ADLINK STC-15W04 - Manual (Page 48)

40 BIOS
C4 Exit Timing
This option controls a programmable time for the CPU voltage
to stabilize when exiting from a C4 state. Set this value to
Default, Fast, Slow.
C-state Popdown
Disabling the option, prevents automatic return to a previous
C3 or C4 state. Set this value to Disabled, Enabled.
C-state Popup
When enabled, SB observes bus master request, will take sys-
tem from a C3/C4 state to a C2 state and auto enables bus
masters. Set this value to Disabled, Enabled.