linux-kernel - Re: [PATCH] Bluetooth: Do not cancel advertising when starting a scan

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Message-ID: <CAO1O6sdfdVavo9U0UKewbS9YAjCVzdXDYms-OJZNEJVzMmkgMg@mail.gmail.com>
Date:   Wed, 18 Mar 2020 12:31:35 +0100
From:   Emil Lenngren <emil.lenngren@...il.com>
To:     Marcel Holtmann <marcel@...tmann.org>
Cc:     Manish Mandlik <mmandlik@...gle.com>,
        Yoni Shavit <yshavit@...omium.org>,
        Alain Michaud <alainm@...omium.org>,
        Miao-chen Chou <mcchou@...omium.org>,
        Bluez mailing list <linux-bluetooth@...r.kernel.org>,
        Dmitry Grinberg <dmitrygr@...gle.com>,
        "David S. Miller" <davem@...emloft.net>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Network Development <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Jakub Kicinski <kuba@...nel.org>
Subject: Re: [PATCH] Bluetooth: Do not cancel advertising when starting a scan

Hi,

Den ons 18 mars 2020 kl 12:27 skrev Marcel Holtmann <marcel@...tmann.org>:
>
> Hi Manish,
>
> > BlueZ cancels adv when starting a scan, but does not cancel a scan when
> > starting to adv. Neither is required, so this brings both to a
> > consistent state (of not affecting each other). Some very rare (I've
> > never seen one) BT 4.0 chips will fail to do both at once. Even this is
> > ok since the command that will fail will be the second one, and thus the
> > common sense logic of first-come-first-served is preserved for BLE
> > requests.
> >
> > Signed-off-by: Dmitry Grinberg <dmitrygr@...gle.com>
> > Signed-off-by: Manish Mandlik <mmandlik@...gle.com>
> > ---
> >
> > net/bluetooth/hci_request.c | 17 -----------------
> > 1 file changed, 17 deletions(-)
>
> patch has been applied to bluetooth-next tree.
>
> If you know the controller that doesn’t support this, can we blacklist that one and just disable advertising (peripheral mode) for that controller.

Can't the "LE Supported States" be inspected instead to figure out
what simultaneous capabilities are supported? It seems a bit rough to
always assume the worst.

/Emil