Re: Rebuilding brcmfmac Wi-Fi driver with the help of AI

Mar 10, 2026 20:33:53 Vladimir Varankin <vladimir@varank.in>:

> I recently wrote a blog post [1] sharing my experience of rebuilding
> a Wi-Fi driver for BCM4350 for FreeBSD with the help of agenting AI
> tooling.
>
Omitting any comments about AI usege,...cool and impressive! :)

Very practical question:
Given the workflow, prompts, AI models to use, etc. are in place AND you have a physical Raspberry Pi 4, how long would it take to vibe-port brcmfmac43455-sdio wifi driver? The complication it is attached via SDIO interface, not PCI!

Question out of curiosity:
C/Zig split rationale - at the end 94.7% of code is in C, 4.7% in Zig. Would you still go for anything in Zig again?

> I'm aware that different groups of people have different opinions about
> the topic of using AI in software development. Still I think this was
> a fairly interesting experiment, and I'm curious to hear the opinion
> on the approach and the results, from people close to in-tree drivers
> development.
>
> The GitHub repository [2] includes documentation about the testing
> approach, recorded decisions and know issues (which I'm — still with
> the help of AI agents — addressing in my spare time).
>
> P.S. Just to be absolute clear: I'm not proposing or suggesting to
> upstream the code of this driver. Neither do I think that in the current
> state the AIs can vibe-code something reliable in one go. But I do think,
> the tooling can be a huge multiplier for building, testing, explaining,
> reviewing, etc large bodies of complex code.
>
> Cheers,
> V.
>
> [1]: https://vladimir.varank.in/notes/2026/02/freebsd-brcmfmac/
> [2]: https://github.com/narqo/freebsd-brcmfmac
>
> --
> Vladimir Varankin
> vladimir@varank.in