Re: BCM4360 AC-PHY support for b43 — reverse-engineered, seeking guidance on a clean path upstream

[Alessio Ferri <alessio.ferri@mythread.it>]

Il giorno Thu, 01 Oct 2026 12:06:05 +0000
"andreas.wendleder" <andreas.wendleder@proton.me> ha scritto:

> Hi Alessio,
> 
> Thanks for the 2.4 GHz trace work. Short status, then the questions.
> 
> Status: b43 now runs as the daily connection on my MacBookAir6,1
> (BCM4360, core rev 42, radio 2069 rev 4). The 2.4 GHz station works
> with legacy rates and a TX status fix. Upload is about 18 Mbit/s and
> download about 10.
> 
> The open problem: only about 21% of fresh inits can transmit. The
> state is fixed at init. In a bad init the PHY holds CRS|TXF and every
> TX ends in a PHY transmission error, so auth frames are never ACKed.
> A reload wrapper retries until an init connects, which takes 2-5
> tries. I've ruled out temperature, DMA, ASPM, PLL lock, clocks, TX
> core mask, TX power control, the CRS threshold and the MAC setup
> order.
> 
> I've updated the clean-room spec (§10 covers this) and can send it if
> it's useful.
> 
> Questions:
> 
> Do you have a bus-level trace (wl-mmio-trap) of a 2.4 GHz cold init
> and first transmit on a BCM4360 (agcombo or TG789vac), including the
> calibration phase? I'd diff it against mine at register level. Can
> your harness score our driver's register-write sequence against your
> captures? That would show where we diverge without hardware tests.
> Does stock wl ever give you a "bad init" on any of your boards (the
> PHY cannot transmit until the next reset)? That would tell us whether
> the cause is in our init or in the chip.
> 
> If your 2.4 GHz support lands, I'll test it on this laptop right away.
> 

Oh, i forgot, you have femctrl = 2, all of my boards have femctrl = 6,
so probably the calibration is wrong for your card, but now i try to
fix it. Thank again!

> Thanks,
> Andreas