Processor Configuration Registers
164
Datasheet, Volume 2
2.10.27 SS_CAPID—Subsystem ID and Vendor ID Capabilities
Register
This capability is used to uniquely identify the subsystem where the PCI device resides.
Because this device is an integrated part of the system and not an add-in device, it is
anticipated that this capability will never be used. However, it is necessary because
Microsoft will test for its presence.
1:0
RW
00b
Uncore
Power State (PS)
This field indicates the current power state of this device and can
be used to set the device into a new power state. If software
attempts to write an unsupported state to this field, write
operation must complete normally on the bus, but the data is
discarded and no state change occurs.
00 = D0
01 = D1 (Not supported in this device.)
10 = D2 (Not supported in this device.)
11 = D3
Support of D3cold does not require any special action.
While in the D3hot state, this device can only act as the target of
PCI configuration transactions (for power management control).
This device also cannot generate interrupts or respond to MMR
cycles in the D3 state. The device must return to the D0 state in
order to be fully-functional.
When the Power State is other than D0, the bridge will Master
Abort (that is, not claim) any downstream cycles (with exception of
type 0 configuration cycles). Consequently, these unclaimed cycles
will go down DMI and come back up as Unsupported Requests,
which the processor logs as Master Aborts in Device 0 PCISTS[13].
There is no additional hardware functionality required to support
these Power States.
B/D/F/Type:
0/6/0/PCI
Address Offset:
84–87h
Reset Value:
00000008h
Access:
RO, RW
Size:
32 bits
BIOS Optimal Default
000000h
Bit
Attr
Reset
Value
RST/
PWR
Description
B/D/F/Type:
0/6/0/PCI
Address Offset:
88–8Bh
Reset Value:
0000800Dh
Access:
RO
Size:
32 bits
BIOS Optimal Default
0000h
Bit
Attr
Reset
Value
RST/
PWR
Description
31:16
RO
0h
Reserved
15:8
RO
80h
Uncore
Pointer to Next Capability (PNC)
This contains a pointer to the next item in the capabilities list that
is the PCI Power Management capability.
7:0
RO
0Dh
Uncore
Capability ID (CID)
Value of 0Dh identifies this linked list item (capability structure) as
being for SSID/SSVID registers in a PCI-to-PCI Bridge.