From 59c3ee19ca88210bfc0e22ce59218091cb1a3c48 Mon Sep 17 00:00:00 2001 From: Ismail Tarim Date: Sat, 15 Aug 2026 14:56:23 +0300 Subject: [PATCH] Bluetooth: btmtk: Do not report success when subsys reset fails btmtk_usb_subsys_reset() validates the subsystem reset by reading the chip id back. When that read succeeds at the bus level but yields an id of zero, the reset has demonstrably not taken effect: the function logs "Can't get device id, subsys reset fail." and then returns the return value of btmtk_usb_id_get(), which in that case is zero, i.e. success. btusb_mtk_reset() returns that value unchanged, so its caller cannot tell a completed reset from a failed one. Return -ENODEV when the chip id reads back as zero, leaving the existing MT6639 exemption intact. Observed on an MT7902 [13d3:3579]. The path can be reached on demand by asking the controller for a coredump, since btmtk requests a reset once the dump completes: # echo 1 > /sys/class/bluetooth/hci0/device/coredump Bluetooth: hci0: Mediatek coredump end Bluetooth: hci0: Can't get device id, subsys reset fail. usb 3-10: reset high-speed USB device number 5 using xhci_hcd usb 3-10: device descriptor read/64, error -110 usb usb3-port10: attempt power cycle usb usb3-port10: unable to enumerate USB device The same sequence occurs unprompted when the controller firmware asserts on its own. Note that this corrects the error reporting only; it does not by itself make the controller recoverable in the case above. Fixes: 25b6d7593a3a ("Bluetooth: btmtk: introduce btmtk reset work") Signed-off-by: Ismail Tarim Signed-off-by: Luiz Augusto von Dentz --- drivers/bluetooth/btmtk.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c index 66b346761043..dc702c0a6034 100644 --- a/drivers/bluetooth/btmtk.c +++ b/drivers/bluetooth/btmtk.c @@ -968,8 +968,10 @@ int btmtk_usb_subsys_reset(struct hci_dev *hdev, u32 dev_id) } err = btmtk_usb_id_get(hdev, 0x70010200, &val); - if (err || (!val && dev_id != 0x6639)) + if (err || (!val && dev_id != 0x6639)) { bt_dev_err(hdev, "Can't get device id, subsys reset fail."); + return err ? err : -ENODEV; + } return err; }