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Date: Sun, 1 Jan 2017 08:52:09 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Wim Van Sebroeck <wim@...ana.be>
Cc: "linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Laxman Dewangan <ldewangan@...dia.com>,
Mans Rullgard <mans@...sr.com>,
Justin Chen <justinpopo6@...il.com>,
Wenyou Yang <wenyou.yang@...el.com>,
Naidu Tellapati <naidu.tellapati@...il.com>
Subject: Re: Stopping watchdog in watchdog driver remove functions
On 01/01/2017 03:14 AM, Wim Van Sebroeck wrote:
> Hi Guenter,
>
>> I noticed that several watchdog drivers stop the watchdog in trhe driver
>> remove function.
>> A non-exhaustive list of drivers doing that is
>>
>> drivers/watchdog/bcm7038_wdt.c
>> drivers/watchdog/cadence_wdt.c
>> drivers/watchdog/imgpdc_wdt.c
>> drivers/watchdog/jz4740_wdt.c
>> drivers/watchdog/kempld_wdt.c
>> drivers/watchdog/max77620_wdt.c
>> drivers/watchdog/moxart_wdt.c
>> drivers/watchdog/sama5d4_wdt.c
>> drivers/watchdog/tangox_wdt.c
>> drivers/watchdog/tegra_wdt.c
>>
>> Since a watchdog has to be closed for its driver to be removable, one
>> situation
>> where a watchdog is still running on unload is where the watchdog was
>> opened but
>> not closed properly (eg by killing the watchdog application, or if the
>> 'nowayout'
>> flag is set).
>>
>> Given that, does it even make sense to stop the watchdog in the remove
>> function ?
>> Should it even be permitted ?
>
>>>From an API point of view: if WDIOF_MAGICCLOSE is being used then the watchdog
> _SHOULD_ continue to run when the watchdog was not properly closed (which
> normally also results in a reboot of the system).
> if WDIOF_MAGICCLOSE is not being used then closing the watchdog device means
> that the driver needs to stop the watchdog.
>
All the above have WDIOF_MAGICCLOSE set. Does that mean they should not stop
the watchdog on remove ?
Happy new year everyone !
Guenter
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