bluez: avrcp: Initial value of absolute volume

bluez: avrcp: Initial value of absolute volume

[Arun Raghavan]

Hello,
I'm using BlueZ as A2DP Sink and AVRCP controller on my laptop, and had a question about how absolute volume should work when I connect a phone to my laptop.

I notice in btmon that at connection time, the phone sends a register notification for the absolute volume event, and BlueZ responds with a current absolute volume of 100%. In the code, this seems to be initialised at media_transport_init_sink() and the initial volume is hard-coded to 127.

What this means is that after my initial connection to the device, I set some volume, disconnect and reconnect, and the volume is now 100% and any changes on the phone cause the device to play at full volume.

I can, of course, set a volume as soon as the transport is created from the client side, but it seems wrong to me that we communicate an incorrect initial value.

Am I missing something? If not, perhaps we can allow an initial volume to be passed during SetConfiguration so that the transport is initialised with the correct volume?

Cheers,
Arun