# Power Management

&Dario.Freddi;&Dario.Freddi.mail;
2010-09-21
&kde; 4.5
KDE
System Settings
powerdevil
power management
laptop power

## PowerDevil, a Power Management Daemon

This module is a configuration tool for managing Power Management in &kde;. It is a configurator for the PowerDevil daemon, that you can start or stop from the Service Manager module.

Through this module, you can define your computer's behavior in various situations, allowing you to save as much energy as possible.

Powerdevil works with Solid only and it's integrated in your desktop. You won't even notice it is running, apart from notifications. Moreover, Powerdevil checks your system capabilities first, so you'll see only options available for your system in this module. You can also have a better glance at them through the Capabilities page.

Note that PowerDevil does not poll your system. This means that it will not waste energy while trying to save it, as some other power managers do.

### General Settings

Here you can configure some general options for the module.

#### Settings and Profiles

Lock screen on resume

  When this box is checked, every time the PC gets suspended, the screen will be locked when resuming.

Let PowerDevil manage screen powersaving

  If checked, PowerDevil will handle Screen powersaving through DPMS. If you want to have different timeouts for your screen powersaving features when your profile changes, you probably want to have this enabled. Otherwise, you can have constants timeouts in the Screen tab on the Edit Profiles page.

Before doing a suspend action, wait

  If this box is checked, when a suspend action gets automatically triggered (for example, when the system is idle for a long time or the lid gets closed) it will not be performed immediately, but it will be delayed of the amount of seconds you will specify in the spin box. A notification will be displayed, and if clicked, the action will be canceled. This option is useful if you want to have the possibility to avoid automatic suspension.

Profiles assignment

  In this section you have to assign your profiles to the specified situations. You can edit and create new profiles in Edit Profiles section. Everytime one of that events will be triggered, the chosen profile will be activated.

Configure Notifications

  If you want a deeper control over your notifications, you can refine them by clicking this button

#### Advanced Battery Settings

When battery remaining is critical

  Defines the action that will be done when battery reaches the critical level.

Battery is at low level at

  Here you can set the percentage after which the battery will be considered low.

Battery is at warning level at

  Here you can set the percentage after which the battery will be considered at warning level.

Battery is at critical level at

  Here you can set the percentage after which the battery will be considered at critical level.

### Edit Profiles

In this section you can edit, create and delete PowerDevil profiles. The list on the left shows you all currently available profiles. Select the one you want to edit, and tweak it with the options you see on the right, described hereafter. You can create or delete an existing profile thanks to the buttons you see at the bottom of the list, or you can even import profiles from a file, or export your existing ones to a file.

There are a lot of options you can configure for each profile, splitted in 3 main sections.

#### Actions

Disable desktop effects, if active

  &kwin; compositing will be disabled, if active. It will be re-enabled when a profile that does not have this option gets loaded.

When the system is idle for more than

  After the time you will specify in the spinbox, the action you select in the combobox will be performed. Simply choose "Do nothing" if you want to disable it.

When Laptop Lid Closed

  Defines the action that will be done when the laptop lid gets closed.

When Power Button pressed

  Defines the action that will be done when the power button gets pressed.

When Sleep Button pressed

  Defines the action that will be done when the sleep button gets pressed.

#### Screen

Brightness

  Sets the screen's brightness using a slider.

Dim display when idle for more than

  If checked, the display will be progressively dimmed, until reaching brightness 0, in the amount of time you specify in the spin box.

Enable display power management

  Here you can define power saving for your monitor. This section needs DPMS support available, you can check if your system supports them in the Capabilities page.

  The check box defines if DPMS support should be enabled or disabled. If you choose to activate it, set the timeouts in the spin boxes below. You can also prevent the monitor entering a certain status by unchecking the corresponding box.

#### CPU and System

Here you can define preferences for CPU management and system settings

Enable system power saving

  Check this option set system power management on or off.

When loading profile, execute

  You can specify a script to be run upon profile loading here.

### Capabilities

In this section you can have a look at your system's capabilities. If the Status is ok, your configuration works correctly and PowerDevil is running with every best option available. If some issues are found, you will be displayed a warning, with a possible solution.

PowerDevil is usually able to solve the issue by itself. In most cases what you need to do is clicking the suggested button, though sometimes issues are the result of compiling the application without support for a specific component. In that case, PowerDevil will not provide a solution but will just notify you about the problem.

## PowerDevil Runner

PowerDevil can be manually controlled through &krunner; (&Alt;F2). This makes changing profile, brightness, governor and more much easier and faster. The runner has various keywords you can enter to access its functions

### Runner Keywords

Here comes a list of keywords you can enter in &krunner; to perform PowerDevil related actions.

Power Profile

  You can manually choose a profile using this keyword. All available profiles will be shown in form of &krunner; matches.

Power Governor

  This keyword lets you manually set the CPU frequency governor. Available governors will be shown as &krunner; matches.

Power Scheme

  Lets you manually set the system powersaving scheme. Available schemes will be shown as &krunner; matches.

Screen Brightness

  You can control screen brightness through this keyword. In this form, some &krunner; matches that let you do some common actions will be shown. If you enter a value after the keyword (&eg;: `Screen Brightness 50`), the brightness will be set to that value.

Suspend

  You can suspend your pc through this keyword. Available suspend methods will be shown as &krunner; matches.