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From: Peter Robinson <pbrobinson@gmail.com>
Date: Tue, 19 Sep 2017 00:23:27 +0100
Message-ID: <CALeDE9PaZvfEwSBOuELNbJxBjR3DfWj61rEBMhYTAF6DJd+bcA@mail.gmail.com>
Subject: Re: Fedora 27 kernel and RPi3 Bluetooth oops
To: Marcel Holtmann <marcel@holtmann.org>
Cc: linux-bluetooth@vger.kernel.org, Loic Poulain <loic.poulain@gmail.com>
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On Mon, Sep 18, 2017 at 6:14 PM, Marcel Holtmann <marcel@holtmann.org> wrot=
e:
> Hi,
>
> the latest Fedora 27 kernel which has all the RPi3 patches applied doesn=
=E2=80=99t actually work. It provides this backlog.
>
> [  229.162921] CPU: 1 PID: 582 Comm: kworker/u9:1 Not tainted 4.13.2-300.=
fc27.armv7hl #1
> [  229.171285] Hardware name: Generic DT based system
> [  229.176774] Workqueue: hci0 hci_cmd_work [bluetooth]
> [  229.176774] Workqueue: hci0 hci_cmd_work [bluetooth]
> [  229.182117] [<c0312af4>] (unwind_backtrace) from [<c030d264>] (show_st=
ack+0x18/0x1c)
> [  229.190374] [<c030d264>] (show_stack) from [<c0b66174>] (dump_stack+0x=
a0/0xd8)
> [  229.198122] [<c0b66174>] (dump_stack) from [<c03aeaec>] (register_lock=
_class+0x298/0x514)
> [  229.206835] [<c03aeaec>] (register_lock_class) from [<c03b1f9c>] (__lo=
ck_acquire+0xe4/0x1608)
> [  229.215952] [<c03b1f9c>] (__lock_acquire) from [<c03b3fd0>] (lock_acqu=
ire+0x280/0x2dc)
> [  229.224386] [<c03b3fd0>] (lock_acquire) from [<c0b80ba4>] (_raw_read_l=
ock+0x4c/0x5c)
> [  229.232740] [<c0b80ba4>] (_raw_read_lock) from [<bf47903c>] (hci_uart_=
tx_wakeup+0x1c/0x98 [hci_uart])
> [  229.242725] [<bf47903c>] (hci_uart_tx_wakeup [hci_uart]) from [<bf47a0=
e0>] (hci_uart_send_frame+0x54/0x6c [hci_uart])
> [  229.254485] [<bf47a0e0>] (hci_uart_send_frame [hci_uart]) from [<bf3cb=
260>] (hci_send_frame+0xc8/0xf4 [bluetooth])
> [  229.266157] [<bf3cb260>] (hci_send_frame [bluetooth]) from [<bf3cb334>=
] (hci_cmd_work+0xa8/0x124 [bluetooth])
> [  229.277005] [<bf3cb334>] (hci_cmd_work [bluetooth]) from [<c036f154>] =
(process_one_work+0x43c/0x83c)
> [  229.286689] [<c036f154>] (process_one_work) from [<c0370934>] (worker_=
thread+0x290/0x40c)
> [  229.295355] [<c0370934>] (worker_thread) from [<c0376784>] (kthread+0x=
14c/0x168)
> [  229.303195] [<c0376784>] (kthread) from [<c03080d0>] (ret_from_fork+0x=
14/0x24)
>
> It results in the first HCI command going through and then every other fa=
iling.
>
> =3D Index Info: 00:00:00:00:00:00 (Broadcom Corporation)
> < HCI Command: Broadcom Update UART Baud Rate (0x3f|0x0018) plen 6
>         Encoded baud rate: Not used (0x0000)
>         Explicit baud rate: 2000000 Mbps
>> HCI Event: Command Complete (0x0e) plen 4
>       Broadcom Update UART Baud Rate (0x3f|0x0018) ncmd 1
>         Status: Success (0x00)
> < HCI Command: Reset (0x03|0x0003) plen 0
>
> The HCI Reset command actually times out.
>
> [  231.349802] Bluetooth: hci0 command 0x0c03 tx timeout
>
> What we really need is some kernel specific debug tracing when driver cha=
nge baud rate etc. to show up in btmon. Drivers need the capability to inse=
rt HCI transport level specifics into monitoring interface.

Thanks for noticing this, I've have that exact backlog sitting there
to send out but I'd just not got to it yet, let me know if there's
anything that needs tweaking on the Fedora side or patch.

Peter