[PATCH] Bluetooth: btmtk: Route firmware debug event to the diag channel

Chris Lu chris.lu at mediatek.com
Wed Aug 26 04:16:17 PDT 2026


MediaTek controllers may emit a firmware debug event on the ACL channel
using the reserved handle 0x0efd, which shows up in the ACL header as
0x2efd once the start fragment flag is included.

Neither btmtk_usb_recv_acl() nor btmtksdio_recv_acl() recognizes it, so
the packet is passed to the HCI core, which has no connection with that
handle and complains:

  Bluetooth: hci0: ACL packet for unknown connection handle 3837

Handle it the same way as the existing firmware debug logging packets and
forward it to the diagnostic channel instead.

Signed-off-by: Chris Lu <chris.lu at mediatek.com>
---
 drivers/bluetooth/btmtk.c     | 1 +
 drivers/bluetooth/btmtksdio.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 73ba4a029e9c..8563ab06a99f 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -1006,6 +1006,7 @@ int btmtk_usb_recv_acl(struct hci_dev *hdev, struct sk_buff *skb)
 		fallthrough;
 	case 0x05ff:		/* Firmware debug logging 1 */
 	case 0x05fe:		/* Firmware debug logging 2 */
+	case 0x2efd:		/* Firmware debug event */
 		return hci_recv_diag(hdev, skb);
 	}
 
diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
index b7f0be7fc42a..cba52724f867 100644
--- a/drivers/bluetooth/btmtksdio.c
+++ b/drivers/bluetooth/btmtksdio.c
@@ -460,6 +460,7 @@ static int btmtksdio_recv_acl(struct hci_dev *hdev, struct sk_buff *skb)
 		fallthrough;
 	case 0x05ff:
 	case 0x05fe:
+	case 0x2efd:		/* Firmware debug event */
 		/* Firmware debug logging */
 		return hci_recv_diag(hdev, skb);
 	}
-- 
2.45.2




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