Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754845Ab3EaJf7 (ORCPT ); Fri, 31 May 2013 05:35:59 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:63863 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753367Ab3EaJfv (ORCPT ); Fri, 31 May 2013 05:35:51 -0400 MIME-Version: 1.0 In-Reply-To: <20130530220247.GA2275@roeck-us.net> References: <20130527090756.GA14258@spo001.leaseweb.com> <1369678434-13515-1-git-send-email-johannes.thumshirn@men.de> <20130527182554.GB14258@spo001.leaseweb.com> <20130528081053.GC818@jtlinux> <20130528162218.GA22351@roeck-us.net> <20130530215928.GL14258@spo001.leaseweb.com> <20130530220247.GA2275@roeck-us.net> Date: Fri, 31 May 2013 15:05:50 +0530 Message-ID: Subject: Re: [PATCH v4 1/2] watchdog: New watchdog driver for MEN A21 watchdogs From: anish singh To: Guenter Roeck Cc: Wim Van Sebroeck , Johannes Thumshirn , linux-watchdog@vger.kernel.org, linux-kernel-mail Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2012 Lines: 47 Hi Guenter, On Fri, May 31, 2013 at 3:32 AM, Guenter Roeck wrote: > On Thu, May 30, 2013 at 11:59:28PM +0200, Wim Van Sebroeck wrote: >> Hi Guenter, >> >> > On Tue, May 28, 2013 at 10:10:53AM +0200, Johannes Thumshirn wrote: >> > > On Mon, May 27, 2013 at 08:25:54PM +0200, Wim Van Sebroeck wrote: >> > > [...] >> > > > > + watchdog_set_drvdata(&a21_wdt, drv); >> > > > >> > > > I am missing the initialisation of the watchdog's timeout value here... >> > > >> > > This watchdog only knows two timeout values, 1s and 30s with the constraint >> > > that you can't go back to 30s once your in a 1s timeout without a reset of the >> > > CPLD. I could initially set it to 30s but that would be redundant. >> > > >> > I wonder - why bother with supporting one-second timeouts ? >> > >> > Is this realistic, ie can you guarantee that the watchdog will be pinged fast >> > enough to keep the system alive under all load conditions ? As far as I know >> > you can not even configure the watchdog application for less than 1 second >> > ping intervals. >> >> that's why certain drivers use a timer to keep kicking the watchdog at >> a rate of 0.5s (do a grep on HZ/2) untill userspace times out. >> (example: drivers/watchdog/pika_wdt.c or drivers/watchdog/pcwd.c). >> > Yes, I have used the same trick in a couple of my drivers. That isn't done here, > though. > > I even thought about adding this capability to the infrastructure. If you don't mind can I give it a try? > > Thanks, > Guenter > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/