Latency Tolerance Reporting (LTR) Extended Capability Header Register @0x1b8

This register contains the PCI Express Extended Capability ID for the Latency Tolerance Reporting (LTR) Capability, its capability version, and the pointer to the next capability structure. This register is implemented only for Physical Function 0. A read from this address of other Physical Functions configuration space returns all zeroes.

Table 1. i_LTR_ext_cap_hdr
Bits SW Name Description Reset
15:0 R PCI Express Extended Capability ID [PECID] This field is hardwired to the Capability ID assigned by PCI SIG to the Latency Tolerance Reporting Capability (0018 hex). 0x018
19:16 R Capability Version [CV] Specifies the SIG assigned value for the version of the capability structure. This field is set by default to 1, but can be modified from the local management bus. 0x01
31:20 R Next Capability Offset [NCO] Indicates offset to the next PCI Express capability structure. The default next pointer value is dynamic and is dependent on whether the strap or LMI bits are set. 12'h1c0