I2S DAC not loading

[Graham Haddock]

I am attempting to add an I2S DAC for line level output on a Raspberry Pi 5.

The hardware is a Pimoroni Audio DAC Shim which uses the dtoverlay=hifiberry-dac

The hardware, when used with Raspberry Pi OS (Bookworm) configured per instructions works fine, this I2S output DAC appears in the sound output selector pull-down, line-out works, so hardware and connections are good.

When installed and configured on Ubuntu 23.10 Desktop, fully updated to current, the I2S DAC output does appear in the sound pull-down selector window, so the I2S DAC output can not be selected, and is not functional.

Configuration consists of adding the following to the /boot/firmware/config.txt file:
dtparam=i2s=on
dtoverlay=hifiberry-dac

When a user signs into Ubuntu, a pair of error messages appears 25 times in the CLI ttyAMA10 output:

[ 23.126215] designware-i2s 1f000a0000.i2s: ASoC: error at snd_soc_dai_set_bclk_ratio on 1f000a0000.i2s: -22

[ 23.136303] HifiBerry DAC: ASoC: error at snd_soc_link_hw_params on HifiBerry DAC: -22

This seems to reference some kind of failure to initialize an I2S bit clock ratio parameter on the part of designware-i2s, which causes HiFiBerry DAC to error out.

~$ lsb_release -rd
No LSB modules are available.
Description: Ubuntu 23.10
Release: 23.10

All updates are current as of 2024 FEB 29
the dtoverlay=hifiberry-dac is the one distributed with the Ubuntu 23.10 Desktop release.

ProblemType: Bug
DistroRelease: Ubuntu 23.10
Package: alsa-base 1.0.25+dfsg-0ubuntu7
ProcVersionSignature: Ubuntu 6.5.0-1011.14-raspi 6.5.8
Uname: Linux 6.5.0-1011-raspi aarch64
ApportVersion: 2.27.0-0ubuntu5
Architecture: arm64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: graham 1907 F.... wireplumber
 /dev/snd/seq: graham 1894 F.... pipewire
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Thu Feb 29 16:08:26 2024
PackageArchitecture: all
ProcEnviron:
 LANG=C.UTF-8
 PATH=(custom, no user)
 SHELL=/bin/bash
 TERM=xterm-256color
 XDG_RUNTIME_DIR=<set>
SourcePackage: alsa-driver
Symptom: audio
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.