[Bug 222151] New: MT7925 (0489:e111): BT firmware 20260813113236 (linux-firmware 50e034a2) breaks HFP calls and fails WMT init; 20260605184935 works

[Bug 222151] New: MT7925 (0489:e111): BT firmware 20260813113236 (linux-firmware 50e034a2) breaks HFP calls and fails WMT init; 20260605184935 works

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=222151

            Bug ID: 222151
           Summary: MT7925 (0489:e111): BT firmware 20260813113236
                    (linux-firmware 50e034a2) breaks HFP calls and fails
                    WMT init; 20260605184935 works
           Product: Drivers
           Version: 2.5
          Hardware: All
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P3
         Component: Bluetooth
          Assignee: linux-bluetooth@vger.kernel.org
          Reporter: purpleritza@gmail.com
        Regression: No

Hardware / software
  Laptop:    Lenovo Legion 5 Pro 16AFR10
  Bluetooth: MediaTek MT7925, USB 0489:e111 (btusb/btmtk)
  Headset:   Bose NC 700 HP (HFP/A2DP)
  Distro:    Arch Linux, bluez 5.87, wireplumber 0.5.15, pipewire 1.6.8
  Kernels:   7.1.8, 7.2.9, 7.2.10 (Arch)

Firmware
  Bad:  linux-firmware commit 50e034a2 ("mediatek MT7925: update bluetooth
        firmware to 20260813113236"),
        file mediatek/mt7925/BT_RAM_CODE_MT7925_1_1_hdr.bin, build
20260813113236
  Good: commit 2d705393, build 20260605184935

  Arch package versions: linux-firmware-mediatek 20260916-1 (bad) vs 20260810-2
  (good). Between them the MT7925 WiFi blob also changed (commit 3c11e660,
  "update firmware for MT7925 WiFi device", same day). WiFi worked normally on
  both; only Bluetooth broke.

Calls regression (good / bad / good / bad)

  Period                          BT build        Kernel             Calls
  ------------------------------  --------------  ----------------- 
---------------------------------
  until 2026-09-27 (first chip    20260605184935  7.1.x / 7.2.2      worked
    init with the new blob)
  2026-09-27 onward               20260813113236  7.2.2 - 7.2.8      headset
audio drops mid-call,
                                                                       mic lost
  2026-10-07 - 10-15              20260605184935  7.1.8, then 7.2.9  worked
    (daily calls for a week)
  2026-10-17 onward               20260813113236  7.2.10             headset
audio drops mid-call

  Userspace (wireplumber 0.5.15, pipewire 1.6.8) was the same in the last two
  rows. One data point not covered by the table: on 2026-10-07 the first calls
  after downgrading the firmware still failed, while that boot ran kernel 7.2.8
  with wireplumber 0.5.18 / pipewire 1.6.9. Calls worked once those were rolled
  back too.

  Failure on the bad build (2026-10-19, kernel 7.2.10): the HFP transport dies
  mid-call, both headset nodes fail at once, and the call app falls back to the
  laptop microphone, so the remote side still hears me while I hear nothing:

12:02:56 wireplumber: pw.node: (bluez_input.78_2B_64_D2_1D_66.0-74) running ->
error (Received error event)
12:02:56 wireplumber: pw.node: (bluez_output.78_2B_64_D2_1D_66.1-73) running ->
error (Received error event)
12:02:56 wireplumber: spa.bluez5: Failure in Bluetooth audio transport
/org/bluez/hci1/dev_78_2B_64_D2_1D_66/fd46
12:02:57 bluetoothd: src/profile.c:ext_io_disconnected() Unable to get io data
for Hands-Free Voice gateway: getpeername: Transport endpoint is not connected
(107)

  bluetoothd reconnects A2DP signaling 8 s later (12:03:04), and A2DP streaming
  is back after 74 s (12:04:10); the call audio over the headset is gone.

WMT init failure (only ever seen on the bad build)

  Counted per firmware load across 30 boots of the journal:

  BT build        Loads  WMT init failures
  --------------  -----  --------------------------
  20260605184935     71  0
  20260813113236     16  2 (2026-09-27, 2026-10-17)

Oct 17 19:53:29 kernel: Bluetooth: hci0: HW/SW Version: 0x00000000, Build Time:
20260813113236
Oct 17 19:53:40 kernel: Bluetooth: hci0: Execution of wmt command timed out
Oct 17 19:53:40 kernel: Bluetooth: hci0: Failed to send wmt func ctrl (-110)
Oct 17 19:53:40 kernel: Bluetooth: hci1: HW/SW Version: 0x00000000, Build Time:
20260813113236
Oct 17 19:53:42 kernel: Bluetooth: hci1: Device setup in 1751211 usecs

  The controller recovers by re-enumerating as hci1. I know WMT timeouts are
  reported on other MT7925 machines with older builds (bug 220237, Ubuntu LP
  2163428); on this machine they only occur with 20260813113236.

Related
  - Bug 221722: blanket HCI_QUIRK_BROKEN_ENHANCED_SETUP_SYNC_CONN breaks mSBC
mic
    on MT7925 (0489:e111). The quirk is active on both builds here, so it does
    not explain the difference between them.
  - Bug 220237: MT7925 BT firmware load timeout (-110).
  - Bug 220682 (same USB ID, libmtp/mtp-probe probing the adapter): not
    applicable here. libmtp and libgphoto2 are not installed, mtp-probe never
    ran, and udev sets no media-device tags on the adapter.
  - bluetooth-next a6491451f8b8 "Bluetooth: mt7925: trigger reset on WMT
timeout".
  - "ACL/SCO packet for unknown connection handle 3837/3584" appears on both
    builds and doesn't correlate with the failures.

Workaround
  Pinning linux-firmware-mediatek 20260810-2 (BT build 20260605184935).

Happy to test a new firmware build or capture btmon traces of a failing call on
request.

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[Bug 222151] MT7925 (0489:e111): BT firmware 20260813113236 (linux-firmware 50e034a2) breaks HFP calls and fails WMT init; 20260605184935 works

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=222151

purpleritza@gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
 Bisected commit-id|                            |50e034a2c2141c902089c09aa5f
                   |                            |e9363c1be6e56
                 CC|                            |purpleritza@gmail.com
     Kernel Version|                            |7.2.10
         Regression|No                          |Yes

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[Bug 222151] MT7925 (0489:e111): BT firmware 20260813113236 (linux-firmware 50e034a2) breaks HFP calls and fails WMT init; 20260605184935 works

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=222151

purpleritza@gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |high

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[Bug 222151] MT7925 (0489:e111): BT firmware 20260813113236 (linux-firmware 50e034a2) breaks HFP calls and fails WMT init; 20260605184935 works

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=222151

--- Comment #1 from purpleritza@gmail.com ---
Correction after further analysis: most of the call failures in my original
report were NOT caused by the firmware. The repeating failures correlate with
the wireplumber version, not the BT firmware build.

Per boot, counting "Failure in Bluetooth audio transport" loops (>= 4 within
3 minutes: HFP/A2DP profile flip-flopping, both bluez nodes going to error):

  Boot start        wireplumber  BT firmware build          Loops
  ----------------  -----------  -------------------------  -----
  2026-09-28 12:40  0.5.15       20260813113236                 0
  2026-10-03 11:07  0.5.18       20260605 + 20260813            3
  2026-10-07 11:36  0.5.18       20260605184935                 1
  2026-10-07 11:59  0.5.15       20260605184935                 0
  2026-10-15 11:00  0.5.15       20260605184935                 0
  2026-10-17 19:53  0.5.15       20260605 + 20260813            0
  2026-10-25 15:49  0.5.18       20260605184935                 5

Every loop happened on wireplumber 0.5.18, with either firmware build; none
on 0.5.15. I will report that part to wireplumber separately.

What remains attributable to firmware 20260813113236:

1. WMT init failure on this machine:

  BT build        Loads  WMT init failures
  20260605184935     71  0
  20260813113236     16  2 (2026-09-27, 2026-10-17)

2. Single mid-call HFP drops with wireplumber 0.5.15:

  BT build        Time on wireplumber 0.5.15  Mid-call HFP drops
  20260605184935  ~16 days                    0
  20260813113236  ~7.5 days                   2 (2026-09-28, 2026-10-19
12:02:56)

   The 2026-10-19 drop is the log in my original report. The only drop seen
   on 20260605184935 was during A2DP playback, not a call. Small sample, so
   weaker evidence than the WMT init failure.

Current setup, no call problems so far: linux-firmware-mediatek 20260810-2
(BT build 20260605184935) + wireplumber 0.5.15, kernel 7.2.11.

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[Bug 222151] MT7925 (0489:e111): BT firmware 20260813113236 (linux-firmware 50e034a2) intermittently fails WMT init, possibly drops HFP calls; 20260605184935 does not

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=222151

purpleritza@gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|MT7925 (0489:e111): BT      |MT7925 (0489:e111): BT
                   |firmware 20260813113236     |firmware 20260813113236
                   |(linux-firmware 50e034a2)   |(linux-firmware 50e034a2)
                   |breaks HFP calls and fails  |intermittently fails WMT
                   |WMT init; 20260605184935    |init, possibly drops HFP
                   |works                       |calls; 20260605184935 does
                   |                            |not

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