Re: [RFC] Fix Device Power Management States

[Pavel Machek <pavel@ucw.cz>]

Hi!

> > I still do not see it... swsusp does not care about logical state of
> > device. (Actually manipulating logical state of device might make
> > swsusp less transparent). It cares about device not doing DMA (I also
> > said "no interrupts", but that is not strictly neccessary: we disable
> > interrupts for atomic copy. Device should do no NMIs, through).
> 
> Perhaps it is unncessary to do at a class level, at least at this point.
> I think we all agree that we need some sort of stop/start methods for
> devices, though. In which, we can add to struct bus_type:
> 
> 	int (*dev_stop)(struct device *);
> 	int (*dev_start)(struct device *);
> 
> Sound good?

I fail to see why dev_stop(device) is better than suspend(device,
PM_PLEASE_QUIESCE_OR_WHATEVER). It has one big advantage: drivers that
ignore second argument (most do) will automagically work.

There is no fundamental problem with dev_stop/dev_start, I just fail
to see why they need to be separate from suspend/resume.
								Pavel
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