Intel E7520 用户手册
Dual-Core Intel
®
Xeon
®
processor LV with Intel
®
E7520 Chipset and Intel
®
6300ESB ICH
April 2007
User’s Manual
Order Number: 311274-009
37
Dual-Core Intel Xeon processor LV / E7520 Chipset / 6300ESB ICH
4.0
Platform Management
The following sections describe how the system power management operates, and how
the different ACPI states are implemented. Platform management involves:
• ACPI implementation-specific details
• System monitoring, control, and response to thermal, voltage, and intrusion events
• BIOS security
• System monitoring, control, and response to thermal, voltage, and intrusion events
• BIOS security
4.1
Power Button
The system power button is connected to the I/O controller component. When the
button is pressed, the I/O controller receives the signal and transitions the system to
the proper sleep state as determined by the operating system and software. If the
power button is pressed and held for four seconds, the system powers off (S5 state).
This feature is called power button override and is particularly helpful in case of system
hang and system lock. The power button is located next to the SATA connectors on the
board.
4.2
Sleep States Supported
The I/O controller controls the system sleep states. States S0, S1, S3, and S5 are
supported. The platform enters sleep states in response to BIOS, operating system, or
user actions. Normally the operating system determines which sleep state to transition
into. However, a four second power button override event places the system
immediately into S5. When transitioning into a software-invoked sleep state, the I/O
controller attempts to gracefully put the system to sleep by first going into the
processor C2 state.
4.2.1
S0 State
This is the normal operating state, even though there are some power savings modes
in this state using processor Halt and Stop Clock (processor C1 and C2 states). S0
affords the fastest wake-up response time of any sleep state because the system
remains fully powered and memory is intact.
4.2.2
S1 State
This state is entered via a processor Sleep signal from the I/O controller (processor C3
state). The system remains fully powered with memory contents intact but the
processors enter their lowest power state. The operating system disables bus masters
for uniprocessor configurations while flushing and invalidating caches before entering
this state in multiprocessor configurations. Wake-up latency is slightly longer in this
state than in S0; however, power savings are improved from S0.
4.2.3
S2 State
This state is not supported.
4.2.4
S3 State
This state is called Suspend to RAM (STR). The system context is maintained in system
DRAM, but power is shut off to non-critical circuits. Memory is retained, and refreshes
continue. All clocks stop except the RTC. S3 is entered when the I/O controller asserts
the SLP_S3# signal to downstream circuitry to control 1.8 V power plane switching.