linux6.18-6.18.32_1: Bluetooth no longer works on MT7921

[meator]

Is this a new report?

Yes

System Info

Void 6.18.32_1 x86_64 GenuineIntel uptodate rrrrrrmdFFFFF

Package(s) Affected

linux6.18-6.18.32_1, linux-6.18_1, linux7.0-7.0.9_1, linux-mainline-7.0_1

Does a report exist for this bug with the project's home (upstream) and/or another distro?

These seem to be related:
https://bbs.archlinux.org/viewtopic.php?id=313561
https://bbs.archlinux.org/viewtopic.php?id=313552

Expected behaviour

Bluetooth working.

Actual behaviour

Here's some dmesg:

[  +0.071632] mt7921e 0000:02:00.0: WM Firmware Version: ____010000, Build Time: 20260224110949
...
[  +0.020868] Bluetooth: hci0: HW/SW Version: 0x008a008a, Build Time: 20260224111243
...
[  +0.364153] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[  +0.000007] Bluetooth: BNEP filters: protocol multicast
[  +0.000008] Bluetooth: BNEP socket layer initialized
...
[  +0.802675] Bluetooth: hci0: Failed to send wmt func ctrl (-22)
[  +0.000050] Bluetooth: hci0: HCI Enhanced Setup Synchronous Connection command is advertised, but not supported.

The issue started occurring after I updated my system yesterday.

I have tested the current linux-mainline and it's broken too.

I can confirm that linux 6.18.25_1 (older version) works fine.

As described in one of the linked Arch Linux issues, bluetooth now becomes rfkill sofblocked on boot. This doesn't happen with linux-mainline, but it still doesn't work there.

Steps to reproduce

1. Boot the computer.

[Slyrc]

This can by fixed by applying the following patch:

https://kernel.googlesource.com/pub/scm/linux/kernel/git/bluetooth/bluetooth/+/e3ac0d9f1a205f33a43fba3b79ef74d2f604c78b%5E%21

I tried building the kernel for 7 locally on my pc and can confirm that this fixes the problem. Should work the same way for 6.18. See:
Slyrc@c532ecc