linux-kernel - Re: w83697hf_wdt.c stops watchdog on load

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Date:	Wed, 12 Mar 2008 11:54:12 +0000
From:	Pádraig Brady <P@...igBrady.com>
To:	Samuel Tardieu <sam@...1149.net>
CC:	Wim Van Sebroeck <wim@...ana.be>, junker@...uras.de,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: w83697hf_wdt.c stops watchdog on load

Samuel Tardieu wrote:
> On 11/03, Wim Van Sebroeck wrote:
> 
> | > > Isn't it a two-edged sword?
> | > 
> | > True, but one should be able to set things up so that there is no race.
> | > I.E. if you add the autodisable, it should only be done as an option.
> | > Best have it =no by default, but as least one could turn this off.
> | 
> | In my opinion it should be the other way around: the default behaviour is to
> | stop the watchdog and to let userspace (the watchdog-daemon) control the
> | watchdog. So if we add a module parameter to take over the watchdog's
> | bios-setting, then the default behaviour should be to stop the watchdog and
> | add an option that takes the value from the bios.
> 
> Hi Wim.
> 
> That was my intent: disable the watchdog by default

When doing this it would be useful to print a warning iif the watchdog was running.
I.E. the following would be possible for the w83697:

init() {
  if (watchdog_already_running) {
     printk("warning, stopping watchdog. Use the nodisable option to keep running");
     disable_watchdog();
  }
}

See the w83627 driver for how to determine watchdog is running.

>, and add an option
> not to disable it (let it untouched, so getting the BIOS setting) at
> module initialization, as Pádraig request is totally reasonable.

cool, thanks.

Pádraig.

p.s. I'm still not sure it should default to turning off.
It would be unusual for userspace to take over 60s to _start_
If that was the case then the user shouldn't enable the watchdog in the BIOS at all.
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