Enable and evaluate Qualcomm Linux overlays

An overlay is a collection of loadable kernel modules and userspace libraries. Some overlays are loadable kernel modules only, whereas other overlays include both kernel modules and userspace libraries. Each overlay component has its own source tree or prebuilt tar that contains all required artifacts. Qualcomm Linux overlays are modular, value‑added components that integrate with upstream components. They consist of sources or prebuilt binaries for technologies, such as audio, camera, graphics, video, and sensors. Overlays are delivered as recipes in the meta-qcom BSP OpenEmbedded layer. Note The sensors overlay functionality is supported only on QCS5430 and QCS6490. Evaluate Qualcomm Linux overlays Use Qualcomm Linux overlays to choose between upstream and Qualcomm technology stacks. Qualcomm technology stacks are integrated as overlays in Qualcomm Linux to support additional features. You can leverage hardware capabilities on Qualcomm SoCs that upstream components may not support, and benefit from optimizations tailored for Qualcomm SoCs. Use these technology stacks to experiment with features and determine which overlays suit your product needs and use cases. You can evaluate overlays in one of the following ways:

• Flash qcom-multimedia-proprietary-image on the Qualcomm evaluation kits. This method is suitable if you want to evaluate the Qualcomm technology stacks as the default software stack enabled.
• Flash qcom-multimedia-image and install packages for Qualcomm technology stacks from the corresponding release on the device. This method is suitable if you want to do the following:

  • Start with an image where upstream components are default.
  • Evaluate the upstream software stack features on Qualcomm EVKs and then install the packages from the Qualcomm Linux package feed.

• Build from the meta-qcom source release. This method is suitable if you want to evaluate an image that uses a combination of Qualcomm technology stacks and upstream stacks. For example, Qualcomm graphics stack (Adreno), Qualcomm camera stack (CamX), and other components from the upstream stack.

The reference distribution layer for Qualcomm Linux, meta-qcom-distro, provides reference image recipes that show how a distribution layer integrates overlays. For example, qcom-multimedia-proprietary-image.bb includes the BSP recipes that build these overlays into the image, as listed in the following table: Table: Multimedia overlays and corresponding recipes

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Next steps

• Learn how modules are blacklisted to implement and load overlays at bootup
• Use overlay configurations to derive image recipes
• Evaluate overlays using supported workflows
• Uninstall overlay configurations and switch to upstream drivers