Hi...

On Tue, Sep 13, 2011 at 11:55, Kaustubh Ashtekar [off-list ref] wrote:

On Fri, Sep 9, 2011 at 5:51 PM, sandeep kumar [off-list ref]
wrote:

quoted

Hi all,
I wanted to manipulate the watchdog timer driver to see how it works in
deadlocks.

quoted

<snip>

quoted

My question is this,
When watch dog timer expires(hardware watchdog), its interrupt directly
resets the system
(or) it is treated as an interrupt and a handler is executed.

AFAIK, after the watchdog is triggered, the SoC/processor is completely
reset including all the peripherals. The main purpose of a watchdog is to
reset a processor which has locked up somewhere in some thread (with
interrupts disabled, maybe), effectively starving the thread which is
supposed to reset the watchdog periodically.

Just to add, AFAIK watchdog is used in "locked" scenario because it
can't be masked and disabled...and it receives highest priority in
trap/interrupt by the processors.

AFAIK too, in most scenarios, handler is placed to picked up watchdog
signal...and it is this handler which is then fix the situation.

Only my 2 cents idea...


-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com