© 2008 Advanced Micro Devices, Inc.
41978 AMD RS690M Databook 3.06
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 RS690M. The RS690M supports ACPI
Revision 1.0b. The hardware, system BIOS, video BIOS, and drivers of the RS690M have all 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 RS690M,”
describes the ACPI states supported by
the RS690M.
Table 6-2, “ACPI Signal Definitions,”
describes the signals used in the ACPI power management scheme
of the RS690M.
Note:
Also supported are additional processor power states that are not part of the ACPI specification, e.g. C1E (C1
Enhanced) and C3 pop-up. Please refer to the
SB600 Databook
and the
RS690 Register Programming Requirements
for
more information.
Table 6-1 ACPI States Supported by the RS690M
ACPI State
Description
Graphics States:
D0
Full on, display active.
D1
Display Off. RS690M power on. Configuration registers, state, and main memory contents retained.
D3 Hot
Similar to D1, with additional power saving and the graphics PLLs shut off.
D3 Cold
RS690M power off.
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 Not Snoopable
Stop Grant or Cache not Snoopable Sleep state. The CPU’s caches maintain state but ignore any snoops.
This state offers more power savings but has a higher latency on resume than the C1 and C2 states.
System States:
S3: Standby
Suspend to RAM
System is off but context is saved to RAM. OEM support of this state is optional. 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.
Table 6-2 ACPI Signal Definitions
Signal Name
Description
Source
ALLOW_LDTSTOP
Output to the Southbridge to allow LDTSTOP# assertion.
Northbridge
LDTSTOP#
HyperTransport
TM
Technology Stop: Enables and disables links during
system state transitions.
Southbridge
POWERON#
Power on
Power switch
RESET#
Global Reset
Southbridge