From: Guenter Roeck <linux@roeck-us.net>
To: Doug Anderson <dianders@chromium.org>, wim@iguana.be
Cc: jszhang@marvell.com, linux-watchdog@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] watchdog: dw_wdt: keepalive the watchdog at write time
Date: Thu, 07 May 2015 18:47:46 -0700 [thread overview]
Message-ID: <554C15C2.60802@roeck-us.net> (raw)
In-Reply-To: <1431036564-4189-2-git-send-email-dianders@chromium.org>
On 05/07/2015 03:09 PM, Doug Anderson wrote:
> If you've got code that does this in a tight loop
> 1. Open watchdog
> 2. Send 'expect close'
> 3. Close watchdog
> ...you'll eventually trigger a watchdog reset. You can reproduce this
> by using daisydog (1) and running:
> while true; do daisydog -c > /dev/null; done
>
> The problem is that each time you write to the watchdog for 'expect
> close' it moves the timer .5 seconds out. The timer thus never fires
> and never pats the watchdog for you.
>
> 1: http://git.chromium.org/gitweb/?p=chromiumos/third_party/daisydog.git
>
> Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
next prev parent reply other threads:[~2015-05-08 1:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-07 22:09 [PATCH 1/2] watchdog: dw_wdt: Use a mutex, not a spinlock Doug Anderson
2015-05-07 22:09 ` [PATCH 2/2] watchdog: dw_wdt: keepalive the watchdog at write time Doug Anderson
2015-05-08 1:47 ` Guenter Roeck [this message]
2015-05-08 2:41 ` Jisheng Zhang
2015-05-08 1:47 ` [PATCH 1/2] watchdog: dw_wdt: Use a mutex, not a spinlock Guenter Roeck
2015-05-08 4:01 ` Doug Anderson
2015-05-08 2:40 ` Jisheng Zhang
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