linux-kernel - Re: [PATCH v5 4/7] Bluetooth: Add new quirk for non-persistent setup settings

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Message-Id: <6571C864-B2EC-4806-BC5D-F531792737F6@holtmann.org>
Date:   Mon, 16 Jul 2018 14:56:44 +0200
From:   Marcel Holtmann <marcel@...tmann.org>
To:     Sean Wang <sean.wang@...iatek.com>
Cc:     robh+dt@...nel.org, mark.rutland@....com,
        Johan Hedberg <johan.hedberg@...il.com>,
        devicetree@...r.kernel.org, linux-bluetooth@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 4/7] Bluetooth: Add new quirk for non-persistent setup
 settings

Hi Sean,

>>> Add a new quirk HCI_QUIRK_NON_PERSISTENT_SETUP allowing that a quirk that
>>> runs setup() after every open() and not just after the first open().
>>> 
>>> Signed-off-by: Sean Wang <sean.wang@...iatek.com>
>>> ---
>>> include/net/bluetooth/hci.h | 9 +++++++++
>>> net/bluetooth/hci_core.c    | 3 ++-
>>> 2 files changed, 11 insertions(+), 1 deletion(-)
>>> 
>>> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
>>> index 73e48be..d3ec5b2a8 100644
>>> --- a/include/net/bluetooth/hci.h
>>> +++ b/include/net/bluetooth/hci.h
>>> @@ -183,6 +183,15 @@ enum {
>>> 	 * during the hdev->setup vendor callback.
>>> 	 */
>>> 	HCI_QUIRK_NON_PERSISTENT_DIAG,
>>> +
>>> +	/* When this quirk is set, setup() would be run after every
>>> +	 * open() and not just after the first open().
>>> +	 *
>>> +	 * This quirk can be set before hci_register_dev is called or
>>> +	 * during the hdev->setup vendor callback.
>>> +	 *
>>> +	 */
>>> +	HCI_QUIRK_NON_PERSISTENT_SETUP,
>>> };
>>> 
>>> /* HCI device flags */
>>> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
>>> index f5c21004..0111280 100644
>>> --- a/net/bluetooth/hci_core.c
>>> +++ b/net/bluetooth/hci_core.c
>>> @@ -1396,7 +1396,8 @@ static int hci_dev_do_open(struct hci_dev *hdev)
>>> 	atomic_set(&hdev->cmd_cnt, 1);
>>> 	set_bit(HCI_INIT, &hdev->flags);
>>> 
>>> -	if (hci_dev_test_flag(hdev, HCI_SETUP)) {
>>> +	if (hci_dev_test_flag(hdev, HCI_SETUP) ||
>>> +	    test_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks)) {
>>> 		hci_sock_dev_event(hdev, HCI_DEV_SETUP);
>> 
>> can you include the extract of btmon on how the HCI_DEV_SETUP event shows up in the traces? I remember that I asked about something like that.
>> 
>> Regards
>> 
>> Marcel
>> 
> 
> No, I cannot see any event about HCI_DEV_SETUP in btmon trace, the trace I posted as below is doing some rounds of power off and then on

it will result in this:

        case HCI_DEV_SETUP:
                if (hdev->manufacturer == 0xffff)
                        return NULL;
                                                                                 
        case HCI_DEV_UP:
                skb = bt_skb_alloc(HCI_MON_INDEX_INFO_SIZE, GFP_ATOMIC);

So we will see extra index info events, but I assume that is just fine this we also see them on DEV_UP. They also do not hurt as long as not magically the manufacturer information changes.

I do wonder though if this quirk is set, then hdev->manufacturer needs to be reset and allow hdev->setup() to reset it. This goes with a log of other information as well. Maybe just a look if there are no races here.

Regards

Marcel