Package: linux-image-6.12.88-amd64 Severity: normal Subject: linux-image-6.12.88-amd64: MediaTek Bluetooth regression - Failed to send wmt func ctrl (-22)
After upgrading from kernel 6.12.73 to 6.12.88 on Debian Trixie (testing), the internal MediaTek Bluetooth adapter completely stopped functioning. Hardware detected via lsusb: Bus 001 Device 006: ID 13d3:3585 IMC Networks Wireless_Device (MediaTek MT7921/MT7922) Relevant dmesg output on 6.12.88: [ 54.743379] Bluetooth: hci0: HW/SW Version: 0x008a008a, Build Time: 20241106163512 [ 54.895767] Bluetooth: hci0: Failed to send wmt func ctrl (-22) [ 54.895787] Bluetooth: hci0: HCI Enhanced Setup Synchronous Connection command is advertised, but not supported. A full power-drain/cold boot does not resolve the issue on 6.12.88. Booting back into the previous 6.12.73 kernel completely resolves the issue, and Bluetooth functions normally again. This appears to be an upstream driver/firmware initialization regression introduced in the latest point release. -- System Information: Debian Release: 13 (Trixie) Kernel Version: Linux 6.12.73+deb13-amd64 (working state) / Failed on 6.12.88
