© 2010 Advanced Micro Devices, Inc.
47062 SR5650 Databook 2.00
Proprietary
6-1
Chapter 6
Power Management and ACPI
6.1
ACPI Power Management Implementation
This chapter describes the support for ACPI power management provided by the SR5650. The SR5650 system controller
supports ACPI
Revision 2.0. The hardware, system BIOS, and drivers of the SR5650 have the logic required for meeting
the power management specifications of PC2001, OnNow, and the Windows Logo Program and Device Requirements
version 2.1.
Table 6-1, “ACPI States Supported by the SR5650,”
describes the ACPI states supported by the SR5650
system controller.
Table 6-1 ACPI States Supported by the SR5650
ACPI State
Description
Processor States:
S0/C0: Working State
Working State. The processor is executing instructions.
S0/C1: Halt
CPU Halt state. No instructions are executed. This state has the lowest latency on resume and contributes
minimum power savings.
S0/C2: Stop Grant
Caches Snoopable
Stop Grant or Cache Snoopable CPU state. This state offers more power savings but has a higher latency
on resume than the C1 state.
S0/C3: Stop Grant
Caches Snoopable
Processor is put into the Stop Grant state. Caches are still snoopable. The HyperTransport™ link may be
disconnected and put into a low power state. System memory may be put into self-refresh.
System States:
S1: Standby
Powered On Suspend
System is in Standby mode. This state has low wakeup latency on resume. OEM support of this state is
optional.
S3: Standby
Suspend to RAM
System is off but context is saved to RAM. System memory is put into self-refresh.
S4: Hibernate
Suspend to Disk
System is off but context is saved to disk. When the system transitions to the working state, the OS is
resumed without a system re-boot.
S5: Soft Off
System is off. OS re-boots when the system transitions to the working state.
G3: Mechanical Off
Occurs when system power (AC or battery) is not present or is unable to keep the system in one of the
other states.