While researching, I came across
laptop-power-mode and a whole pile of manual hacks...
I spent a while trying to figure out the merits of each method and whether they conflicted.. and then I saw this..
..which claims that on the latest Ubuntu, these are barely relevant anymore.
It always surprised me how poor Linux battery life is out of the box compared to other OSes, given that it is also often more light weight, so it makes sense that the kernel is integrating these new features and the other tools are just required if your kernel is too old for your hardware... but is that the case?
Is the reasoning in the link above that the kernel now handles all of this - or is it specific to Ubuntu as they have added extra scripts, etc. for a better user experience.
tl;dr - (1) is this also applicable to Debian Jessie / any other distribution from a certain kernel version?
And (2) for people in the future who have the same question for the latest power saving tweak on whatever kernel we are on then - what is the easiest way to find out what tweaks are now handled in a given kernel, to avoid people asking this question every 6 months or so? (Better to learn how to learn about it than keep bothering you all!)