linux-kernel - Re: [PATCH v2] Bluetooth: Shutdown controller after workqueues are flushed or cancelled

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Date:   Thu, 05 Aug 2021 08:55:01 +0200
From:   Mattijs Korpershoek <mkorpershoek@...libre.com>
To:     Kai-Heng Feng <kai.heng.feng@...onical.com>
Cc:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Fabien Parent <fparent@...libre.com>,
        Sean Wang <sean.wang@...iatek.com>,
        "open list:BLUETOOTH SUBSYSTEM" <linux-bluetooth@...r.kernel.org>,
        "open list:NETWORKING [GENERAL]" <netdev@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] Bluetooth: Shutdown controller after workqueues are
 flushed or cancelled

Hi Kai-Heng,

Thanks for your patch,

Kai-Heng Feng <kai.heng.feng@...onical.com> writes:

> On Tue, Aug 3, 2021 at 4:21 PM Mattijs Korpershoek
> <mkorpershoek@...libre.com> wrote:
>>
>> Hi Kai-Heng,
>>
>> Kai-Heng Feng <kai.heng.feng@...onical.com> writes:
>>
>> > Hi Mattijs,
>> >
>> > On Fri, Jul 30, 2021 at 7:40 PM Mattijs Korpershoek
>> > <mkorpershoek@...libre.com> wrote:
>> >>
>> >> Hi Kai-Heng,
>> >
>> > [snipped]
>> >
>> >> Thank you for your help. Sorry I did not post the logs previously.
>> >>
>> >> dmesg: https://pastebin.com/tpWDNyQr
>> >> ftrace on btmtksdio: https://pastebin.com/jmhvmwUw
>> >
>> > Seems like btmtksdio needs shudown() to be called before flush().
>> > Since the order was there for a very long time, changing the calling
>> > order indeed can break what driver expects.
>> > Can you please test the following patch:
>> > diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
>> > index 2560ed2f144d..a61e610a400c 100644
>> > --- a/net/bluetooth/hci_core.c
>> > +++ b/net/bluetooth/hci_core.c
>> > @@ -1785,6 +1785,14 @@ int hci_dev_do_close(struct hci_dev *hdev)
>> >         aosp_do_close(hdev);
>> >         msft_do_close(hdev);
>> >
>> > +       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);
>> > +       }
>> > +
>> >         if (hdev->flush)
>> >                 hdev->flush(hdev);
>> >
>> > @@ -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);
>>
>> Thanks for the patch and your help.
>> I've tried it, but it seems that it does not improve for me.
>> I'm still observing:
>>
>> i500-pumpkin login: root
>> root@...0-pumpkin:~# hciconfig hci0 up
>> Can't init device hci0: Connection timed out (110)
>>
>> Logs for this session:
>> dmesg:   https://pastebin.com/iAFk5Tzi
>> ftrace:  https://pastebin.com/kEMWSYrE
>
> Thanks for the testing!
> What about moving the shutdown() part right after hci_req_sync_lock()
> so tx/rx can still work:
>
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index 2560ed2f144d4..be3113fb7d4b0 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -1727,6 +1727,14 @@ int hci_dev_do_close(struct hci_dev *hdev)
>         hci_request_cancel_all(hdev);
>         hci_req_sync_lock(hdev);
>
> +       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);
> +       }
> +
>         if (!test_and_clear_bit(HCI_UP, &hdev->flags)) {
>                 cancel_delayed_work_sync(&hdev->cmd_timer);
>                 hci_req_sync_unlock(hdev);
> @@ -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);
I confirm this diff works for me:

root@...0-pumpkin:~# hciconfig hci0 up
root@...0-pumpkin:~# hciconfig hci0 down
root@...0-pumpkin:~# hciconfig hci0 up
root@...0-pumpkin:~# hciconfig hci0
hci0:   Type: Primary  Bus: SDIO
        BD Address: 00:0C:E7:55:FF:12  ACL MTU: 1021:8  SCO MTU: 244:4
        UP RUNNING 
        RX bytes:11268 acl:0 sco:0 events:829 errors:0
        TX bytes:182569 acl:0 sco:0 commands:829 errors:0

root@...0-pumpkin:~# hcitool scan 
Scanning ...
        <redacted>       Pixel 3 XL

Tested-by: Mattijs Korpershoek <mkorpershoek@...libre.com>
>
>
>
>
>
>>
>>
>> >
>> > Kai-Heng
>> >
>> >>
>> >> Mattijs
>> >> >
>> >> > Kai-Heng
>> >> >
>> >> >>
>> >> >> Thanks,
>> >> >> Mattijs Korpershoek
>> >> >>
>> >> >>
>> >> >> >
>> >> >> > Regards
>> >> >> >
>> >> >> > Marcel