[pulseaudio-discuss] Bluetooth ports

[Tanu Kaskinen]

On Thu, 2012-11-22 at 16:55 +0100, David Henningsson wrote:
> First, sorry for not being into all the bluetooth details and relying on 
> you to sort it all out correctly...
> 
> ...now, I'm testing PulseAudio 2.99.2 and things do not show up as I 
> expect them to. In PulseAudio 2.x, there were no bluetooth ports at all, 
> in 2.99, "pactl list-cards" looks like this [1]. I don't know if it's a 
> bug, or if it is for a reason, but at least it's an unhappy surprise for me.
> 
> In short; if it's the same physical output on the device, it's *the same 
> port*. Just like my USB headset has one port in each direction, so 
> should my bluetooth headset. I e, there should not be one "hsp-output" 
> and one "a2dp-output" ports, because they go to the same headset, they 
> should share the same port, preferrably called "Headset" or something 
> similar.
> 
> To point out the practical problem for end users is that in GNOME sound 
> settings, it now looks like you're having two different headsets. :-(

Ports were added to the bluetooth card, because the latency offset needs
to be stored per-port. To me it was an obvious choice to go with
separate ports for A2DP and HSP, because they are so different modes. I
probably didn't even think about using the same port for both modes. But
now that you mention it, I agree that they should use the same port.

This was discussed in IRC, and I brought up per-port volumes as a
potential blocker for combining the ports: there's no reliable way to
map A2DP volume to HSP volume and vice versa. Therefore, when the
profile is changed, the perceived volume can change too, even if the
volume slider in pavucontrol or whatever appears to not move. The
discussion didn't lead to any conclusion, but in my opinion this is not
a blocker issue for combining the ports.

-- 
Tanu