Confirming this bug also affects Lenovo IdeaPad 3 15ALC6 (product name: 82KU)
with the same Chicony camera (04f2:b725, bcdDevice=27.36).
--- System Information ---
Machine: Lenovo IdeaPad 3 15ALC6
Product name: 82KU
BIOS version: GLCN57WW (Release Date: 02/23/2024, Revision: 1.57)
Ubuntu version: 24.04.4 LTS
Kernel tested: 6.8.0-101-generic (linux-generic)
Also reproduced on 6.17.0-14-generic (HWE, shipped with
Ubuntu 24.04.4) — identical behavior on both.
Camera USB ID: 04f2:b725, bcdDevice=27.36
Manufacturer: Chicony Electronics Co.,Ltd.
--- Symptom ---
The camera enumerates correctly on boot and remains stable until an
application (confirmed: Microsoft Teams for Linux) attempts to access it.
Upon access, the kernel generates repeated "Failed to query (GET_CUR) UVC
control N on unit N: -71 (exp. N)" errors, followed by an infinite
USB disconnect/reconnect loop that cannot be stopped without a full power
cycle (warm reboot does not clear the xHCI controller state).
--- Key difference from original report ---
The disconnect loop does NOT happen at boot — the camera is stable for
approximately 1h7m–1h19m after boot. The cascade is triggered by a UVC
control query from userspace (Teams for Linux, PipeWire enumeration, or
similar). This suggests the regression is in uvcvideo's UVC control query
handling at runtime, not in the initial device enumeration.
--- Kernel log excerpt showing the cascade ---
[see attached dmesg_6.8.0-101_82KU.txt]
--- Quirks tested (none resolved the issue) ---
- options uvcvideo quirks=0x80 → cascade still occurs after ~1h
- options uvcvideo quirks=0xa2 → cascade still occurs after ~1h
--- Kernels affected ---
6.8.0-101-generic → affected (linux-generic on Ubuntu 24.04.4)
6.17.0-14-generic → affected (linux-hwe on Ubuntu 24.04.4)
--- Also reproduces on ---
- Fedora with equivalent kernel versions (as noted in original report)
- Other IdeaPad 3 variants with same camera (82xx series)
This bug should not expire — it affects the current linux-generic kernel
(6.8.0-101) and the current HWE kernel (6.17.0-14), covering all upgrade
paths in Ubuntu 24.04.4 LTS. The regression is confirmed across multiple
Lenovo IdeaPad 3 models and multiple distributions, pointing to a
kernel-level uvcvideo regression introduced between 6.8.0-84 and
6.8.0-85.
** Attachment added: "dmesg_6.8.0-101_82KU.txt"
https://bugs.launchpad.net/ubuntu/+source/linux-hwe-6.14/+bug/2131988/+attachment/5950044/+files/dmesg_6.8.0-101_82KU.txt
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https://bugs.launchpad.net/bugs/2131988
Title:
Integrated Chicony webcam (04f2:b725) detected but fails to stream on
Ubuntu 24.04
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