The YaST Power Management module serves the configuration of all power management settings described above. When starting the module from the YaST Control Center (‘System’->‘Power Management’), the first dialog of the module is displayed (see Figure 9.1. “YaST Power Management: Scheme Selection”). In this dialog, select the schemes to use for battery operation and AC operation.

Figure 9.1. YaST Power Management: Scheme Selection

In this dialog, select one of the existing schemes or click ‘Edit Schemes’ to access an overview of the existing schemes. This is shown in Figure 9.2. “YaST Power Management: Overview of Existing Schemes”.

Figure 9.2. YaST Power Management: Overview of Existing Schemes

In the schemes overview, select a scheme and click ‘Edit’ to access the editing dialog (see Figure 9.3. “YaST Power Management: Adding a Scheme”). To create a new scheme, click ‘Add’. The subsequent dialog is the same in both cases.

Figure 9.3. YaST Power Management: Adding a Scheme

First, enter a suitable name and description for the new or edited scheme. For the hard disk, define a ‘Standby Policy’ for maximum performance or for energy saving. The ‘Acoustic Policy’ controls the noise level of the hard disk. Click ‘Next’ to enter the ‘CPU’ and ‘Cooling Policy’ dialog. ‘CPU’ comprises the options ‘CPU Frequency Scaling’ and ‘Throttling’. Use these options to define if and to what extent the CPU frequency may be throttled. The ‘Cooling Policy’ determines the cooling method. Complete all settings for the scheme and click ‘OK’ to return to the start dialog (Figure 9.1. “YaST Power Management: Scheme Selection”). In the start dialog, assign the custom scheme to one of the two operating modes. To activate your settings, exit this dialog with ‘OK’.

Apart from selecting schemes for various operating modes, global power management settings can also be made from the start dialog using the ‘Battery Warnings’ or ‘ACPI Settings’ buttons (see Figure 9.1. “YaST Power Management: Scheme Selection”). Click ‘Battery Warnings’ to access the dialog for the battery charge level, shown in Figure 9.4. “YaST Power Management: Battery Charge Level”.

Figure 9.4. YaST Power Management: Battery Charge Level

The BIOS of your system notifies the operating system whenever the charge level drops under certain configurable limits. In this dialog, define three limits: ‘Warning Capacity’, ‘Low Capacity’, and ‘Critical Capacity’. Specific actions are triggered when the charge level drops under these limits. Usually, the first two states merely trigger a notification to the user. The third critical level triggers a suspend, as the remaining energy is not sufficient for continued system operation. Select suitable charge levels and the respective actions then click ‘OK’ to return to the start dialog. Access the dialog for configuring the ACPI buttons using the ‘ACPI Settings’ button. It is shown in Figure 9.5. “YaST Power Management: ACPI Settings”.

Figure 9.5. YaST Power Management: ACPI Settings

The settings for the ACPI buttons determine how the system should respond to the actuation of certain switches. Configure the system response to pressing the Power button, pressing the Sleep button, and closing the laptop lid. Click ‘OK’ to complete the configuration and return to the start dialog (Figure 9.1. “YaST Power Management: Scheme Selection”). Click ‘OK’ again to exit the module and confirm your power management settings.