From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.active-venture.com ([67.228.131.205]:54619 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754063AbaCCOiK (ORCPT ); Mon, 3 Mar 2014 09:38:10 -0500 Message-ID: <531493D0.9000805@roeck-us.net> Date: Mon, 03 Mar 2014 06:38:08 -0800 From: Guenter Roeck MIME-Version: 1.0 To: Markus Pargmann , Wim Van Sebroeck CC: linux-watchdog@vger.kernel.org, kernel@pengutronix.de Subject: Re: [PATCH] watchdog: core: module param to activate watchdog References: <1393604183-8755-1-git-send-email-mpa@pengutronix.de> <20140302094323.GS1484@spo001.leaseweb.com> <20140303092747.GB24953@pengutronix.de> <20140303101940.GX1484@spo001.leaseweb.com> <20140303110932.GD24953@pengutronix.de> In-Reply-To: <20140303110932.GD24953@pengutronix.de> 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 >> To achieve what you want you should make sure that your "BIOS" starts >> with the watchdog enabled and with a very long watchdog heartbeat (so >> that it doesn't need to get pinged). Then the kernel can boot and >> userspace can start and then you can do the necessary with the >> /dev/watchdog functionality. Only thing you need to take care of is >> that you don't stop the watchdog (via a module param or something >> similar) during the probe/init of the driver. >> I believe we allready have a winbond driver doing that. Just checked: >> it's w83697hf_wdt.c with the early_disable module parameter. >> >> So, this is something that needs to be taken into account during >> probe/init of the driver and for each watchdog that needs it. >> And thus not for the first watchdog that get's registered. >> Furthermore: not all watchdog devices have a heartbeat that is long >> enough to achieve this functionality. > > Okay, thanks for the clarification. So I will change the driver and add > an appropriate paramter to it instead as the winbond driver does. > Other drivers do the same, but don't even have a module parameter to disable it if it is already running. They just ping the watchdog during initialization to delay the timeout. w83627hf_wdt.c is an example. Guenter