A set of eight patches were published by Rafael J. Wysocki to provide the latest incarnation of this controversial work. One of the patches introduces support that allows the Linux kernel to trigger system suspend (auto-transitioning into a sleep state) whenever there are no active wake-up sources. This auto-sleep support is the same as "opportunistic suspend", which was talked about previously.
The other big item with this patch-set was the wake locks support, which allows for wake-up sources to be created and manipulated from user-space. Wake locks is an Android feature that may now work its way into the upstream kernel in this implementation. Rafael considers this latest work to be "a kind of proof of concept."
Find more information on this Linux kernel power management work via this mailing list post.