Comment by Joker_vD
> powering down the peripherals
> some peripherals have to be re-initialized
AIUI, these things actually way more hard than it sounds because hardware developers live in their own world, apparently. There's been articles here on HN from mjg59's blog (who's one of the guys maintaining all this power management stuff in the Linux kernel) like this one [0] about how some hardware simply chooses to do things that make this "re-initialization" impossible to do reliably.