Re: [PATCH v3 0/8] Bluetooth: Add MediaTek MT7927 (MT6639) support

[Javier Tia]

Hi Luiz,

Thank you for the review.

On Thu, Mar 27, 2026 Luiz Augusto von Dentz wrote:
> https://sashiko.dev/#/patchset/20260326-mt7927-bt-support-v3-0-fa7ebd424323%40jetm.me
>
> First one is more concerning since it may mean it can lead to crashes
> with SDIO driver, the other comment may actually need to be addressed
> separately, perhaps WBS handling needs to be fixed on this family of
> controllers.

Both issues are addressed in v4.

For the SDIO concern: btmtk_setup_firmware_79xx now takes dev_id
as a parameter instead of reading it from hci_get_priv. The SDIO
caller passes its own dev_id, so there is no out-of-bounds read
from a mismatched private struct layout.

For the subsys reset: btmtk_usb_subsys_reset now skips the
post-reset CHIPID validation for 0x6639. On affected boards the
register always reads back 0x0000, so the validation would always
fail. This is scoped to 0x6639 only.

Regarding WBS, I verified it on MT7927 hardware (ASUS ROG
Crosshair X870E Hero). The controller reports LMP_TRANSPARENT
and LMP_ERR_DATA_REPORTING in its LMP features, and
HCI_Read_Local_Supported_Codecs returns CVSD, Transparent, and
mSBC. A btmon capture confirms eSCO links establish with
Transparent air mode (0x03) and 60-byte mSBC frames. WBS works
correctly on this controller family, no fix needed.

Link to v4: https://lore.kernel.org/linux-bluetooth/20260330-mt7927-bt-support-v4-0-cecc025e7062@xxxxxxx/

Best,
Javier