[PATCH 1/3] wifi: mt76: connac: use a helper to cache txpower_cur

[Sean Wang]

Hi, Lucid

On Thu, Mar 26, 2026 at 12:04 PM Lucid Duck <lucid_duck at justthetip.ca> wrote:
>
> Sean,
>
> Tested the full 3-patch series on MT7921AU. All three bands working
> correctly -- txpower reporting is fixed.
>
> Test environment:
>
>   Kernel:     6.19.8-200.fc43.x86_64 (Fedora 43)
>   Device:     MediaTek MT7921AU USB (0e8d:7961)
>   Firmware:   HW/SW 0x8a108a10, WM 20251223091148
>   AP:         Tri-band (2.4/5/6 GHz)
>   Regdomain:  CA (DFS-FCC), also tested US, JP, DE
>   Note:       Internet maintained via separate USB ethernet
>               adapter during WiFi testing
>
> Baseline (stock 6.19.8, pre-patch):
>
>   txpower 3.00 dBm on all bands
>
> Post-patch txpower:
>
>   2.4 GHz  ch 1   (2412 MHz, 20 MHz):   36.00 dBm
>   5 GHz    ch 100 (5500 MHz, 80 MHz):    26.00 dBm
>   6 GHz    ch 5   (5975 MHz, 80 MHz):    12.00 dBm
>
> All values match expected CA regulatory limits. Connectivity verified
> with 0% packet loss on every band.
>
> Stress testing (28 tests, 28 passed, 0 failed):
>
>   - Connect/disconnect: 10 cycles per band (30 total), txpower
>     correct and ping 0% loss on every cycle
>   - Band switching: 30 sequential hops (2.4 -> 5 -> 6 -> repeat),
>     txpower correct on every hop, ping 30/30
>   - Module reload: 15 full rmmod/insmod cycles of all mt76 modules,
>     txpower correct after every reload
>   - Throughput: 100-ping per band, 0% loss on all
>       2.4 GHz: avg 2.4 ms, max 23.6 ms
>       5 GHz:   avg 1.9 ms, max 8.0 ms
>       6 GHz:   avg 2.2 ms, max 3.3 ms
>   - Soak: 20-minute continuous test per band (60 min total),
>     txpower sampled every 30 seconds, never deviated
>       2.4 GHz: 40/40 samples at 36.00 dBm, slab delta -4 kB
>       5 GHz:   40/40 samples at 26.00 dBm, slab delta +16 kB
>       6 GHz:   40/40 samples at 12.00 dBm, slab delta -16 kB
>   - Memory: 50 connect/disconnect cycles, slab delta +64 kB
>     (negligible, no leak)
>   - Band-hop marathon: 200 random band hops, 200/200 pass,
>     ping 200/200 OK, completed in 1232 seconds
>   - Concurrent managed + monitor: txpower stable on all bands
>     with a monitor VIF present, ping 0% loss
>   - Regulatory domain switching: txpower correctly adjusts
>     per country on 5 GHz
>       CA: 26.00 dBm
>       US: 24.00 dBm
>       JP: 23.00 dBm
>       DE: 26.00 dBm
>
> Zero kernel warnings in dmesg throughout all testing.
>
> For context, I originally reported this bug and submitted a fix in
> January (v1 through v4 on linux-wireless, as Lucid Duck). Patches 1
> and 2 in this series address the same core issue -- capturing the rate
> power loop output and subtracting the path delta before caching
> txpower_cur. Patch 3 (the per-vif-link get_txpower callback) is a
> good addition that was not in my series.

Thanks a lot for the detailed testing and for confirming the fix on MT7921AU.

This was my mistake. Patches 1 and 2 do overlap with the core fix
direction from your January series, and I should have credited that
more clearly.

I’ll add a Co-developed-by tag for you in patches 1 and 2, along with
proper attribution in the next revision.

                  Sean
>
> Reported-by: Lucid Duck <lucid_duck at justthetip.ca>
> Tested-by: Lucid Duck <lucid_duck at justthetip.ca>