Device Power Management - Compal Notebook User Manual

S4 Sleeping State

4.6.4 Device Power Management

Under ACPI mode, the device specific power management supported by this
notebook includes the CPU throttling, monitor power management and the hard disk.
4.6.4.1 CPU power management
ACPI mode
The operating system detects when the system is idle and places the CPU in one of
the 3 CPU low power states (C1, C2, C3 up to C6) depending on how much latency it
believes the system can afford.
The C1 state is simply the CPU halt instruction.
The C2 state is the CPU stop grant state.
The C3 state is the CPU stops clock state.
The CPU stays in this state until an interrupt occurs.
4.6.4.2 Hard Disk
The operating system uses the spin down timer of the hard drive to set time-outs.
The BIOS time-out of the hard disk must be disabled in ACPI mode. The user can
sets the hard disk spin down time-out in the control panel power applet.
4.6.4.3 Display Device
The monitor can be turned off after a period of no activity based on the settings of the
OS.
4.6.4.4 System Wake Up Sources
The table below lists the wake up events for all low power states:
Events
Internal Keyboard
Internal pointing device
USB
Lid Switch
Power button
LAN (On board)
RTC
System Saves all system states and data
onto disk prior to power off the whole
system.
S3 S4
Yes No
No No
No No
No No
Yes Yes
Yes Yes(AC mode only)
Yes Yes(AC mode only)
S5
No
No
No
No
Yes
Yes(AC mode only)
Yes(AC mode only)
Process
required
No
No
No
No
No
Yes
Yes