Re: regression: Bluetooth interface broken on systems with Mediatek CPU

[Kai-Heng Feng <kai.heng.feng@canonical.com>]

Hi Guenter,

On Mon, Aug 9, 2021 at 12:10 PM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On Mon, Aug 09, 2021 at 10:35:34AM +0800, Kai-Heng Feng wrote:
> > On Sat, Aug 7, 2021 at 6:22 AM Guenter Roeck <linux@roeck-us.net> wrote:
> > >
> > > [ Greg asked me to submit a report to regressions@, so here it is. ]
> > >
> > > The following error was observed on Chromebooks with MT8183 CPU
> > > (ASUS Chromebook Detachable CM3, HP Chromebook 11a, and others):
> > >
> > > [  224.735198] Bluetooth: qca_setup() hci0: setting up ROME/QCA6390
> > > [  225.205024] Bluetooth: qca_read_soc_version() hci0: QCA Product ID   :0x00000008
> > > [  225.205040] Bluetooth: qca_read_soc_version() hci0: QCA SOC Version  :0x00000044
> > > [  225.205045] Bluetooth: qca_read_soc_version() hci0: QCA ROM Version  :0x00000302
> > > [  225.205049] Bluetooth: qca_read_soc_version() hci0: QCA Patch Version:0x000003e8
> > > [  225.205055] Bluetooth: qca_uart_setup() hci0: QCA controller version 0x00440302
> > > [  225.205061] Bluetooth: qca_download_firmware() hci0: QCA Downloading qca/rampatch_00440302.bin
> > > [  227.252653] Bluetooth: hci_cmd_timeout() hci0: command 0xfc00 tx timeout
> > > ...
> > > [  223.604971] Bluetooth: qca_recv() hci0: Frame reassembly failed (-84)
> > > [  223.605027] Bluetooth: qca_recv() hci0: Frame reassembly failed (-84)
> > > (repeated several times)
> > > ...
> > >
> > > The Bluetooth interface on those Chromebooks can not be enabled.
> > >
> > > Bisect suggests that upstream commit 0ea9fd001a14 ("Bluetooth: Shutdown
> > > controller after workqueues are flushed or cancelled") introduced the problem.
> > > Reverting it fixes the problem.
> > >
> > > The problem was also reported at [1] on a Mediatek Pumpkin board.
> > >
> > > As of this writing, the problem is still present in the upstream kernel
> > > as well as in all stable releases which include commit 0ea9fd001a14.
> >
> > Thanks. Can you please test the following patch:
> >
> I would love to, but I am unable to apply the patch. It failed to apply
> to mainline, to linux-next, and to all stable releases I tried.

I think it has something to do with how the code gets pasted to the mail client.
So can you please give this a try:
https://paste.ubuntu.com/p/CsRrQWNYKr/

Kai-Heng

>
> Guenter
>
> > diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> > index 2560ed2f144d4..131e69a9a66a0 100644
> > --- a/net/bluetooth/hci_core.c
> > +++ b/net/bluetooth/hci_core.c
> > @@ -1757,6 +1757,14 @@ int hci_dev_do_close(struct hci_dev *hdev)
> >                         cancel_delayed_work_sync(&adv_instance->rpa_expired_cb);
> >         }
> >
> > +       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);
> > +       }
> > +
> >         /* Avoid potential lockdep warnings from the *_flush() calls by
> >          * ensuring the workqueue is empty up front.
> >          */
> > @@ -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,
> > > Guenter
> > >
> > > ---
> > > [1] https://lkml.org/lkml/2021/7/28/569