Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 375 — #401
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17
Power Management
Using ACPI, powersave Does Not Notice Battery Limit
With ACPI, the operating system can request the BIOS to send a message
when the battery charge level drops under a certain limit. The advantage
of this method is that the battery state does not need to be polled con-
stantly, which would impair the performance of the computer. However,
this notification may not take place when the charge level drops under the
specified limit, even though the BIOS supposedly supports this feature.
If this happens on your system, set the variable POWERSAVED_FORCE_-
BATTERY_POLLING in the file /etc/powersave.conf to yes to force
battery polling.
17.6 The YaST Power Management
Module
The YaST Power Management module can configure all power manage-
ment 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 17.1 on the following page). 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 17.2 on page 377.
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 (see Figure 17.3 on page 378).
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 17.1 on
the next page). In the start dialog, assign the custom scheme to one of the
two operating modes. To activate your settings, exit this dialog with ‘OK’.
Global power management settings can also be made from the intial dia-
log using ‘Battery Warnings’ or ‘ACPI Settings’. Click ‘Battery Warnings’
to access the dialog for the battery charge level, shown in Figure 17.4 on
page 379.
375SUSE LINUX Enterprise Server