pf-vdisplay's IddCx adapter enumerates as a perfect DXGI twin of the GPU it
renders on — same Description, VendorId/DeviceId/SubSysId, even
DedicatedVideoMemory; only the LUID differs (verified on the RTX box: the
twins were byte-identical in DXGI). Every host with the driver installed
therefore listed each render GPU twice: the console picker offered a dead
twin (display-only — D3D11 device creation on it fails), and auto-select's
max-VRAM tie between the twins was settled by enumeration order — the real
GPU won by luck, not construction.
The kernel adapter type is the only field that separates the twins, so
enumerate() now queries KMTQAITYPE_ADAPTERTYPE per adapter (raw gdi32 FFI —
the windows crate's Wdk bindings aren't enabled, and one 3-call query
doesn't justify them) and drops indirect-display, display-only, and software
adapters. Fail-open: a failed query keeps the adapter — better a listed twin
than a hidden real GPU. Incidentally also filters other vendors' virtual
displays (Parsec-VDD class) from user machines' pickers.
Existing manual preferences heal via find_preferred's same-model fallback
when occurrence indices shift — a ghost accidentally pinned as -0 now
resolves to the real GPU. The regression test pins the adapter-type words
captured from real hardware; a Windows-gated smoke test runs enumerate()
against the live machine (on the RTX box it actively exercises ghost
exclusion: the inventory went from twin 4090s to exactly one).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
enricobuehler
c19c87c435