Alert Standard Format (ASF) Specification

Alert Standard Format (ASF) Specification v2.0 DMTF Document DSP0136
DSP0136 23 April 2003 Page 67 of 94
8 1 8 1
Rd Data1 A Rd Data2 A
• • •
Event Status Count 0 Status 1/0 0
8 1 8 1 1
Rd Data N A PEC ~A P
Status 2*(N-2)-
1/2*(N-2)
0 [data dependent] 1
5.1.2 Asynchronous Alert Notification to SMBus Host
This message notifies the SMBus host or an Auxiliary Management Device of a pending alert,
and provides a common context that conforms to the strict rules for communicating with the
system SMBus host. This asynchronous notification includes an Event Status Index (see 5.1.1)
so that the alert receiver can quickly determine the type of event and its location within the
transmitting ASF-sensor when multiple events are monitored by the ASF-sensor address.
These are behavior rules governing when the ASF-sensor sends notifications:
1. The Asynchronous Alert Notification message must not be sent to an alert-sending
device, the Push Alert message (see 5.1.5) must be used instead.
2. Stop sending a notification once the message has been completely sent with ACKs to all
bytes according to [SMBus 2.0] definitions, or if the event causing the alert notification is
cleared.
3. Retry any notification that is NACKed by the target device at a minimum retry interval of 4
seconds until (a) the event is cleared, (b) the notification function is masked by a re-
configuration of the notifying device or (c) the notification retry limit is exceeded.
4. Asynchronous notifications are disabled globally by default or on power-on-reset of a
notifying device, and can be globally disabled at any time.
The notifying device includes the following fields as part of the asynchronous notification:
Field
Name
Bit(s) Meaning
Interface 7 Set to 1b. This identifies that the message is an asynchronous notification
and prevents the write-word from being interpreted as a 1-byte write-block
SMBus command.
6:4 Interface Class for the asynchronous notification, one of:
000b ASF
001b IPMI
010b Vendor (OEM)
Others Reserved for future definition by this specification