RE: [EXT] Re: [PATCH BlueZ v1 1/1] LE Create Connection command timeout increased to 20 secs from 4 secs

From: Mahesh Talewad <mahesh.talewad@nxp.com>
To: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: "linux-bluetooth@vger.kernel.org"
	<linux-bluetooth@vger.kernel.org>,
	Devyani Godbole <devyani.godbole@nxp.com>,
	Sarveshwar Bajaj <sarveshwar.bajaj@nxp.com>
Subject: RE: [EXT] Re: [PATCH BlueZ v1 1/1] LE Create Connection command timeout increased to 20 secs from 4 secs
Date: Mon, 22 Apr 2024 09:01:00 +0000	[thread overview]
Message-ID: <AS5PR04MB9754B55170413A2FD0A00F0A89122@AS5PR04MB9754.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <CABBYNZK5YS6paOYbx4yL6R7Wt9o+oGrtmfiQNmOaTAUo2DBfdQ@mail.gmail.com>

Hi Luiz,

On our DUT, we can see that the host issues create connection cancel command after 4-sec if there is no connection complete event for LE create connection cmd.
As per core spec v5.3 section 7.8.5, advertisement interval range is -

Advertising_Interval_Min
Default : 0x0800(1.28s)
Time Range: 20ms to 10.24s

Advertising_Interval_Max
Default : 0x0800(1.28s)
Time Range: 20ms to 10.24s

If the remote device is using adv interval of > 4 sec, it is difficult to make a connection with the current timeout value.
Also, with the default interval of 1.28 sec, we will get only 3 chances to capture the adv packets with the 4 sec window.
Hence we want to increase this timeout to 20sec.
Note: In Android this timeout value is 29 secs.
Does setting via 'conn->conn_timeout' mean setting 'Autoconnecttimeout=value' in main.conf file?

Thanks and regards,
Mahesh Vithal Talewad

-----Original Message-----
From: Luiz Augusto von Dentz <luiz.dentz@gmail.com> 
Sent: Wednesday, March 20, 2024 5:13 PM
To: Mahesh Talewad <mahesh.talewad@nxp.com>
Cc: linux-bluetooth@vger.kernel.org; Devyani Godbole <devyani.godbole@nxp.com>; Sarveshwar Bajaj <sarveshwar.bajaj@nxp.com>
Subject: Re: [EXT] Re: [PATCH BlueZ v1 1/1] LE Create Connection command timeout increased to 20 secs from 4 secs

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Hi Mahesh,

On Wed, Mar 20, 2024 at 10:56 AM Mahesh Talewad <mahesh.talewad@nxp.com> wrote:
>
> Hi Luiz,
>
> Yes, its auto connect scenario.
> While running connect disconnect in a loop on one of the chip, we are getting issue with this default timeout . Hence we increased this timeout value to standard LE timeout i.e 20s.
> Kindly let us know, is there any timeout explicitly defined for the autoconnect in the spec.

What exactly is the issue though, or are you saying it is a controller issue because the attempts are too closely together when the timeout is just 4 seconds, note that you are just working around the problem because users can bypass the default when set via conn->conn_timeout.

> Thanks and regards,
> Mahesh Vithal Talewad
>
> -----Original Message-----
> From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
> Sent: Wednesday, March 20, 2024 3:21 PM
> To: Mahesh Talewad <mahesh.talewad@nxp.com>
> Cc: linux-bluetooth@vger.kernel.org; Devyani Godbole 
> <devyani.godbole@nxp.com>; Sarveshwar Bajaj <sarveshwar.bajaj@nxp.com>
> Subject: [EXT] Re: [PATCH BlueZ v1 1/1] LE Create Connection command 
> timeout increased to 20 secs from 4 secs
>
> Caution: This is an external email. Please take care when clicking 
> links or opening attachments. When in doubt, report the message using 
> the 'Report this email' button
>
>
> Hi Mahesh,
>
> On Mon, Mar 18, 2024 at 12:37 PM Mahesh Talewad <mahesh.talewad@nxp.com> wrote:
> >
> >  - As per specs LE Connection timeout is 20 secs but in implementation,
> >    it was 4 secs. Hence increased this timeout to 20 Secs.
> >
> > Signed-off-by: Mahesh Talewad <mahesh.talewad@nxp.com>
> > ---
> >  net/bluetooth/hci_event.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c 
> > index 4ae224824012..06fe5f6b9546 100644
> > --- a/net/bluetooth/hci_event.c
> > +++ b/net/bluetooth/hci_event.c
> > @@ -6067,7 +6067,7 @@ static struct hci_conn *check_pending_le_conn(struct hci_dev *hdev,
> >         }
> >
> >         conn = hci_connect_le(hdev, addr, addr_type, addr_resolved,
> > -                             BT_SECURITY_LOW, hdev->def_le_autoconnect_timeout,
> > +                             BT_SECURITY_LOW, HCI_LE_CONN_TIMEOUT,
> >                               HCI_ROLE_MASTER);
> >         if (!IS_ERR(conn)) {
> >                 /* If HCI_AUTO_CONN_EXPLICIT is set, conn is already 
> > owned
> > --
> > 2.34.1
>
> Afaik this is on purpose since it is the autoconnect procedure, rather than user initiate connection, so are you running into a problem if the timeout is different?
>
> --
> Luiz Augusto von Dentz

--
Luiz Augusto von Dentz