pm-powersave

pm-powersave [true|false]

true
    Enables aggressive power-saving optimizations. This typically involves applying various system tweaks to minimize power consumption.

false
    Disables or reverts the aggressive power-saving optimizations, returning the system to a more standard or performance-oriented state.

The pm-powersave command, typically part of the pm-utils (power management utilities) package, is designed to apply or revert a set of aggressive power-saving optimizations across the system. Its primary role was often to prepare the system for suspend or hibernate operations by reducing power consumption as much as possible, or to toggle system-wide power-saving features. Unlike general power management daemons, pm-powersave usually performs one-time tweaks like disabling specific hardware features, optimizing device power states, or adjusting CPU governors for maximum power efficiency. While its direct execution might involve true or false arguments to enable or disable these settings, its functionality is frequently integrated into the suspend/hibernate process managed by other pm-utils commands like pm-suspend or pm-hibernate.

The pm-powersave command and the pm-utils suite it belongs to are largely considered deprecated in many modern Linux distributions, especially those using systemd. systemd now handles suspend, hibernate, and power management through its own mechanisms (e.g., systemd-suspend.service, systemd-hibernate.service, systemd-sleep(8)). Functionality similar to pm-powersave is often managed by systemd sleep hooks or specialized power management tools like TLP. Using pm-powersave on a systemd-based system might lead to conflicts, unexpected behavior, or simply have no effect.

pm-powersave is often called internally by other pm-utils scripts (like pm-suspend) based on configuration settings (e.g., PM_POWERSAVE in /etc/pm/config.d/). It applies a set of power-saving tweaks defined by scripts in directories like /usr/lib/pm-utils/defaults/ or /etc/pm/power.d/.

When enabled, pm-powersave might adjust settings such as CPU governors (e.g., to 'powersave'), disable PCIe ASPM (Active State Power Management) unless specified, or modify USB device power states. The specific actions depend on the version of pm-utils and system configuration.

The pm-powersave command is a component of the pm-utils package, which emerged as a standard power management suite for Linux systems, particularly before the widespread adoption of systemd. It provided a unified interface for system suspend, hibernate, and related power-saving operations across various hardware and kernel versions. As systemd matured and integrated its own comprehensive power management capabilities (via logind and systemd-sleep), the role of pm-utils and consequently pm-powersave diminished. While still available on some legacy systems or distributions not fully embracing systemd's power management, its active development and primary usage have largely been superseded.

pm-suspend(8), pm-hibernate(8), systemctl(1), systemd-sleep(8), TLP (Third-party power management daemon)