forked from unom/punktfunk
enricobuehler
9a1d8be4cc
Last change's docs concluded "AUTO never splits, retire the arm" from the sub-frame-ON measurement alone. Measured the missing leg before implementing it, and the conclusion was wrong. On .21 at 4K, plain AUTO (env unset, the resolver's fallthrough): sub-frame ON -> 5023/5157 us/frame ~= DISABLE 4979/5000 (does NOT split) sub-frame OFF -> 2401/2352 us/frame ~= TWO_FORCED 2319/2378 (DOES split) So AUTO is CONDITIONAL, not dead. Retiring it would have silently cost every sub-frame-off session its second engine -- a regression introduced while "cleaning up" an arm that looked inert. Split and sub-frame are mutually unsupported for HEVC, so the driver resolves AUTO to no-split only in that combination. Fix is disclosure, not removal: - resolve_split_subframe debug-logs the inert HEVC + AUTO + sub-frame case, which is the fleet default shape: "split_mode=AUTO" has meant "no split" for every default session and nothing said so. Deliberately NOT rewritten to DISABLE -- the mode we pass is what the driver was actually given, and the ceiling-cache key must keep describing that. - New unit test `auto_survives_the_arbitration_in_both_subframe_states` pins the contract so the arm cannot be simplified away later. - The resolver doc now records both measured legs instead of "AUTO is dead". Also in this change: - WP1.6: `resolve_subframe`'s doc said "Windows passes `false`". Stale since the 2026-07-31 .173 A/B flipped Windows to caps-gated default-on. It mattered: it made the AUTO-plus-sub-frame dead combination look Linux-only when it is fleet-wide. - Windows session-ready log parity: split_mode + engines + subframe. The Windows line had no split_mode at all, so a Windows field report could not answer "did this session actually split?" -- the question that started this whole thread. Verified: fmt clean; .21 clippy -p pf-encode --features nvenc --all-targets -D warnings clean, 58 unit tests (1 new), 22/22 NVENC on-hardware tests green; .133 Windows clippy --features nvenc --all-targets -D warnings clean (15m cold, zero errors or warnings) -- the Windows backend is cfg'd out on both macOS and the Linux box, so that leg needed a real Windows host.