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

Fri Aug 3 10:05:54 UTC 2012
Ned Slider <ned at unixmail.co.uk>

On 03/08/12 08:05, Mathieu Baudier wrote:
> Hello,
> 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
> (in /boot/efi/EFI/redhat/grub.conf since I use EFI,
> /boot/grub/grub.conf otherwise)
> As measured using PowerTop, this made the power consumption decrease
> from 20W to 11W !
> (I had already decreased it from 25W to 20W with the usual tips of
> disabling hardware, shutting down services, switching tuned profiles,
> etc.)
> All in all, battery time was more than multiplied by two, and the
> computer is now much more silent since the fan is not always running
> like mad in order to cool the processor. The bottom of the laptop is
> not anymore hot as hell.
> I don't know whether this would have an impact on other hardware, but
> it may be worth looking at it (even on servers?), since the above link
> points to descriptions of a regression in the kernel which seems more
> general.
> As a side note, the Power Management Guide of Red Hat is a good
> resource (analysis tools + tuned profiles):
> http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html-single/Power_Management_Guide/
> Cheers,
> Mathieu
> PS: Do you think I should book a bug in the upstream bug tracker?

Rather than filing a bug upstream, I would think it more appropriate to 
document the various settings on the CentOS Wiki in the laptops section: