Re: [PATCH v2 3/3] Bluetooth: hci_qca: Fix frame reassembly errors for wcn3990

Matthias Kaehlcke
2018-11-27T00:27:48Z

On Mon, Nov 26, 2018 at 04:09:50PM -0800, Matthias Kaehlcke wrote:
> On Thu, Nov 22, 2018 at 05:45:12PM +0530, Balakrishna Godavarthi wrote:
> > During initalization of wcn3990, we observed UART is reading some
> > stray bytes on the Rx line. This is logging Frame reassembly errors
> > on the serial console. This could be because of tristate of Tx line
> > of wcn3990 during boot up.
> >
> > [ 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)
> >
> > Now we enable a flag during bootup to stop executing proto receive
> > function and clear it back once the initialization is done.
> >
> > Signed-off-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
> > Tested-by: Matthias Kaehlcke <mka@chromium.org>
> > ---
> > v2:
> > * Updated commit text & comments.
> > v1:
> > * initial patch
> > ---
> > drivers/bluetooth/hci_qca.c | 18 ++++++++++++++++++
> > 1 file changed, 18 insertions(+)
> >
> > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> > index ed905ea1c58a..2f3d9e16ba5a 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 because of BT chip Tx line is in tristate.
> > + * Due to this we read some garbage data on UART Rx.
> > + */
> > + 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)) {
> > @@ -1193,6 +1202,7 @@ static int qca_setup(struct hci_uart *hu)
> > if (ret)
> > return ret;
> >
> > + clear_bit(STATE_DISCARD_RX, &qca->flags);
> > ret = qca_read_soc_version(hdev, &soc_ver);
> > if (ret)
> > return ret;
> > @@ -1269,6 +1279,14 @@ static const struct qca_vreg_data qca_soc_data = {
> >
> > static void qca_power_shutdown(struct hci_uart *hu)
> > {
> > + struct qca_data *qca = hu->priv;
> > +
> > + /* 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);
>
> Is IBS actually related to the frame reassembly errors or is this
> addressing a different issue? In 100 iteratios of 'hciconfig up/down'
> without clearing the flag I didn't observe any frame reassembly
> errors.

Looks like this addresses the "Bluetooth: Received HCI_IBS_SLEEP_IND
in rx state 0" messages that are seen when the interface is brought up
on a system with firmware binaries (with IBS support?). Please spin
this out into a separate patch.

Thanks

Matthias