meta-flutter

Yocto Layer for Google Flutter related projects.

Recommended development flow:

• Build Flutter application using desktop tools
• Use Flutter Engine Runtime=Debug build confirming it works on target. Debug as needed via flutter attach
• Create Yocto Recipe for Flutter application using flutter-gallery as template.
• 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 LC_ALL set. Check /usr/share/locale/ on your target for available locale, and set LC_ALL appropriately. Example: export LC_ALL=en_GB

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

• Toyota ivi-homescreen (Recommended embedder for Wayland)
• flutter-pi (DRM w/VSync - Recommended embedder for DRM)
• flutter-engine (channel selection, default is beta)
• flutter-sdk (channel selection, default is beta)
• flutter-gallery Application (interpreted and AOT - requires dev channel override)
• flutter-wayland (POC) / waylandpp/ipugxml (archived)
• Sony embedders

Notes

CI Jobs

• linux-dummy.yml - meta-flutter canary CI job builds all recipes against linux-dummy kernel (except x11 client)

• rpi-32 (DRM, flutter-pi, flutter-gallery, vulkan)

  RPI3 DRM - 32-bit RaspberryPi3 image - No X11/Wayland (Vulkan driver responds to Vulkan)

  RPI4 DRM - 32-bit RaspberryPi3 image - No X11/Wayland (Mesa Vulkan Driver functional)

• rpi-64 (DRM, flutter-pi, flutter-gallery, vulkan)

  RPI3 DRM - 32-bit RaspberryPi3 image - No X11/Wayland (Vulkan driver loaded and not functional)

  RPI4 DRM - 32-bit RaspberryPi3 image - No X11/Wayland (Mesa Vulkan Driver functional)

Notes: CI job sstate is cleared between builds for all meta-flutter recipes; clean builds.

CI jobs for common targets will be added. STM32MP157x is planned next.

General

Targets flutter-engine is known to work on

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

Note: 32-bit ARM builds currently require Flutter Channel = Master until commit makes it into dev->beta->stable.

Include the Flutter SDK into Yocto SDK

Add to local.conf file:

TOOLCHAIN_HOST_TASK:append = " nativesdk-flutter-sdk"

Then run:

bitbake <image name> -c populate_sdk

NVIDIA Xavier/Nano

local.conf changes

TARGET_GCC_VERSION = "8.3.0"
FLUTTER_CHANNEL = "master"
IMAGE_INSTALL_append = " flutter-drm-eglstream-backend"
IMAGE_INSTALL_append = " flutter-gallery"

OR

TARGET_GCC_VERSION = "8.3.0"
FLUTTER_CHANNEL = "master"
CORE_IMAGE_EXTRA_INSTALL += "\
    flutter-drm-eglstream-backend \
    flutter-gallery \
"

Build EGL image

bitbake demo-image-egl

Run Flutter application on target (defaults to AOT)

FLUTTER_DRM_DEVICE=/dev/dri/card0 flutter-drm-eglstream-backend -b /usr/share/flutter-gallery/sony

NXP i.MX 8QuadXPlus MEK

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/jwinarske/meta-flutter.git
popd
bitbake-layers add-layer ../sources/meta-clang ../sources/meta-flutter
echo -e 'TARGET_GCC_VERSION = "10.2.0"' >> conf/local.conf
echo -e 'FLUTTER_CHANNEL = "dev"' >> conf/local.conf
echo -e 'IMAGE_INSTALL_append = " flutter-wayland"' >> conf/local.conf
echo -e 'IMAGE_INSTALL_append = " flutter-gallery"' >> conf/local.conf
bitbake fsl-image-multimedia

Raspberry PI 3/4 (aarch64)

See rpi-32.yml/rpi-64.yml for example usage, or download build artifacts from this repo.

STM32MP157x Discovery Board

See Dunfell branch for CI job example.

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"