Messages in this thread | | | Date | Sat, 11 May 2013 15:21:48 -0700 | Subject | Re: [RFC PATCHv2 2/2] PM: compile-time configuration of device suspend/resume watchdogs. | From | Colin Cross <> |
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On Sat, May 11, 2013 at 2:28 AM, Pavel Machek <pavel@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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