Intel® Core™ Ultra Series 3 Processors I/O Registers
| ID | Date | Version | Classification |
|---|---|---|---|
| 872352 | 04/14/2026 | 001 | Public |
Device Capabilities (DEVCAP) – Offset 84
This register identifies PCI Express device Function specific capabilities.
| Bit Range | Default | Access | Field Name and Description |
|---|---|---|---|
| 31:29 | 0h | RO | Reserved (Zero) (RSVD31) SW must use zeros for writes. |
| 28 | 0h | RO | Reserved |
| 27:26 | 0h | RO | Captured Slot Power Limit Scale (SPLS) Hardwired to 0. |
| 25:18 | 0h | RO | Captured Slot Power Limit Value (SPLV) Hardwired to 0. |
| 17 | 0h | RO | Reserved (Zero) (RSVD17) SW must use zeros for writes. |
| 16 | 0h | RO | ERR_COR Subclass Capable (ECSC) When Set, this bit indicates that the Function supports the ERR_COR Subclass field in ERR_COR Messages, allowing different subclasses to be distinguished. |
| 15 | 0h | RO | Reserved |
| 14 | 0h | RO | Power Indicator Present (PIP) Hardwired to 0. |
| 13 | 0h | RO | Attention Indicator Present (AIP) Hardwired to 0. |
| 12 | 0h | RO | Attention Button Present (ABP) Hardwired to 0. |
| 11:9 | 0h | RO/V | Endpoint L1 Acceptable Latency (L1CAP) 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. |
| 8:6 | 0h | RO/V | Endpoint L0s Acceptable Latency (L0SCAP) 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. |
| 5 | 1h | RO | Extended Tag Field Support (ETCAP) This bit, in combination with the 10-Bit Tag Requester Supported bit in the Device Capabilities 2 Register, indicates the maximum supported size of the Tag field as a Requester. This bit must be Set if the 10-Bit Tag Requester Supported bit is Set. |
| 4:3 | 0h | RO | Phantom Functions Supported (PFCAP) Indicates phantom functions not supported. |
| 2:0 | 0h | RO | Max Payload Size Supported (MPCAP) This field indicates the maximum payload size that the Function can support for TLPs. |