Intel SE7501WV2 User Manual

Page of 169
SE7501WV2 ACPI Implementation 
Intel® Server Board SE7501WV2 TPS 
  
Revision 
1.0 
 
Intel reference number C25653-001 
136
7. SE7501WV2 
ACPI 
Implementation 
7.1 ACPI 
An ACPI aware operating system (OS) generates an SMI to request that the system be 
switched into ACPI mode. The BIOS responds by sending the appropriate command to the 
BMC to enable ACPI mode. The system automatically returns to legacy mode upon hard reset 
or power-on reset. 
The SE7501WV2 platform supports S0, S1, S4, and S5 states. When the system is operating in 
ACPI mode, the operating system retains control of the system and operating system policy 
determines the entry methods and wakeup sources for each sleep state. Sleep entry and 
wakeup event capabilities are provided by the hardware but are enabled by the operating 
system. 
S0 Sleep State 
The S0 sleep state is when everything is on. This is the state that no sleep is 
enabled. 
S1 Sleep State 
The S1 sleep state is a low wake-up latency sleep state. In this state, no 
system context is lost (Processor or chip set). The system context is 
maintained by the hardware. 
S4 Sleep State 
The S4 Non-Volatile Sleep state (NVS) is a special global system state that 
allows system context to be saved and restored (relatively slowly) when 
power is lost to the baseboard. If the system has been commanded to enter 
the S4 sleep state, the operating system will write the system context to a 
non-volatile storage file and leave appropriate context markers.  
S5 Sleep State 
The S5 sleep state is similar to the S4 sleep state except the operating 
system does not save any context nor enable any devices to wake the 
system. The system is in the “soft” off state and requires a complete boot 
when awakened.  
7.1.1 
Front Panel Switches 
The SE7501WV2 server board supports up to four front panel buttons (via anyone of three 
different front panel interface connectors):  
• 
Power button/ sleep button 
• 
Reset button 
• 
System identification button 
• 
NMI button 
The power button input (FP_PWR_BTN*) on the SE7501WV2 design is a request that is 
forwarded by the BMC to the power state functions in the National* PC87417 Super I/O chip. 
The power button state is monitored by the BMC. It does not directly control power on the power 
supply.