Public bug reported:
Hardware: Lenovo ThinkPad X9-14 Gen 1 (21QACTO1WW), Intel Lunar Lake, BIOS
N4DET41W (1.24) 06/22/2026
Camera: MIPI sensor Sony IMX471 (ACPI SONY471A:00) behind Intel IPU7 (PCI
0000:00:05.0, device 0x645d rev 4)
OS: Ubuntu 26.04, kernel 7.0.0-38-generic (Secure Boot enabled)
Packages: oem-sutton-danby-meta 26.04ubuntu1,
linux-modules-ipu7-generic-hwe-26.04 7.0.0-38.38,
libcamhal-ipu7x 0~git202604141000.58e6f01-1~ubuntu26.04.1, libcamera 0.7.0,
v4l2-relayd 0.2.0.
The imx471 module in use is
/lib/modules/7.0.0-38-generic/ubuntu/dkms/ipu6/imx471.ko.zst
(signed by Canonical); I found no in-tree imx471 module.
PROBLEM
The webcam does not work. /dev/media* does not exist, "cam -l" lists no
cameras, and the
v4l2loopback device "Intel MIPI Camera" (/dev/video0) exists but delivers no
video.
WHAT dmesg SHOWS (full log attached: dmesg-camera.txt)
1. intel-ipu7 prints "Found supported sensor SONY471A:00", then:
sysfs: cannot create duplicate filename '/kernel/software_nodes/SONY471A-0'
Call trace: swnode_register <- software_node_register_node_group <-
ipu_bridge_connect_sensor <- ipu_bridge_init <- ipu7_pci_probe
kobject_add_internal failed for SONY471A-0 with -EEXIST
intel-ipu7 0000:00:05.0: error -EEXIST: IPU bridge init failed
intel-ipu7 0000:00:05.0: probe with driver intel-ipu7 failed with error -17
2. About 30 ms later, in an async ACPI worker:
refcount_t: addition on 0; use-after-free.
Trace: kobject_get <- software_node_notify <- device_add <-
i2c_new_client_device <-
i2c_acpi_notify <- acpi_default_enumeration <- acpi_scan_clear_dep_fn
3. imx471 then repeats "imx471 i2c-SONY471A:00: failed to check hwcfg: -517"
indefinitely.
REPRODUCIBILITY
- Happens on every boot.
- Also happens when intel_ipu7 is loaded by hand ~100 s after boot (boot with
modprobe.blacklist=intel_ipu7, then "sudo modprobe intel_ipu7"): same -EEXIST
error.
So it does not look like a boot-time ordering race.
- Reinstalling the camera stack (oem-sutton-danby-meta, ipu7 modules,
libcamhal-ipu7x,
v4l2-relayd) and removing leftover 6.17-oem packages did not change anything.
- Running "sudo modprobe -r imx471 intel_ipu7" hangs forever with modprobe in D
state;
/proc/<pid>/stack:
klist_remove <- bus_remove_driver <- driver_unregister <- i2c_del_driver <-
imx471_i2c_driver_exit <- __do_sys_delete_module. A reboot was needed.
NOTES
The kernel is tainted by the staging driver (C) and by the out-of-tree
v4l2loopback 0.15.3 DKMS
module (O). I can retest without v4l2loopback if needed.
The audio problem on the same machine was a separate xe/SOF ordering issue, now
fixed.
I do not know which code registers the SONY471A-0 software node first.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-38-generic 7.0.0-38.38
ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14
Uname: Linux 7.0.0-38-generic x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: valentina 2553 F.... pipewire
valentina 2557 F.... wireplumber
/dev/snd/pcmC0D2p: valentina 2553 F...m pipewire
/dev/snd/seq: valentina 2553 F.... pipewire
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Mon Oct 5 13:41:26 2026
InstallationDate: Installed on 2025-09-10 (390 days ago)
InstallationMedia: Kubuntu 24.04.3 LTS "Noble Numbat" - Release amd64
(20250805.1)
IwDevWlp0s20f3Link: Not connected.
MachineType: LENOVO 21QACTO1WW
ProcFB: 0 xedrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-38-generic
root=UUID=dadbf384-e531-4179-86a2-985afd40b857 ro quiet splash
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
SourcePackage: linux
StagingDrivers: intel_ipu7
UpgradeStatus: Upgraded to resolute on 2026-09-30 (5 days ago)
dmi.bios.date: 06/22/2026
dmi.bios.release: 1.24
dmi.bios.vendor: LENOVO
dmi.bios.version: N4DET41W (1.24 )
dmi.board.asset.tag: Not Available
dmi.board.name: 21QACTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: SDK0T76576 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.ec.firmware.release: 1.21
dmi.modalias:
dmi:bvnLENOVO:bvrN4DET41W(1.24):bd06/22/2026:br1.24:efr1.21:svnLENOVO:pn21QACTO1WW:pvrThinkPadX9-14Gen1:rvnLENOVO:rn21QACTO1WW:rvrSDK0T76576WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_21QA_BU_Think_FM_ThinkPadX9-14Gen1:pfaThinkPadX9-14Gen1:
dmi.product.family: ThinkPad X9-14 Gen 1
dmi.product.name: 21QACTO1WW
dmi.product.sku: LENOVO_MT_21QA_BU_Think_FM_ThinkPad X9-14 Gen 1
dmi.product.version: ThinkPad X9-14 Gen 1
dmi.sys.vendor: LENOVO
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute staging wayland-session
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https://bugs.launchpad.net/bugs/2169579
Title:
ThinkPad X9-14 Gen 1 (Lunar Lake): intel-ipu7 probe fails with -EEXIST
"duplicate filename /kernel/software_nodes/SONY471A-0"; webcam not
usable
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