Hi Joshua, >>>> Yes, for secure connection the LTK is generated locally. >>>> But issue here is observed that after Pairing is complete the key >>>> distribution is not completed from Master. >>>> >>>> i.e. After Slave sends the "Signature key:" but Master doesn't >>>> share any key. Attached logs. >>> I get that and that is clear from the logs. Something is stalling here >>> and because of that, you run into the 30 seconds SMP timeout. We just >>> need to know if the 4.9 kernel is doing this correctly. If so, then >>> you can bi-sect that patch that fixes. Without proof that 4.9 is also >>> broken, nobody will even bother to chase this down. >> >> I think the problem here is race between ACL data and HCI events on USB >> dongle... We get initial slave keys but those get dropped due to encryption >> changed event not being received yet. Since keys were silently dropped we later >> on get unexpected SMP PDU and ignoring remaining keys as well which >> eventually leads to SMP timeout. >> >> If this is USB dongle (using btusd) then only (AFAIK) solution would be to have a >> workaround for this inside chip (it would delay ACL data received right after >> encryption change giving host time to handle encpryption change event). >> Bluetooth specification for USB transport is unfortunatelly kinda broken. >> >> -- >> pozdrawiam >> Szymon Janc > > Thank you for your reply. Your inputs are valuable to us in helping to debug the issue. Yes, we are indeed using the btusb kernel module and it is using a USB interface (Bluetooth over USB). > > I noticed that when btmgmt settings are set to turn 'bredr off', the 'ssp' mode also turns off. Is this behavior expected to occur? > My current settings are 'powered connectable discoverable bondable le secure-conn’ the SSP (Secure Simple Pairing) is a BR/EDR only feature. So when you disable BR/EDR, it will be disabled as well. Regards Marcel -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
