gta02, debian, fso: pairing (and using) bleutooth headset?

Al Johnson openmoko at
Sat Sep 6 19:04:36 CEST 2008

On Friday 05 September 2008, Jim Morris wrote:
> Angus Ainslie wrote:
> > OK reproduced a few times now.
> >
> > Some times the bluetooth/alsa/dbus gets into a state where this will not
> > work so you should reboot to start everything fresh.
> >
> > I've created a new state file that prodices NOISY audio , I will be
> > looking into the source of noisy and getting the mic path properly setup
> > as well.
> >
> >
> >
> > Pair the headset ( only needs doing once )
> >
> > run
> >
> > ./ <bluetooth address>
> >
> > You should hear static in the headset at this point. If not try
> > rerunning If you still don't have static reboot.
> >
> > start the phone call. Once connected
> >
> > alsactl restore 0 -f gsm_headset.txt
> > ./bluetooth_pcm
> Good work, The step you did that I did not even think of was running the
> bluetooth_pcm.c file. To be honest I don't really see why/how this should
> even work. But as it is the only step that was different from what I did I
> suppose it must be the missing link.

It looks like it's configuring the Wolfson voice PCM interface to use the data 
format the Bluetooth chip is using, and opening the interfaces for read/write 
so that it's expecting the data to flow. It just seems like an odd thing to 
do because we're used to the CPU being the source/sink for the PCM data, not 
a separate device as it is in this case.

> Do you know if the audio is being routed directly from GSM to BT or through
> the CPU via PCM then into the BT via the USB interface?

It should be GSM<->Wolfson<->BT without the CPU playing a part other than to 
set it up. I'm having trouble working out how anything gets to the GSM mic 
input though, as all of the 'Mono Mixer (whatever) Playback Switch'es  
(Controls 74 through 78) are set to false. GSM playback goes via the ALC 
mixer to the left ADC.

> Thanks for working on this, I had given up!

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