Processor Configuration Registers
2.6.46
DCAP2—Device Capabilities 2 Register
B/D/F/Type:
Address Offset:
Reset Value:
Access:
0/1/0–2/PCI
C4–C7h
00000800h
RO, RW-O
32 bits
Size:
BIOS Optimal Default
0000000h
Reset
Value
RST/
PWR
Bit
Access
Description
31:12
RO
0h
Reserved (RSVD)
Latency Tolerance and BW reporting Mechanism
Supported (LTRS)
A value of 1b indicates support for the optional Latency Tolerance
& Bandwidth Requirement Reporting (LTBWR) mechanism
capability.
Root Ports, Switches and Endpoints are permitted to implement
this capability. For Switches that implement LTBWR, this bit must
be set only at the upstream port.
11
RO
1b
Uncore
For a multi-Function device, each Function must report the same
value for this bit.
For Bridges, Downstream Ports, and components that do not
implement this capability, this bit must be hardwired to 0b.
10:6
5
RO
0h
0b
Reserved (RSVD)
ARI Forwarding Supported (ARIFS)
Applicable only to Switch Downstream Ports and Root Ports; must
be 0b for other Function types. This bit must be set to 1b if a
Switch Downstream Port or Root Port supports this optional
capability.
RW-O
Uncore
Uncore
Completion Time-out Disabled Supported (CTODS)
A value of 1b indicates support for the Completion Timeout
Disable mechanism.
The Completion Timeout Disable mechanism is required for
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.
4
RO
0b
This mechanism is optional for Root Ports.
The Root port does not support completion timeout disable.
Completion Timer Ranges Supported (CTOR)
Device Function support for the optional Completion Timeout
programmability mechanism. This mechanism allows system
software to modify the Completion Timeout value.
This field is applicable only to Root Ports, 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.
3:0
RO
0000b
Uncore
0000b = Completion Timeout programming not supported – the
Function must implement a time-out value in the range 50 μs to
50 ms.
Datasheet, Volume 2
127
INTEL [ INTEL ]
