As I look more and more closely at the wakelock structure I'm struck by how similar it is to some ideas we tossed around on the CELF PM working group a few years back. Ideas that fizzled a little at that time.
The high level notion of having a "fall-line" to low power states subject to constraints keeping components from "falling' to a lower power state is still quite interesting. FWIW at the time we worked on this concept in CELF things got complex around the dependency and notification networks that needed to be managed to make things work.
Wakelock implements a type of constraint method. I think the API has problems but the general idea of of constraint based steepest descent PM still has appeal. To me anyway.