Root cause, proven on-glass across five driver builds: a declared IddCx
hardware cursor is IRREVOCABLE. There is no un-declare DDI, the
empty-caps re-setup is rejected INVALID_PARAMETER, and after a
successful same-mode re-commit with the driver's re-declare provably
suppressed (sticky per-target flag, zero re-setups logged) DWM still
never composites the software cursor back into the monitor's frames.
Every DWM-based composite flip is therefore unfixable.
The composite (capture) model is now implemented in OUR pipeline:
- the driver keeps its hardware cursor declared for the session's whole
life (the state that works) — frames stay pointer-free always;
- in composite mode try_consume routes the conversion through a blend
scratch: slot copy + one alpha-blended quad of the GDI poller's shape
at its polled position (CursorBlendPass — fullscreen-triangle VS with
viewport placement, straight-alpha PS, sRGB→linear for FP16/HDR
rings), covering all four convert paths (NV12, 4:4:4 copy, P010,
PyroWave) GPU-side under the slot's keyed mutex;
- pointer-only motion produces no driver publish (declared hw cursor),
so try_consume REGENERATES from the last slot whenever the polled
cursor state changes — the cursor moves on a static desktop at tick
rate, without faking freshness for the stall/death watchdogs;
- set_cursor_forward becomes purely host-internal state; the
SET_CURSOR_FORWARD IOCTL machinery is no longer used by the host
(driver keeps it, dormant) and its sender plumbing is removed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehlerandClaude Opus 4.8
0af280a793