Since the 0.22.0 cursor work (the seat-pointer park + the metadata
composite), a KWin capture-model stream always has a cursor — and it never
went away again: not in game, not in Big Picture, not with a controller in
hand (field report, 2026-08-01). The host blended the arrow forever because
pf-capture deliberately ignores SPA_META_Cursor id 0, and once `visible`
latched true nothing on Linux ever cleared it.
Two producer contracts meet on id 0, and one flag now carries which one a
stream follows. KWin rewrites the cursor meta on EVERY enqueued buffer and
writes id 0 whenever Cursor::isOnOutput says the pointer is not in this
stream — which covers both a globally hidden cursor and a client null-cursor
surface (empty geometry intersects nothing). There id 0 IS the hide, and
honoring it is what lets a game hide the pointer mid-stream. Mutter only
rewrites a buffer's meta when the cursor changed, so recycled buffers carry
stale id-0 regions between damage frames — honoring those flickered the
cursor off between hovers (on-glass round 5), and that path keeps its
last-known-state behavior.
The flag rides from the backend that created the output (correct for
registry-pooled reuse too — a kept display only ever matches its own
backend) through capture_virtual_output into the parser's CursorState. The
portal-monitor path stays on the stale-meta contract: the only thing routed
through it today is Mutter's HDR mirror.
Verified on .25: pf-capture 45/45, punktfunk-host 369/369, clippy
-D warnings clean (pf-capture, punktfunk-host, cursor-probe), fmt clean.
On-glass KDE validation still owed.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
enricobuehlerandClaude Fable 5
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