# Customize
This section provides details about audio customizations, software
configurations, interface customization, and custom module additions.
## Source code of audio modules
Source code for audio modules is available for custom application
development.
| Module | Source Code Location |
| --- | --- |
| [PulseAudio](https://docs.qualcomm.com/doc/80-70015-16/topic/software.html#pulseaudio-sw) | `build-qcom-wayland/workspace/sources/pulseaudio` |
| [PAL](https://docs.qualcomm.com/doc/80-70015-16/topic/apis_and_sample_apps.html#pal-sw) | `build-qcom-wayland/workspace/sources/qcom-pal/opensource/arpal-lx` |
| [TinyALSA](https://docs.qualcomm.com/doc/80-70015-16/topic/apis_and_sample_apps.html#tinyalsa-sw) | `build-qcom-wayland/workspace/sources/tinyalsa`
and
`build-qcom-wayland/workspace/sources/tinycompress` |
| [Audio Graph Manager (AGM)](https://docs.qualcomm.com/doc/80-70015-16/topic/software.html#agm-sw) | `build-qcom-wayland/workspace/sources/qcom-agm/opensource/agm` |
Note
Additional audio modules are available for developers who have full access to the proprietary software shipped with Qualcomm Linux. See
the [Qualcomm Linux Audio Guide - Addendum](https://docs.qualcomm.com/bundle/resource/topics/80-70015-16A/customize_addendum.html#source-code-of-audio-modules) for more information.
The following table shows the configuration files for different hardware
versions:
| Variant | Sound card name | Conf file | mixer\_paths.xml | ResourceManager.xml |
| --- | --- | --- | --- | --- |
| Core Kit (RB3) | qcm6490-rb3-snd-card | qcm6490-rb3-snd-card.conf | mixer\_paths\_qcm6490\_rb3.xml | resourcemanager\_qcm6490\_rb3.xml |
| Vision Kit | qcm6490-vision-snd-card | qcm6490-vision-snd-card.conf | mixer\_paths\_qcm6490\_vision.xml | resourcemanager\_qcm6490\_vision.xml |
| Video Collab Kit | qcm6490-vc-snd-card | qcm6490-vc-snd-card.conf | mixer\_paths\_qcm6490\_vc.xml | resourcemanager\_qcm6490\_vc.xml |
## Sync and compile audio components
The audio software involves the user space and kernel space modules,
which are available in the Linux-enabled audio software directory.
The audio user space and kernel module source trees are extracted to the
<workspace>/build-qcom-wayland/workspace/sources path. Instructions for
using [devtool Linux
utility](https://docs.qualcomm.com/bundle/publicresource/topics/80-70015-27/user_customizations.html#use_of_devtool)
to fetch and extract the audio module source code and build the user
space and kernel mode modules are described below.
Note
Go to the workspace (`/build-qcom-wayland$`) to access the source code trees using devtool.
### PulseAudio
1. Run the following command to extract the source tree:
devtool modify pulseaudio
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The PulseAudio source tree is extracted to
`build-qcom-wayland/workspace/sources/pulseaudio`.
2. Run the following command to build the source tree:
devtool build pulseaudio
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### PAL
1. Run the following command to extract the source tree:
devtool modify pal
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The pal source tree is extracted to
`build-qcom-wayland/workspace/sources/qcom-pal/opensource/arpal-lx`.
2. Run the following command to build the source tree:
devtool build pal
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### TinyALSA
1. Run the following command to extract the source tree:
devtool modify tinyalsa
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The TinyALSA source tree is extracted to
`build-qcom-wayland/workspace/sources/tinyalsa`.
2. Run the following command to build the source tree:
devtool build tinyalsa
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## PAL configuration
Audio use cases can be configured at the PAL level using the
mixer\_paths, resourcemanager, and usecasekvmanager XML files.
### mixer\_paths XML
Mixer control is a control variable exposed from the ALSA mixer to the
user space. It allows the user space to access set and get functions and
pass parameters to the ALSA mixer.
For example, the following is the entry for enabling the mono speaker
device in the `mixer_path.xml`. Whenever playback is triggered and the
device selected is speaker, the following mixer controls will be fired
with the help of the audio route helper class.
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The name of the mixer path used by the platform will generally be
`mixer_paths_.xml` and can be found at `/etc/` directory
on the target.
### Resourcemanager XML
This XML file includes all possible devices, use cases, and
combinations. It also includes the various configurations, module
parameters, and global parameters.
The following is an example for the entry of a speaker device in the
resource manager XML file. It will have all the configurations for the
speaker device such as back-end name, channels, sample-rate, bit-width,
etc.
PAL_DEVICE_OUT_SPEAKER
CODEC_DMA-LPAIF_WSA-RX-0
2
2
48000
16
speaker
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### Usecasekvmanager XML
This XML file contains the GKV details for each use case. PAL uses this
XML file to retrieve the KV configuration for each use case and
subsequently use that configuration to retrieve graph information from
the ACDB files. This file is located at the `/etc` path on the device.
The following is an example of one stream and device graph key vector
configuration.
**Stream KV**
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**Device KV**
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**DevicePP KV**
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## MI2S/TDM interfaces
MI2s and TDM interfaces allow devices to connect and transfer audio data.
### MI2S
MI2S is a serial bus interface used to connect multiple digital audio
devices. It is a simple data interface without any form of address or
device selection.
MI2S consists of only one bus master, one transmitter, and one receiver.
The transmitter or receiver can be a bus master. The MI2S bus carries
two or more audio channels on the data lines. Each data line carries
two-channel data, the left and right channels, which are used to carry
stereo audio data streams. The data alternates between the left and
right channels, as controlled by a word select (WS) signal driven by the
bus master.
### TDM
The TDM interface is the most common mechanism used to transfer multiple
channels of audio data between devices within a system. The TDM
interface consists of two control clocks: a frame synchronization pulse
(FSYNC) and a serial clock (SCLK), also known as the bit clock (BCLK).
Additionally, it includes two or more serial audio data lines (SDATA or
SD).
Additional details about MI2S/TDM configurations are available for
developers who have full access to the proprietary software shipped with
Qualcomm Linux. See the [Qualcomm Linux Audio Guide –
Addendum](https://docs.qualcomm.com/bundle/resource/topics/80-70015-16A/customize_addendum.html#configuration)
for more information.
Last Published: Oct 15, 2024
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