8814: clamp CCK TX rate to OFDM on 5GHz channels (fixes 5GHz TX, #50)#94
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8814: clamp CCK TX rate to OFDM on 5GHz channels (fixes 5GHz TX, #50)#94josephnef wants to merge 1 commit into
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send_packet defaults fixed_rate to MGN_1M (1M CCK) and only overrides it from the radiotap RATE/VHT fields (or HT-MCS when DEVOURER_TX_HT_MCS is set). CCK rates (1/2/5.5/11M) do not exist at 5GHz: the RTL8814AU silently drops a CCK-rated frame on a 5GHz channel -- the bulk-OUT completes (rc ok, 100% URB completion) but nothing goes on-air. 2.4GHz CCK transmits fine. On a 5GHz channel (Channel > 14), clamp a CCK fixed_rate to the lowest OFDM rate (MGN_6M). The 8812 chip happens to auto-fall-back CCK->OFDM at 5G; the 8814 does not, so devourer must do it in software. Verified on hardware (RTL8814AU 0bda:8813, 8821 kernel-monitor witness): 8814 TX at ch100 with the default rate goes 0 -> ~13770 on-air frames (6M OFDM, 11a); ch6 (2.4G CCK) unaffected. Addresses the 5GHz half of the 8814 devourer-TX on-air gate (#50). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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What
8814 devourer-TX produced 0 on-air frames at 5 GHz (the 5GHz half of #50) despite 100% URB completion. 2.4 GHz TX worked fine.
Root cause
send_packetdefaultsfixed_ratetoMGN_1M(1 Mbps CCK) and only overrides it from the radiotap RATE/VHT fields (or HT-MCS underDEVOURER_TX_HT_MCS). CCK rates (1/2/5.5/11M) do not exist at 5 GHz — the RTL8814AU silently drops a CCK-rated frame on a 5 GHz channel: the bulk-OUT completes (rc ok), but nothing goes on-air. The 8812 chip happens to auto-fall-back CCK→OFDM at 5 GHz; the 8814 does not.Fix
On a 5 GHz channel (
_channel.Channel > 14), clamp a CCKfixed_rateto the lowest OFDM rate (MGN_6M).Validation — real hardware (RTL8814AU
0bda:8813, RTL8821AU kernel-monitor witness)send_packet— OFDM on-air.Together with the merged 5GHz-RX fix (#93), this brings the 8814 to TX+RX on 2.4 GHz and 5 GHz.
🤖 Generated with Claude Code