MIME-Version: 1.0
References: <87ee5fc2175747e1a7cf5b50bad819d4@ausx13mpc124.AMER.DELL.COM>
 <CAO1O6seYhTMHrgCQ+9gPCo_UOtXfhh9mRCVoUosP_Eq0FXD=sw@mail.gmail.com>
 <bcaa44382c80428ba59b743678be0b18@ausx13mpc120.AMER.DELL.COM>
 <CAO1O6sebmS8P0EVVL=U+eFFq+u0NdtbHUP0dO1D+LPa4vXOWqg@mail.gmail.com> <f3d5e376e4364350b06b665d4351fac9@ausx13mpc120.AMER.DELL.COM>
In-Reply-To: <f3d5e376e4364350b06b665d4351fac9@ausx13mpc120.AMER.DELL.COM>
From:   Emil Lenngren <emil.lenngren@gmail.com>
Date:   Wed, 17 Apr 2019 20:52:12 +0200
Message-ID: <CAO1O6sc4UD2QVaTt9sbO6e7GzdnqN++SzwhphX5CUX0CeHZGKQ@mail.gmail.com>
Subject: Re: Pairing failure with BLE 4.0
To:     YouRen.Chen@dellteam.com,
        Bluez mailing list <linux-bluetooth@vger.kernel.org>
Cc:     Jared.Dominguez@dell.com
Content-Type: text/plain; charset="UTF-8"
Sender: linux-bluetooth-owner@vger.kernel.org
Precedence: bulk

Hi,

Den ons 17 apr. 2019 kl 20:46 skrev <YouRen.Chen@dellteam.com>:
> > Could you try remove these two lines at
> > https://github.com/torvalds/linux/blob/v5.0/net/bluetooth/smp.c#L693
> > to see if it works (also make sure by looking at the log later that those bits
> > were not set in the Key Distribution field)?:
> > local_dist |= SMP_DIST_LINK_KEY;
> > remote_dist |= SMP_DIST_LINK_KEY;
> >
> > We have seen the exact same problem when Android 6 was released.
> > However they have a workaround that they don't set the LinkKey bit if they
> > suspect the device doesn't support it. I think they look at the advertising data
> > which indicates in the flags that it doesn't support BR/EDR. I think BlueZ
> > should do the same to workaround these incompatibility issues.
> >
> > /Emil
>
> Sorry for the late response, the pairing process succeeds when the two
> lines are removed from smp.c. I'm inquiring whether we have a patch
> that already addresses this issue and if not, how it can be implemented.

Good. Tell me if you need help with the patch on the peripheral side.

> Just to make sure I understand this correctly, the PN557W sees the Link
> Bit and returns Invalid Parameters because the bit is nonzero, correct?
> This causes the pairing process to fail. By commenting out those two
> lines, we are telling the master to not set the link bit to 1 before sending
> the parameters?
>
> /Joey

Exactly.

/Emil