2021-08-10 06:38:37

by Hsin-Yi Wang

[permalink] [raw]
Subject: Re: [PATCH] Bluetooth: Move shutdown callback before flushing tx and rx queue

On Tue, Aug 10, 2021 at 1:44 AM Kai-Heng Feng
<[email protected]> wrote:
>
> Commit 0ea9fd001a14 ("Bluetooth: Shutdown controller after workqueues
> are flushed or cancelled") introduced a regression that makes mtkbtsdio
> driver stops working:
> [ 36.593956] Bluetooth: hci0: Firmware already downloaded
> [ 46.814613] Bluetooth: hci0: Execution of wmt command timed out
> [ 46.814619] Bluetooth: hci0: Failed to send wmt func ctrl (-110)
>
> The shutdown callback depends on the result of hdev->rx_work, so we
> should call it before flushing rx_work:
> -> btmtksdio_shutdown()
> -> mtk_hci_wmt_sync()
> -> __hci_cmd_send()
> -> wait for BTMTKSDIO_TX_WAIT_VND_EVT gets cleared
>
> -> btmtksdio_recv_event()
> -> hci_recv_frame()
> -> queue_work(hdev->workqueue, &hdev->rx_work)
> -> clears BTMTKSDIO_TX_WAIT_VND_EVT
>
> So move the shutdown callback before flushing TX/RX queue to resolve the
> issue.
>
> Reported-and-tested-by: Mattijs Korpershoek <[email protected]>
> Tested-by: Hsin-Yi Wang <[email protected]>

Hello,

Sorry for confusion, but the version I tested is this one:
https://lkml.org/lkml/2021/8/4/486 (shutdown is prior to the
test_and_clear HCI_UP)
I tested this version and still see the error I've seen before.




> Cc: Guenter Roeck <[email protected]>
> Fixes: 0ea9fd001a14 ("Bluetooth: Shutdown controller after workqueues are flushed or cancelled")
> Signed-off-by: Kai-Heng Feng <[email protected]>
> ---
> net/bluetooth/hci_core.c | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index cb2e9e513907..8da04c899197 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -1735,6 +1735,14 @@ int hci_dev_do_close(struct hci_dev *hdev)
>
> hci_leds_update_powered(hdev, false);
>
> + if (!hci_dev_test_flag(hdev, HCI_UNREGISTER) &&
> + !hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
> + test_bit(HCI_UP, &hdev->flags)) {
> + /* Execute vendor specific shutdown routine */
> + if (hdev->shutdown)
> + hdev->shutdown(hdev);
> + }
> +
> /* Flush RX and TX works */
> flush_work(&hdev->tx_work);
> flush_work(&hdev->rx_work);
> @@ -1798,14 +1806,6 @@ int hci_dev_do_close(struct hci_dev *hdev)
> clear_bit(HCI_INIT, &hdev->flags);
> }
>
> - if (!hci_dev_test_flag(hdev, HCI_UNREGISTER) &&
> - !hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
> - test_bit(HCI_UP, &hdev->flags)) {
> - /* Execute vendor specific shutdown routine */
> - if (hdev->shutdown)
> - hdev->shutdown(hdev);
> - }
> -
> /* flush cmd work */
> flush_work(&hdev->cmd_work);
>
> --
> 2.31.1
>


2021-08-10 06:48:37

by Kai-Heng Feng

[permalink] [raw]
Subject: Re: [PATCH] Bluetooth: Move shutdown callback before flushing tx and rx queue

On Tue, Aug 10, 2021 at 12:10 PM Hsin-Yi Wang <[email protected]> wrote:
>
> On Tue, Aug 10, 2021 at 1:44 AM Kai-Heng Feng
> <[email protected]> wrote:
> >
> > Commit 0ea9fd001a14 ("Bluetooth: Shutdown controller after workqueues
> > are flushed or cancelled") introduced a regression that makes mtkbtsdio
> > driver stops working:
> > [ 36.593956] Bluetooth: hci0: Firmware already downloaded
> > [ 46.814613] Bluetooth: hci0: Execution of wmt command timed out
> > [ 46.814619] Bluetooth: hci0: Failed to send wmt func ctrl (-110)
> >
> > The shutdown callback depends on the result of hdev->rx_work, so we
> > should call it before flushing rx_work:
> > -> btmtksdio_shutdown()
> > -> mtk_hci_wmt_sync()
> > -> __hci_cmd_send()
> > -> wait for BTMTKSDIO_TX_WAIT_VND_EVT gets cleared
> >
> > -> btmtksdio_recv_event()
> > -> hci_recv_frame()
> > -> queue_work(hdev->workqueue, &hdev->rx_work)
> > -> clears BTMTKSDIO_TX_WAIT_VND_EVT
> >
> > So move the shutdown callback before flushing TX/RX queue to resolve the
> > issue.
> >
> > Reported-and-tested-by: Mattijs Korpershoek <[email protected]>
> > Tested-by: Hsin-Yi Wang <[email protected]>
>
> Hello,
>
> Sorry for confusion, but the version I tested is this one:
> https://lkml.org/lkml/2021/8/4/486 (shutdown is prior to the
> test_and_clear HCI_UP)
> I tested this version and still see the error I've seen before.

Ah, sorry for causing your trouble, I am the one who got confused :(
HCI_UP is obviously required for hci_req_sync() to work.

Let me resend one, and sorry again!

Kai-Heng

>
>
>
>
> > Cc: Guenter Roeck <[email protected]>
> > Fixes: 0ea9fd001a14 ("Bluetooth: Shutdown controller after workqueues are flushed or cancelled")
> > Signed-off-by: Kai-Heng Feng <[email protected]>
> > ---
> > net/bluetooth/hci_core.c | 16 ++++++++--------
> > 1 file changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> > index cb2e9e513907..8da04c899197 100644
> > --- a/net/bluetooth/hci_core.c
> > +++ b/net/bluetooth/hci_core.c
> > @@ -1735,6 +1735,14 @@ int hci_dev_do_close(struct hci_dev *hdev)
> >
> > hci_leds_update_powered(hdev, false);
> >
> > + if (!hci_dev_test_flag(hdev, HCI_UNREGISTER) &&
> > + !hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
> > + test_bit(HCI_UP, &hdev->flags)) {
> > + /* Execute vendor specific shutdown routine */
> > + if (hdev->shutdown)
> > + hdev->shutdown(hdev);
> > + }
> > +
> > /* Flush RX and TX works */
> > flush_work(&hdev->tx_work);
> > flush_work(&hdev->rx_work);
> > @@ -1798,14 +1806,6 @@ int hci_dev_do_close(struct hci_dev *hdev)
> > clear_bit(HCI_INIT, &hdev->flags);
> > }
> >
> > - if (!hci_dev_test_flag(hdev, HCI_UNREGISTER) &&
> > - !hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
> > - test_bit(HCI_UP, &hdev->flags)) {
> > - /* Execute vendor specific shutdown routine */
> > - if (hdev->shutdown)
> > - hdev->shutdown(hdev);
> > - }
> > -
> > /* flush cmd work */
> > flush_work(&hdev->cmd_work);
> >
> > --
> > 2.31.1
> >