[PATCH 0/2] Bluetooth: btmtk: fix subsystem reset error reporting

[Ismail Tarim <ismailtarim7@gmail.com>]

Two bugs in btmtk_usb_subsys_reset() that make it report success to its
caller when the subsystem reset has actually failed.

Patch 1 covers the case where the post-reset chip id reads back as zero:
the function logs "Can't get device id, subsys reset fail." and then
returns the (zero) return value of the register read, i.e. success.

Patch 2 restores propagation of the MTK_BT_RST_DONE poll timeout, which
has been silently overwritten since commit 3dcb122b3064 ("Bluetooth:
btusb: mediatek: return error for failed reg access") started assigning
err at the chip id read.

Found while investigating an MT7902 [13d3:3579] whose controller firmware
asserts and never returns to the USB bus. Both patches only correct the
error reporting; neither changes the recovery behaviour or makes that
controller recoverable. They are a prerequisite for anything that wants
to react to a failed reset, since today the failure is not visible to
the caller.

Compile tested on x86_64 (W=1, no new warnings); checkpatch --strict clean.

Ismail Tarim (2):
  Bluetooth: btmtk: Fix btmtk_usb_subsys_reset() reporting success on
    failure
  Bluetooth: btmtk: Do not discard the subsystem reset timeout

 drivers/bluetooth/btmtk.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)


base-commit: 15ef2f78c49d20d53ec7c0f1c9b40b02e089f2d6
-- 
2.55.0