Datasheet

Intel
®
Xeon
®
Processor C5500/C3500 Series
February 2010 Datasheet, Volume 1
Order Number: 323103-001 233
PCI Express Non-Transparent Bridge
3.19.4.30 DEVCAP2: PCI Express Device Capabilities 2 Register
NTB Primary is a RCiEP but needs to have some capabilities associated with a RP so
that transactions are guaranteed to complete. This register controls transactions sent
from local CPU to an external device through the PCIE NTB port.
Register:DEVCAP2
Bus:0
Device:3
Function:0
Offset:1B4h
Bit Attr Default Description
31:6 RO 0h Reserved
5RO 1
Alternative RID Interpretation (ARI) Capable - This bit is set to 1b indicating
RP supports this capability.
4RO 1
Completion Time-out Disable Supported - IIO supports disabling completion
time-out
3:0 RO 1110b
Completion Time-out Values Supported – This field indicates device
support for the optional Completion Time-out programmability mechanism.
This mechanism allows system software to modify the Completion Time-out
range. Bits are one-hot encoded and set according to the table below to show
time-out value ranges supported. A device that supports the optional
capability of Completion Time-out Programmability must set at least two bits.
Four time values ranges are defined:
Range A: 50us to 10ms
Range B: 10ms to 250ms
Range C: 250ms to 4s
Range D: 4s to 64s
Bits ares set according to table below to show time-out value ranges
supported.
0000b: Completions Time-out programming not supported -- values is fixed
by implementation in the range 50us to 50ms.
0001b: Range A
0010b: Range B
0011b: Range A & B
0110b: Range B & C
0111b: Range A, B, & C
1110b: Ranges B, C & D
1111b: Range A, B, C & D
All other values are reserved.
IIO supports time-out values up to 10ms-64s.
PCI Express Base Specification, Revision 2.0 states This field is applicable only
to RPs, Endpoints that issue Requests on their own behalf, and PCI Express to
PCI/PCI-X Bridges that take ownership of Requests issued on PCI Express. For
all other Functions this field is reserved and must be hardwired to 0000b.