[PATCHv8 03/10] watchdog: core: Introduce default watchdog policy

Timo Kokkonen timo.kokkonen at offcode.fi
Tue May 19 22:45:44 PDT 2015

On 20.05.2015 04:13, Guenter Roeck wrote:
> On 05/19/2015 01:26 AM, Timo Kokkonen wrote:
>> Traditionally there have been no such thing as a policy for
>> watchdogs. The watchdog timer was simply explicitly stopped at driver
>> probe time and there was nothing else to do. Now that we have ability
>> to work around HW disabilities in the watchdog core, it is time to
>> introduce more policy options.
>> The default option is to shut down the watchdog driver, as
>> before. This ensures backward compatibility with current kernels and
>> hardware that might have a watchdog, but user has not set up a
>> watchdog daemon at all.
>> A new option is introduced to keep the watchdog running or start it up
>> at boot up. This is useful on many production systems that rely on the
>> watchdog to reboot the device in case a crash. With this option even
>> early kernel crashes or early user space crashes will lead to a reboot
>> even though watchdog daemon has not opened and started the watchdog
>> device yet.
>> The third introduced option is to not touch the hardware at all in
>> case bootloader have made an intelligent decision about the watchdog
>> state and does not know how to tell kernel about it. The watchdog
>> state is not touched until userspace takes over it.
>> Signed-off-by: Timo Kokkonen <timo.kokkonen at offcode.fi>
> Dislike. I don't think it is a good idea to have configuration options
> like this. This means users will have to deal with those "default"
> options for an entire distribution, which I don't think is desirable.
> Maybe for you, but not for everyone, and definitely not for me.

The configuration option was suggested by Uwe Kleine-König. I think it 
makes sense as there would not be otherwise any other way to enable the 
early-timeout-sec as device tree. I would think that for example in some 
server environment it would be good to enable watchdogs as early as 
possible and there probably are no device tree available.

> I think you are trying to do too much in your patch set.
> Can we possibly focus on getting early timeout to an acceptable form
> instead of trying to do everything at the same time.

I would be happy to do it the way that guarantees the inclusion, but I 
feel that I am getting conflicting feedback from different people giving 
review. I appreciate any concrete guidance you can give about the 
direction I should go with the patch set.


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