Public bug reported:
I am reporting a possible kernel regression affecting a C-Media
CMI8738/CMI8768 PCI audio card in a Dell OptiPlex 9020.
With Ubuntu kernel 6.8.0-136-generic, the CMI8738 has remained
stable during normal operation.
After upgrading to kernel 6.8.0-137-generic, the CMI8738 initially
works normally, but after approximately two hours the sound card
disappears.
When the failure occurs, the device disappears from both:
aplay -l
and:
lspci
The PCI device normally appears as:
05:00.0 Multimedia audio controller:
C-Media Electronics Inc CMI8738/CMI8768 PCI Audio (rev 10)
Because the device disappears from lspci, this appears to be below
the PipeWire/ALSA user-space audio stack.
Rebooting restores the device.
The same hardware and Ubuntu installation remain stable when booted
with 6.8.0-136-generic.
Expected behavior:
The CMI8738 PCI audio device should remain available during normal
operation.
Actual behavior:
The device disappears after approximately two hours when running
6.8.0-137-generic.
This appears to be a possible regression between kernel
6.8.0-136-generic and 6.8.0-137-generic.
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-image-6.8.0-136-generic 6.8.0-136.136
ProcVersionSignature: Ubuntu 6.8.0-136.136-generic 6.8.12
Uname: Linux 6.8.0-136-generic x86_64
ApportVersion: 2.28.2-0ubuntu0.1
Architecture: amd64
CRDA: N/A
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sun Aug 9 16:00:32 2026
InstallationDate: Installed on 2024-01-09 (943 days ago)
InstallationMedia: Ubuntu 22.04.3 LTS "Jammy Jellyfish" - Release amd64
(20230807.2)
IwConfig:
lo no wireless extensions.
eno1 no wireless extensions.
MachineType: Dell Inc. OptiPlex 9020
ProcEnviron:
LANG=en_US.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.8.0-136-generic
root=UUID=4b74565e-7d6f-48f1-80b4-0e0e3fd569ad ro quiet splash vt.handoff=7
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
linux-restricted-modules-6.8.0-136-generic N/A
linux-backports-modules-6.8.0-136-generic N/A
linux-firmware 20240318.git3b128b60-0ubuntu2.27
RfKill:
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/27/2017
dmi.bios.release: 65.21
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A21
dmi.board.name: 0N4YC8
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 6
dmi.chassis.vendor: Dell Inc.
dmi.modalias:
dmi:bvnDellInc.:bvrA21:bd12/27/2017:br65.21:svnDellInc.:pnOptiPlex9020:pvr00:rvnDellInc.:rn0N4YC8:rvrA00:cvnDellInc.:ct6:cvr:sku05A4:
dmi.product.name: OptiPlex 9020
dmi.product.sku: 05A4
dmi.product.version: 00
dmi.sys.vendor: Dell Inc.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble wayland-session
** Attachment added: "Kernel version signature and detailed PCI
device/configuration information collected while running kernel
6.8.0-136-generic."
https://bugs.launchpad.net/bugs/2163126/+attachment/5990883/+files/lspci-vvnn.log
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https://bugs.launchpad.net/bugs/2163126
Title:
CMI8738 PCI audio device disappears with kernel 6.8.0-137
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