In a post on his blog, Ubuntu kernel engineer Colin King explained that the plan is to provide power savings in a variety of ways, including PCI Express Active State Power Management (ASPM). Furthermore, testing of Aggressive Link Power Management (ALPM) that puts the SATA link to your disk drive into a low power mode during periods of inactivity is in the works, as is placing USB and PCI controllers of peripherals and wireless connections into lower power states. The folks at Canonical are putting Precise Pangolin through its power-saving paces, but are also calling upon members of the Ubuntu community to help out with the QA to see which methods will work best. So, if you're into doing a good deed for the next Ubuntu distro, head on down to the source to learn how to lend a hand.
Canonical Ubuntu 14.04