I use Ubuntu 16.04 with kernel 4.4.0-53-generic and i3-wm on my Thinkpad W540 20BH with i7-4600M and Nvidia Quadro K2100

I disabled the discrete GPU via acpi_call to save battery

However the notebook is still consuming around 24 watts on idle (peaks up to 30W):

$ upower --show-info /org/freedesktop/UPower/devices/battery_BAT0         
  native-path:          BAT0
  vendor:               SANYO
  model:                45N1779
    energy-full:         97.36 Wh
    energy-full-design:  99.47 Wh
    energy-rate:         24.508 W

Powertop does not show anything suspicious: screenshot

In Powertop's tab "Tunables" I see "Good" for every item listed.

cpu-info shows "powersave" for all cores.

I boot with:

GRUB_CMDLINE_LINUX_DEFAULT="acpi_osi=Linux nmi_watchdog=0 i915.i915_enable_rc6=1 i915.i915_enable_fbc=1"

Any ideas how I could save battery?

UPDATE 2018-03-02

Disabling some cores does not reduce the power consumption:

for i in {2..7}; do echo 0 | sudo tee /sys/devices/system/cpu/cpu$i/online; done

According to powertop CPUs are in state "C7s-HSW" > 90% of the time.

Running the following command did not make any difference (suggested by Doug Smythies):

for p in /sys/devices/system/cpu/cpu*/cpuidle/state0/disable; do echo 1 | sudo tee $p; done
  • Suggest you upgrade to the current kernel, 4.4.0-116-generic. Suggest use of turbostat for insight into processor power and GFX power. As a long shot test, try to disable idle state 0, (as su) for file in /sys/devices/system/cpu/cpu*/cpuidle/state0/disable; do echo "1" > $file; done – Doug Smythies Feb 28 '18 at 15:21
  • @DougSmythies Thank you for your suggestions! Turbostat: Busy% < 0.5%, CPU%c1 around 0.5% (except from core0 around 3%), CPU%c3 < 0.3%, CPU%c6 < 0.1%, CPU%c7 > 95%, CoreTmp around 60°C, GFX%rc6 around 98%, GFXMHz 200, PkgWatt around 6.8W, CorWatt 0.1W, GFXWatt 0.01W; cpu*/cpuidle/state0/disable=1 did not make any difference – canochordo Mar 2 '18 at 13:57
  • O.K. so your excessive power consumption does not appear to be from the processor or graphics (at least any graphics that turbostat knows about). Processor power is a little high, but my experience is with servers (where "idle" can be really quite idle) and not desktops (where "idle" really isn't at all). – Doug Smythies Mar 2 '18 at 19:05

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