[PATCH v2 0/8] Bluetooth: Add MediaTek MT7927 (MT6639) support

[Javier Tia]

This series adds Bluetooth support for the MediaTek MT7927 (Filogic 380)
combo WiFi 7 + BT 5.4 module. The BT subsystem uses hardware variant
0x6639 and connects via USB.

The MT7927 is shipping in motherboards and PCIe add-in cards from ASUS,
Gigabyte, Lenovo, MSI, and TP-Link since mid-2024. Without these patches,
users see "Unsupported hardware variant (00006639)" or the BT subsystem
hangs during firmware download.

Jean-Francois Marliere independently identified the same three root
causes and posted an analysis to the list in February [1], though the
patch diff was not included in that message. This series provides the
complete, split patches addressing the same issues.

The series consists of nine patches:

  [1/9] Bluetooth: btmtk: Add MT6639 (MT7927) Bluetooth support
  [2/9] Bluetooth: btmtk: fix ISO interface setup for single alt setting
  [3/9] Bluetooth: btusb: Add MT7927 ID for ASUS ROG Crosshair X870E Hero
  [4/9] Bluetooth: btusb: Add MT7927 ID for Lenovo Legion Pro 7 16ARX9
  [5/9] Bluetooth: btusb: Add MT7927 ID for Gigabyte Z790 AORUS MASTER X
  [6/9] Bluetooth: btusb: Add MT7927 ID for MSI X870E Ace Max
  [7/9] Bluetooth: btusb: Add MT7927 ID for TP-Link Archer TBE550E
  [8/9] Bluetooth: btusb: Add MT7927 ID for ASUS X870E / ProArt X870E-Creator

Three driver changes are needed for MT6639:

1. CHIPID workaround: On some boards the BT USB MMIO register reads
   0x0000 for dev_id, causing the driver to skip the 0x6639 init path.
   Force dev_id to 0x6639 when it reads zero, matching the equivalent
   WiFi-side workaround that forces chip=0x7927.

2. Firmware naming: MT6639 uses firmware version prefix "2_1" instead of
   "1_1" used by MT7925 and other variants. The firmware path is
   mediatek/mt6639/BT_RAM_CODE_MT6639_2_1_hdr.bin.

3. Section filtering: The firmware binary contains 9 sections, but only
   sections with (dlmodecrctype & 0xff) == 0x01 are Bluetooth-related.
   Sending WiFi/other sections causes an irreversible BT subsystem hang.
   The filter is gated on dev_id == 0x6639 to avoid affecting other chips.

Additionally, patch 2 fixes the ISO interface setup for devices that
expose only a single alternate setting (alt 0) on the ISO endpoint.
Without this fix, btmtk_usb_claim_iso_intf() fails with EINVAL,
causing ~20 second initialization delays.

Changes in v2:
- Split USB device IDs into per-device commits as requested (Luiz)
- Added 0489:e110 (MSI X870E Ace Max, new hardware report)
- Added ISO interface fix for single alt setting (13d3:3588 devices)
- Added Tested-by trailers for all USB IDs except 0489:e110
- Added USB descriptor output to all per-device commits
- Removed BTMTK_FIRMWARE_LOADED skip logic; firmware persistence is
  handled by the existing framework (Sean Wang)

The firmware blob (BT_RAM_CODE_MT6639_2_1_hdr.bin) is being submitted
separately to linux-firmware via GitLab MR. The firmware path and
filename have not been finalized yet; the driver currently requests
mediatek/mt6639/, but this may change based on the linux-firmware
review.

Tested hardware:
- ASUS ROG Crosshair X870E Hero (BT 0489:e13a)
- ASUS ROG STRIX X870-I (BT 0489:e13a)
- ASUS ROG STRIX X870E-E (BT 13d3:3588)
- ASUS ProArt X870E-Creator WiFi (BT 13d3:3588)
- Gigabyte Z790 AORUS MASTER X (BT 0489:e10f)
- Gigabyte Z790 AORUS ELITE X WiFi7 (BT 0489:e10f)
- MSI MEG X870E ACE MAX (BT 0489:e110)
- Lenovo Legion Pro 7 16ARX9 (BT 0489:e0fa)
- Lenovo Legion Pro 7 16AFR10H (BT 0489:e0fa)
- TP-Link Archer TBE550E PCIe (BT 0489:e116)

Tested on Arch Linux, CachyOS, Fedora (Bazzite), and Ubuntu
across kernels 6.13-6.19.

The companion WiFi support for MT7927 (mt76/mt7925e driver) has been
submitted separately to linux-wireless.

[1] https://lore.kernel.org/linux-bluetooth/496b0f8505eb6ffb19fdbee6f963c62aa6790fba.camel@marliere.fr/

Link: https://bugzilla.kernel.org/show_bug.cgi?id=221096
Link: https://github.com/openwrt/mt76/issues/927

Assisted-by: Claude (Anthropic)
Signed-off-by: Javier Tia <floss at jetm.me>
---
Javier Tia (8):
      Bluetooth: btmtk: Add MT6639 (MT7927) Bluetooth support
      Bluetooth: btmtk: fix ISO interface setup for single alt setting
      Bluetooth: btusb: Add MT7927 ID for ASUS ROG Crosshair X870E Hero
      Bluetooth: btusb: Add MT7927 ID for Lenovo Legion Pro 7 16ARX9
      Bluetooth: btusb: Add MT7927 ID for Gigabyte Z790 AORUS MASTER X
      Bluetooth: btusb: Add MT7927 ID for MSI X870E Ace Max
      Bluetooth: btusb: Add MT7927 ID for TP-Link Archer TBE550E
      Bluetooth: btusb: Add MT7927 ID for ASUS X870E / ProArt X870E-Creator

 drivers/bluetooth/btmtk.c | 26 +++++++++++++++++++++++---
 drivers/bluetooth/btmtk.h |  1 +
 drivers/bluetooth/btusb.c | 12 ++++++++++++
 3 files changed, 36 insertions(+), 3 deletions(-)
---
base-commit: 50003ce2085a7f7dacf2426065d1a69c84b5b963
change-id: 20260305-mt7927-bt-support-6589a50c961f

Best regards,
--  
Javier Tia <floss at jetm.me>