On Thu, 2018-06-14 at 00:05 -0700, João Paulo Rechi Vita wrote: > 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. Maybe we could increase the timeout. A long timeout doesn't matter with properly working hardware, because the wait is terminated as soon as all advertised profiles have become connected. > 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. This is without increasing the timeout, right, so the problem is that module-card-restore is trying to restore a2dp_sink before it's available? module-card-restore has been fixed to not to try to restore unavailable profiles: https://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/?id=d65974d8501052bafb03e65f5df954511e9949a2 > 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. If module-bluetooth-policy is sufficient, then module-card-restore won't do anything anyway, because you never set the profile manually. If you ever set the profile manually, that's an indication that module- bluetooth-policy isn't always good enough. > 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. This is outside of my area of expertise. Could you just clarify one thing: did I understand correctly that if you increase the profile waiting timeout, then the headset doesn't disconnect AVDTP? So everything works perfectly, except that the connection takes a very long time? -- Tanu https://liberapay.com/tanuk https://www.patreon.com/tanuk
