System BIOS

Intel® Server Board SE7520JR2

The BIOS supports a control panel sleep button. The sleep button may not be provided on all control panel designs. On systems where the sleep button is optional, a system configuration option will be provided to enable or disable the sleep button. The ACPI tables will be updated to indicate the presence or absence of the sleep button. Removal of the sleep button does not prevent an ACPI OS from entering a sleep state.

The sleep button has no effect unless an operating system is running. If the OS is running, pressing the sleep button causes an event. The OS will cause the system to transition to the appropriate ACPI system state depending on the current user settings.

The platform supports a control panel reset button. The reset button is a request that is forwarded by the mBMC to the chipset. The BIOS does not affect the behavior of the reset button.

The BIOS supports a control panel NMI button. The NMI button may not be provided on all control panel designs. The NMI button is a request that causes the mBMC to generate an NMI (non-maskable interrupt). The NMI is captured by the BIOS during Boot Services time or the OS during Runtime. The BIOS will simply halt the system upon detection of the NMI.

4.9.2.2Power Switch Off to On

The chipset may be configured to generate wakeup events for several different system events: Wake on LAN, PCI Power Management Interrupt (PMI), and Real Time Clock Alarm are examples of these events. The operating system will program the wake sources before shutdown. A transition from either source results in the mBMC starting the power-up sequence. Since the processors are not executing, the BIOS does not participate in this sequence. The hardware receives power good and reset from the mBMC and then transitions to an ON state.

4.9.2.3On to Off (OS absent)

The SCI interrupt is masked. The firmware polls the power button status bit in the ACPI hardware registers and sets the state of the machine in the chipset to the OFF state. The mBMC monitors power state signals from the chipset and de-asserts PS_PWR_ON to the power supply. As a safety mechanism, the mBMC automatically powers off the system in 4-5 seconds if the BIOS fails to service the request.

4.9.2.4On to Off (OS present)

If an operating system is loaded, the power button generates a request (via SCI) to the OS to shutdown the system. The OS retains control of the system and OS policy determines what sleep state (if any) the system transitions into.

4.9.2.5On to Sleep (ACPI)

If an operating system is loaded, the sleep button generates a request (via SCI) to the OS to place the system in “sleep” mode. The OS retains control of the system and OS policy determines what sleep state (if any) the system transitions into.

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C78844-002