[Bug 221722] Blanket HCI_QUIRK_BROKEN_ENHANCED_SETUP_SYNC_CONN for all MediaTek chips breaks HFP mSBC microphone on MT7925 (0489:e111)

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=221722

Ender Bonnet (enbonnet@gmail.com) changed:

           What    |Removed                     |Added
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                 CC|                            |enbonnet@gmail.com

--- Comment #1 from Ender Bonnet (enbonnet@gmail.com) ---
Additional affected hardware — new USB ID for this quirk:

  Adapter:  MediaTek MT7925, USB ID 0e8d:e025 (MediaTek Inc. Wireless_Device)
            — note: different from the reporter's 0489:e111 (Foxconn), so the
            blanket quirk affects at least two MT7925 USB variants.
  Machine:  Lenovo ThinkPad P14s Gen 6 AMD (21QL), BIOS R2XET40W 1.20
(2026-05-26)
  Kernel:   7.1.4-204.fc44.x86_64 (Fedora 44)
  Stack:    bluez 5.87, pipewire 1.6.8, wireplumber 0.5.14
  BT FW:    Build Time 20260605184935

dmesg confirms the blanket quirk fires on this variant too:

  Bluetooth: hci0: HCI Enhanced Setup Synchronous Connection command is
  advertised, but not supported.

Possibly related additional impact beyond the broken mSBC microphone:
on this machine, roughly every 2nd reconnect of an A2DP-only-use headset
(SLEVE EVO) comes up either stuck in the HFP profile (16 kHz mono sink)
or with garbled audio while bluetoothctl reports the connection healthy.
Forcing the profile back with `pactl set-card-profile ... a2dp-sink`
sometimes recovers; otherwise only a full adapter power cycle
(`bluetoothctl power off / on`) heals it. Frequency: 5 occurrences in the
last 30 days, logged by a watchdog script I run as a workaround.

Since the quirk forces all SCO/profile setup on MT7925 down the legacy
fallback path, this reconnect misbehavior may share the same root cause.
Happy to test a kernel with the quirk scoped per-chip (the proposed
one-line change in btusb_probe()) and report back.

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