バッテリ駆動時にCPUをpowersaveにする

/etc/laptop-mode/conf.d/cpufreq.conf の BATT_CPU_MAXFREQ, BATT_CPU_MINFREQ, BATT_CPU_GOVERNOR を以下のように編集

BATT_CPU_MAXFREQ=slowest
BATT_CPU_MINFREQ=slowest
BATT_CPU_GOVERNOR=powersave

cpufreq-info の出力が以下のような感じになる。

analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0 1 2 3
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 10.0 us.
  hardware limits: 800 MHz - 1.90 GHz
  available frequency steps: 1.90 GHz, 1.90 GHz, 1.80 GHz, 1.70 GHz, 1.60 GHz, 1.50 GHz, 1.40 GHz, 1.30 GHz, 1.20 GHz, 1.10 GHz, 1000 MHz, 900 MHz, 800 MHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 800 MHz and 800 MHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency is 800 MHz.
  cpufreq stats: 1.90 GHz:0.06%, 1.90 GHz:0.00%, 1.80 GHz:0.00%, 1.70 GHz:0.00%, 1.60 GHz:0.00%, 1.50 GHz:0.00%, 1.40 GHz:0.00%, 1.30 GHz:0.00%, 1.20 GHz:0.00%, 1.10 GHz:0.00%, 1000 MHz:0.00%, 900 MHz:0.00%, 800 MHz:99.94%  (2)

バッテリ駆動時の省エネ関連設定マニュアルは、

man laptop-mode.conf

関連パッケージは多分 laptop-mode-tools . apt-cache show laptop-mode-tools で詳細表示。Ubuntu オリジナルっぽい。