In two separate email threads this week, I have been asked about the
status of the Android wakelock issue that has been described in the
past. It turns out that people don't realize that the Linux kernel now
supports this type of locking, and has for a few releases now.
Rafael J. Wysocki has merged a solution for this into the kernel and
done the unthinkable, he documented everything! He wrote an
here  on lwn.net, and there is a pointer in that article to a
18 page paper describing in great detail the history, proposed solutions
and eventual resolution of the problem.
Astute readers will realize that now there are no barriers for merging
any out-of-tree Android specific kernel drivers. Send them in, we will