Re: Change behaviour when tracing ... nasty trap (was Re: [PATCH] PM/Trace: get rid of synchronous resume limit during PM trace)

Pavel Machek
2015-01-26T11:05:22Z

On Mon 2015-01-26 10:39:04, Liu, Chuansheng wrote:
> Hello Pavel,
>
> > > There are some kind of dependency between devices in some
> > > hardware platforms. So, asynchronous resuming devices may
> > > hang system due to wrong resume order. As a result, should
> > > not fore synchronously resuming devices during tracing
> > > PM events.
> > >
> > > Signed-off-by: Zhonghui Fu <zhonghui.fu@linux.intel.com>
> > > ---
> > > drivers/base/power/main.c | 3 +--
> > > include/linux/resume-trace.h | 7 -------
> > > 2 files changed, 1 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> > > index 9717d5f..5df148b 100644
> > > --- a/drivers/base/power/main.c
> > > +++ b/drivers/base/power/main.c
> > > @@ -517,8 +517,7 @@ static int device_resume_noirq(struct device *dev,
> > pm_message_t state, bool asyn
> > >
> > > static bool is_async(struct device *dev)
> > > {
> > > - return dev->power.async_suspend && pm_async_enabled
> > > - && !pm_trace_is_enabled();
> > > + return dev->power.async_suspend && pm_async_enabled;
> > > }
> > >
> >
> > Actually... whoever did the original patch was evil person. Changing
> > behaviour when tracing is requested is evil, evil, evil. Git blame
> > tells me
> >
> > Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
> >
> > went to the dark side.
>
> Although I didn't get where is something wrong, but the is_async() is not created by my commit,
> it is from commit (PM: Start asynchronous resume threads upfront), I just moved it ahead.
>
> And like other phases, I added it into resum/suspend_noirq()...

I see, blame blamed wrong person. It looks like Rafael is evil:

commit 97df8c12995c5bac73e3bfeea4c5be155c1f4401
Author: Rafael J. Wysocki <rjw@sisk.pl>
Date: Sat Jan 23 22:25:31 2010 +0100

PM: Start asynchronous resume threads upfront

Pavel
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