I installed/upgraded ArchLinux (which is at 2.6.38 now) on a bunch of laptops lately and noticed a raise in power usage (in the range of 10%), with mostly some

I installed/upgraded ArchLinux (which is at 2.6.38 now) on a bunch of laptops lately and noticed a raise in power usage (in the range of 10%), with mostly some high kworker activity (100+ wakeup/s when idle, that's 80% of overall wakeups) in powertop. But the worst contender has been s2ram power usage: the laptops go to sleep yet leaving them sleeping overnight pumps 40% out of the battery (should be 2~4%, tops). Unfortunately I can't downgrade easily as .38 introduced proper support for core components of those laptops.