`pf_capture::hdr_capture_failed()` had exactly one consumer: `open_portal_monitor`, which uses it to
drop the HDR offer (`want_hdr && !hdr_capture_failed()`). The RTSP negotiation consulted only
`gnome_hdr_monitor_active()`. So once the latch was set — an HDR negotiation timed out, the monitor
left HDR mode between probe and negotiation, NVIDIA EGL not listing LINEAR for XR30, a pre-50 Mutter
— the host kept telling the client HDR while capturing and encoding SDR: `cfg.hdr` flowed to
`open_portal_monitor`, which then silently opened the SDR offer.
The client renders an SDR stream as PQ. Washed out, wrong gamut, and no error anywhere. The latch is
sticky until host restart, so every reconnect repeated it.
Consulted at RTSP honor time rather than folded into `host_hdr_capable()` for the same reason as the
colour-mode probe next to it: that fn is the STATIC serverinfo capability (it decides whether to
advertise SCM_HEVC_MAIN10 at all), and this is a live per-session fact.
The native plane needs no equivalent — `capturer_supports_hdr()` is hard-false on Linux, and the
latch is a fact about the portal capturer, which that plane never uses. Noted in handshake.rs so it
isn't re-derived.
Listed in the sweep's confirmed-defect register as cross-cutting/medium, then absent from every
phase of its implementation plan. Verification is on-glass (force the latch, reconnect a client that
requests HDR, confirm the Welcome/SDP reports SDR).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
enricobuehlerandClaude Opus 5
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