Datasheet

PCI Express Non-Transparent Bridge
Intel
®
Xeon
®
Processor C5500/C3500 Series
Datasheet, Volume 1 February 2010
262 Order Number: 323103-001
11:9 RWO 110b
Endpoint L1 Acceptable Latency
This field indicates the acceptable latency that an Endpoint can withstand due
to the transition from L1 state to the L0 state. It is essentially an indirect
measure of the Endpoint’s internal buffering. Power management software
uses the reported L1 Acceptable Latency number to compare against the L1
Exit Latencies reported (see below) by all components comprising the data
path from this Endpoint to the Root Complex Root Port to determine whether
ASPM L1 entry can be used with no loss of performance.
Defined encodings are:
000b Maximum of 1 us
001b Maximum of 2 us
010b Maximum of 4 us
011b Maximum of 8 us
100b Maximum of 16 us
101b Maximum of 32 us
110b Maximum of 64 us
111b No limit
BIOS must program this value
8:6 RWO 000b
Endpoint L0s Acceptable Latency
This field indicates the acceptable total latency that an Endpoint can withstand
due to the transition from L0s state to the L0 state. It is essentially an indirect
measure of the Endpoint’s internal buffering. Power management software
uses the reported L0s Acceptable Latency number to compare against the L0s
exit latencies reported by all components comprising the data path from this
Endpoint to the Root Complex Root Port to determine whether ASPM L0s entry
can be used with no loss of performance.
Defined encodings are:
000b Maximum of 64 ns
001b Maximum of 128 ns
010b Maximum of 256 ns
011b Maximum of 512 ns
100b Maximum of 1 us
101b Maximum of 2 us
110b Maximum of 4 us
111b No limit
BIOS must program this value
5RO 1
Extended Tag Field Supported
IIO devices support 8-bit tag
1 = Maximum Tag field is 8 bits
0 = Maximum Tag field is 5 bits
4:3 RO 00b
Phantom Functions Supported
IIO does not support phantom functions.
00b = No Function Number bits are used for Phantom Functions
2:0 RO 001b
Max Payload Size Supported
IIO supports 256B payloads on PCI Express ports
001b = 256 bytes max payload size
Register:DEVCAP
Bar:PB01BASE + 500h + Offset, SB01BASE + 500h + Offset
Bus:M
Device:0
Function: 0
Offset:94h
Bit Attr Default Description