From 3c0d41f141c97e516d986f0571b0d7a745a4e2a8 Mon Sep 17 00:00:00 2001 From: Qiqi Zhang Date: Tue, 4 Apr 2023 10:27:11 +0800 Subject: [PATCH] Bluetooth: hci_h5: Complements reliable packet processing logic As shown in the schematic diagram below.There may be a critical scenario in the current code. If the device does not receive an pure ack sent by the host due to insufficient receive buffer or other reasons and triggers a retransmission, the host will always be in an 'out-of-order' state.The state machine will get stuck. host device SEQ3,ACK4 ---------> <--------- SEQ4,ACK4 pure ACK ---------> (not received) (out-of-order) <--------- SEQ4,ACK4(retransmission) ........ (out-of-order) <--------- SEQ4,ACK4(retransmission) According to the description in the core specification: "whenever a reliable packet is received, an acknowledgment shall be generated." So set H5_TX_ACK_REQ bit to trigger retransmission of pure ack packet when "out-of-order" occurs. Signed-off-by: Qiqi Zhang Signed-off-by: Luiz Augusto von Dentz --- drivers/bluetooth/hci_h5.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c index e90670955df2..fefc37b98b4a 100644 --- a/drivers/bluetooth/hci_h5.c +++ b/drivers/bluetooth/hci_h5.c @@ -463,6 +463,8 @@ static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c) if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) { bt_dev_err(hu->hdev, "Out-of-order packet arrived (%u != %u)", H5_HDR_SEQ(hdr), h5->tx_ack); + set_bit(H5_TX_ACK_REQ, &h5->flags); + hci_uart_tx_wakeup(hu); h5_reset_rx(h5); return 0; }