Return-Path: Message-ID: <54105D42.7040003@lampreynetworks.com> Date: Wed, 10 Sep 2014 10:16:34 -0400 From: Tom Harada MIME-Version: 1.0 To: linux-bluetooth@vger.kernel.org Subject: Re: BLE Delayed encryption change using References: <001301cfc950$ecd06240$c67126c0$@lampreynetworks.com> <3A0E8851-3F10-40A4-A5E8-43BCC727D053@holtmann.org> <002a01cfcc7d$8d290dd0$a77b2970$@lampreynetworks.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Marcel, >>>> I am attempting to reconnect to a BLE glucometer with gatttool after >>>> pairing with bluetoothctl. A quick connection update seems to cause a >>>> large delay (around a minute) in the transmission of the LL_ENC_REQ. >>>> >>>> Description: >>>> Attempting to connect to an agent which after connecting immediately >>>> sends an L2CAP update connection parameters request with minimum >>>> connection interval set to 20 ms, and maximum connection interval set to >> 40 ms. >>>> Increasing both values by 100 ms causes the problem to stop being >> generated. >>>> The problem happens only if the dongle using the Broadcom BCM20702 >>>> chipset is used, using a CSR8510 A10 dongle I cannot generate this >>>> issue. I am using BlueZ 5.22, using Linux kernel 3.10.17. The hardware >> platform is a Utilite. >>> try using a 3.17-rc3 kernel. We added storing of the connection parameters. >> New connections >>> will then use the previously requested connection parameters when >> establishing the connection. >>> Which means the peripheral does not have to request connection updates on >> every connection. >> >> According to the HCI dump I am not using the saved parameters. I see the >> updated parameters getting saved, but the outgoing connection appears to not >> be using them. > if you run btmon, do you see a mgmt command that indicates that the parameters are actually send to userspace. I think at the moment, we only really store the parameters for devices that are a) in our device list or b) we have paired with. > We do see this command in btmon, right after the connection update. The parameters also appear to be written to /var/lib/bluetooth/.../.../info. Regards, Tom Harada