[How To] increase battery life with the Debian/Ubuntu Laptop

  1. Enabling ALPM will save 1-2 W power, but may cause corruption of data for some devices.
    echo SATA_ALPM_ENABLE=true | sudo tee /etc/pm/config.d/sata_alpm
  2. Change your desktop background to a lighter color for the notebook LCD-screen increases the duration of about 1%.
  3. Enable power-saving mode for RC6 Intel i915 video cards through transmission kernel parameter
    i915.i915_enable_rc6 = 1

    will save 25-40% energy of devices based on the architecture Sandybridge, but in rare cases may hang on some laptops.

  4. Enabling compression frame buffer (FrameBuffer Compression) for driver
    i915 through the transmission parameter of kernel

    i915.i915_enable_fbc = 1

    will save 0.6 Watts

  5. Setting a delay blanking retrace the beam vertical deflection (DRM vblank off) via the kernel parameter
    drm.vblankoffdelay = 1

    reduces the number of wakeup events of CPU and possibly save a little energy.

  6. Turn off all wireless subsystems, if they are not used. In particularly disabling bluetooth (“blacklist bluetooth” in /etc/modprobe.d/blacklist.conf) will save ~1-2 Watts
  7. Disabling web-camera (“blacklist uvcvideo” in /etc/modprobe.d/blacklist.conf) will save ~1-2 Watts
  8. Use PowerTop tool to put the following devices in the state economic use of energy:
    • Webcam
    • Audio
    • DRAM
    • Ethernet
    • Wifi
    • Bluetooth
    • SATA
    • MMC/SD
  9. Using the Linux kernel which fixed the problem with the activation of ASPM (Active State Power Management) for all PCI Express cards. The test version of Ubuntu 12.04 already contains the patch. For other systems it is recommended to set kernel parameter “Pcie_aspm = powersave”, which is the default mode activates the maximum energy saving. For some laptop models this action may reduce energy by 10-30%.
  10. Muting the screen brightness up to two thirds of the maximum value will save 1 watt.
  11. Disable blinking cursor in gnome-terminal will get rid of unnecessary CPU wakeups:
    gconftool-2 --type string --set /apps/gnome-terminal/profiles/Default/cursor_blink_mode off
  12. Identifying problems with overly frequent awakening excessive CPU and CPU usage for commonly used applications with the package powertop or utilities eventstat and cpustat from PPA repository colin-king/powermanagement.

    For example, to identify the most active events for 10 seconds:

    sudo eventstat 10 1
      Evnt/s PID   Task            Init Function             Callback
       96.10 12659 npviewer.bin    hrtimer_start_range_ns    hrtimer_wakeup
       58.10     0 [kern sched]    Load balancing tick       tick_sched_timer
       49.80  2026 alsa-source     hrtimer_start_range_ns    hrtimer_wakeup
       49.30  2024 alsa-sink       hrtimer_start_range_ns    hrtimer_wakeup
       47.20     0 kworker/0:0     hrtimer_start_range_ns    tick_sched_timer

    To monitor for 60 seconds and output processes that generate more than 5 events per second:

       sudo eventstat -t 5 60 1
      Evnt/s PID   Task            Init Function             Callback
       54.00  2003 compiz          hrtimer_start_range_ns    hrtimer_wakeup
       49.35  2024 alsa-sink       hrtimer_start_range_ns    hrtimer_wakeup
       18.92     0 [kern sched]    Load balancing tick       tick_sched_timer
       17.57     0 kworker/0:0     hrtimer_start_range_ns    tick_sched_timer
       16.13     0 [kern core]     usb_hcd_poll_rh_status    rh_timer_func
        9.98  2386 gwibber-service hrtimer_start_range_ns    hrtimer_wakeup
        9.88 10063 desktopcouch-se hrtimer_start_range_ns    hrtimer_wakeup
        9.87  2382 ubuntuone-syncd hrtimer_start_range_ns    hrtimer_wakeup
        9.83 10109 desktopcouch-se hrtimer_start_range_ns    hrtimer_wakeup
        5.23     0 [kern core]     hrtimer_start             tick_sched_timer
       12046 Total events, 200.77 events/sec



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