This extends the display-codec association introduced by Hi-Jiajun in PR #284. The five AppleHDA properties and shared CEA scan follow that contribution; this extension reads the connector type from NVKMS, copies the owning GPU's hda-gfx value without changing its OSData or OSString type, and lets a machine name its own codec/pin mapping.
Set NVRMFBDisplayAudioCodecInfo as a four-byte OSData property on the NVRMFB personality or framebuffer service. The property is passed through as audio-codec-info; it must identify the codec and pin used by the GPU. For example, 00 01 05 00 describes the local RTX 5080 Laptop test mapping to pin 05. Without the property the driver uses 00 01 04 00 (codec 0, pin 04), the mapping measured on an RTX 5060 desktop in #284. A board whose display audio is on another pin sets the property; a malformed value publishes no association.
The current mapping describes one external audio display per GPU: one codec/pin value is shared by the framebuffer personality, and port-number is zero. Do not apply the same mapping to multiple active external displays unless they are known to share the same codec route. Concurrent multi-display audio and per-connector mapping are not implemented.
Without a mapping, NVRMFB keeps its existing ELD and hda-gfx publication behavior and does not publish an effective five-property audio route. The five route properties are published only for an external display with a valid mapping, an NVKMS HDMI/DisplayPort connector, and at least one CEA Short Audio Descriptor. Disconnects clear the ELD and all association properties; reconnects and monitor swaps refresh them.
Run python3 tools/check_nvrmfb_display_audio_mapping.py to compile and execute the production connector-type and CEA-scan helpers in a host fixture, and to check the publication/cleanup path. This check is not a kext build or a substitute for a physical boot. The 5080 Laptop/macOS 26.7/pin 05 playback result comes from the submitter's prior hardware validation; other GPUs, connectors, and concurrent displays remain unverified.