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A transition to the Grant Snoop state will occur when the processor detects a snoop on
the front side bus (see
While in the Stop-Grant state, SMI#, INIT#, BINIT# and LINT[1:0] will be latched by
the processor, and only serviced when the processor returns to the Normal state. Only
one occurrence of each event will be recognized upon return to the Normal state.
While in Stop-Grant state, the processor will process snoops on the front side bus and it
will latch interrupts delivered on the front side bus.
The PBE# signal can be driven when the processor is in Stop-Grant state. PBE# will be
asserted if there is any pending interrupt latched within the processor. Pending
interrupts that are blocked by the EFLAGS.IF bit being clear will still cause assertion of
PBE#. Assertion of PBE# indicates to system logic that it should return the processor to
the Normal state.
7.2.4
Extended HALT Snoop or HALT Snoop State, Stop Grant
Snoop State
The Extended HALT Snoop state is used in conjunction with the Extended HALT state. If
the Extended HALT state is not enabled in the BIOS, the default Snoop state entered
will be the HALT Snoop state. Refer to the sections below for details on HALT Snoop
state, Stop Grant Snoop state and Extended HALT Snoop state.
7.2.4.1
HALT Snoop State, Stop Grant Snoop State
The processor will respond to snoop or interrupt transactions on the front side bus
while in Stop-Grant state or in HALT state. During a snoop or interrupt transaction, the
processor enters the HALT/Grant Snoop state. The processor will stay in this state until
the snoop on the front side bus has been serviced (whether by the processor or another
agent on the front side bus) or the interrupt has been latched. After the snoop is
serviced or the interrupt is latched, the processor will return to the Stop-Grant state or
HALT state, as appropriate.
7.2.4.2
Extended HALT Snoop State
The Extended HALT Snoop state is the default Snoop state when the Extended HALT
state is enabled via the BIOS. The processor will remain in the lower bus to core
frequency ratio and VID operating point of the Extended HALT state.
While in the Extended HALT Snoop state, snoops and interrupt transactions are handled
the same way as in the HALT Snoop state. After the snoop is serviced or the interrupt is
latched, the processor will return to the Extended HALT state.
7.3
Enhanced Intel SpeedStep® Technology
Quad-Core Intel® Xeon® Processor 5300 Series support Enhanced Intel SpeedStep®
Technology. This technology enables the processor to switch between multiple
frequency and voltage points, which results in platform power savings. Enhanced Intel
SpeedStep Technology requires support for dynamic VID transitions in the platform.
Switching between voltage/frequency states is software controlled. For more
configuration details also refer to the Conroe and Woodcrest Processor Family BIOS
Writer's Guide.
Note:
Not all Quad-Core Intel® Xeon® Processor 5300 Series are capable of supporting
Enhanced Intel SpeedStep Technology. More details on which processor frequencies will
Quad-Core Intel® Xeon® Processor 5300 Series Datasheet
Section
7.2.4.1).
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