33.6. The YaST Power Management Module

The YaST power management module can configure all power management settings already described. When started from the YaST Control Center with System+Power Management, the first dialog of the module opens (see Figure 33.1, “Scheme Selection”).

Figure 33.1. Scheme Selection

Scheme Selection

In this dialog, select the schemes to use for battery operation and AC operation. To add or modify the schemes, click Edit Schemes, which opens an overview of the existing schemes like that shown in Figure 33.2, “Overview of Existing Schemes”.

Figure 33.2. Overview of Existing Schemes

Overview of Existing Schemes

In the scheme overview, select the scheme to modify then click Edit. To create a new scheme, click Add. The dialog that opens is the same in both cases and is shown in Figure 33.3, “Configuring a Scheme”.

Figure 33.3. Configuring a Scheme

Configuring a Scheme

First, enter a suitable name and description for the new or edited scheme. Determine if and how the CPU performance should be controlled for this scheme. Decide if and to what extent frequency scaling and throttling should be used. In the following dialog 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 (supported by few hard disks). The Cooling Policy determines the cooling method to use. Unfortunately, this type of thermal control is rarely supported by the BIOS. Read /usr/share/doc/packages/powersave/powersave_manual.html#Thermal to learn how you can use the fan and passive cooling methods.

Global power management settings can also be made from the initial dialog using Battery Warnings, ACPI Settings, or Enable Suspend. Click Battery Warnings to access the dialog for the battery charge level, shown in Figure 33.4, “Battery Charge Level”.

Figure 33.4. Battery Charge Level

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 shutdown, because the remaining energy is not sufficient for continued system operation. Select suitable charge levels and the desired actions then click OK to return to the start dialog.

Figure 33.5. ACPI Settings

ACPI Settings

Access the dialog for configuring the ACPI buttons using ACPI Settings. It is shown in Figure 33.5, “ACPI Settings”. The settings for the ACPI buttons determine how the system should respond to 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.

Click Enable Suspend to enter a dialog in which to determine if and how users of this system may use the suspend or standby functionality. Click OK to return to the main dialog. Click OK again to exit the module and confirm your power management settings.