307013-003 Datasheet, PDF (153/848 Pages) Intel Corporation – Intel I/O Controller Hub 7

Functional Description
5.14 Power Management (D31:F0)
5.14.1 Features
• Support for Advanced Configuration and Power Interface, Version 2.0 (ACPI)
providing power and thermal management
— ACPI 24-Bit Timer
— Software initiated throttling of processor performance for Thermal and Power
Reduction
— Hardware Override to throttle processor performance if system too hot
— SCI and SMI# Generation
• PCI PME# signal for Wake Up from Low-Power states
• System Clock Control
— (Mobile/Ultra Mobile Only) ACPI C2 state: Stop Grant (using STPCLK# signal)
halts processor’s instruction stream
— (Mobile/Ultra Mobile Only) ACPI C3 State: Ability to halt processor clock (but
not memory clock)
— (Mobile/Ultra Mobile Only) ACPI C4 State: Ability to lower processor voltage.
— (Mobile/Ultra Mobile Only) CLKRUN# Protocol for PCI Clock Starting/Stopping
• System Sleep State Control
— ACPI S1 state: Stop Grant (using STPCLK# signal) halts processor’s instruction
stream (only STPCLK# active, and CPUSLP# optional)
— ACPI S3 state — Suspend to RAM (STR)
— ACPI S4 state — Suspend-to-Disk (STD)
— ACPI G2/S5 state — Soft Off (SOFF)
— Power Failure Detection and Recovery
• Streamlined Legacy Power Management for APM-Based Systems
5.14.2 Intel^® ICH7 and System Power States
Table 5-25 shows the power states defined for ICH7-based platforms. The state names
generally match the corresponding ACPI states.
Table 5-25. General Power States for Systems Using Intel^® ICH7 (Sheet 1 of 2)
State/
Substates
Legacy Name / Description
G0/S0/C0
Full On: Processor operating. Individual devices may be shut down to save
power. The different processor operating levels are defined by Cx states, as
shown in Table 5-26. Within the C0 state, the Intel^® ICH7 can throttle the
processor using the STPCLK# signal to reduce power consumption. The throttling
can be initiated by software or by the operating system or BIOS.
G0/S0/C1
Auto-Halt: Processor has executed an AutoHalt instruction and is not executing
code. The processor snoops the bus and maintains cache coherency.
G0/S0/C2
(Mobile/Ultra
Mobile Only)
Stop-Grant: The STPCLK# signal goes active to the processor. The processor
performs a Stop-Grant cycle, halts its instruction stream, and remains in that
state until the STPCLK# signal goes inactive. In the Stop-Grant state, the
processor snoops the bus and maintains cache coherency.
Intel ^® ICH7 Family Datasheet
153