On Sat, May 11, 2013 at 2:28 AM, Pavel Machek <pa...@ucw.cz> wrote:
> Hi!
>
>> Power management debug option to configure device suspend/resume watchdogs.
>> Available options are:
>> 1. Enable/disable the feature.
>> 2. Select triggered watchdog action between:
>> - system panic (default)
>> - dump stacktrace
>> - log event
>> 3. Select timeout value for the watchdog(s).
>
> People disliked the previous behaviour, so you add 10 config
> options... with different behaviours. Also 1 second timeout is not
> acceptable for endusers (will break the system), so it should not be
> offered. In fact, remove that option, too. People doing that kind of
> debugging can modify the sources, right?
Greg KH asked for more configurable options. I agree this may be a
little too far (I would replace the action choice with a simple "panic
on timeout?"), but its better than it was before. Also, a 1 second
timeout is perfectly reasonable, especially if you configure it to
dump a stack trace but not panic. Mobile devices normally finish
suspending within a few hundred ms.
> (Maybe it would make sense to do same action regular watchdog does,
> but...)
>
> That's not the way to go. If "panic" is right behaviour, just go with
> panic.
I can see uses for both panic and stack trace. If you have a driver
that takes too long, but eventually suspends, then a panic is
unnecessary and a stack trace that you can see in the logs is better,
especially for a short timeout.
>> @@ -402,13 +422,9 @@ static int dpm_run_callback(pm_callback_t cb, struct
>> device *dev,
>> static void dpm_wd_handler(unsigned long data)
>> {
>> struct dpm_watchdog *wd = (void *)data;
>> - struct device *dev = wd->dev;
>> - struct task_struct *tsk = wd->tsk;
>> -
>> - dev_emerg(dev, "**** DPM device timeout ****\n");
>> - show_stack(tsk, NULL);
>>
>> - BUG();
>> + dev_emerg(wd->dev, "**** DPM device timeout ****\n");
>> + dpm_wd_action(wd);
>> }
>>
>> /**
>
> And merge this to previous patch. Introducing the code then redoing it
> in next patch does not help review.
>
> Pavel
>
> --
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures)
> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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