Re: Raspberry Pi POE+ hat overlay

On Sat, 13 May 2023 at 13:45, Doug Rabson <dfr@rabson.org> wrote:

> I was able to build an updated rpi-firmware port based on 1.20210805 and
> this boots successfully on pi400 as well as rpi4. With this, I can load the
> rpi-poe-plus overlay and I just need to try and reverse engineer the
> undocumented mailbox API by reading the Linux code.
>

I have a first approximation of a fan driver which works with the
1.20210805 firmware (actually, I substituted rpi-poe-plus.dtbo from
1.20210831 which just changes the fan levels for the POE+). I'm testing
with an rpi4B rev 1.5 with 'make -j4 buildworld' and the fan is keeping the
cpu temperature below 65 degrees which is nice, especially since I set
arm_boost=1 in config.txt which boosts the cpu frequency up to 1800 for
this board.

Does anyone have a pointer to the problem with firmware later than
20210805? Would it make any kind of sense to try to get the fix into
releng/13.2 as an errata?