Technical Product Specification

Intel® Server Boards S4600LH2/T2 TPS
Revision 2.0
66
State
Supported
Description
S5
Yes
Soft off.
 The front panel buttons are not locked.
 The fans are stopped.
 The power-up process goes through the normal boot process.
 The power, reset, front panel NMI, and ID buttons are unlocked.
6.3 Power Control Sources
The server board supports several power control sources which can initiate a power-up or power-down activity.
Table 21. Power Control Initiators
Source
External Signal Name or
Internal Subsystem
Capabilities
Power button
Front panel power button
Turns power on or off
BMC watchdog timer
Inte rna l BMC time r
Turns power off, or power cycle
Command
Routed through command processor
Turns power on or off, or power cycle
Power state retention
Implemented by means of BMC
internal logic
Turns power on when AC power returns
Chipset
Sleep S4/S5 signal (same as
POWER_ON )
Turns power on or off
CPU Thermal
CPU Thermtrip
Turns power off
WOL(Wake On LAN)
LAN
Turns power on
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 a 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: 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.