On Tue, Nov 06, 2018 at 05:35:28PM +0530, Balakrishna Godavarthi wrote:
> [  176.929612] Bluetooth: hci_qca.c:qca_recv() hci0: Frame reassembly failed 
> (-84)
> [  176.945734] Bluetooth: hci_qca.c:qca_recv() hci0: Frame reassembly failed 
> (-84)
> [  176.953298] Bluetooth: hci_qca.c:qca_recv() hci0: Frame reassembly failed 
> (-84)
> [  177.010660] Bluetooth: hci_qca.c:qca_recv() hci0: Frame reassembly failed 
> (-84)
> [  177.067633] Bluetooth: hci_qca.c:qca_recv() hci0: Frame reassembly failed 
> (-84)
> 
> The above errors log on console due to receiving of stray bytes
> when wcn3990 boot up's i.e. when during initial setup procedure.

Please shortly introduce the topic instead of starting with the log
messages.

> Signed-off-by: Balakrishna Godavarthi <bgoda...@codeaurora.org>
> ---
>  drivers/bluetooth/hci_qca.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 97b57e0f4725..341f80606574 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -56,6 +56,7 @@
>  
>  /* Controller states */
>  #define STATE_IN_BAND_SLEEP_ENABLED  1
> +#define STATE_DISCARD_RX             2
>  
>  #define IBS_WAKE_RETRANS_TIMEOUT_MS  100
>  #define IBS_TX_IDLE_TIMEOUT_MS               2000
> @@ -511,6 +512,7 @@ static int qca_open(struct hci_uart *hu)
>               } else {
>                       hu->init_speed = qcadev->init_speed;
>                       hu->oper_speed = qcadev->oper_speed;
> +                     set_bit(STATE_DISCARD_RX, &qca->flags);
>                       ret = qca_power_setup(hu, true);
>                       if (ret) {
>                               destroy_workqueue(qca->workqueue);
> @@ -903,6 +905,13 @@ static int qca_recv(struct hci_uart *hu, const void 
> *data, int count)
>       if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
>               return -EUNATCH;
>  
> +     /* We discard Rx data received while device is in booting
> +      * stage, this is due multiple baudrate switch is causing
> +      * UART to read some garbage data.
> +      */

This isn't entirely correct. I saw frame reassembly errors before
qca_wcn3990_init() is called, i.e. no baudrate changes. Some of the
garbage seems to be sent shortly after powering on the controller.

> +     if (test_bit(STATE_DISCARD_RX, &qca->flags))
> +             return 0;
> +
>       qca->rx_skb = h4_recv_buf(hu->hdev, qca->rx_skb, data, count,
>                                 qca_recv_pkts, ARRAY_SIZE(qca_recv_pkts));
>       if (IS_ERR(qca->rx_skb)) {
> @@ -1192,10 +1201,12 @@ static int qca_setup(struct hci_uart *hu)
>               set_bit(HCI_QUIRK_USE_BDADDR_PROPERTY, &hdev->quirks);
>               clear_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
>               hu->hdev->shutdown = qca_power_off;
> +
>               ret = qca_wcn3990_init(hu);
>               if (ret)
>                       return ret;
>  
> +             clear_bit(STATE_DISCARD_RX, &qca->flags);
>               ret = qca_read_soc_version(hdev, &soc_ver);
>               if (ret)
>                       return ret;
> @@ -1278,8 +1289,15 @@ static void qca_power_shutdown(struct hci_uart *hu)
>       struct serdev_device *serdev = hu->serdev;
>       unsigned char cmd = QCA_WCN3990_POWEROFF_PULSE;
>  
> -     host_set_baudrate(hu, 2400);
> +     /* From this point we go into power off state,
> +      * disable IBS and discard all the queued data.
> +      */
> +     clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
> +     set_bit(STATE_DISCARD_RX, &qca->flags);
> +     qca_flush(hu);
> +
>       hci_uart_set_flow_control(hu, true);
> +     host_set_baudrate(hu, 2400);
>       serdev_device_write(serdev, &cmd, sizeof(cmd), 0);
>       serdev_device_wait_until_sent(serdev, 0);
>       hci_uart_set_flow_control(hu, false);

This change won't win a beauty price, but it seems it is needed to
suppress the 'frame reassembly' spam, unless the controller can be
convinced to stop sending garbage in the first place.

Tested-by: Matthias Kaehlcke <m...@chromium.org>

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