From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support Date: Fri, 5 Feb 2016 15:54:37 -0800 Message-ID: <56B5363D.20200@roeck-us.net> References: <1454519923-25230-1-git-send-email-fu.wei@linaro.org> <1454519923-25230-6-git-send-email-fu.wei@linaro.org> <56B23883.7000501@codeaurora.org> <56B23E99.1030604@codeaurora.org> <56B2423B.1020109@codeaurora.org> <56B24642.8090105@codeaurora.org> <56B24AB5.3070001@codeaurora.org> <56B2DEE4.7060901@roeck-us.net> <56B4B4E2.40105@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-doc-owner@vger.kernel.org To: Fu Wei Cc: Timur Tabi , Rob Herring , =?UTF-8?Q?Pawe=c5=82_Moll?= , Mark Rutland , Ian Campbell , Kumar Gala , Wim Van Sebroeck , Jon Corbet , Catalin Marinas , Will Deacon , Suravee Suthikulpanit , LKML , linux-watchdog@vger.kernel.org, linux-doc@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Linaro ACPI Mailman List , rruigrok@codeaurora.org, "Abdulhamid, Harb" , Christopher Covington , Dave Young , Pratyush Anand , G Gregory , Al List-Id: devicetree@vger.kernel.org On 02/05/2016 10:21 AM, Fu Wei wrote: > On 5 February 2016 at 22:42, Guenter Roeck wrote: >> On 02/05/2016 01:51 AM, Fu Wei wrote: >>> >>> Hi Guenter, >>> >>> On 4 February 2016 at 13:17, Guenter Roeck wrote: >>>> >>>> On 02/03/2016 03:00 PM, Fu Wei wrote: >>>>> >>>>> >>>>> On 4 February 2016 at 02:45, Timur Tabi 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