Hi Thomas, On 30 December 2015 at 17:44, Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> wrote: > Guenter, > > On Tue, 29 Dec 2015 09:28:48 -0800, Guenter Roeck wrote: > >> Probem with SBSA and pretimeout is two-fold. First, it adds a quite a bit of >> complexity to the driver, second, it adds a lot of risk to the driver. >> Reason is that this is not one specific watchdog, but a watchdog implementation >> based on a standard which, in my opinion, is less than well thought out >> and leaves a lot of ambiguity when it comes to implementation details. > > I agree that calling the SBSA watchdog specification a "specification" > is a strong word. At least in the version I have, it's 4-5 pages of > somewhat random thoughts on what a standardized watchdog could look > like, but not a very well-defined specification that guarantees that > all implementations will behave in the same way. Although the basic function is described well in spec 2.3, but it do need some improvement, in my opinion. > >> The more functionality is used, the higher the risk that some implementation >> won't work. > > Maybe we should enforce that all users of the driver use two Device > Tree compatible strings: > > compatible = "<vendor>,sbsa-gwdt", "arm,sbsa-gwdt"; > > So that the SBSA watchdog driver can implement vendor specific quirks > if needed. Though it is true that the HW has some identification > registers that should allow to differentiate between the implementation. I think the implementation can be different, but all the SBSA watchdog should be able to use the same driver. > >> I think we should stick with the basic implemementation and not support >> pretimeout at all with the SBSA driver. If the maximum timeout is insufficient, >> there are two options: Use the soft-timeout handled by the watchdog core, >> which will hopefully make it for 4.6, or live with it. > > For now, I'm personally fine with a SBSA driver that does not support > the pretimeout. Is anyone working on submitting something like this ? I am working on a new non-pretimeout SBSA driver. There are two patchsets : (1) Timur's v4 patch : http://www.spinics.net/lists/linux-watchdog/msg06567.html (2) my previous non-pretimeout version : https://lkml.org/lkml/2015/6/10/766 > > Best regards, > > Thomas > -- > Thomas Petazzoni, CTO, Free Electrons > Embedded Linux, Kernel and Android engineering > http://free-electrons.com -- 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) Room 1512, Regus One Corporate Avenue,Level 15, One Corporate Avenue,222 Hubin Road,Huangpu District, Shanghai,China 200021 -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
