Intel® Server Board S2600CO Family TPS Platform Management Functional Overview
Revision 1.0 57
Intel order number G42278-002
External Signal Name or Internal
Subsystem
6.4 BMC Watchdog
The BMC FW is increasingly called upon to perform system functions that are time-critical in
that failure to provide these functions in a timely manner can result in system or component
damage. Intel
®
S1400/S1600/S2400/S2600/S4600 Server Platforms introduce a BMC watchdog
feature to provide a safe-guard against this scenario by providing an automatic recovery
mechanism. It also can provide automatic recovery of functionality that has failed due to a fatal
FW defect triggered by a rare sequence of events or a BMC hang due to some type of HW
glitch (for example, power).
This feature is comprised of a set of capabilities whose purpose is to detect misbehaving
subsections of BMC firmware, the BMC CPU itself, or HW subsystems of the BMC component,
and to take appropriate action to restore proper operation. The action taken is dependent on
the nature of the detected failure and may result in a restart of the BMC CPU, one or more BMC
HW subsystems, or a restart of malfunctioning FW subsystems.
The BMC watchdog feature will only allow up to three resets of the BMC CPU (such as HW
reset) or entire FW stack (such as a SW reset) before giving up and remaining in the uBOOT
code. This count is cleared upon cycling of power to the BMC or upon continuous operation of
the BMC without a watchdog-generated reset occurring for a period of > 30 minutes. The BMC
FW logs a SEL event indicating that a watchdog-generated BMC reset (either soft or hard reset)
has occurred. This event may be logged after the actual reset has occurred. Refer sensor
section for details for the related sensor definition. The BMC will also indicate a degraded
system status on the Front Panel Status LED after an BMC HW reset or FW stack reset. This
state (which follows the state of the associated sensor) will be cleared upon system reset or (AC
or DC) power cycle.
Note: There will no SEL event and front panel LED status change for BMC reset due to Linux
“kernel panic”.
A reset of the BMC may result in the following system degradations that will require a system
reset or power cycle to correct:
1. Timeout value for the rotation period can be set using this parameterPotentially incorrect
ACPI Power State reported by the BMC.
2. Reversion of temporary test modes for the BMC back to normal operational modes.
3. FP status LED and DIMM fault LEDs may not reflect BIOS detected errors.
6.5 Fault Resilient Booting (FRB)
Fault resilient booting (FRB) is a set of BIOS and BMC algorithms and hardware support that
allow a multiprocessor system to boot even if the bootstrap processor (BSP) fails. Only FRB2 is
supported using watchdog timer commands.
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