Specifications

QSSC-S4R Technical Product Specification BMC Functional Specifications
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23.1.5.1 Power Button Signal
The POWER_BUTTON signal is filtered through a 16 ms hardware debounce. The signal must be in a constant state
for more than 16 ms before it is treated as asserted.
The signal is routed to the chipset power button signal through passthrough and SIO circuitry that allows the BMC to
lock out the signal. The chipset responds to the assertion of the signal; it reacts to the press of the button, not the
release of it.
23.1.5.2 Chipset Sleep S4 / S5
The BMC is notified of S4/S5 transitions by the BIOS, through the SMM interface.
23.1.5.3 Power Power-On Enable
The front panel pass-through is set ‘on’ as the default. Although front panel lockout settings are available through BIOS
setup screens, front panel lockout is controlled by the BMC firmware. BIOS should send the “Set Front Panel Button
Enables” IPMI command to the BMC to set the lockout status. The BMC disables any valid wakeup event, including the
power button press, for 1 second after the power has been turned off. This feature protects the power supply from
repeated on/off switching.
Assertion of the FORCE_UPDATE jumper signal allows power on to occur. This includes the case in which the BMC
operational code is not functional.
23.1.5.4 Power Power-down Disable
The BMC disables all wakeup events for 1 second after the power-down. This event is handled by firmware.
23.1.6 Power State Retention
The BMC persistently stores the latest power state that was attained due to a power state change initiator. Refer to the
power state sources in Table 172. This capability supports the power state restoration feature.
23.1.7 Power State Restoration
The BMC provides the ability to control the AC power-on behavior of the server. The Set Power Restore Policy
command configures the BMC to restore the power state in one of three ways.
x Power always off – Leave power off when AC is restored.
x Power always on – Power server on when AC is restored.
x Restore power state – Restore power state to the state it was in when AC was lost.
When standby power returns after an AC power loss, BMC firmware activates the server power as directed by the
configuration.
23.1.8 Wake-On-LAN (WOL)
The BMC does not directly participate in WOL. The NICs directly interact with the chipset to initiate the power on of the
system via the SLPS3n and SLPS5n signals to the BMC as a wakeup event.
23.2 Advanced Configuration and Power Interface (ACPI)
Table 173. ACPI States
State Supported Description
S0 Yes Working
x The front panel power LED is on (not controlled by the BMC).
x The fans spin at the normal speed, as determined by sensor inputs.
x Front panel buttons work normally.
S1 Yes Sleeping. Hardware context maintained; equates to processor and chipset clocks stopped.
x The front panel power LED blinks at a rate of 1 Hz with a 50% duty cycle(not
controlled by the BMC).