Since 2011, Linux users has been suffering from power consumption in most Linux distribution (most likely Ubuntu-based) that were released using previous version of Linux Kernel prior to Linux Kernel 3.2. This problem has been spotted by Michael Larabel from Phoronix and it was traced down to ASPM bad handling on Linux that are not the same as in Windows.
Since then, so many efforts has been spent on fixing this problem, and Matthew Garrett is one of the developer who is working on this problem. He finished the rework of the ASPM code, but then the merge window for Linux Kernel 3.2 had been closed by Linus and he was strict about it. So the work must be postponed for the next release and here we are. Since the merge window for Linux Kernel 3.3 is now open, Jesse Barnes had asked Linus to pull his work which contain the ASPM reworked code by Matthew.
Since many Linux distribution that will be released this year will be based on Linux Kernel 3.2 (Ubuntu and Fedora for example), this feature will not be included unless the developer back-ported this patch into their kernel stock.
It's good to know that this problem is finally resolved and only a matter of time before the kernel gets released by Linus and users may enjoy the benefit of this work.