Specifications

QSSC-S4R Technical Product Specification BMC-HSC Interactions
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28. BMC-HSC Interactions
28.1 HSC Availability
QSSC-S4R supports Hot-Swap Controller (HSC), the HSC is not available when the system is in standby. The HSC
requires at least three seconds after DC-power-on to reach a working state where it will respond to IPMI commands.
The state of the HSC is not preserved across system reset or AC/DC cycle.
When a single HSC is present in a system, it will respond on the primary IPMB at address C0h. When two HSCs are
present, the “primary” HSC will respond at address C0h, and the “secondary” HSC will respond at address C2h.
28.2 Interactions
All HSC interaction is dependent on a properly formatted type 12 (management controller) SDR entry per HSC. Without
a type 12 entry for the HSC, the BMC will not attempt any HSC communication with the exception of IPMI bridging
commands. For each type 12 SDR found, the BMC will:
x Attempt to verify the presence of the HSC using an IPMI “Get Device ID” command. This occurs when the system
is DC powered-on or reset.
x If the HSC is not found, or is in firmware update mode, the BMC will suspend communication with the HSC.
Communication will resume if the HSC exits firmware transfer mode, or the system is reset (at which time, the HSC
will be queried again).
x Send sensor initialization commands during the BMC’s IPMI initialization agent runtime. The initialization command
sequence is described in the Intelligent Platform Management Interface Specification Second Generation v2.0.
x Sensor initialization data for the HSC is kept within the BMC’s SDR, and is distributed as part of the BMC’s SDR
package.
x Push the current power state to the HSC using the HSC supported OEM command, Set Power Supply State. This
happens in 30 second intervals, unless there is an emergency power state change.
x For Details on the Set Power Supply State command, please see the appropriate platform Hot Swap Controller
(HSC) EPS.
x Scan HSC disk status sensors at a 30 second interval, and cause the system status LED to indicate a fault
condition if any of the disks are experiencing a fault.
x Disk fault detection is done by the host bus adapter, and is not controlled by the HSC or BMC. The HSC receives
disk fault status through a separate management bus. The BMC may only read disk fault status from the HSC.
The BMC firmware will always bridge commands through the BMC to the HSC via the IPMB. This is supported by the
IPMI command, Send Message. This command is used by system software to access the HSC status or to update the
HSC firmware.