#1152962 linux: 6.12.115+deb13.1-amd64: Regression USB Audio Interface UMC204HD distorted

Package:
src:linux
Source:
src:linux
Submitter:
Robin Rolf
Date:
2026-11-03 19:05:02 UTC
Severity:
normal
Tags:
#1152962#5
Date:
2026-11-03 18:53:49 UTC
From:
To:
Dear Maintainer,

After upgrading from 6.12.113+deb13-amd64 to 6.12.115+deb13.1-amd64,
audio playback through my Behringer UMC204HD (USB ID 1397:0508) became
distorted.

I initially saw #1152914 and started bisecting following Salvatore
Bonaccorso's instructions there, but it now seems they aren't the same
bug. My interface initializes and plays audio, aside from the
distortion, without any errors.

The bisect identified 81e4b0009f2acc841d77a24fd796528b0bf62c4e ("ALSA:
usb-audio: Prevent excessive number of frames") as the bad commit.

# OUTPUT OF git bisect log
git bisect start
# status: waiting for both good and bad commits
# good: [7fdb7c1824a1f9979d648d7ae28ac446bcee9c6e] Linux 6.12.113
git bisect good 7fdb7c1824a1f9979d648d7ae28ac446bcee9c6e
# status: waiting for bad commit, 1 good commit known
# bad: [03bae623ec326c2738198739625832aab0eb120a] Linux 6.12.115
git bisect bad 03bae623ec326c2738198739625832aab0eb120a
# bad: [9afcfc4c6597547c20d6354fa68f1d6012e31c0e] wifi: iwlwifi: dvm:
pair transport op-mode enter/leave
git bisect bad 9afcfc4c6597547c20d6354fa68f1d6012e31c0e
# bad: [33201705179d94985c788ae9186ceeab044fb6bd] ceph: Remove uses of
page from ceph_process_folio_batch()
git bisect bad 33201705179d94985c788ae9186ceeab044fb6bd
# good: [39870dbccdea99e1aa0ae445ab913748e912a352] ASoC: Intel: avs: Use
topology information for endpoint numbers
git bisect good 39870dbccdea99e1aa0ae445ab913748e912a352
# bad: [58a4c2dbe6f746cdf9ea06fcaeda535aecb4b80b] bnxt_en: Update
firmware interface spec to 1.10.3.85
git bisect bad 58a4c2dbe6f746cdf9ea06fcaeda535aecb4b80b
# good: [20b3c72c1b83054c568d2322a95e217fdc281bc3] bpf: Mark
bpf_refcount field as unique
git bisect good 20b3c72c1b83054c568d2322a95e217fdc281bc3
# bad: [4eca06a55417c3b2e538656d12c89e224343653e] bpf: Fix exception
exit lock checking for subprogs
git bisect bad 4eca06a55417c3b2e538656d12c89e224343653e
# bad: [f8b8ec0ddde74066d4452a7a961da544f193e00f] riscv: trace: fix
snapshot deadlock with sbi ecall
git bisect bad f8b8ec0ddde74066d4452a7a961da544f193e00f
# good: [f32ae3cfc976074e9c5927893ce49bcf12f53748] idpf: fix error
handling in the init_task on load
git bisect good f32ae3cfc976074e9c5927893ce49bcf12f53748
# good: [d1e9614a142eff34c93e94a15a71ad0e806799c4] virtio_net: Fix
misalignment bug in struct virtnet_info
git bisect good d1e9614a142eff34c93e94a15a71ad0e806799c4
# bad: [81e4b0009f2acc841d77a24fd796528b0bf62c4e] ALSA: usb-audio:
Prevent excessive number of frames
git bisect bad 81e4b0009f2acc841d77a24fd796528b0bf62c4e
# first bad commit: [81e4b0009f2acc841d77a24fd796528b0bf62c4e] ALSA:
usb-audio: Prevent excessive number of frames

Applying the following mainline commit onto 6.12.115 solves the issue
for me:

70b4db7d258118a7464f039112a74ddb49a95b06 ("ALSA: usb-audio: Use the
right limit for PCM OOB check")

Could this fix be included in the next kernel update for trixie? Happy
to test patched builds or provide further information if needed.