Kontron AT8242 - Manual (Page 56)

40 AT8242
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4.3.2 Sensor Data Records
Information that describes the IPMC capabilities is provided through two mechanisms: capabilities
commands and Sensor Data Records (SDRs). Capabilities commands are commands within the IPMI command
set that return fields providing information on other commands and functions the controller can handle.
Sensor Data Records are data records containing information about the type and number of sensors in the
platform, sensor threshold support, event generation capabilities, and information on what types of
readings the sensor provides. The primary purpose of Sensor Data Records is to describe the sensor
configuration of the hardware management subsystem to system software.
The IPMC is required to maintain Device Sensor Data Records for the sensors and objects it manages. Access
methods for the Device SDR entries are described in the [IPMI 2.0] specification, Section 35, "Sensor Device
Commands."
After a FRU is inserted, the System Manager, using the Shelf Manager, may gather the various SDRs from the
FRU's IPM Controller to learn the various objects and how to use them. The System Manager uses the "Sensor
Device Commands" to gather this information. Thus, commands, such as "Get Device SDR Info" and "Get
Device SDR," which are optional in the IPMI specification, are mandatory in AdvancedTCA systems.
Most of the current Shelf Manager implementation gathers the individual Device Sensor Data Records of each
FRU into a centralized SDR Repository. This SDR Repository may exist in either the Shelf Manager or System
Manager. If the Shelf Manager implements the SDR Repository on-board, it shall also respond to "SDR
Repository" commands.
This duplication of SDR repository commands creates sometimes some confusion among AdvancedTCA users.
It is mandatory for the IPMC to support the Sensor Device Commands for IPMC built-in SDR as described in the
[IPMI 2.0] specification, Section 35, "Sensor Device Commands." For the ShMC, the same set of commands
for the centralized SDR Repository must be supported but they are described in the [IPMI 2.0] specification,
Section 33, "SDR Repository Commands.”