Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support

From	Guenter Roeck <linux@roeck-us.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support
Date	2016-02-06 01:00 +0100
Message-ID	<qYYsa-7ev-11@gated-at.bofh.it> (permalink)
References	(11 earlier) <qYeIG-fd-3@gated-at.bofh.it> <qYkuJ-4bg-3@gated-at.bofh.it> <qYLlg-6Xi-11@gated-at.bofh.it> <qYPRV-1xp-25@gated-at.bofh.it> <qYTiO-3MR-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 02/05/2016 10:21 AM, Fu Wei wrote:
> On 5 February 2016 at 22:42, Guenter Roeck <linux@roeck-us.net> wrote:
>> On 02/05/2016 01:51 AM, Fu Wei wrote:
>>>
>>> Hi Guenter,
>>>
>>> On 4 February 2016 at 13:17, Guenter Roeck <linux@roeck-us.net> wrote:
>>>>
>>>> On 02/03/2016 03:00 PM, Fu Wei wrote:
>>>>>
>>>>>
>>>>> On 4 February 2016 at 02:45, Timur Tabi <timur@codeaurora.org> wrote:
>>>>>>
>>>>>>
>>>>>> Fu Wei wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> As you know I have made the pre-timeout support patch, If people like
>>>>>>> it, i am happy to go on upstream it separately.
>>>>>>>
>>>>>>> If we want to use pre-timeout here, user only can use get_pretimeout
>>>>>>> and disable panic by setting pretimeout to 0
>>>>>>> but user can not really set pretimeout, because "pre-timeout  ==
>>>>>>> timeout / 2 (always)".
>>>>>>> if user want to change pretimeout, he/she has to set_time instead.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Ok, I think patches 4 and 5 should be combined, and I think the Kconfig
>>>>>> entry should be removed and just use panic_enabled.
>>>>
>>>>
>>>>
>>>> Agreed.
>>>
>>>
>>> np, will do
>>>
>>>>>
>>>>>
>>>>> NP, will update this patchset like that ,  thanks :-)
>>>>>
>>>>
>>>> Also, if panic is enabled, the timeout needs to be adjusted accordingly
>>>> (to only panic after the entire timeout period has expired, not after
>>>> half of it). We can not panic the system after timeout / 2.
>>>
>>>
>>> OK, my thought is
>>>
>>> if panic is enabled :
>>> |--------WOR-------WS0--------WOR-------WS1
>>> |------timeout------(panic)------timeout-----reset
>>>
>>> if panic is disabled .
>>> |--------WOR-------WS0--------WOR-------WS1
>>> |---------------------timeout---------------------reset
>>>
>>>    panic_enabled only can be configured when module is loaded by module
>>> parameter
>>>
>>> But user should know that max_timeout(panic_enable) =
>>> max_timeout(panic_disable) / 2
>>>
>>
>> That means you'll have to update max_timeout accordingly.
>
> panic_enabled only can be configured when module is loaded, so we
> don't need to update it.
>
> max_timeout will only be set up in the init stage.
>
> Does it make sense ? :-)
>
Not sure I understand your problem or question.

max_timeout will have to reflect the correct maximum timeout, under
all circumstances. It will have to be set to the correct value before
the watchdog driver is registered.

Guenter

Thread

Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Timur Tabi <timur@codeaurora.org> - 2016-02-03 18:30 +0100
  Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-03 18:50 +0100
    Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Timur Tabi <timur@codeaurora.org> - 2016-02-03 19:00 +0100
      Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-03 19:10 +0100
        Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Timur Tabi <timur@codeaurora.org> - 2016-02-03 19:10 +0100
          Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-03 19:20 +0100
            Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Timur Tabi <timur@codeaurora.org> - 2016-02-03 19:30 +0100
              Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-03 19:40 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Timur Tabi <timur@codeaurora.org> - 2016-02-03 19:50 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-04 00:10 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Guenter Roeck <linux@roeck-us.net> - 2016-02-04 06:20 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Timur Tabi <timur@codeaurora.org> - 2016-02-04 14:50 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Guenter Roeck <linux@roeck-us.net> - 2016-02-04 15:50 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-05 11:00 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Timur Tabi <timur@codeaurora.org> - 2016-02-05 14:10 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half  timeout panic support Thomas Petazzoni <thomas.petazzoni@free-electrons.com> - 2016-02-05 14:40 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half  timeout panic support Thomas Petazzoni <thomas.petazzoni@free-electrons.com> - 2016-02-05 14:10 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Guenter Roeck <linux@roeck-us.net> - 2016-02-05 15:50 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-05 19:30 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Guenter Roeck <linux@roeck-us.net> - 2016-02-06 01:00 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-06 19:10 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Timur Tabi <timur@codeaurora.org> - 2016-02-06 20:00 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-07 03:10 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Guenter Roeck <linux@roeck-us.net> - 2016-02-06 20:00 +0100
                Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-07 03:20 +0100

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