dis_cca / EDCCA-disable: measured NULL for monitor RX — safe J3 knob + harness#198
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…arness, not promoted The adaptive-link recipes flag dis_cca as a community "doubles range / removes stuttering" tweak on the rtl88x2eu. Measure-first before shipping it as API. Finding (8822EU, swept B210 AWGN, DEVOURER_DIS_CCA A/B): - Full vendor recipe DEAFENS the RX: the BB 0x1d58[0xff8]=0x1ff write is "OFDM CCA off" (the CW-tone path uses it to stop OFDM detection), so it drops 8822EU delivery from ~6800 to ~10 frames. - MAC EDCCA-disable alone (0x520[15]/0x524[11]) is an exact NULL: delivery within 1% at every noise gain (33700 vs 33400 hits over 46..76 dB; IGI pinned, FA identical). Mechanism: EDCCA gates TX *deferral*, not RX decode — and devourer injects in monitor mode, which already bypasses the CSMA/EDCCA backoff the community's range benefit comes from. So there is nothing a runtime RX-side knob adds here. Disposition (same discipline as the #190 DIG and the J3 per-packet-power probe): - SetCcaMode is a Jaguar3 research knob only (DEVOURER_DIS_CCA=1) — NOT promoted to IRtlDevice. It writes ONLY the safe MAC EDCCA bit; the RX-deafening BB writes are deliberately omitted (documented in the code). - tests/dis_cca_onair.sh kept as the reusable swept-AWGN A/B rig for anyone re-measuring on a real (non-monitor) link — this bench can't bury the wanted beacon under B210 AWGN (near-field front-end limit), so the null is "no effect in the testable regime" + the mechanism above. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Measure-first outcome: NULL (documented), knob kept safe & un-promoted
/tmp/adaptive-link-recipes.md§8 flags dis_cca as a community "doubles range / removes stuttering" tweak on the rtl88x2eu. Per the session's measure-first discipline (cf. #190 DIG, the J3 per-packet-power probe #195), I implemented it, measured, and gated shipping on the result.What the measurement found (8822EU, swept B210 AWGN,
DEVOURER_DIS_CCAA/B)0x1a9c/0x1a14/0x1d58)0x520[15]/0x524[11])0x1d58[0xff8]=0x1ffwrite is literally "OFDM CCA off" (the CW-tone path uses it to stop OFDM detection) → it deafens the receiver to OFDM. Not implemented.What landed
RtlJaguar3Device::SetCcaMode— Jaguar3 research knob only (DEVOURER_DIS_CCA=1), writes only the safe MAC EDCCA bit (the RX-deafening BB writes are deliberately omitted + documented). NOT promoted toIRtlDevice.tests/dis_cca_onair.sh— the reusable swept-AWGN delivery A/B rig, kept for re-measurement on a real (non-monitor) link. This bench can't bury the wanted beacon under B210 AWGN (near-field front-end limit), so the null is "no effect in the testable regime" + the mechanism above.Full all-chips build +
ctest(8/8) green. Merge or close at your discretion — the value here is the documented measurement; see the linked help-wanted issue for real-link verification.🤖 Generated with Claude Code