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 <eddy.zhang@rock-chips.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
index e90670955df2c311bea6eaf00297951f356e3c84..fefc37b98b4ac168c2d777a9c82439ec31c15cd2 100644 (file)
--- 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;
        }