Re: PCI PM & compatibility

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

> 
> - When a device is suspended, the pm_users count of its pm_parent is 
>   decremented, and incremented when the device is resumed. 
> 
> - device_suspend() makes multiple passes over the device list, in case
>   power dependencies cause some devices to be deferred. It fails with an 
>   error (and resumes all suspended devices) if a pass was made in which 
>   no devicse were suspended, but there are still devices with a positive
>   pm_users count. 

How do you intend to deal with the childs of the device that has
pm_users non null ?

If you don't suspend it, you must also postpone all of it's childs.
That makes the list walking slightly more tricky, or you finally go
to a real tree structure ? (Which you may have to do to implement
the set_parent() thing too, no ?

Ben.