[pulseaudio-discuss] [PATCH v1 0/3] bluetooth: Headset port availability

[Tanu Kaskinen]

On Mon, 2013-02-04 at 15:50 +0100, David Henningsson wrote:
> On 02/04/2013 03:44 PM, Tanu Kaskinen wrote:
> >>> I don't think merging ports with sinks/sources is the most relevant
> >>> question here. The question is how to simultaneously present a Bluetooth
> >>> headset as a single routing endpoint to the user and have means to
> >>> sufficiently distinguish between A2DP and HSP inside PulseAudio.
> >>
> >> I haven't fully understood the problem with having merged ports for A2DP
> >> and HSP - there are still different sources and sinks, so one could just
> >> look at the current active sink if that's what you need to know.
> >>
> >> I do understand that if something was modelled in one way, and then we
> >> had to do an emergency fix because the model caused regressions in the
> >> UI, the fixups become ugly as a result. What I don't know yet is why
> >> multiple ports for A2DP and HSP would be a better model inside
> >> PulseAudio from start?
> >>
> >>> I have proposed that we use the routing nodes of the policy work done by
> >>> Janos and Jaska to represent the headset as a single routing endpoint,
> >>> and associate multiple ports (A2DP and HSP) with that routing endpoint.
> >>> I would like to reach a consensus about this proposal. Is it ok for
> >>> everybody? David? Janos? Jaska? Please comment.
> >>
> >> It is difficult to have an opinion without knowing more about the
> >> routing framework and what a routing endpoint really is. But even if
> >> this proposal gets implemented, still somebody needs to rewrite the UI
> >> to use routing endpoints instead of ports - which should be an argument
> >> against this proposal in the first place.
> >
> > Mikel knows the details of the problem that he's working on right now,
> > I'll repeat an argument that I have stated earlier: sometimes the
> > Bluetooth setup is such that the HSP audio is routed through ALSA and
> > the A2DP audio is routed through BlueZ. Having a single port for the
> > headset is problematic in this scenario. I'd rather have a separate
> > "routing endpoint" concept for representing the headset. Do you prefer
> > merging ports even in this case?
> 
> If A2DP and HSP audio go through different sound cards, we have no 
> possibility to merge them right now.
> 
> Not that I have ever seen such a setup. Can it happen on desktop/laptop 
> computers you buy in the store, or only on highly specialised embedded 
> environments (which are likely to have their own UI anyway)?

I have no idea about desktop/laptop machines. I know that 100% of
smartphones that I've worked with (i.e. 3 Nokia models) have used ALSA
for HSP, but I expect there to be phones that use the "normal"
everything-through-BlueZ setup. I don't consider phone UIs any more
specialized than desktop UIs: in both cases, one UI codebase should work
with a wide variety of hardware. I don't think the Ubuntu Phone UI
developers, for example, want to care about the Bluetooth hardware
details.

-- 
Tanu