Files
punktfunk/crates/pf-zerocopy
enricobuehlerandClaude Fable 5 9b3ec9204c fix(capture): a refused EGL→CUDA dmabuf offer stops being asked
The raw-dmabuf passthrough has had a negotiation-timeout latch since the
hybrid-Intel case: one conclusive timeout and later captures negotiate the
CPU path instead of re-paying it. The EGL→CUDA dmabuf-only offer had no
equivalent — a compositor that accepts none of the importer's modifiers
timed out the same 10 s negotiation on every session, forever, under the
generic 'format negotiation never completed' diagnosis.

Now the symmetric latch (note_gpu_dmabuf_negotiation_failed) gates
build_importer in the one negotiation resolver, scoped to this offer alone
(raw passthrough, worker-death latch, encoder untouched), with the same
operator escape as the raw arm: an explicit PUNKTFUNK_ZEROCOPY=1 keeps
erroring loudly instead of downgrading.

One correctness detail beyond the handoff's sketch: whether the GPU offer
was ACTUALLY advertised is a runtime fact of the PipeWire thread (the
importer may fail to construct — no CUDA — in which case no dmabuf was
offered and a timeout must not latch it off). plan.build_importer alone
cannot answer that, so the thread records the made-offer on CaptureSignals
(gpu_dmabuf_offer) and the timeout diagnosis branches on the offer that
really happened, not the plan's intent.

Also renames vaapi_dmabuf_forced → zerocopy_forced (it now guards both
timeout arms; single caller). New plan invariant pinned in tests: the
latch gates only the importer, never the raw passthrough.

(V3 from design/pf-zerocopy-sweep-handoff.md — the deferred design call,
now decided in favour of the symmetric latch.)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-28 13:15:36 +02:00
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