Yocto 3.1 Build Procedure for rdk-generic-mediaclient-image - 2020 - M5

Introduction

This manual describes the rdk-generic-mediaclient-image build procedure for Yocto 3.1 builds. This will upgrade the default build system used in RDK Video, from morty(2.2) to dunfell(3.1). In addition to upgrades to opensource packages, Yocto 3.1 also contain Long term Support release feature. The current version lacks the variety of features available in the dunfell. The upgraded build tools will be used to generate rdk-generic-mc-image for Raspberrypi reference platform. 

Yocto 3.1 Upgradation support the following:

• Yocto BSP layer for meta-raspberrypi.
• OpenEmbedded and Yocto Dunfell.
• Linux kernel 4.19.
• Version upgrades for bitbake, gstreamer and other oe/wpe recipes.
• Playing a given stream using gst-launch command.
• rmfApp Support.
• Controlling apps using appmanager.

Each component in RDK is a standalone repository with its own individual build tools producing a library or set of binaries. When we upgrade the OE layers to the newer versions, we need to make necessary changes in the RDK layers which use these components, to avoid build failures.

Host Setup

The OpenEmbedded build system should be able to run on Ubuntu 18.04 distribution/other compatible linux distribution with the following versions for Git, tar, and Python.

• Git 1.8.3.1 or greater
• tar 1.27 or greater
• Python 3.4.0 or greater
• Coreutils(E.g realpath)

Note: You should also have about 50 Gbytes of free disk space for building images.

The essential packages you need for a supported Ubuntu or Debian distribution are shown in the following command:

$ sudo apt-get install gawk wget git-core diffstat unzip texinfo gcc-multilib \
  build-essential chrpath socat cpio python python3 python3-pip python3-pexpect \
  xz-utils debianutils iputils-ping python3-git python3-jinja2 libegl1-mesa libsdl1.2-dev \
  pylint3 xterm bmap-tools

Repo Setup

In order to use Yocto build system, the repo tool must be properly installed on the machine.

To install Repo make sure you have a /bin directory in your home directory and that it is included in your path

$ mkdir ~/bin
$ PATH=~/bin:$PATH
Download the repo tool and ensure that it is executable
$ curl http://commondatastorage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
$ chmod a+x ~/bin/repo

Note: it is also recommended to put credentials in ~/.netrc when interacting with repo.

A sample ~/.netrc file is illustrated below

machine code.rdkcentral.com
login YOUR_USERNAME
password YOUR_PASSWORD

Executing System

To tackle the build issues from moving one version to another, we have decided to split the problem into different subtasks. So instead of building a complete image at one go, we have planned for the generation of following images:

• core-minimal-image for Raspberrypi
• wpe-westeros-image
• rdk-generic-image for hybrid and mediaclient
• rdk-generic-wpe-image for hybrid and mediaclient

These images need to be tested against different configurations in cmf, to ensure that nothing has broken the existing system.

In order to provide a smooth transition without disturbing the existing branch, we have created a branch called `yocto-dunfell-upgrade` for non-OE layers and another branch called `rdk/yocto-dunfell-upgrade` for OE layers.

Right now we are in the process of resolving build/parse errors. The main source for errors can be classified into 4 categories.

--> Incompatible license with RDK.
--> Trying to apply older patches into newer version of recipes.
--> Recipe version changes due to dependency.
--> If there is a license upgrade to a new recipe which is not compatible with RDK terms then we need to stick to the older version.

Going forward no more RDK specific BSP layer(meta-cmf-raspberrypi for instance) will be available and RDK specific changes will be brought under dynamic layer in SoC/OEM layer. Hence the important recipes and append files will be kept in the SoC/OEM layer in future.

Some of the build errors and its root cause is described in the below table. We will keep updating the table as we encounter more errors.

error: 'strncpy' output truncated before terminating nul 
copying 23 bytes from a string of the same length.

Currently, all the changes are being pushed in these branches. Once it is merged, you will be able to follow the build instructions without any error.

Yocto Build Steps

To build, follow below instructions

$ mkdir <workspace dir>
$ cd <workspace dir>
$ repo init -u https://code.rdkcentral.com/r/manifests -b yocto-dunfell-upgrade -m rdkv-asp-nosrc.xml
$ repo sync -j4 --no-clone-bundle
$ MACHINE=rpi3-rdk-mc source meta-cmf/setup-environment
$ bitbake rdk-generic-mediaclient-image

Flashing Procedure

Following command can be used to flash the RPI image to sd card using linux machine . bmap tool should be available in linux

bzip2 -d <path to ImageName.wic.bz2>
sudo -E bmaptool copy --nobmap <path to ImageName.wic> <path to SD card space>

Example:

$ bzip2 -d rdk-generic-mediaclient-image-raspberrypi-rdk-mc.wic.bz2
$ sudo -E bmaptool copy --nobmap rdk-generic-mediaclient-image-raspberrypi-rdk-mc.wic /dev/sdc

Known Issues and Limitations

1. Certain services like dsmgr.service and netsrvmgr.service are crashing and as a result of this sysint is triggering a reboot. To avoid this issue we need to disable the above-mentioned services after a remote login using systemctl command.
2. Audio is not working with gst-launch command
3. rmfApp prompt is not getting displayed after playing video using launch/play command. So we need to hard close the video using Ctrl + C combination.
4. appmanager application is exiting automatically even if it is running in background.
5. pxscene browser is not launching.