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From:   Martin Townsend <mtownsend1973@gmail.com>
Date:   Sat, 10 Nov 2018 18:29:22 +0000
Message-ID: <CABatt_wSMSiW+Fmi5cccAnejMbAAHdNWb-jW0qLcijtdWETHzw@mail.gmail.com>
Subject: Re: Operating central and peripheral roles concurrently
To:     luiz.dentz@gmail.com
Cc:     linux-bluetooth@vger.kernel.org
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Sender: linux-bluetooth-owner@vger.kernel.org
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Hi,
On Sat, Nov 10, 2018 at 6:03 PM Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
>
> Hi Martin,
> On Fri, Nov 9, 2018 at 7:57 PM Martin Townsend <mtownsend1973@gmail.com> wrote:
> >
> > On Fri, Nov 9, 2018 at 4:32 PM Martin Townsend <mtownsend1973@gmail.com> wrote:
> > >
> > > Hi,
> > >
> > > I see someone has already asked this question not long ago but I am
> > > seeing the same problem.  I have an embedded platform running 4.9
> > > kernel and Bluez 5.50 and the bluetooth device is the BroadCom
> > > BCM4343W which supports bluetooth 4.1.
> > >
> > > I can run the btgatt-server and example-gatt-server fine and connect
> > > to it from my phone using nRF and read the relevant attributes.  This
> > > I believe is where my device is in the peripheral role.  If I close
> > > the GATT server down I can use gatttool to query the characteristics
> > > of another GATT server setup on my PC, I think this is then acting as
> > > central role.
> > >
> > > But if I can't do both at the same time, once the GATT server is
> > > running and I try and query the other GATT server, I get
> > > root@mach-cw-rnet-ppm-1717:~# gatttool -b 5D:3C:72:B5:23:BE -t random
> > > --characteristics
> > > connect error: Connection refused (111)
> > >
> > > I've noticed that if I start bluetoothctl whilst the GATT server is
> > > running it looks as if it has connected to my phone
> > >
> > > root@mach-cw-rnet-ppm-1717:~# bluetoothctl
> > > Agent registered
> > > [LG K8 (2017)]#
> > >
> > > Maybe this is expected but it does look like it has made a connection
> > > back to the phone and I'm wondering if this is stopping it from acting
> > > in the central role?
> > >
> > > Not really knowing much about the bluetooth stack I was wondering if
> > > anyone has any pointers on how to debug this or let me know if I'm
> > > doing something wrong?  I'm quite comfortable putting debug code into
> > > the kernel and/or bluez5 and recompiling to get more information if
> > > required.
> > >
> > > Any help would be greatly appreciated,
> > > Martin.
> >
> > I turned on DEBUG for a few of the hci_.c files and here's the output
> > of the failed connect in case it helps
> >
> > These occur on connect from gatttool:
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: 00:00:00:00:00:00 ->
> > 7b:bd:e7:6a:8a:8d
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 orig refcnt 9
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: requesting refresh of dst_addr
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 dst 7b:bd:e7:6a:8a:8d
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 orig refcnt 10
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: addr 7b:bd:e7:6a:8a:8d (type 1)
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: addr 7b:bd:e7:6a:8a:8d
> > (type 1) auto_connect 5
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hcon 97310400 orig refcnt 0
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 hcon 97310400
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 cmd_cnt 1 cmd queued 2
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 type 1 len 10
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 Event packet
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 opcode 0x200b
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: opcode 0x200b status 0x00
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 opcode 0x200b
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 cmd_cnt 1 cmd queued 1
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 type 1 len 5
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 Event packet
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 opcode 0x200c
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: opcode 0x200c status 0x00
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 opcode 0x200c
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0
> > Nov 09 08:03:00 mach-cw-rnet-ppm-1717 kernel: hci0 Event packet
> >
> >
> > Then just before Error: connect error: Connection refused (111) many
> > seconds later:
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hcon 97310400 state BT_CONNECT
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 hcon 97310400
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 orig refcnt 10
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 hcon 97310400
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: addr 7b:bd:e7:6a:8a:8d (type 1)
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hcon 97310400
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 hcon 97310400 chan 97421c80
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 orig refcnt 11
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 cmd_cnt 1 cmd queued 1
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 type 1 len 5
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 orig refcnt 10
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 Event packet
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 opcode 0x200c
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: opcode 0x200c status 0x00
> > Nov 09 08:03:41 mach-cw-rnet-ppm-1717 kernel: hci0 opcode 0x200c
>
> Not sure if it is exactly the same problem but you can try checking if
> the following like is causing the problem:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git/tree/net/bluetooth/hci_event.c#n5075
>
> So we cannot be both slave and central, or at least that is what the
> code suggests, though I think we should drop that line and leave the
> controller to fail if that is the case.
>
>
>
> --
> Luiz Augusto von Dentz

Thanks for replying, just to confirm that this maybe the code to take a look at

/* Most controller will fail if we try to create new connections
* while we have an existing one in slave role.
*/
if (hdev->conn_hash.le_num_slave > 0)
return NULL;

If so, I'll put some debug code around it and try disabling it to see
if it makes a difference.

Regards, Martin.