Public bug reported:
Title: LG gram 16UD55U-GX5JK: internal speakers missing on ACP 7.0
(NAU8821), DMIC only
Symptom
-------
- Ubuntu 26.04 LTS (resolute), kernel 7.0.0-15-generic (latest in archive)
- Internal laptop speakers: no playback PCM
- $ aplay -l → "no soundcards found..."
- /proc/asound/cards:
card0 = HDA-Intel (HDMI audio only, works)
card1 = acp-pdm-mach (DMIC capture only)
LGElectronics-16UD55U_GX5JK-Type1Version-16U55U
- PCI 04:00.5 AMD ACP 7.0 [1022:15e2] enabled; snd_soc_nau8821 loaded via
snd_acp_mach but no I2S/NAU8821 speaker machine child under acp_asoc_acp70.0
(only acp-pdm-mach + dmic-codec)
Hardware (dmidecode)
--------------------
- Manufacturer: LG Electronics
- Product: 16UD55U-GX5JK
- Board: 16U55U
Related work
------------
- Launchpad OEM #2098457: ACP70/ACP71 infrastructure — Fix Released (Noble OEM);
does not include LG gram NAU8821 I2S machine quirk
- Linux 7.0-rc6: ASUS ProArt PX13 (HN7306EA) ACP70 fix (d0426510, 399b6fd3,
2594196f) — same class of issue, different DMI board
Upstream
--------
- Reported to alsa-devel / linux-sound on 2026-05-17 from [email protected]
- No prior lore.kernel.org reports for "16UD55U" / "16U55U" found
Request
-------
- Add DMI quirk + ACP machine config for LGElectronics-16UD55U_GX5JK (NAU8821
I2S on ACP 7.0) to linux (resolute) / SRU when upstream patch available
- Review linux-firmware for AMD ACP70 SOF topology if needed
Attachment
----------
- lggram-audio-bug-bundle-v2.tar.gz (dmesg, dmidecode, asound, lsmod, DSDT.dsl
excerpt, etc.) — attach manually if apport does not include it
Workaround
----------
- HDMI / Bluetooth / USB audio OK; internal mic (DMIC) OK
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-15-generic 7.0.0-15.15
ProcVersionSignature: Ubuntu 7.0.0-15.15-generic 7.0.0
Uname: Linux 7.0.0-15-generic x86_64
ApportVersion: 2.34.0-0ubuntu2
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: nawooki 2508 F.... wireplumber
/dev/snd/controlC0: nawooki 2508 F.... wireplumber
/dev/snd/seq: nawooki 2458 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sun May 17 21:20:47 2026
InstallationDate: Installed on 2026-05-09 (8 days ago)
InstallationMedia: Ubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423.1)
MachineType: LG Electronics 16UD55U-GX5JK
ProcEnviron:
LANG=ko_KR.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=dumb
XDG_RUNTIME_DIR=<set>
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-15-generic
root=UUID=a01bde90-8188-4bcc-bc64-f13fe0fd7b59 ro quiet splash
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/24/2026
dmi.bios.release: 5.35
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: GP115
dmi.board.asset.tag: Type2Assettag
dmi.board.name: 16U55U
dmi.board.vendor: LG Electronics
dmi.board.version: 1.0
dmi.chassis.asset.tag: Type2Assettag
dmi.chassis.type: 10
dmi.chassis.vendor: Quanta
dmi.chassis.version: Type3Version
dmi.ec.firmware.release: 0.14
dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvrGP115:bd03/24/2026:br5.35:efr0.14:svnLGElectronics:pn16UD55U-GX5JK:pvrType1Version:rvnLGElectronics:rn16U55U:rvr1.0:cvnQuanta:ct10:cvrType3Version:skuBASE:pfagramBook:
dmi.product.family: gram Book
dmi.product.name: 16UD55U-GX5JK
dmi.product.sku: BASE
dmi.product.version: Type1Version
dmi.sys.vendor: LG Electronics
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
** Attachment added: "lggram-audio-bug-bundle-v2.tar.gz"
https://bugs.launchpad.net/bugs/2152835/+attachment/5970972/+files/lggram-audio-bug-bundle-v2.tar.gz
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https://bugs.launchpad.net/bugs/2152835
Title:
LG gram 16UD55U-GX5JK: internal speakers missing on ACP 7.0 (NAU8821),
DMIC only
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