meta-flutter

Yocto Layer for Google Flutter related projects.

Updates:

• Breaking Change

  Suffix for flutter runtime types has been changed to better define it. Less confusing.

  -runtimerelease (was -release) -runtimeprofile (was -profile) -runtimedebug (was -debug)

• 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" or not defined in local.conf, the engine commit used is master channel. Otherwise the engine.version file in flutter/flutter is used to set the engine commit.

• build failure due to gn unknown parameter for --no-build-embedder-examples. One solution to resolve this is to exclude disable-embedder-examples from PACKAGECONFIG in local.conf using:

  PACKAGECONFIG:pn-flutter-engine-runtimerelease = "disable-desktop-embeddings embedder-for-target fontconfig release"
  PACKAGECONFIG:pn-flutter-engine-runtimedebug = "disable-desktop-embeddings embedder-for-target fontconfig debug"
  PACKAGECONFIG:pn-flutter-engine-runtimeprofile = "disable-desktop-embeddings embedder-for-target fontconfig profile"
  

  This issue is related to missing gn options --build-embedder-examples and --no-build-embedder-examples from certain builds. I have disable-embedder-examples defined in PACKAGECONFIG by default, so if you have an engine commit that is missing this option, you need to use the PACKAGECONFIG sequence above. Once the gn option rolls into all channels this override will no longer be needed.

Recommended development flow:

• Create flutter workspace using ./tools/setup_flutter_workspace.py
• Debug and validate application on host using flutter-auto, AGL QEMU, or Linux GTK.
  • 1P Linux plugins should be avoided. They may work on a runtime=debug image, but will not work in an AOT (runtime=release) image.
• Create Yocto Recipe for your Flutter application using flutter-gallery-* or one of the many app recipes as the template. Nested projected are supported using FLUTTER_APPLICATION_PATH. Passing Dart defines are done with FLUTTER_EXTRA_BUILD_ARGS.
• Add your app, and selected embedder to your release image. The flutter engine will be implicitly added to the image.
• Image device

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.

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.

Notes

• There are no OSS Linux embedders (that I am aware of that currently support software rendering). The engine does support it.

• flutter-auto is the agl branch of https://github.com/toyota-connected/ivi-homescreen the main branch has moved to quarterly releases, the agl branch is directly supporting AGL development work.

CI Jobs

• kirkstone-agl-renesas-m3.yml - Renesas M3 build. Time boxed GPU driver (30 minutes?). AGL canaray build.

• kirkstone-agl-x86_64.yml - meta-flutter QEMU image used with tools/seup_flutter_workspace.py. Test build for AGL downstream work.

• kirkstone-imx8mmevk.yml - NXP imx8mmevk baseline Wayland image.

• kirkstone-linux-dummy.yml - Tests all recipes in the layer without a dummy Linux kernel (save build time).

• kirkstone-qc-dragonboard.yml - DB410C and DB820C Wayland images.

• kirkstone-rpi-zero2w-64.yml - RPI Zero2W Wayland image (flutter-auto). Farily full featured with Network Manager, BT, WiFi, etc.

• kirkstone-stm32mp15.yml - eglfs (flutter-pi) st-core-image+SDK and wayland (flutter-auto) st-core-image+SDK.

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

General

Targets flutter-engine-* is known to work on

• AGL QEMU images - aarch64/x86_64
• Intel icore7-64
• NVIDIA Nano, Xavier Dev Kits - aarch64
• NXP iMX7 (caveats), iMX8
• Qualcomm DragonBoard DB410c, DB820, SA6155P, SA8xxx - aarch64
• Raspberry Pi 3 / Compute - aarch64 / armv7hf
• Raspberry Pi 4 / Compute - aarch64
• Raspberry Pi ZeroW / Zero2W - aarch64
• Renesas R-Car M3/H3 - aarch64
• STM32MP157x - cortexa7t2hf
• etc

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

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"

Flutter Workspade Automation

Please visit here for how to setup Flutter workspace automatically.