Alert Standard Format (ASF) Specification

Alert Standard Format (ASF) Specification v2.0 DMTF Document DSP0136
DSP0136 23 April 2003 Page 63 of 94
Note: The values associated with the Wr, Command, Byte Count, Sub-command, Version
Number, A, and ~A fields for each of the messages in this section are each specified in binary
format with no trailing letter ‘b’.
5.1 Alert-related Messages
SMBus messages defined in this sub-section convey alert-related information to the alert-sending
device, which usually results in a PET frame being transmitted. The Get Event Data, Start
Watchdog Timer, and Push Alert messages include fields that the alert-sending device copies to
a subsequently transmitted PET frame. The fields are Event Sensor Type, Event Type, Event
Offset, Event Source Type, Event Severity, Sensor Device, Sensor Number, Entity, Entity
Instance, and Event Data; values for these fields are described in sections 3.1.3 and 3.1.4.
5.1.1 ASF-Sensor Poll Messages
ASF-sensors support messages defined in this section; those sensors also comply with the
device requirements described in section 6.2.
An ASF-sensor has a single SMBus address, but monitors one or more events. Within the
messages defined in this section, the Event Status Index field identifies a unique event monitored
by the ASF-sensor; once the ASF-sensor has completed its power-up initialization, the index-to-
event relationship remains constant independent of the system sleep-state. Event Status Index
values are zero-based
, sequential, and contiguous within an ASF-sensor. When a sensor
monitors N events, the sensor responds to Event Status Index values in the range 0 to N-1; any
other Event Status Index value is defined as out-of-range
for that ASF-sensor. For example:
• An ASF-sensor that monitors a single event provides support for index value 0 only. If the
device receives a Get Event Data command with an Event Status Index greater than 0, the
device responds with the Status field set to “Event Status End”.
• An ASF-sensor that monitors seven (7) events provides support for index values in the range
0 to 6. If the device receives a Get Event Data command with an Event Status Index greater
than or equal to 7, the device responds with the Status field set to “Event Status End”.
The Event Status Index field value ranges from 0 to 37h
8
, so each ASF-sensor can monitor at
most 56 events.
Messages defined in this section provide a method to retrieve the event state associated with
each device monitored by an ASF-sensor; that state is returned by the ASF-sensor as an
enumerated value in the Status field of the message. The Status field is an 8-bit value:
Bit(s)
Description
7:4 Reserved for future definition by this specification, set to 0000b.
3:0 Status Value
. This enumerated value indicates the event state of the ASF-sensor device
associated with the message’s Event Status Index. Those values are described in the
following table.
8
This value was chosen due to the 32 data byte limitation of the SMBus 2.0 Block Write-Block
Read Process Call protocol that is used by the Get Event Status message. That message
includes 3 bytes for the write portion of the message, and one byte of the read portion defines the
number of events returned: leaving 28 bytes in which to return the status. Each read data byte
returns two events’ Status Value, allowing at most 56 events to be monitored by any one ASF-
sensor.