307013-003 Datasheet, PDF (111/848 Pages) Intel Corporation – Intel I/O Controller Hub 7

Functional Description
5.3.1.5
Note:
Wake-Up Events
There are two types of wake-up events: “Interesting” Packets and Link Status Change.
These two events are detailed below.
If the Wake on LAN bit in the EEPROM is not set, wake-up events are supported only if
the PME Enable bit in the Power Management Control/Status Register (PMCSR) is set.
However, if the Wake on LAN bit in the EEPROM is set, and Wake on Magic Packet* or
Wake on Link Status Change are enabled, the Power Management Enable bit is ignored
with respect to these events. In the latter case, PME# would be asserted by these
events.
“Interesting” Packet Event
In the power-down state, the LAN controller is capable of recognizing “interesting”
packets. The LAN controller supports predefined and programmable packets that can
be defined as any of the following:
• ARP Packets (with Multiple IP addresses)
• Direct Packets (with or without type qualification)
• Magic Packet
• Neighbor Discovery Multicast Address Packet (‘ARP’ in IPv6 environment)
• NetBIOS over TCP/IP (NBT) Query Packet (under IPv4)
• Internetwork Package Exchange* (IPX) Diagnostic Packet
This allows the LAN controller to handle various packet types. In general, the LAN
controller supports programmable filtering of any packet in the first 128 bytes.
When the LAN controller is in one of the low power states, it searches for a predefined
pattern in the first 128 bytes of the incoming packets. The only exception is the Magic
Packet, which is scanned for the entire frame. The LAN controller classifies the
incoming packets as one of the following categories:
• No Match: The LAN controller discards the packet and continues to process the
incoming packets.
• TCO Packet: The LAN controller implements perfect filtering of TCO packets. After
a TCO packet is processed, the LAN controller is ready for the next incoming
packet. TCO packets are treated as any other wake-up packet and may assert the
PME# signal if configured to do so.
• Wake-up Packet: The LAN controller is capable of recognizing and storing the first
128 bytes of a wake-up packet. If a wake-up packet is larger than 128 bytes, its
tail is discarded by the LAN controller. After the system is fully powered-up,
software has the ability to determine the cause of the wake-up event via the PMDR
and dump the stored data to the host memory.
Magic Packets are an exception. The Magic Packets may cause a power
management event and set an indication bit in the PMDR; however, it is not stored
by the LAN controller for use by the system when it is woken up.
Link Status Change Event
The LAN controller link status indication circuit is capable of issuing a PME on a link
status change from a valid link to an invalid link condition or vice versa. The LAN
controller reports a PME link status event in all power states. If the Wake on LAN bit in
the EEPROM is not set, the PME# signal is gated by the PME Enable bit in the PMCSR
and the CSMA Configure command.
Intel ^® ICH7 Family Datasheet
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