[linux-pm] calling runtime PM from system PM methods

[Kevin Hilman]

Alan Stern <stern at rowland.harvard.edu> writes:

[...]

>> More specifically, what should be the approach in system suspend when a
>> device is already runtime suspended?  If you treat runtime and system PM
>> as completely independent, you would have to runtime resume the device
>> so that it can then be immediately system suspended.
>
> Assuming the wakeup setting is correct, and assuming you use the same 
> power level for runtime suspend and system suspend, then nothing needs 
> to be done.
>
> If the wakeup setting is not correct, it has to be changed.  That 
> often implies going back to full power in order to change the 
> wakeup setting, then going to low power again.

OK, but how should this be implemented?  

If the device is runtime suspended at system suspend time, it implies
that somwhere in the system suspend path, the device has to be powered
on and enabled (a.k.a. runtime resumed.)