{{Short description|Linux power management middleware}} {{For|the football stadium in Monza, Italy|Stadio Brianteo}} {{Infobox software | logo = UPower logo.png | logo caption = | logo size = | logo alt = UPower logo: a battery cell of size AA | screenshot = Xfce4 pop-up notification draining battery.png | caption = GNOME Power Manager notification about switch to battery power | screenshot size = | screenshot alt = | collapsible = | author = | developer = David Zeuthen, Richard Hughes a.o. (freedesktop.org) | released = {{Start date and age|2008}} | discontinued = | latest release version = {{wikidata|property|reference|edit|P348}} | latest release date = {{Start date and age|{{wikidata|qualifier|P348|P577}}|df=yes}} | latest preview version = | latest preview date = <!-- {{Start date and age|YYYY|MM|DD|df=yes/no}} --> | status = | programming language = C | operating system = Linux | platform = | size = | language = | language count = <!-- Number only --> | language footnote = | genre = | license = GPL (free software) | alexa = | website = {{URL|https://upower.freedesktop.org/}} | AsOf = }} '''UPower''' (previously '''DeviceKit-power''') is a piece of middleware (an abstraction layer) for power management on Linux systems.<ref name="energy"/> It enumerates power sources, maintains statistics and history data on them and notifies about status changes. It consists of a daemon (upowerd), an application programming interface and a set of command line tools. The daemon provides its functionality to applications over the system bus (an instance of D-Bus, service <code>org.freedesktop.UPower</code>).<ref name="D-Bus"/> PolicyKit restricts access to the UPower functionality for initiating hibernate mode or shutting down the operating system (freedesktop.upower.policy).<ref name="PolicyKit"/> The command-line client program <code>upower</code> can be used to query and monitor information about the power supply devices in the system. Graphical user interfaces to the functionality of UPower include the GNOME Power Manager and the Xfce Power Manager.<ref name="XfcePM"/>
UPower is a product of the cross-desktop freedesktop.org project. As free software it is published with its source code under the terms of version 2 or later of the GNU General Public License (GPL).
It was conceived as a replacement for the corresponding features of the deprecated HAL. In 2008, David Zeuthen started a comprehensive rewrite of HAL. This resulted in a set of separate services under the new name "DeviceKit".<ref name="HALrewrite"/> In 2010 the included ''DeviceKit-power'' was renamed. UPower was first introduced and established as a standard in GNOME.<ref name="GNOME"/> In January 2011 the desktop environment Xfce followed (version 4.8).
== Sources == <references>
<ref name="energy">{{citation|surname1=Michael Kofler|title=Linux 2011 : Debian, Fedora, openSUSE, Ubuntu|edition=10|publisher=Pearson Education Deutschland GmbH|publication-place=München|pages=504|isbn=9783827330253|date= 2011|language=German}}</ref>
<ref name="D-Bus">Oliver Diedrich (The H Open), 11 February 2013: [https://web.archive.org/web/20131207080422/http://www.h-online.com/open/news/item/D-Bus-is-coming-to-the-Linux-Kernel-1801485.html D-Bus is coming to the Linux Kernel]</ref>
<ref name="PolicyKit">{{citation|surname1=Richard Petersen|title=Fedora 14 : Administration and Security|publisher=Surfing Turtle Press|publication-place=Alameda, CA|isbn=9781936280230|date= 2010|language=German}}</ref>
<ref name="XfcePM">{{Cite web|url=https://goodies.xfce.org/projects/applications/xfce4-power-manager|title=Xfce:xfce4-power-manager:start [Xfce Docs]}}</ref>
<ref name="HALrewrite">{{citation|surname1=David Zeuthen|editor-surname1=freedesktop.org|periodical=HAL-Mailingliste|title=Update on DeviceKit |date=7 May 2008|language=German|url=https://lists.freedesktop.org/archives/hal/2008-May/011560.html}}</ref>
<ref name="GNOME">Thorsten Leemhuis (The H Open), 7 August 2012: [http://h-online.com/-1662354 Comment: Desktop Fragmentation]{{Dead link|date=July 2018 |bot=InternetArchiveBot |fix-attempted=no }}</ref>
</references> == External links == {{Commons category}} * {{official website|https://upower.freedesktop.org/}} * Red Hat, Inc.: Red Hat Enterprise Linux 7 – Power Management Guide, sections [https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Power_Management_Guide/upower.html 2.6.: UPower], [https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Power_Management_Guide/gnome-power-manager.html 2.7.: GNOME Power Manager]
Category:Servers (computing) Category:Free system software Category:Freedesktop.org