On Wed, 2011-04-13 at 02:05 +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rjw@xxxxxxx> > > Change the PM core's behavior related to power domains in such a way > that, if a power domain is defined for a given device, its callbacks > will be executed instead of and not in addition to the device > subsystem's PM callbacks. > > The idea behind the initial implementation of power domains handling > by the PM core was that power domain callbacks would be executed in > addition to subsystem callbacks, so that it would be possible to > extend the subsystem callbacks by using power domains. It turns out, > however, that this wouldn't be really convenient in some important > situations. > > For example, there are systems in which power can only be removed > from entire power domains. On those systems it is not desirable to > execute device drivers' PM callbacks until it is known that power is > going to be removed from the devices in question, which means that > they should be executed by power domain callbacks rather then by > subsystem (e.g. bus type) PM callbacks, because subsystems generally > have no information about what devices belong to which power domain. > Thus, for instance, if the bus type in question is the platform bus > type, its PM callbacks generally should not be called in addition to > power domain callbacks, because they run device drivers' callbacks > unconditionally if defined. > > While in principle the default subsystem PM callbacks, or a subset of > them, may be replaced with different functions, it doesn't seem > correct to do so, because that would change the subsystem's behavior > with respect to all devices in the system, regardless of whether or > not they belong to any power domains. Thus, the only remaining > option is to make power domain callbacks take precedence over > subsystem callbacks. > > Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> Leaving the issue of to (re)name this field aside: Acked-by: Kevin Hilman <khilman@xxxxxx> _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
