On Fri, Jan 06, 2006 at 04:00:05PM +0100, Dominik Brodowski wrote: > Hi, > > On Thu, Jan 05, 2006 at 05:37:30PM -0800, Patrick Mochel wrote: > > And, appended is a patch to export PM controls for PCI devices. The file > > "pm_possible_states" exports the states a device supports, and "pm_state" > > exports the current state (and provides the interface for entering a > > state). > > Your patch doesn't handle the PM dependencies, unfortunately... > > Thanks, > Dominik Physical power dependencies are a very bus and platform specific matter. I don't expect to see much core level help or infustructure. I think in the PCI case, we would first require PCI bus power management support. This feature is currently nonexistent. As I understand, PCI express links are capable of handling much of this at the hardware level, so it's not especially important for newer hardware. At the moment, I think the biggest X86 pm dependency issue is ACPI power resources. Logical dependencies might be another matter. For example, if we have a bus-instance structure at the driver core level, it may make sense to call some sort of ->prepare_for_children mechansim before starting up a child device. Thanks, Adam
