Package: linux
Version: 6.12.88-1
Severity: important
Hardware: Lenovo IdeaPad, MediaTek MT7961 (USB ID 0e8d:e0cd)
Dear Maintainer,
Bluetooth has stopped working on my system after upgrading the kernel from
6.12.74+deb13+1 to 6.12.85+deb13 (and all subsequent versions up to and
including 6.12.88+deb13, the current one). Downgrading back to
6.12.74+deb13+1 restores Bluetooth functionality.
-- System information --
Kernel (broken): 6.12.88+deb13-amd64
Kernel (working): 6.12.74+deb13+1-amd64
Bluetooth chip: MediaTek MT7961 (USB ID 0e8d:e0cd, PCI: mt7921e,
ASIC revision 79610010)
Firmware package: firmware-mediatek (reinstallation did not help)
Distro: Debian 13 (trixie)
-- Symptom --
Bluetooth adapter is detected but fails to initialize. The following
errors appear in dmesg on the broken kernels:
Bluetooth: hci0: HW/SW Version: 0x008a008a, Build Time: 20241106151414
Bluetooth: hci0: Failed to send wmt func ctrl (-22)
Bluetooth: hci0: HCI Enhanced Setup Synchronous Connection command is
advertised, but not supported.
rfkill shows no block (soft or hard). The bluetooth.service is running.
Reinstalling firmware-mediatek had no effect.
-- Bisection --
Working: linux-image-6.12.74+deb13+1-amd64 (6.12.74-2)
Broken: linux-image-6.12.85+deb13-amd64 (6.12.85-1) and all newer
All kernels between 6.12.75 and 6.12.84 were already removed from my
system (rc state), so I cannot bisect further without additional packages.
-- Related reports and upstream fix --
This is a known issue affecting MediaTek MT7921/MT7922/MT7961 chips across
multiple distributions. An upstream fix was submitted in December 2024:
Subject: [PATCH] Bluetooth: btmtk: Fix failed to send func ctrl for
MediaTek devices.
Author: Chris Lu <[email protected]>
Fixes: 5c5e8c52e3ca ("Bluetooth: btmtk: move btusb_mtk_[setup,
shutdown] to btmtk.c")
URL:
https://patchew.org/linux/[email protected]/
The fix adds usb_autopm_get_interface() / usb_autopm_put_interface()
calls in btmtk_usb_shutdown() to handle USB autosuspend correctly.
Similar reports:
- Ubuntu: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2097139
- Arch Linux: https://bbs.archlinux.org/viewtopic.php?id=313561
Thanks,
Roman Hocke
