linux-kernel - Re: [PATCH v1 3/4] Bluetooth: hci_qca: clear HCI_QUIRK_RESET_ON

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Date:   Tue, 06 Nov 2018 18:44:07 +0530
From:   Balakrishna Godavarthi <bgodavar@...eaurora.org>
To:     Marcel Holtmann <marcel@...tmann.org>
Cc:     Johan Hedberg <johan.hedberg@...il.com>,
        Matthias Kaehlcke <mka@...omium.org>,
        open list <linux-kernel@...r.kernel.org>,
        linux-bluetooth@...r.kernel.org, hemantg@...eaurora.org,
        linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v1 3/4] Bluetooth: hci_qca: clear HCI_QUIRK_RESET_ON_CLOSE
 flag

Hi Marcel,

On 2018-11-06 18:32, Marcel Holtmann wrote:
> Hi Balakrishna,
> 
>>>> During hci down we are sending reset command to chip, which
>>>> is not required for wcn3990, as hdev->shutdown() will turn off the
>>>> regulators.
>>>> Signed-off-by: Balakrishna Godavarthi <bgodavar@...eaurora.org>
>>>> ---
>>>> drivers/bluetooth/hci_qca.c | 1 +
>>>> 1 file changed, 1 insertion(+)
>>>> diff --git a/drivers/bluetooth/hci_qca.c 
>>>> b/drivers/bluetooth/hci_qca.c
>>>> index 8301663f0004..97b57e0f4725 100644
>>>> --- a/drivers/bluetooth/hci_qca.c
>>>> +++ b/drivers/bluetooth/hci_qca.c
>>>> @@ -1190,6 +1190,7 @@ static int qca_setup(struct hci_uart *hu)
>>>> 		 */
>>>> 		set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
>>>> 		set_bit(HCI_QUIRK_USE_BDADDR_PROPERTY, &hdev->quirks);
>>>> +		clear_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
>>>> 		hu->hdev->shutdown = qca_power_off;
>>>> 		ret = qca_wcn3990_init(hu);
>>>> 		if (ret)
>>> I am pretty certain that you didn’t want this quirk:
>>>        /* When this quirk is set, the HCI Reset command is send when
>>>         * closing the transport instead of when opening it.
>>> This quirk is for Bluetooth 1.0b devices where the HCI_Reset behavior
>>> was not clear or for devices that actually misbehave with the initial
>>> HCI_Reset.
>>> In addition, you commit message is totally misleading. That is not
>>> what is happening with this quirk.
>>> Regards
>>> Marcel
>> 
>> My intention was reset command is not required when we do an hci down.
>> this is because of hdev->shutdown will turn off the regulators.
>> It is like turning off the chip. sending reset command after turning 
>> off the chip is not required.
>> 
>> I understand the usage of the quirk, will update the commit text.
> 
> you are papering over the issue. Actually
> hci_serdev.c:hci_uart_register_device() is the culprit with the legacy
> code copied over from hci_ldisc.c:hci_uart_register_dev(). I think
> there is no point doing all this legacy line discipline quirk handling
> until it is really needed. The serdev drivers are all for recent
> hardware.
> 
> That said, having moved over to a btuart.c approach and killed the
> whole hci_serdev.c thing would have been a lot better here. You will
> keep running in weird situations where 18 year old code keeps
> surprising you.

[Bala]: even i feel the same. they are lot such kind of HACK's we need 
to do with current arch.
         when can we expect btuart.c merged to bt-next. i think having 
btuart will helps us to have the control of
         vendor porto's call's like in btusb.c

> 
> Regards
> 
> Marcel

-- 
Regards
Balakrishna.