D43399 FreeBSD Review, enable VCHIQ HDMI Audio subsystem for BCM2711 Raspberry Pi 4B, 400 adding 3 patch files.

From: Fred Finster <fred_at_thegalacticzoo.com>
Date: Fri, 12 Sep 2025 06:10:52 UTC
Hello fellow FreeBSD Arm users,

To be complete,  I usually place too many URLs in a short email. But 
then "Too Long Didn't Read"  TLDR  symptom shows up unannounced.  If you 
are interested in videos and audios playing out on your own Television 
Speakers, please read the following few paragraphs.

  I wish to see the 14.3-RELEASE and 15.0-CURRENT supported RPI binary 
images on the https://FreeBSD.org website, to actually support HDMI 
audio out through the TV speakers, out of the box (OOTB).     Review 
D43399 was my attempt to show how to use Marcos Devesas Campos 3 patch 
files in  reviews D36431, D37878, D37879 to patch the FreeBSD Kernel 
source /usr/src and support the VCHIQ subsystem of the Broadcom BCM2711 
Raspberry Pi 4B, 400
and (BCM2835) Raspberry Pi 3B+  SOCs, running 32 bit armv7 software. ( 
yes, I know armv7 was moved to Tier 2 in FreeBSD support.)

URLS to view:
FreeBSD RPI image. downloaded here is without the VCHIQ subsystem HDMI 
Audio Sound device driver.
https://www.freebsd.org/where/
https://download.freebsd.org/releases/ISO-IMAGES/14.3/
https://download.freebsd.org/releases/ISO-IMAGES/14.3/FreeBSD-14.3-RELEASE-arm64-aarch64-RPI.img.xz
https://download.freebsd.org/releases/ISO-IMAGES/14.3/CHECKSUM.SHA512-FreeBSD-14.3-RELEASE-arm64-aarch64-RPI

https://download.freebsd.org/releases/ISO-IMAGES/15.0/
https://download.freebsd.org/releases/ISO-IMAGES/15.0/FreeBSD-15.0-ALPHA1-arm64-aarch64-RPI-20250906-0b3d82579a01-280099.img.xz
https://download.freebsd.org/releases/ISO-IMAGES/15.0/CHECKSUM.SHA512-FreeBSD-15.0-ALPHA1-arm64-aarch64-RPI-20250906-0b3d82579a01-280099

How can that binary RPI image be improved?  Who can or what update of 
this build process can be modified to include HDMI audio support from 
the BCM2711  VCHIQ subsystem hardware?  Yes, having the SDIO Cy43455 
wifi driver written will help out, to use a WIFI connection from the 
raspberry Pi to the local WIFI WAN network.

https://reviews.freebsd.org/D43399  This is the 3 patch files to add the 
VCHIQ HDMI Audio subsystem device driver to the kernel /usr/src codehttps://

https://reviews.freebsd.org/D36431   vchiq: update printf-s to more 
architecture-independent format specifiers
https://reviews.freebsd.org/D37878   arm64: Add support to vchiq and 
bcm2835_audio (plus some fixes)
https://reviews.freebsd.org/D37879   vchiq: add compat_freebsd32 ioctls 
and respective datatypes Authored by devesas.campos_gmail.com on Dec 26 
2022, 8:15 PM.

Fred Finsters tested set of written steps to follow for using the 3 
patch files:     https://reviews.freebsd.org/F75131370
or  https://reviews.freebsd.org/F75131370#30

Can someone with a Raspberry Pi 4B, or 400 Keyboard run through these 
steps and prove that VCHIQ subsystem HDMI Audio output works on the TV 
Speakers? or work on the Raspberry Pi 4B 3.5mm output jack analog sound.

Then can we include this VCHIQ HDMI Audio source code in the FreeBSD 
kernel source code and also in the created 14.3 or 15.0 RPI Images?

Mike Karels, a strong Arm64 FreeBSD supporter, has passed on.  He might 
have competed this work.  Can we incorporate this tested, useful source 
code in the FreeBSD Kernel and in the created binary image to download 
and burn into a MicroSD card or into a USB Flash drive stick to boot 
FreeBSD.  I prefer to have a supported Raspberry Pi binary image that 
includes HDMI Audio available for others to download and use.

Is there a different method to support the Raspberry Pi 5, 500 BCM2712 
and RP1 chip hardware with updated VCHIQ device driver?
https://x.com/i/grok/share/z5megTW93mZt9B5fioCz7Zzzv  Grok notes 
differences between BCM2711 and BCM2712 in the VCHIQ driver software.

Your thoughts, suggestions, comments are welcome about supporting VCHIQ 
subsystem HDMI Audio for Raspberry Pi (BCM2711) 4B, 400, RPI (BCM2712) 
5, 500,  (BCM2835) RPI3 RPI3+ 64 bit hardware ?

pss:    RUSPIPRO is Rust supported VCHIQ hardware device driver 
software.  URL link here:   https://github.com/RusPiRo  There was a 
VCHIQ bare metal driver here somewhere.