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Subject: Re: [PATCH v4] Bluetooth: Add ncmd=0 recovery handling
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <20210429102415.v4.1.I14da3750a343d8d48921fffb7c6561337b6e6082@changeid>
Date:   Fri, 7 May 2021 10:31:51 +0200
Cc:     Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        CrosBT Upstreaming <chromeos-bluetooth-upstreaming@chromium.org>,
        Bluetooth Kernel Mailing List 
        <linux-bluetooth@vger.kernel.org>,
        Alain Michaud <alainm@chromium.org>,
        Abhishek Pandit-Subedi <abhishekpandit@chromium.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        open list <linux-kernel@vger.kernel.org>,
        netdev@vger.kernel.org
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Message-Id: <A59D973F-B135-4943-AA5A-0A9F8FFC3DF0@holtmann.org>
References: <20210429102415.v4.1.I14da3750a343d8d48921fffb7c6561337b6e6082@changeid>
To:     Manish Mandlik <mmandlik@google.com>
Precedence: bulk

Hi Manish,

> During command status or command complete event, the controller may set
> ncmd=0 indicating that it is not accepting any more commands. In such a
> case, host holds off sending any more commands to the controller. If the
> controller doesn't recover from such condition, host will wait forever,
> until the user decides that the Bluetooth is broken and may power cycles
> the Bluetooth.
> 
> This patch triggers the hardware error to reset the controller and
> driver when it gets into such state as there is no other wat out.
> 
> Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
> Signed-off-by: Manish Mandlik <mmandlik@google.com>
> ---
> 
> Changes in v4:
> - Update comment in hci_ncmd_timeout
> - Add a new inline function to handle cmd_cnt and timers
> 
> Changes in v3:
> - Restructure ncmd_timer scheduling in hci_event.c
> - Cancel delayed work in hci_dev_do_close
> - Do not inject hw error during HCI_INIT
> - Update comment, add log message while injecting hw error
> 
> Changes in v2:
> - Emit the hardware error when ncmd=0 occurs
> 
> include/net/bluetooth/hci.h      |  1 +
> include/net/bluetooth/hci_core.h |  1 +
> net/bluetooth/hci_core.c         | 22 ++++++++++++++++++++++
> net/bluetooth/hci_event.c        | 29 +++++++++++++++++++----------
> 4 files changed, 43 insertions(+), 10 deletions(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel