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From: Jerry Hoemann <jerry.hoemann@hpe.com>
To: Corey Minyard <cminyard@mvista.com>
Cc: Guenter Roeck <linux@roeck-us.net>,
	Convert@minyard.net, the@minyard.net, IPMI@minyard.net,
	watchdog@minyard.net, to@minyard.net, standard@minyard.net,
	interface@minyard.net, linux-watchdog@vger.kernel.org,
	Wim Van Sebroeck <wim@linux-watchdog.org>
Subject: Re: [PATCH 02/12] watchdog: Add the ability to provide data to read
Date: Mon, 19 Aug 2019 19:09:46 -0600
Message-ID: <20190820010946.GF25435@anatevka.americas.hpqcorp.net> (raw)
In-Reply-To: <20190820002309.GI445@minyard.net>

On Mon, Aug 19, 2019 at 07:23:09PM -0500, Corey Minyard wrote:
> On Mon, Aug 19, 2019 at 03:43:45PM -0700, Guenter Roeck wrote:
> > On Mon, Aug 19, 2019 at 03:37:01PM -0500, minyard@acm.org wrote:
> > > From: Corey Minyard <cminyard@mvista.com>
> > > 
> > > This is for the read data pretimeout governor.
> > > 
> > > Signed-off-by: Corey Minyard <cminyard@mvista.com>
> > 
> > On further thought, I think it would be a bad idea to add this
> > functionality: It changes the userspace ABI for accessing the watchdog
> > device. Today, when a watchdog device is opened, it does not provide
> > read data, it does not hang, and returns immediately. A "cat" from it
> > is an easy and quick means to test if a watchdog works.
> 
> Umm, why would a "cat" from a watchdog tell you if a watchdog works?

cat /dev/watchdog starts the watchdog running.

Then one can do useful things like monitor /sys/class/watchdog/watchdogN and see
time ticking down, etc..,

echo V > /dev/watchdog stops the watchdog assuming driver supports WDIOF_MAGICCLOSE.

So I can test without having to reboot.

One can't test magic close with the proposed change as /dev/watchdog
is exclusive open.




-- 

-----------------------------------------------------------------------------
Jerry Hoemann                  Software Engineer   Hewlett Packard Enterprise
-----------------------------------------------------------------------------

  reply index

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190819203711.32599-1-minyard@acm.org>
2019-08-19 20:37 ` [PATCH 01/12] watchdog: NULL the default governor if it is unregistered minyard
2019-08-19 22:35   ` Guenter Roeck
2019-08-19 20:37 ` [PATCH 02/12] watchdog: Add the ability to provide data to read minyard
2019-08-19 21:50   ` Guenter Roeck
2019-08-19 22:43   ` Guenter Roeck
2019-08-20  0:23     ` Corey Minyard
2019-08-20  1:09       ` Jerry Hoemann [this message]
2019-08-20 12:12         ` Corey Minyard
2019-08-20 13:53           ` Guenter Roeck
2019-08-20 15:58             ` Corey Minyard
2019-08-20 17:14               ` Guenter Roeck
2019-08-20 18:16                 ` Corey Minyard
2019-08-19 20:37 ` [PATCH 03/12] watchdog: Add a pretimeout governor to provide read data minyard
2019-08-19 20:37 ` [PATCH 04/12] watchdog: Allow pretimeout governor setting to be accessed from modules minyard
2019-08-19 21:49   ` Guenter Roeck
2019-08-20  0:24     ` Corey Minyard
2019-08-19 20:37 ` [PATCH 05/12] watchdog:ipmi: Move the IPMI watchdog to drivers/watchdog minyard
2019-08-19 20:37 ` [PATCH 06/12] watchdog:ipmi: Convert over to the standard watchdog infrastructure minyard
2019-08-19 20:37 ` [PATCH 07/12] watchdog:ipmi: Add the ability to fetch the current time left minyard
2019-08-19 20:37 ` [PATCH 08/12] watchdog: Add the ability to set the action of a timeout minyard
2019-08-19 21:58   ` Guenter Roeck
2019-08-20  0:39     ` Corey Minyard
2019-08-20 14:17       ` Guenter Roeck
2019-08-20 19:39         ` Corey Minyard
2019-08-19 20:37 ` [PATCH 09/12] watchdog:ipmi: Implement action and preaction functions minyard
2019-08-19 20:37 ` [PATCH 10/12] watchdog: Add a way to set the governor through the ioctl minyard
2019-08-19 20:37 ` [PATCH 11/12] watchdog: Add a sample program that can fully use the watchdog interface minyard
2019-08-19 20:37 ` [PATCH 12/12] watchdog: Set the preaction fields for drivers supporting pretimeout minyard

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