301467-005 Datasheet, PDF (154/426 Pages) Intel Corporation – Express Chipset

Host-PCI Express* Bridge Registers (D1:F0)
(Intel® 82915G/82915P/82915PL Only)
R
8.1.36
LCAP—Link Capabilities (D1:F0)
PCI Device:
Address Offset:
Default Value:
Access:
Size:
1
ACh
02012E01h
R/WO
16 bits
This register indicates PCI Express device specific capabilities.
Bit
31:24
23:18
17:15
14:12
11:10
9:4
3:0
Access &
Default
Description
RO
02h
R/WO
010b
R/WO
010b
R/WO
11b
RO
10h
RO
1h
Port Number: This field indicates the PCI Express* port number for the given PCI
Express link. This field matches the value in Element Self Description [31:24].
Reserved
L1 Exit Latency: This field indicates the length of time this Port requires to
complete the transition from L1 to L0. The value 010 b indicates the range of 2 µs
to less than 4 µs. If this field is required to be any value other than the default,
BIOS must initialize it accordingly.
Both bytes of this register that contain a portion of this field must be written
simultaneously in order to prevent an intermediate (and undesired) value from
ever existing.
L0s Exit Latency: This field indicates the length of time this Port requires to
complete the transition from L0s to L0. The value 010 b indicates the range of 128
ns to less than 256 ns. If this field is required to be any value other than the
default, BIOS must initialize it accordingly.
Note:
When PCI Express* is operating with separate reference clocks, L0s exit
latency may be greater than the setting in the L0s Exit Latency Register.
Expect longer exit latency then setting in L0s Exit Latency Register. The
link may enter Recovery state before reaching L0. System BIOS can
program the appropriate Exit Latency and advertised N_FTS value if it
detects that the downstream device is not using the common reference
clock (indicated in the Slot Clock Configuration bit 12 of the device’s Link
Status Register)
Active State Link PM Support: L0s & L1 entry supported.
Max Link Width: Hardwired to indicate X16.
When Force X1 mode is enabled on this PCI Express* x16 Graphics Interface
device, this field reflects X1 (01h).
Max Link Speed: Hardwired to indicate 2.5 Gb/s.
154
Datasheet