How to include Pulseaudio and dnsmasq in the kernel

Technical Support
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1

Setup:
Colibri iMX8QXP 2GB WB IT V1.0D
Iris carrier board V1.1B
Linux BSP 5.4

We are trying to provide wifi internet access and voice calls to clients in a noisy environment using the iMX8 as a wifi access point and the ethernet connected to a DHCP server coming from a modem. The modem can also provide voice calls, so we want to route the call to a bluetooth headset that uses noise cancelling using Pulseaudio and BlueZ. We have got a demo up and running with a Raspberry Pi 4 but that was easier as both Pulseaudio and dnsmasq are included in the kernel. Is there an image that has these 2 modules or is there steps to include them in the kernel so we can test on the iMX8?

Thanks.

2

Hi @robple11 , you can add dnsmasq according to this ticket. Pulseaudio is included in our multimedia image.

3

Hi ben,

I was able to compile the multimedia image and like you said in the other post to include dnsmasq just modify the local.conf, that worked great.
I installed my compiled kernel and dnsmasq is there and working but PulseAudio doesnt seem to be installed properly, all I can see is /etc/pulse/client.conf and a pulseaudio library file, there doesnt seem to be any binaries or daemons to run. On the Raspberry Pi 4 I could run the pulseaudio daemon and configure the sinks and sources from the command line to send/receive audio to/from a bluetooth headset.

4

Hi @robple11 , the multimedia image doesn’t come with a demo binary for PulseAudio. You may need to compile your PulseAudio application. How do you test on Pi4? For example, what is the command line?

5

It was all just on the command line:
To connect the bluetooth headset I used
“bluetoothctl connect macaddr”
macaddr=F5:42…etc

To list cards I used:
“pacmd list cards”

To set headset profile:
“pacmd set-card-profile 3 headset_head_unit”

To loopback speaker to mic:
“pactl load-module module-loopback sink=bluez_sink.macaddr.headset_head_unit source=bluez_source.macaddr.headset_head_unit”
macaddr= F4_45_56…etc of the bluetooth device

Then I plugged in a usb device providing speaker and mic and was able to cross that with the bluetooth headset using the pactl commands.

Thats as far as I wanted to go until I could reproduce something similar on the iMX8

6

Hi @robple11 , on multimedia bsp, you can use bluez-alsa instead of pulseaudio to make BT HFP work. The bluez-alsa recipe from Yocto Project needs to be replaced by this one. After the new image is built and installed, add bluealsa policy to /etc/dbus-1/system.d/bluetooth.conf on the device.

<busconfig>
...
  <policy user="bluealsa">
      <allow send_destination="org.bluez"/>
  </policy>
</busconfig>

Modify /lib/systemd/system/bluez-alsa.service and reboot.

 [Service]
 Type=simple
-ExecStart=/usr/bin/bluealsa
+ExecStart=/usr/bin/bluealsa -p hfp-ofono -p a2dp-sink -p a2dp-source

 [Install]
 WantedBy=multi-user.target

check if the bluetooth device is either hardware or software blocked:

# rfkill list
0: phy0: Wireless LAN
        Soft blocked: yes
        Hard blocked: no
1: hci0: Bluetooth
        Soft blocked: yes
        Hard blocked: no

If it is, unblock it.

# rfkill unblock 1
# rfkill list
0: phy0: Wireless LAN
        Soft blocked: yes
        Hard blocked: no
1: hci0: Bluetooth
        Soft blocked: no
        Hard blocked: no

Use bluetoothctl to discover and connect the Bluetooth device by its MAC address.

# bluetoothctl
[bluetooth]# power on
Changing power on succeeded
[bluetooth]# scan on
Discovery started
[CHG] Controller 00:E9:3A:D6:4F:30 Discovering: yes
[bluetooth]# devices
[NEW] Device F4:4E:FD:DE:4A:59 XMFHZ02
[bluetooth]# connect F4:4E:FD:DE:4A:59
Attempting to connect to F4:4E:FD:DE:4A:59
[CHG] Device F4:4E:FD:DE:4A:59 Connected: yes
[CHG] Device F4:4E:FD:DE:4A:59 UUIDs: 0000110b-0000-1000-8000-00805f9b34fb
[CHG] Device F4:4E:FD:DE:4A:59 UUIDs: 0000110c-0000-1000-8000-00805f9b34fb
[CHG] Device F4:4E:FD:DE:4A:59 UUIDs: 0000110e-0000-1000-8000-00805f9b34fb
[CHG] Device F4:4E:FD:DE:4A:59 UUIDs: 0000111e-0000-1000-8000-00805f9b34fb
[CHG] Device F4:4E:FD:DE:4A:59 ServicesResolved: yes
Request confirmation
[agent] Confirm passkey 220288 (yes/no): yes
[CHG] Device F4:4E:FD:DE:4A:59 Paired: yes
Connection successful
[XMFHZ02]# exit

Now you will find the audio device and play the sound file.

# bluealsa-aplay -L
bluealsa:SRV=org.bluealsa,DEV=F4:4E:FD:DE:4A:59,PROFILE=a2dp
    XMFHZ02, audio-card, playback
    A2DP (SBC): S16_LE 2 channels 48000 Hz
# aplay -D bluealsa:SRV=org.bluealsa,DEV=F4:4E:FD:DE:4A:59,PROFILE=a2dp ~/sound/Gong.

If you would like to loop devices, alsaloop is the tool. This is the example.

7

Thanks, I will check it out and let you know how I go!