Features
92 Dual-Core Intel® Xeon® Processor 3000 Series Datasheet
A transition to the Grant Snoop state will occur when the processor detects a snoop on
the FSB (see Section 6.2.4).
While in the Stop-Grant State, SMI#, INIT#, 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 a FSB snoop.
6.2.3.2 Extended Stop Grant State
Extended Stop Grant is a low power state entered when the STPCLK# signal is asserted
and Extended Stop Grant has been enabled via the BIOS.
The processor will automatically transition to a lower frequency and voltage operating
point before entering the Extended Stop Grant state. When entering the low power
state, the processor will first switch to the lower bus ratio and then transition to the
lower VID.
The processor exits the Extended Stop Grant state when a break event occurs. When
the processor exits the Extended Stop Grant state, it will resume operation at the lower
frequency, transition the VID to the original value, and then change the bus ratio back
to the original value.
6.2.4 Extended HALT Snoop State, HALT Snoop State, Extended
Stop Grant Snoop State, and Stop Grant Snoop State
The Extended HALT Snoop State is used in conjunction with the new Extended HALT
state. If 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, and Extended
Stop Grant Snoop State.
6.2.4.1 HALT Snoop State, Stop Grant Snoop State
The processor will respond to snoop transactions on the FSB while in Stop-Grant state
or in HALT Power Down state. During a snoop transaction, the processor enters the
HALT Snoop State:Stop Grant Snoop state. The processor will stay in this state until the
snoop on the FSB has been serviced (whether by the processor or another agent on the
FSB). After the snoop is serviced, the processor returns to the Stop Grant state or HALT
Power Down state, as appropriate.
6.2.4.2 Extended HALT Snoop State, Extended Stop Grant 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 ratio and VID
operating point of the Extended HALT state or Extended Stop Grant state. While in the
Extended HALT Snoop State or Extended Stop Grant Snoop State, snoops are handled
the same way as in the HALT Snoop State or Stop Grant Snoop State. After the snoop is
serviced, the processor will return to the Extended HALT state or Extended Stop Grant
state.
