2008-07-27 20:41:32

by Ludovico Cavedon

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Subject: [Bluez-devel] Why always disconnect the headset?

Hi all,
I noticed that every time an application closes a SCO audio device, my
headset gets disconnected (HEADSET_STATE_DISCONNECTED). This means that
when the application reopens the device, it requires some seconds to get
the audio working.

So, why is the headset disconnected and not just left in the state
HEADSET_STATE_CONNECTED? (i.e. the same stat that the headset enters
when I turn it on and pairs with my pc).

Thanks,
Ludovico

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2008-07-28 11:15:52

by Johan Hedberg

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Subject: Re: [Bluez-devel] Why always disconnect the headset?

Hi Ludovico,

On Jul 27, 2008, at 23:41, Ludovico Cavedon wrote:
> I noticed that every time an application closes a SCO audio device, my
> headset gets disconnected (HEADSET_STATE_DISCONNECTED). This means
> that
> when the application reopens the device, it requires some seconds to
> get
> the audio working.
>
> So, why is the headset disconnected and not just left in the state
> HEADSET_STATE_CONNECTED? (i.e. the same stat that the headset enters
> when I turn it on and pairs with my pc).

You didn't mention which version of BlueZ you use, but in recent
versions the logic is such that only implicitly created connections
are automatically disconnected (after a 3 second timeout) but
explicitly created connections stay up until you manually disconnect
them. An implicitly created connection would be one caused by an ALSA
application when it opens the audio device. Connections that fall into
the explicitly created category are those that happen when you turn
the headset on and it connects to the PC or when you call the
Headset.Connect() D-Bus method and the PC connects to the headset.

Johan

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2008-08-24 09:34:29

by Ludovico Cavedon

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Subject: Re: [Bluez-devel] Why always disconnect the headset?

Hi Johan,

Johan Hedberg wrote:
> On Jul 27, 2008, at 23:41, Ludovico Cavedon wrote:
>> I noticed that every time an application closes a SCO audio device, my
>> headset gets disconnected (HEADSET_STATE_DISCONNECTED). This means
>> that
>> when the application reopens the device, it requires some seconds to
>> get
>> the audio working.
>>
>> So, why is the headset disconnected and not just left in the state
>> HEADSET_STATE_CONNECTED? (i.e. the same stat that the headset enters
>> when I turn it on and pairs with my pc).
>
> You didn't mention which version of BlueZ you use, but in recent
> versions the logic is such that only implicitly created connections
> are automatically disconnected (after a 3 second timeout) but
> explicitly created connections stay up until you manually disconnect
> them. An implicitly created connection would be one caused by an ALSA
> application when it opens the audio device. Connections that fall into
> the explicitly created category are those that happen when you turn
> the headset on and it connects to the PC or when you call the
> Headset.Connect() D-Bus method and the PC connects to the headset.

Sorry I forgot: I am using 3.26 provided with Ubuntu hardy.
Good news, I'll update my bluez version!

Thank you for your answer,
Ludovico

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