Laptop users are concerned with getting the most out of their battery power. KDE provides a Power Management utility that makes it easy to see your current battery settings and to create power profiles that best match your needs. If you click on the battery icon in your system tray, the Power Management window will open, as seen in Figure 7.4a:
Figure 7.4a: Power Management Window of Battery Widget in the System Tray
If you don't see a battery icon, you may need to click the up arrow in the system tray to view hidden icons. If it is still not there, you can add this widget to the system tray by clicking on the Panel tool box icon (located in far right corner of the panel) -> +Add Widgets. Search for the term "battery" and double-click the battery icon. You can then click the red X to close the Add Widget window.
As seen in Figure 7.4a, this window will indicate if the battery is plugged in and the percentage of the charge. If you click the Power Profile drop down menu, you will have the option to choose from five power profiles: Performance, Powersave, Agressive Powersave, Xtreme Powersave, and Presentation. The rest of this section will show you how to view and modify the settings for each power profile.
If you wish to conserve some battery power, you can use the slider to adjust the screen brightness to the lowest usability level.
If your BIOS supports it, you can click the Sleep or Hibernate buttons whenever you wish to enter that mode.
Note: if you encounter problems with Sleep or Hibernate mode, the section on ACPI may help you to diagnose or fix the problem.
If you click the wrench icon, you will enter the Power Management utility, seen in Figure 7.4b. You can also start this utility from Kicker -> System Settings -> Power Management.
Figure 7.4b: General Settings Window of KDE's Power Management Utility
The Settings and Profile tab of the General Settings window allows you to configure the following:
Lock screen on resume: if this box is checked, the screen will be locked when leaving suspend mode. This means that you will need to input your password to unlock the screen.
Let PowerDevil manage screen powersaving: if checked, KDE will use DPMS
Before doing a suspend action, wait: the number of seconds KDE will wait before suspending the system (e.g. after closing the lid).
The Profile Assignment section allows you to determine which of the 5 power profiles is used for each of the following situations:
- When AC Adaptor is plugged in
- When on battery power
- When battery is at low level
When battery is at warning level
If you click the Configure Notifications button, you'll see a screen similar to Figure 7.4c:
Figure 7.4c: Configuring Notifications for Power Management
The upper frame of this window lists various power management events and the lower frame of this window configures the type of notification associated with each event. If you highlight an event, such as "The power adaptor has been plugged in", you can view and edit the possible notifications:
Play a sound:
Show a message in a popup:
Log to a file:
Mark taskbar entry: