Hello Luiz and Tanuk, I have been trying to understand a problem when trying to establish a connection between my Sony MW-600 headset and my laptop (PulseAudio 11.1 + a backport that gives higher priority to A2DP, BlueZ 5.47, Linux 4.16.9). When the connection is initiated by the peripheral, after it has already been paired on a previous connection, the peripheral does not remain connected. When the computer initiates the connection everything works fine. The problem seems to be that when we create the card in PulseAudio is created before the AVDTP connection reaches the OPEN state, the headset decides to abort the AVDTP connection. In this case the card was created before the transport for the card profile a2dp_sink is available and headset_head_unit was the active profile, because WAIT_FOR_PROFILES_TIMEOUT_USEC was reached. Increasing the timeout to 60s makes the problem go away. The AVDTP channel becomes connected about 50s after the HSP connection has started and the card is created with a2dp_sink as the active profile. I also had to disable module-card-restore, otherwise it tries to switch to the saved a2dp_sink profile right when the card is created, which also makes the device abort the AVDTP connection for some reason. I have collected btmon dumps with a slightly modified version of btmon to avoid flooding the logs with SCO data and uploaded to https://gist.github.com/jprvita/a7482db4601d099788c4f820ea984ba9. Similar symptoms have been reported by our QA team with another Sony model (MDR-XB950N1) and with a few Chinese headsets, but the MW-600 is the only one I have access to where I can reproduce the problem consistently (works fine on a Sennheiser MM-450 and a JBL Flip 2). Also, the involvement of module-card-restore in this problem made me think whether it actually makes sense to restore the active profile from the previous connection on bluetooth cards, since we already have module-bluetooth-policy to automatically select the right profile depending on the stream type. Please let me know if you can help me understand what is making the headset decide to disconnect AVDTP in these cases, and what is the best way to fix this, or any ideas that may help investigating this further. Thanks! -- João Paulo Rechi Vita http://about.me/jprvita
