Re: [PATCH] PM: add dpm_use_runtime_{suspend, resume} helper functions

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Wednesday 03 March 2010, Alan Stern wrote:
> On Tue, 2 Mar 2010, Rafael J. Wysocki wrote:
> 
> > +/**
> > + * __pm_generic_call - Generic suspend/freeze/poweroff/thaw subsystem callback.
> > + * @dev: Device to handle.
> > + * @event: PM transition of the system under way.
> > + *
> > + * If the device has not been suspended at run time, execute the
> > + * suspend/freeze/poweroff/thaw callback provided by its driver, if defined, and
> > + * return the error code returned by it.  Otherwise, return zero.
> > + */
> > +static int __pm_generic_call(struct device *dev, int event)
> > +{
> > +	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> > +	int (*callback)(struct device *);
> > +
> > +	if (!pm || pm_runtime_suspended(dev))
> > +		return 0;
> > +
> > +	switch (event) {
> > +	case PM_EVENT_SUSPEND:
> > +		callback = pm->suspend;
> > +		break;
> > +	case PM_EVENT_FREEZE:
> > +		callback = pm->freeze;
> > +		break;
> > +	case PM_EVENT_HIBERNATE:
> > +		callback = pm->poweroff;
> > +		break;
> > +	case PM_EVENT_THAW:
> > +		callback = pm->thaw;
> > +		break;
> > +	default:
> > +		callback = NULL;
> > +		break;
> > +	}
> > +
> > +	return callback ? callback(dev) : 0;
> > +}
> 
> Are you sure you want to avoid calling pm->thaw if the device is 
> runtime-suspended?  Maybe it would be better to treat thaw like resume 
> or restore.

In .freeze() we check if the device is runtime suspended and skip the driver's
.freeze() in that case, so the device is still suspended.  I don't think
.thaw() should call the driver's .thaw() in that case and change the runtime
suspended status (that won't serve any practical purpose IMO).

> > --- linux-2.6.orig/include/linux/pm_runtime.h
> > +++ linux-2.6/include/linux/pm_runtime.h
> > @@ -62,6 +62,11 @@ static inline void device_set_run_wake(s
> >  	dev->power.run_wake = enable;
> >  }
> >  
> > +static inline bool pm_runtime_suspended(struct device *dev)
> > +{
> > +	return dev->power.runtime_status == RPM_SUSPENDED;
> > +}
> > +
> 
> You didn't add this to the documentation file.

Yes,  I realized that after sending the patch, sorry.

Rafael