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

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Message-ID: <CADyBb7sxPg-QUjTbeHFtYkctKc_g7D8O=+jqbXN+DCCoCEnFqA@mail.gmail.com>
Date:	Thu, 4 Feb 2016 01:49:02 +0800
From:	Fu Wei <fu.wei@...aro.org>
To:	Timur Tabi <timur@...eaurora.org>
Cc:	Rob Herring <robh+dt@...nel.org>,
	Paweł Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Wim Van Sebroeck <wim@...ana.be>,
	Guenter Roeck <linux@...ck-us.net>,
	Jon Corbet <corbet@....net>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will.deacon@....com>,
	Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-watchdog@...r.kernel.org, linux-doc@...r.kernel.org,
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Linaro ACPI Mailman List <linaro-acpi@...ts.linaro.org>,
	rruigrok@...eaurora.org, "Abdulhamid, Harb" <harba@...eaurora.org>,
	Christopher Covington <cov@...eaurora.org>,
	Dave Young <dyoung@...hat.com>,
	Pratyush Anand <panand@...hat.com>,
	G Gregory <graeme.gregory@...aro.org>,
	Al Stone <al.stone@...aro.org>,
	Hanjun Guo <hanjun.guo@...aro.org>,
	Jon Masters <jcm@...hat.com>, Arnd Bergmann <arnd@...db.de>,
	Leo Duran <leo.duran@....com>, sudeep.holla@....com
Subject: Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout
 panic support

Hi Timur,

Thanks for your rapid feedback :-)

On 4 February 2016 at 01:27, Timur Tabi <timur@...eaurora.org> wrote:
> fu.wei@...aro.org wrote:
>>
>> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
>> +static bool panic_enabled = true;
>
>
> I think this should default to 'false', because IMHO, this seems like an odd

yes, It make sense to make it default to 'false'.

> feature.  I'm not crazy about the fact that there's a Kconfig option for it
> either, but I'm not going to NACK this patch.
>
> I personally would prefer to drop this patch, and just wait for full-blown
> pre-timeout support.  It feels like a debugging feature that doesn't really

sorry, are you saying : using pre-timeout instead of this half timeout?

But even we have pre-timeout support, pre-timeout  == timeout / 2, it
can not be configured without touch timeout.

if you want pre-timeout  != timeout / 2, we have to modify WCV in the
interrupt routine.
 (because of the explicit watchdog refresh  mechanism)

Could you let me know why we need pre-timeout  here ?? :-)

> belong upstream.  But like I said, it's just my opinion, and I won't
> complain if I'm outvoted.

 I think this debugging feature is the  purpose of the two-stage
watchdog, if I understand correctly



-- 
Best regards,

Fu Wei
Software Engineer
Red Hat Software (Beijing) Co.,Ltd.Shanghai Branch
Ph: +86 21 61221326(direct)
Ph: +86 186 2020 4684 (mobile)
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