Arch Linux

killer_siller

Member

Registered: 2011-08-28

Posts: 21

reducing power consumption on Intel Sandy Bridge architecture

I know this topic has created constant chatter, but the permanence of the internet has caused some confusion with me.  It seems most of the "fixes" for power drain on Sandy Bridge architecture concerns Ubuntu and it's depricated, non-vanilla kernel.

So here is what I have, and what I'm seeing:

V131 w/ Core i5 2430M 8G ram 64G SSD

Arch Linux vanilla kernel
KDE
cpufreq utils

boot options currently enabled
i915.915_enable_rc6=1

noatime,dirnoatime in fstab

I ordered my V131 from Dell with Ubuntu 11.04 pre-installed, so I have no idea what kind of power drain this thing would have with Windows installed.  Right now powertop says I'm idling at 1W, which seems to be about twice what it should.  enabling RC6 has calmed the fan, which ran rather schizophrenically without it.

I've read through the laptop wiki, but I'm confused as to what would work best with KDE's power management stuffs and what would be redundant.

Any further suggestions?

cgarcia

Member

Registered: 2010-08-09

Posts: 39

Re: reducing power consumption on Intel Sandy Bridge architecture

There is a known bug in all kernels since some point at 2.6.3X which won't be fixed in mainline until 3.3 kernel (see the Phoronix web site for more details). In my laptop (Dell E5420) it halved the battery liffe, an kept the fan at high speed, as well as the computer too hot. After some googling, yes I do managed to fix it in the current kernels also by adding these kernel parameters in grub:

    pcie_aspm=force   i915.i915_enable_rc6=1

Now I run the battery for about 11 hours (up from 5-6), and the fan periodically even stops (zero noise with SSD!). Talking about the battery, I also need another boot options to prevent the mouse to become sometimes veeeeryyyy slow in X window while charging the battery:

    drm_kms_helper.poll=N  irqpoll

Hope the "standard default" situation will improve in the future.

Last edited by cgarcia (2012-01-18 23:23:28)

killer_siller

Member

Registered: 2011-08-28

Posts: 21

Re: reducing power consumption on Intel Sandy Bridge architecture

I've been reading through ways to enable a few different suggestions from powertop, but have noticed no real reduction in consumption.

What power management tools work WITH KDE's, and which ones would be redundant, or fighting it?

killer_siller

Member

Registered: 2011-08-28

Posts: 21

Re: reducing power consumption on Intel Sandy Bridge architecture

Today I disabled all of my kernel options in syslinux to see what would happen.  Powertop is reporting 1.6W usage.  It was 1.1W before.  Fan is running much more than it was before.  I'm trimming down my boot options to see what happens.