Alert Standard Format (ASF) Specification

Alert Standard Format (ASF) Specification v2.0 DMTF Document DSP0136
DSP0136 23 April 2003 Page 81 of 94
Host
Alert
Register
D
C
Q
Poll Alert
Register
Host Clear
Event
6.2.4 Device Power On Reset Time
ASF-sensor and remote-control devices are allowed up to 500ms to complete their Power On
Reset once they have detected that their supply power is stable. These devices don’t appear on
the SMBus (i.e. a NACK is generated for the associated slave address) before the device is
prepared to communicate.
Note: Alert-sending devices that begin communicating over the SMBus after auxiliary power has
stabilized but before main power has stabilized must tolerate a change in available devices; there
may be a mix of auxiliary powered and main powered types.
6.3 Remote Control Device
If remote-control devices are included in an ASF managed client’s implementation, the client’s
firmware identifies the characteristics and access methods for the devices via the ASF_RCTL
ACPI data structure.
6.3.1 Device Requirements
Beyond the SMBus transaction requirements in section 5.4, remote-control devices must meet
the following requirements:
1. The remote control actions must be write-able by doing an SMBus Byte Write transaction.
2. The remote control action must be initiated immediately by the managed client system’s
hardware after the Remote-Control Device Action Message is issued by the alert-sending
device.
3. The remote control actions must work independent of local client software support.
6.3.2 Usage of Firmware Remote Control Device Information
An alert-sending device, acting as an SMBus master, will issue SMBus Remote Control actions
when the appropriate RMCP remote control packet is received (see 3.2.4.1 and 3.2.4.2 for more
information). For the appropriate remote control action, the ASF_RCTL fields Control Device
Address, Control Command, and Control Data Value are used for the SMBus Device Address,
Command, and Data Write, respectively. Additionally, bit 0 of the ASF_RCTL Control Device
Address field determines whether (1) or not (0) a PEC is appended to the Byte Write command
by the alert-sending device.
6.3.3 Remote Control Functions
The remote control functions supported by this specification are defined here; the duration of
each of these operations is managed client system-specific.