Hi Timur

On 4 February 2016 at 01:53, Timur Tabi [off-list ref] wrote:

Fu Wei wrote:

quoted

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 ??:-)

What I meant was that if we had full-blown pre-timeout support in the
watchdog layer, then you could use that to implement the
panic-on-half-timeout feature.

When pre-timeout is implemented, will you modify the interrupt handler to
use it?

Sorry I am little confused.

Actually I am taking your suggestion to avoid touching WCV in
interrupt routine.
So even we have pre-timeout support , it is useless for this
panic-on-half-timeout feature,
because pre-timeout  == timeout / 2 (always).

So maybe I misunderstand your suggestion,
could you let me know : why we want pre-timeout here?

quoted

quoted

quoted

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

Hmmm... that make sense.  I think maybe you should drop the Kconfig option,
and just have "static bool panic_enabled = false;"  Also, then do this:

if (panic_enabled) {
        ret = devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0,
                               pdev->name, gwdt);
        if (ret) {
                dev_err(dev, "unable to request IRQ %d\n", irq);
                return ret;
        }
}

yes, agree

That way, the interrupt handler is never registered if the command-line
parameter is not specified.

-- 
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