[ltp] Re: [W510] decreasing power use, increasing battery life

[Tino Keitel]

On Thu, Dec 06, 2012 at 08:03:10 -0800, keitho@strucktower.com wrote:

[...]

> So, why am I only getting 4 hours battery time? Really, until you
> mentioned gettting 10 hours I thought it was "normal" to get only four
> hours. I had tried playing around with powertop a year ago or so, with no
> apparent improvements.
> 
> Using the Lenovo 55+ battery (5.2Ah 57Wh).

4 hours with a laptop like the W510 sounds reasonable, given that you
use the display at full brightness. Using xbacklight to reduce the
display brightness should give much more battery runtime. Other hints
to enhance the battery runtime:

- set the SATA ports to powersave, also the unused ones
  (/sys/class/scsi_host/host*/link_power_management_policy)

- make sure that rc6 power saving in the intel graphics driver is
  enabled (boot with i915.i915_enable_rc6=1), you can check if it is
  already used by looking into
  /sys/module/i915/parameters/i915_enable_rc6

- make sure that PCIe power saving is enabled (boot with
 pcie_aspm=force)

- enable wireless powersaving, if possible (this differs between
  drivers, so I can't help here)

- disable bluetooth, unless you really need it

- enable powersaving in the audio driver
  (/sys/module/snd_hda_intel/parameters/power_save)
- make sure general powersaving in the intel graphics driver is enabled
  (/sys/module/i915/parameters should be set to 1)

- make sure the ondemand CPU scaling governor is used on all cores
  (grep "" /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor)

Some of the above should be covered by powertop. You might check all
the "tunables" listed in powertop to see if they gain any battery
runtime. However, you have to find out yourself what to do to make
these settings permanent. AFAIK powertop doesn't help to see what it
does to toggle the tuneables.

Regards,
Tino