From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from bh-25.webhostbox.net ([208.91.199.152]:34881 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752785AbcDUOwZ (ORCPT ); Thu, 21 Apr 2016 10:52:25 -0400 Subject: Re: watchdoug group ping To: "fixed-term.Oleksij.Rempel" , linux-watchdog@vger.kernel.org, "Dirk.Behme" References: <57172B7C.4060407@de.bosch.com> From: Guenter Roeck Message-ID: <5718E924.2030103@roeck-us.net> Date: Thu, 21 Apr 2016 07:52:20 -0700 MIME-Version: 1.0 In-Reply-To: <57172B7C.4060407@de.bosch.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-watchdog-owner@vger.kernel.org List-Id: linux-watchdog@vger.kernel.org On 04/20/2016 12:10 AM, fixed-term.Oleksij.Rempel wrote: > Hallo all, > > my target is to provide pretimout support for devices which do not have > this functionality. > > Pre-requirement is this patchset (i contacted the author to rebase it > against latest watchdog core branch): > https://www.mail-archive.com/linux-watchdog@vger.kernel.org/msg02394.html > > The idea is to use different watchdogs/timers or what ever as one group > - one virtual device. > One driver will be responsible for reseting the system, other for > generating an interrupt on pre-timout. > It can be also useful for systems which require redundant watchdogs - > two or more watchdog pinged over one /dev/watchdog > > I assume i would need to create a master virtual watchdog driver to > bypass/broadcast all pings to child devices. > > Do you have some ideas or suggestions? > Seems to add a lot of complexity. It might be much simpler to add support for a 'soft' pretimeout in such situations, ie a timer which fires at the correct interval and results in a reset. It might even be possible to use the new internal heartbeat function for this purpose. Guenter