor has tested > > it on Windows). > > > > [1] http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1230607.html > > Thanks for pointing this out. My motherboard's BIOS does not have > this ACPI table, unfortunately, but it's at least good to know that > some do, and take the hardware watchdog seriously. The ones that take the hardware watchdog seriously will command the power supply to do a power cycle when it triggers, which pretty much cuts power to everything that is not hanging off the +5VSB (standby power) line. Let's just say that SSDs don't like it, at all. Avoid at *all* *costs*. I have been using the kernel's software watchdog on most systems because of that: it just soft-reboots, which is good enough almost every time and doesn't mess with the SSDs. The proper fix is to have two levels of watchdogs, a soft reboot on time T for the first level, and a power cycle on time 5T (to give the BIOS enough of a time window to reset the second level watchdog during a soft reboot). -- Henrique Holschuh