meta-flutter

Yocto Layer for Google Flutter related projects.

Updates:

• FLUTTER_CHANNEL support has been deprecated.
• FLUTTER_SDK_TAG - New approach. Allows locking SDK and Engine to specific commit hash. Valid values for FLUTTER_SDK_TAG are here: https://github.com/flutter/flutter/tags
• Flutter Engine Commit If FLUTTER_SDK_TAG is set to "AUTOINC", the engine commit used is master channel. Otherwise the engine.version file in flutter/flutter is used to set the engine commit.

Recommended development flow:

• Build Flutter application using desktop tools
• Use Flutter Engine Runtime=Debug build confirming it works on target. Debug as needed using customdevices
• Create Yocto Recipe for your Flutter application using flutter-gallery-* as the template. Nested projected are supported using FLUTTER_APPLICATION_PATH. Passing Dart defines are done with FLUTTER_EXTRA_BUILD_ARGS.
• Add flutter-gallery, selected embedder, flutter-engine runtime=Release to your release image.
• Image device

Note: If you get a gray screen running the Gallery app, chances are you don't have a locale set. Ensure your platform has a valid locale set. See GLIBC_GENERATE_LOCALES and IMAGE_LINGUAS in one of the NVidia CI projects on how to do this.

Note: In theory Swift Shader (CPU render) engine builds should work with the right build flags. Be warned it won't work out of the box. Select a SoC with a GPU that supports OpenGL 3.0+ and save yourself the Engineering NRE.

Layers dependencies

• meta-clang

Clang generates smaller runtime images, and is used by Google to build the the flutter engine for Android and iOS. Changing toolchains should be avoided, as this would provide a path with little to no test milage. If you are trying to port the flutter-engine to QNX 7.0 feel free to contact me.

Overview

Target BSP is expected to have a GPU with OpenGLES v2.0+ support.
If you selecting a part go with v3.0+, ideally one with Vulkan support.

This layer includes recipes to build

• flutter-sdk (channel selection, default is master if FLUTTER_SDK_TAG is not set)
• flutter-engine (tracks engine.version from FLUTTER_SDK_TAG)
• flutter-gallery Application (debug, profile, and release) requires master
• ivi-homescreen (Toyota/AGL - Wayland Embedder)
• flutter-pi (DRM w/VSync - Recommended embedder for DRM)
• flutter-wayland (POC) / waylandpp/ipugxml (archived)
• Sony embedders

Notes

CI Jobs

• dunfell-agl-aarch64.yml - AGL emaultor build that uses non-locked values. This is used as health gate for rolling commits in AGL. No Vulkan support.

• dunfell-agl-x86_64.yml - AGL emaultor build that uses non-locked values. This is used as health gate for rolling commits in AGL. No Vulkan support.

• dunfell-dart-mx8m-mini.yml - Variscite DART-MX8M-MINI (NXP iMX8) Weston build + ivi-homescreen. No Vulkan support.

• dunfell-linux-dummy.yml - meta-flutter canary CI job builds all recipes against linux-dummy kernel

• dunfell-nvidia-jetson-nano-devkit.yml - NVidia Jetson Nano Devkit weston build with ivi-homescreen and Vulkan suport.

• dunfell-nvidia-jetson-xavier-nx-devkit.yml - NVidia Jetson Xavier NX Devkit weston build with ivi-homescreen and Vulkan suport.

• dunfell-rpi4-64.yml - Raspberry PI4 EGL/DRM build with Flutter-pi and Vulkan (Mesa 21.2) support.

• dunfell-stm32mp15.yml - ST Microelectronics STM32MP15 EGL and Weston builds. EGL build has flutter-pi (currently has rendering issues), and Weston build has ivi-homescreen which works beautifully.

For more Raspberry PI images see the Honister branch.

General

Targets flutter-engine-* is known to work on

• AGL QEMU images - aarch64/x86_64 (CI job)
• DragonBoard 410c - aarch64
• Intel MinnowBoard Max (BayTrail) - intel-icore7-64
• NVIDIA Nano Dev Kit - aarch64 (CI job)
• NVIDIA Xavier NX Dev Kit - aarch64 (CI job)
• Raspberry Pi 3 / Compute - aarch64 / armv7hf (CI job)
• Raspberry Pi 4 / Compute - aarch64 (CI job)
• Renesas R-Car m3ulcb - aarch64
• STM32MP157x - cortexa7t2hf (CI job)
• etc, etc

Note: 32-bit ARM builds were broken for a period, so if you have build issues only with 32-bit try moving to a newer tag.

Include the Flutter SDK into Yocto SDK

Add to local.conf file:

TOOLCHAIN_HOST_TASK_append = " flutter-sdk-nativesdk"

Then run:

bitbake <image name> -c populate_sdk

STM32MP157x Discovery Board

See dunfell-stm32mp15.yml (CI job) for more detail

See Wiki for flashing image and using customdevice: https://github.com/meta-flutter/meta-flutter/wiki/STM32MP1-Disco-Notes

NXP i.MX 8QuadXPlus MEK Example

repo init -u https://source.codeaurora.org/external/imx/imx-manifest -b imx-linux-gatesgarth -m imx-5.10.9-1.0.0.xml
repo sync -j20
DISTRO=fslc-wayland MACHINE=imx8qxpmek source setup-environment build
pushd ../sources
git clone -b dunfell https://github.com/meta-flutter/meta-flutter.git
popd
echo -e 'FLUTTER_SDK_TAG = "2.10.0-0.2.pre"' >> conf/local.conf
echo -e 'IMAGE_INSTALL_append = " flutter-engine-debug ivi-homescreen-debug flutter-gallery-debug"' >> conf/local.conf
bitbake-layers add-layer ../sources/meta-clang ../sources/meta-flutter
bitbake fsl-image-multimedia

Raspberry PI 3/Zero (aarch64)

See honister branch README.md and CI jobs for more detail

General Yocto Notes

When building on systems with GCC version > than uninative in Yocto distro add the following to conf/local.conf

INHERIT_remove = "uninative"