IDT Power Management
Link States
PES12N3 User Manual
5 - 2
June 7, 2006
Notes
PME Messages
The PES12N3 does not support generation of PME messages from the D3
cold
state. Downstream ports
(i.e., PCI-PCI bridges associated with ports B and C) support the generation of hot-plug PME events (i.e., a
PM_PME power management message) from the D3
hot
state. This includes both the case when the down-
stream port is in the D3
hot
state or the entire switch is in the D3
hot
state. The generation of a PME message
by downstream ports necessitates the implementation of a PME service time-out mechanism to ensure that
PME messages are not lost.
Link States
The PES12N3 supports the following link states:
–
L0 — Fully operational link state
–
L0s — Automatically entered low power state with shortest exit latency
–
L1 — Lower power state than L0s. May be automatically entered or directed by software by
placing the device in the D3
hot
state.
–
L2/L3 Ready — The L2/L3 state is entered after the acknowledgement of a PM_Turn_Off
Message. There is no TLP or DLLP communications over a link in this state.
–
L3 — Link is completely unpowered and off.
Link states are shown in Figure 5.2.
From State
To State
Description
Any
D0 Uninitialized
Power-on fundamental reset.
D0 Uninitialized
D0 Active
PCI-PCI bridge configured by software
D0 Active
D3
hot
The Power Management State (PMSTATE) field in the PCI Power
Management Control and Status (PMCSR) register is written with
the value that corresponds to the D3
hot
state.
D3
hot
D0 Uninitialized
The Power Management State (PMSTATE) field in the PCI Power
Management Control and Status (PMCSR) register is written with
the value that corresponds to D0 state.
D3
hot
D3
cold
Power is removed from the device.
Table 5.6 PES12N3 Power Management State Transition Diagram
Summary of Contents for 89HPES12N3
Page 10: ...IDT Table of Contents PES12N3 User Manual iv June 7 2006 Notes...
Page 14: ...IDT List of Figures PES12N3 User Manual viii June 7 2006 Notes...
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Page 50: ...IDT Switch Operation Switch Core Errors PES12N3 User Manual 4 10 June 7 2006 Notes...
Page 54: ...IDT Power Management Active State Power Management PES12N3 User Manual 5 4 June 7 2006 Notes...
Page 62: ...IDT Hot Plug and Hot Swap Hot Swap PES12N3 User Manual 6 8 June 7 2006 Notes...
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Page 148: ...IDT Test and Debug SerDes Test Clock PES12N3 User Manual 10 6 June 7 2006...
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