upowerd

upowerd

upowerd is the daemon behind the UPower system service. It provides an abstraction for enumerating power devices on the system, monitoring power events, and querying history and statistics about power usage. It typically communicates with hardware via D-Bus. upowerd aggregates information from various kernel subsystems (like ACPI, sysfs, and others) and hardware sensors to present a unified view of battery state, AC adapter presence, and other power-related data to applications and the desktop environment.

Its primary goal is to allow applications to react intelligently to changes in power status, for example, dimming the screen or suspending the system when battery power is low. It also provides data for displaying battery status in the system tray. upowerd runs as a system service, usually started at boot time, and handles device enumeration, state changes, and power event notifications asynchronously. It is a crucial component of modern Linux desktop environments for power management.

upowerd often requires specific kernel modules and drivers to be loaded for proper operation. Problems with these components can lead to inaccurate power status reporting or failure to detect devices.
upowerd relies on D-Bus for communication. D-Bus configuration issues can prevent applications from receiving power status updates.

To debug upowerd, look at its logs, often in /var/log/syslog or journalctl. Using 'upower' command can help you check power devices status.

upowerd's configuration is usually handled through systemd and does not usually need to be manually configured. The configuration files should not be modified directly.

upowerd evolved from earlier power management solutions in Linux. It aims to provide a more standardized and robust interface for power management compared to previous approaches. The development of upowerd was driven by the need for better integration with desktop environments and consistent handling of power-related events across different hardware platforms.

upower(1)