Revision as of 21:15, 6 April 2010

Testing GSM <-> BT

Basics: We need to tell audio codec to route sound from GSM chip to BT chip. Codec is controlled by ALSA and mixer settings.

Prerequisites: BT device must be paired before the operation.

Step one: powering on bluetooth, setting up bluetoothd, pairing

Set /etc/bluetooth/audio.conf like this:

# SCO routing. Either PCM or HCI (in which case audio is routed to/from ALSA)   
# Defaults to HCI                                                               
SCORouting=PCM                                                                  

Then

echo 1 > /sys/bus/platform/devices/neo1973-pm-bt.0/power_on
hciconfig hci0 up
bluetoothd

then use simple-agent from here: http://wiki.openmoko.org/wiki/Manually_using_Bluetooth#Pair to pair the device.

Test: "hcitool con" should say:

Connection
     ACL 00:13:17:78:7B:A3 handle 0 state 5 lm MASTER

Step two: make a call

Call to the phone and answer (or place a call, whichever is cheaper).

Step three: load ALSA settings to switch codec "mode" to GSM <=> BT

Wait till frameworkd sets its statefile and then overwrite it with your own:

alsactl restore < /path/to/the/statefile

(Find working statefile first)

Then due to kernel bug, do:

amixer sset "Capture Left Mixer" "Analogue Mix Right"
amixer sset "Capture Left Mixer" "Analogue Mix Left"

Then issue dbus call (check what it is exactly) this starts exchanging audio between GSM and BT (hopefully):

org.bluez.Headset Play()

We would also need to set bluetooth IIS to 8000 rate:

import alsaaudio

pcm_play = alsaaudio.PCM( alsaaudio.PCM_PLAYBACK, alsaaudio.PCM_NONBLOCK, "hw:0,1" )
pcm_play.setchannels(1)
pcm_play.setrate(8000)
pcm_play.setformat(alsaaudio.PCM_FORMAT_S16_LE)
pcm_play.setperiodsize(500000)

pcm_cap = alsaaudio.PCM( alsaaudio.PCM_CAPTURE, alsaaudio.PCM_NONBLOCK, "hw:0,1" )
pcm_cap.setchannels(1)
pcm_cap.setrate(8000)
pcm_cap.setformat(alsaaudio.PCM_FORMAT_S16_LE)
pcm_cap.setperiodsize(500000)

We should hear something in the BT headset and not in phone's speaker.