powered is the power event daemon. It is designed to replace the mode
control entity (mce). powered will pretend to be mce if mce is not
running. By default, the startup script for powered will stop mce
before starting powered unless you edit /etc/default/powered. This
means that powered is possibly reachable on DBus under two different
names: org.maemo.Powered and com.nokia.mce.
powered implements all of mce's DBus interface so replacing mce with
powered should be completely transparent to applications. In addition
to mce's functions, there are additional functions not available with
mce. For example, you can selectively lock the touchscreen using
powered's dbus interface. Unlike mce, powered was designed to do as
little active stuff as possible. It simply passes events out via dbus
and handles requests from dbus. This allows other programs to control
the system interface completely.
The easiest way to communicate with powered is via the helper program
powerline. For example, "powerline softpoweroff" will send
the dbus call SoftPowerOff to powered. The method name is not
DBus Interface The definitive DBus interface for
powered is here.
You can also run "powerline introspect" to get the interface via DBus introspection.
powered reads /etc/powered.conf as its configuration file. It will
also read LED patterns from /etc/mce/mce.ini. The format of this file
is currently undocumented other than the comments that exist in the
The one active part of powered is a "failsafe mode" which can be
customized in the config file. By default, if one holds down the power
key for 5 seconds, powered goes into a failsafe mode for a short
period of time (and the LEDs should blink). In this mode, you can
press one hardware key and have it mapped to some action. For example,
by default, the down key is mapped to /sbin/reboot. That means, if the
system is frozen for some reason, you can enter failsafe mode, push
down and reboot (similar to ctrl-alt-del).