BlueZ Wiki site the following is written.
The Sony Ericsson HBH-DS970 and HBH-DS980 are not compliant with the
bluetooth spec. Currently, they do not work well with bluez, but a
workaround is in development.
As far as I know, BlueZ wiki site was used for BlueZ 3.xx
However even if I use with BlueZ 4.44(latest), they do not work well..
If you know the workaround your site mentioned , could you explain that for
What I found is below.
After HFP RFCOMM connection and 10 seconds later,
A2DP session is so slow.. MTU is so small and their respond is too late.
I guess that in case of another phone, it's no problem because their
connections(HFP,A2DP)are made simultaneously.
However in BlueZ case HFP,A2DP connection is separated. As a result it takes
more time to connect stereo Headset A2DP service than another device.