about UCM on bluetooth headset

about UCM on bluetooth headset

[Lu Guanqun]

Hi Liam,

In alsa-libs:include/use-case.h, there are below lines:

	* a conversation etc. The device describes the physical audio capture and playback
	* hardware i.e. headphones, phone handset, bluetooth headset, etc.

I'm not quite clear about how to set a use case for bluetooth headset.
According to my understanding, bluetooth doesn't fall into the category
of ALSA, therefore there's no such direct devices for it.

Could you shed some lights on this? What's the best practises to use UCM
with bluetooth?

-- 
guanqun

Re: about UCM on bluetooth headset

[Liam Girdwood]

On 22/08/11 07:19, Lu Guanqun wrote:
> Hi Liam,
> 
> In alsa-libs:include/use-case.h, there are below lines:
> 
> 	* a conversation etc. The device describes the physical audio capture and playback
> 	* hardware i.e. headphones, phone handset, bluetooth headset, etc.
> 
> I'm not quite clear about how to set a use case for bluetooth headset.
> According to my understanding, bluetooth doesn't fall into the category
> of ALSA, therefore there's no such direct devices for it.
> 
> Could you shed some lights on this? What's the best practises to use UCM
> with bluetooth?
> 

This is intended for systems where the BT audio is integrated in some way with the other audio ICs. It's intended to configure the other audio devices to allow use cases involving BT in such systems.

Liam 

Re: about UCM on bluetooth headset

[Lu Guanqun]

On Mon, Aug 22, 2011 at 06:46:02PM +0800, Liam Girdwood wrote:
> On 22/08/11 07:19, Lu Guanqun wrote:
> > Hi Liam,
> > 
> > In alsa-libs:include/use-case.h, there are below lines:
> > 
> > 	* a conversation etc. The device describes the physical audio capture and playback
> > 	* hardware i.e. headphones, phone handset, bluetooth headset, etc.
> > 
> > I'm not quite clear about how to set a use case for bluetooth headset.
> > According to my understanding, bluetooth doesn't fall into the category
> > of ALSA, therefore there's no such direct devices for it.
> > 
> > Could you shed some lights on this? What's the best practises to use UCM
> > with bluetooth?
> > 
> 
> This is intended for systems where the BT audio is integrated in some
> way with the other audio ICs. It's intended to configure the other
> audio devices to allow use cases involving BT in such systems.

Hi Liam,

Thanks, I got your point. For example, where BT HSP is implemented over
ALSA PCM, it's most probably exposed as an ALSA device, then we can
configure it.

-- 
guanqun

Re: about UCM on bluetooth headset

[Mark Brown]

On Mon, Aug 22, 2011 at 11:46:02AM +0100, Liam Girdwood wrote:
> On 22/08/11 07:19, Lu Guanqun wrote:

> > 	* a conversation etc. The device describes the physical audio capture and playback
> > 	* hardware i.e. headphones, phone handset, bluetooth headset, etc.

> > Could you shed some lights on this? What's the best practises to use UCM
> > with bluetooth?

> This is intended for systems where the BT audio is integrated in some
> way with the other audio ICs. It's intended to configure the other
> audio devices to allow use cases involving BT in such systems.

Specifically it's for BT SCO (in call 8kHz headset modes).  In call
audio generally doesn't go through the CPU, the BT device has a path to
the baseband via some other route which is typically similar to or part
of the connection the CODEC has which bypasses the CPU entirely allowing
the CPU to be suspended.

[Liam, your mailer still isn't word wrapping within paragraphs.]