Changes in OpenEmbedded layers
Qualcomm Linux uses OpenEmbedded layers to deliver technology components and reference distributions. The following table lists the changes in the OpenEmbedded layers between Qualcomm Linux 1.0 and Qualcomm Linux 2.0: Table: Changes in OpenEmbedded layers
The following table lists the changes made to the Qualcomm-authored OpenEmbedded layers, which are a part of Qualcomm Linux 2.0:
Table: Changes in Qualcomm-authored OpenEmbedded layers
Changes in Qualcomm Linux 2.0 build system
Consider the following key differences between the traditional Qualcomm Linux 1.0 repo-manifest Yocto build workflow and the Qualcomm Linux 2.0 Configuration Automation System (KAS)-based workflow.KAS overview
Qualcomm Linux supports KAS-based build execution. KAS is an open-source tool for BitBake-based projects. It simplifies the process of configuring and launching OpenEmbedded builds using a YAML configuration file. KAS automates the following, making it suitable for both developers and continuous integration/continuous deployment (CI/CD) usage:- Cloning and checking out of necessary layer Git repositories> - Generating the required BitBake configuration files, such as
local.confandbblayers.conf, based on the YAML input - Reducing the number of steps required to set up a workspace by executing the standard BitBake process. For example,
kas build <config.yml>does the following:- Clones the layer repositories
- Sets up the environment
- Starts the BitBake
<image>
- Providing a wrapper kas-container, which can run the build process in Docker
The following table compares the workflows at a high-level between the Repo tool and KAS:
Table: High-level workflow comparison: Repo tool vs. KAS
Sample KAS configuration file
The following example illustrates sample KAS configuration files found inmeta-qcom and explains how each section maps to the repo-manifest workflow concepts and how KAS interprets them. For more information about the configuration file format, see KAS documentation.
base.yml
Thebase.yml file documents the base configuration used by all build combinations.
machine.yml
Themachine.yml file documents machine-specific configuration. This file generally extends the base.yml configuration.
distro.yml
Thedistro.yml file documents distribution-specific configuration and the targets to be built.
Run builds using KAS-based build system
When using KAS, clone the repository containing the KAS YAML files and then build using one of the following methods:- Run the KAS build command
- Start a KAS shell and then run BitBake
qcom-multimedia-image, run the following command from the KAS shell that appears after the preceding output:
meta-qcom/ci/rb3gen2-core-kit.ymlmeta-qcom/ci/qcm6490.ymlmeta-qcom/ci/base.yml
meta-qcom/ci/qcom-distro.ymlmeta-qcom/blob/master/ci/qcom-distro-multimedia-image.yml
Set up CI with KAS using a sample repository
To set up CI with KAS, use the following sample repo: https://github.com/qualcomm-linux/meta-vendor-example Note To set up your Yocto Project build environment, see Yocto Project Reference Manual. To run a KAS-based build, do the following:- To install the KAS tool, run the following command:
- To clone the
meta-vendor-examplelayer, run the following command: - To build using the KAS configuration for one of the supported boards, run the following command:
Qualcomm Linux 2.0 repo-manifest workflow
A repo-manifest-based workflow is provided for Qualcomm Linux 2.0. The high-level changes in Qualcomm Linux 2.0 are as follows:- A repo is used for syncing meta layers from a manifest.
- The setup environment is used for generating the BitBake configuration. In Qualcomm Linux 2.0, the BitBake configuration is generated based on the
machine.ymlanddistro.ymlconfiguration files. Hence, the setup environment takes these configuration files as input. - BitBake is manually invoked for building images.
Build steps comparison
The following table lists the key differences in build steps between Qualcomm Linux 1.0 and Qualcomm Linux 2.0: Table: Build steps comparisonChanges in overrides
Qualcomm Linux 1.0 supports theqcom-base-bsp and qcom-custom-bsp overrides. It uses these overrides to do the following:
- Use separate kernel trees for
qcom-base-bspandqcom-custom-bsp - Include different sets of recipe packages in the
rootfsimage - Include different sets of device tree binaries in
DTB.bin
For Qualcomm Linux 2.0, overrides aren’t used for the following reasons:
- Same kernel tree and kernel binary is used when
qcom-multimedia-imageandqcom-multimedia-proprietary-imageare built. - Same device tree binary and device tree binary overlay are packed in the flattened image tree (FIT) image generated when
qcom-multimedia-imageandqcom-multimedia-proprietary-imageare built. Note
If you’re using theqcom-base-bspandqcom-custom-bspoverrides, discontinue using them in Qualcomm Linux 2.0. To migrate changes that use overrides in Qualcomm Linux 1.0, modify the implementation to use overrides, based on the following examples: Table: Overrides migration examples
Changes in machine configuration
The following table lists the changes in the machine configuration names between Qualcomm Linux 1.0 and Qualcomm Linux 2.0: Table: Machine configuration updatesChanges in BitBake variables
The following table lists the BitBake variables used in the machine configuration for Qualcomm Linux 1.0 and Qualcomm Linux 2.0:Changes in Linux recipes
Qualcomm Linux 2.0 supports a single kernel recipe and its corresponding real-time variant. The following table lists the Linux kernel recipe changes between Qualcomm Linux 1.0 and Qualcomm Linux 2.0: Table: Linux kernel recipe changes
Note
For Qualcomm Linux 2.0, only a single kernel tree is fetched from qcom-next. This kernel tree is built for both the images:
qcom-multimedia-imageprovides arootfswith the upstream stack.qcom-multimedia-proprietary-imageprovides arootfswith the Qualcomm-maintained components.
Changes in image recipes
Themeta-qcom-distro layer supports all the image recipes used in Qualcomm Linux. Qualcomm Linux 2.0 introduces changes to how the image recipes are managed and organized, and no longer uses BitBake overrides in image recipes.
The following table lists the image recipes defined in the meta-qcom-distro open-embedded layer. The naming convention of these image recipes and their evolution from Qualcomm Linux 1.0 has changed. For example:
- The image recipes no longer use
DISTROOVERRIDESto distinguish between package inclusion in the image. qcom-multimedia-proprietary-imageadds Qualcomm software components.
Changes in reference distro configurations
Qualcomm Linux 2.0 introduces changes in reference distro configurations. In Qualcomm Linux 1.0, the reference distros forqcom-wayland are in the distro folder.
The following table lists the reference distros in Qualcomm Linux 2.0:
Table: Qualcomm Linux 2.0 reference distros

