Re: [PATCH 0/8] watchdog: Add support for keepalives triggered by infrastructure

Guenter Roeck
2015-08-04T15:01:28Z

Hi Uwe,

On 08/04/2015 04:24 AM, Uwe Kleine-König wrote:
> Hello Guenter,
>
> On Mon, Aug 03, 2015 at 07:13:26PM -0700, Guenter Roeck wrote:
>> This patch set does not solve all limitations of the watchdog subsystem.
>> Specifically, it does not add support for the following features.
>>
>> - It is desirable to be able to specify a maximum early timeout,
>> from booting the system to opening the watchdog device.
>> - Some watchdogs may require a minimum period of time between
>> heartbeats. Examples are DA9062 and possibly AT91SAM9x.
>
> Other things that come to my mind:
> - move handling of nowayout into the core
> - some drivers use a reboot notifier. Not sure what they are intended
> to do there. For i.MX2x it triggers a reboot; for gpio-wdt it tries
> to stop the watchdog.
>
Be careful - those are different functions. The imx2 driver installs
a _restart_ handler, which indeed is supposed to restart the system.
The gpio wdt driver installs a _reboot_ notifier, which is supposed to
stop the watchdog. Other drivers install a shutdown callback in the
platform driver structure to do the same; not really sure what is better.

> Of course this doesn't mean this should addressed here. I like the
> series in general.
>

The list wasn't supposed to be exhaustive. Otherwise adding "support devm"
should have been there as well. I even have a patch hanging around somewhere
to do that. Guess I should have said something like "does not solve all
timeout related limitations ...".

Thanks,
Guenter