BlueZ health device interface, problems with link security level?
From: Bill Turner <hidden>
Date: 2011-03-22 16:37:20
I've run into a problem trying to use the BlueZ health device plugin (BlueZ 4.89), related to the Bluetooth link security level requested and the device capabilities. I'm connecting to an Omron BP792IT blood pressure monitor and have it correctly paired with my system. The problem I have is when the MCAP instance is created (mcap_create_instance, in health/hdp.c), it uses BT_IO_SEC_HIGH, which sets the link authentication requirement to 5 (MITM protection required, general bonding). Since the BP monitor doesn't have any user input capabilities (IO capabilities returns 3, NoInputNoOutput), the request to change the link authentication level fails, and the connection is refused. I've gotten the device to correctly connect and exchange data if I modify the call to mcap_create_instance to use BT_IO_SEC_MEDIUM instead, so the MITM protection isn't required. I'm not sure if I'm doing something else wrong and BT_IO_SEC_HIGH should work, or if there is indeed a problem in the BlueZ code (and if so what the correct solution is). Does anyone else have the unmodified BlueZ code working correctly with health devices? -- Bill Turner Senior Software Engineer Visionary Mobile Corp. -- Bill Turner Senior Software Engineer Visionary Mobile Corp.