On Thu, 22 Apr 2021 at 21:23, Marijn Suijten <marijns95@xxxxxxxxx> wrote: > > The AVRCP spec (1.6.2) does not mention anything about a version > requirement for Absolute Volume, despite this feature only existing > since spec version 1.4. Android reports a version of 1.3 [1] for its > "AVRCP remote" (CT) service and mentions in the comment above it itself > relies on feature bits rather than the exposed version. As it stands > BlueZ requires at least version 1.4 making it unable to communicate > absolute volume levels with even the most recent Android phones running > Fluoride (have not checked the version on Gabeldorsche). > > The spec states that supporting SetAbsoluteVolume and > EVENT_VOLUME_CHANGED are mandatory when feature level 2 is declared, > excluded otherwise. This feature bit is set on Android and, when used > by this patch, allows for successfully communicating volume back and > forth despite the version theoretically being too low. > > [1]: https://android.googlesource.com/platform/system/bt/+/android-11.0.0_r28/bta/av/bta_av_main.cc#761 > --- > > Hi Luiz, Marek, > > It's been quite a while since our last mail contact. As mentioned > Android simply reports a too low version for its CT despite setting > category 2 for absolute volume support. Using this feature instead of > the version solves being unable to synchronize volume, is that okay with > you? > > - Marijn > > profiles/audio/avrcp.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/profiles/audio/avrcp.c b/profiles/audio/avrcp.c > index 05dd791de..bacd1aeb4 100644 > --- a/profiles/audio/avrcp.c > +++ b/profiles/audio/avrcp.c > @@ -4136,13 +4136,16 @@ static void target_init(struct avrcp *session) > (1 << AVRCP_EVENT_TRACK_REACHED_END) | > (1 << AVRCP_EVENT_SETTINGS_CHANGED); > > + if (target->features & AVRCP_FEATURE_CATEGORY_2) > + session->supported_events |= > + (1 << AVRCP_EVENT_VOLUME_CHANGED); > + > if (target->version < 0x0104) > return; > > session->supported_events |= > (1 << AVRCP_EVENT_ADDRESSED_PLAYER_CHANGED) | > - (1 << AVRCP_EVENT_AVAILABLE_PLAYERS_CHANGED) | > - (1 << AVRCP_EVENT_VOLUME_CHANGED); > + (1 << AVRCP_EVENT_AVAILABLE_PLAYERS_CHANGED); > > /* Only check capabilities if controller is not supported */ > if (session->controller == NULL) > -- > 2.31.1 > Hi Luiz, Has this patch by chance not reached your inbox? Would like to discuss the approach and get this issue fixed. Any suggestions on solving the test bot error? I don't think splitting too-long links over multiple lines is standard practice just to appease it? Thanks for looking into it. - Marijn
