Re: [PATCHv2] watchdog: core: add option to avoid early handling of watchdog

From	Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCHv2] watchdog: core: add option to avoid early handling of watchdog
Date	2017-05-20 18:40 +0200
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Hi,

On Tue, May 16, 2017 at 12:08:32AM +0200, Rasmus Villemoes wrote:
> On Sun, May 14 2017, Guenter Roeck wrote:
> 
> > On 05/12/2017 05:05 AM, Sebastian Reichel wrote:
> >> On some systems its desirable to have watchdog reboot the system
> >> when it does not come up fast enough. This adds a kernel parameter
> >> to disable the auto-update of watchdog before userspace takes over
> >> and a kernel option to set the default. The info messages were
> >> added to shorten error searching on misconfigured systems.
> >>
> >> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
> >
> > Minor nitpicks below (which I fixed up in my watchdog-next branch).
> > Otherwise
> 
> Guenter, Sebastian, can I pursuade you to take a (second) look at the
> patches [1] I sent 4 months ago that implement the same thing, except
> that they also give a .config and a boot-cmdline way to define what
> "fast enough" means - which is necessary in many cases where it's simply
> not realistic to have userspace up-and-running before the dog is hungry.
> 
> [1] https://lkml.org/lkml/2017/1/9/408
> 
> I'm of course happy to rebase and retest those on top of current master,
> but the implementation and semantics should be reviewable as-is.

I wasn't aware of your work. For the hardware I work with at
Collabora my patch is enough, since "fast enough" is defined by
correct watchdog configuration (done by the bootloader).

I guess something like your patch is required for systems, which do
not reach userspace in < 60 seconds (minus some safety margin). This
is not needed by us. OTOH your patches should also work for our use case. 

-- Sebastian

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[PATCHv2] watchdog: core: add option to avoid early handling of watchdog Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-05-12 14:10 +0200
  Re: [PATCHv2] watchdog: core: add option to avoid early handling of  watchdog Guenter Roeck <linux@roeck-us.net> - 2017-05-14 16:50 +0200
    Re: [PATCHv2] watchdog: core: add option to avoid early handling of watchdog Rasmus Villemoes <linux@rasmusvillemoes.dk> - 2017-05-16 00:10 +0200
      Re: [PATCHv2] watchdog: core: add option to avoid early handling of  watchdog Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-05-20 18:40 +0200

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