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

[andreas.wendleder]

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.

Thanks,
Andreas