Programmer’s Guide BCM5722
10/15/07
Broadcom Corporation
Document 5722-PG101-R Advanced Configuration and Power Interface Page 526
The ACPI 2.0 specification defines power management behavior for device classes differently. For example, audio device
states D0–D3, are not similar to modem device states. Refer to Appendix A of the ACPI 2.0 specification for a detailed dis-
cussion of device power management. Table 568 (ACPI 2.0 spec) shows the power management behavior for the network
device class.
The power management policy for the network class specifies how a network device behaves at a Dx power state (see
Table 569). For example, a device, not the wire-speed of the device, needs to wake up during WOL mode. A network wake
up may be initiated by a Magic Packet or similar unique packet format.
Table 568: Power Management Behavior for the Network Device Class
State Implementation Requirement Definition
D0 Required Device is powered on and running.
Device delivers full functionality.
D1 Optional No bus transactions allowed.
No bus reception allowed.
No interrupts can occur.
Device context may be lost.
D2 Optional No bus transactions allowed.
No bus reception allowed.
No interrupts can occur.
Device context may be lost
D3 Required No bus transactions allowed.
No bus reception allowed.
No interrupts can occur.
Device context is lost.
Table 569: Power Management Policy for the Network Class
Current State Next State Cause/Effect
D0 Dx • Cause = System enters sleep state S1-S4
• Effect = If wake is enabled, the lowest Dx state is chosen for the network device.
There is one limitation, in that the Dx state must support the wakeup.
D0 D3
• Cause = System initiated network shutdown
• Effect = System enters sleep state. The device may provide wake capability, but it is
not required.
D1/D2/D3 D0
• Cause = System wakeup.
• Effect = Device moves to full-power operation.
To Next Page
Loading...