[CentOS] CentOS 6 : Tip for significantly increasing battery life / reducing power consumption (Thinkpad X220 Tablet)

> I was not happy with the power consumption of CentOS 6 x86_64 on a new
> Lenovo Thinkpad x220 Tablet and I worked on reducing it. I just wanted
> to share with the list one of the changes which gave me the most
> significant improvement.
>
> As per http://www.williambrownstreet.net/blog/?p=387, add the
> following kernel arguments to the GRUB boot configuration:
>
> pcie_aspm=force i915.i915_enable_rc6=1 i915.lvds_downclock=1
> i915.i915_enable_fbc=1

As a follow-up: since the update to 6.4, these kernel arguments are
*no longer required* in order to have a reasonable power consumption
on a Thinkpad X220.

With tuned profile 'laptop-battery-powersave', the idle laptop
consumes a bit more than 10W (with display turned of: 8W)