linux-kernel - Re: [PATCH v2 2/3] watchdog: sama5d4: Fix setting timeout when watchdog is disabled

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Message-ID: <cc75a19f-0d99-4d26-0789-6cd750983990@roeck-us.net>
Date:   Sun, 19 Feb 2017 20:46:13 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Alexandre Belloni <alexandre.belloni@...e-electrons.com>
Cc:     Wim Van Sebroeck <wim@...ana.be>,
        Nicolas Ferre <nicolas.ferre@...el.com>,
        linux-watchdog@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/3] watchdog: sama5d4: Fix setting timeout when
 watchdog is disabled

On 02/19/2017 03:52 PM, Alexandre Belloni wrote:
> On 19/02/2017 at 08:57:35 -0800, Guenter Roeck wrote:
>>>> That means if the watchdog is running, the timeout would not be updated.
>>>> It should be updated no matter if it is running or not.
>>>>
>>>
>>> No, it is enabling the watchdog, then changing WDV and WDD and finally
>>> disabling the watchdog if necessary. So, WDV and WDD are always changed.
>>>
>> You are correct. Sorry for the noise.
>>
>> Seems odd that the watchdog must be _running_ to change the timeout.
>> Usually, if there is a restriction, it is the opposite. I hope this
>> doesn't cause race conditions, where the watchdog fires immediately
>> after being enabled due to a low timeout.
>>
>
> While it is difficult to reproduce, I can confirm it races and sometimes
> reset the SoC without any good reason. It doesn't matter whether it is
> disabled or not
>

Outch :-(.

> I've raised the issue at Atmel last Thursday so I don't have any answer
> yet.
>

Please keep us in the loop.

Thanks,
Guenter