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From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date: Mon, 18 Sep 2017 21:51:28 +0300
Message-ID: <CABBYNZL-dUNjst2Vf_b6WWrOfqnFeC3a0XZuq4-a5_4-X9-XOg@mail.gmail.com>
Subject: Re: Fedora 27 kernel and RPi3 Bluetooth oops
To: Marcel Holtmann <marcel@holtmann.org>
Cc: "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>, Loic Poulain <loic.poulain@gmail.com>,
	Peter Robinson <pbrobinson@gmail.com>
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List-ID: <linux-bluetooth.vger.kernel.org>

Hi Marcel,

On Mon, Sep 18, 2017 at 8:14 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

Either we are printing the baud rate incorrectly of there gotta be
something wrong with it since 2 Tbps sounds pretty much impossible...
I guess this must be 2 Mbps/2000000 bps.

>> 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.
>
> Regards
>
> Marcel
>
> --
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--=20
Luiz Augusto von Dentz