Maintaining Yocto Project Documentation

For many years, Bootlin has been a strong user and a contributor to the Yocto Project, delivering numerous customized embedded Linux distributions and Board Support Packages based on Yocto Project and OpenEmbedded to its customers, for a wide range of hardware platforms and architectures.

In 2021, we have been able to bring this engagement further, as Bootlin engineer Michael Opdenacker has been given the opportunity to work as a maintainer for Yocto Project’s documentation, thanks to funding from the Linux Foundation. Since the mourning of Scott Rifenbark, the former maintainer, in early 2020, the project was in need for someone to fill this role.

Yocto Project developers and contributors did their best in the meantime though, in particular by migrating the documentation sources from the DocBook format to reStructuredText, to generate documentation using Sphinx. This migration was also done by the Linux kernel community, as reStructuredText seems to make it easier for developers to contribute to documentation.

For Michael Opdenacker, the interest of getting back to Yocto Project and OpenEmbedded was strong: he was one of the early users, over 15 years ago, of BitBake and OpenEmbedded. Many things have changed since Michael was generating his own OPIE and GPE Palmtop Environment images for handheld devices back in 2004 and 2005.

Indeed, since that time, under the Yocto Project umbrella, BitBake and OpenEmbedded have formed what’s probably the smartest, most versatile and most powerful embedded Linux build system. This build system takes a pretty steep learning curve though, and that’s why maintaining high quality documentation was a key focus from the start.

In addition to acting as a maintainer (reviewing and merging patches from contributors, encouraging contributions, managing documentation bugs, keeping the documentation current with the evolution of the code), we have so far also managed to:

  • Create brand new documentation, thanks to studying the source code and to knowledge from core developers. In particular, we documented vulnerability (CVE) management and drafted a first description of Hash Equivalence.
  • Implement a new infrastructure to generate diagrams from SVG sources. Currently, most graphics are bitmaps and do not render well in PDF and EPUB output. The next step is to migrate all diagrams to SVG.
  • Implement styling improvements, trying to eliminate unnecessarily complex sentences and make the documents easier to read.
  • Propose a “Documentation standards” document in markdown format, together with a diagram template with reusable shapes, text boxes and clipart, so that new documentation and diagrams are created in a way that’s consistent with existing documents.
  • Find bugs and improvement opportunities, and implement some of them, thanks to testing the software and reading the code.

Here are our contributions to the project so far, as of Oct. 20, 2021:

Yocto Project is a very welcoming open-source project, in which core developers are keen to help users and contributors. This makes it a real pleasure to participate to this project, in addition to the satisfaction to contribute to the progress of Embedded Linux.

If you are interested in studying Yocto Project and Bitbake’s documentation and contributing to it, you will be most welcome! The best is to get in touch with our community through the docs mailing list or chat with us on IRC. See our mailing lists and chat page for details.

If you’re interested in using Yocto Project for your embedded Linux projects, we also recommend you to check out our Yocto Project and OpenEmbedded system development training course, and its freely available training materials. We recently announced new dates for our upcoming online training classes on the Yocto Project:

Videos and slides from Bootlin talks at Embedded Linux Conference Europe 2020

The Embedded Linux Conference Europe took place online last week. While we definitely missed the experience of an in-person event, we strongly participated to this conference with no less than 7 talks on various topics showing Bootlin expertise in different fields: Linux kernel development in networking, multimedia and storage, but also build systems and tooling. We’re happy to be publishing now the slides and videos of our talks.

From the camera sensor to the user: the journey of a video frame, Maxime Chevallier

Download the slides: PDF, source.

OpenEmbedded and Yocto Project best practices, Alexandre Belloni

Download the slides: PDF, source.

Supporting hardware-accelerated video encoding with mainline Linux, Paul Kocialkowski

Download the slides: PDF, source.

Building embedded Debian/Ubuntu systems with ELBE, Köry Maincent

Download the slides: PDF, source.

Understand ECC support for NAND flash devices in Linux, Miquèl Raynal

Download the slides: PDF, source.

Using Visual Studio Code for Embedded Linux Development, Michael Opdenacker

Download the slides: PDF, source.

Precision Time Protocol (PTP) and packet timestamping in Linux, Antoine Ténart

Download the slides: PDF, source.

Covid-19: Bootlin proposes online sessions for all its courses

Tux working on embedded Linux on a couchLike most of us, due to the Covid-19 epidemic, you may be forced to work from home. To take advantage from this time confined at home, we are now proposing all our training courses as online seminars. You can then benefit from the contents and quality of Bootlin training sessions, without leaving the comfort and safety of your home. During our online seminars, our instructors will alternate between presentations and practical demonstrations, executing the instructions of our practical labs.

At any time, participants will be able to ask questions.

We can propose such remote training both through public online sessions, open to individual registration, as well as dedicated online sessions, for participants from the same company.

Public online sessions

We’re trying to propose time slots that should be manageable from Europe, Middle East, Africa and at least for the East Coast of North America. All such sessions will be taught in English. As usual with all our sessions, all our training materials (lectures and lab instructions) are freely available from the pages describing our courses.

Our Embedded Linux and Linux kernel courses are delivered over 7 half days of 4 hours each, while our Yocto Project, Buildroot and Linux Graphics courses are delivered over 4 half days. For our embedded Linux and Yocto Project courses, we propose an additional date in case some extra time is needed to complete the agenda.

Here are all the available sessions. If the situation lasts longer, we will create new sessions as needed:

Type Dates Time Duration Expected trainer Cost and registration
Embedded Linux (agenda) Sep. 28, 29, 30, Oct. 1, 2, 5, 6 2020. 17:00 – 21:00 (Paris), 8:00 – 12:00 (San Francisco) 28 h Michael Opdenacker 829 EUR + VAT* (register)
Embedded Linux (agenda) Nov. 2, 3, 4, 5, 6, 9, 10, 12, 2020. 14:00 – 18:00 (Paris), 8:00 – 12:00 (New York) 28 h Michael Opdenacker 829 EUR + VAT* (register)
Linux kernel (agenda) Nov. 16, 17, 18, 19, 23, 24, 25, 26 14:00 – 18:00 (Paris time) 28 h Alexandre Belloni 829 EUR + VAT* (register)
Yocto Project (agenda) Nov. 30, Dec. 1, 2, 3, 4, 2020 14:00 – 18:00 (Paris time) 16 h Maxime Chevallier 519 EUR + VAT* (register)
Buildroot (agenda) Dec. 7, 8, 9, 10, and 11, 2020 14:00 – 18:00 (Paris time) 16 h Thomas Petazzoni 519 EUR + VAT* (register)
Linux Graphics (agenda) Dec. 1, 2, 3, 4, 2020 14:00 – 18:00 (Paris time) 16 h Paul Kocialkowski 519 EUR + VAT* (register

* VAT: applies to businesses in France and to individuals from all countries. Businesses in the European Union won’t be charged VAT only if they provide valid company information and VAT number to Evenbrite at registration time. For businesses in other countries, we should be able to grant them a VAT refund, provided they send us a proof of company incorporation before the end of the session.

Each public session will be confirmed once there are at least 6 participants. If the minimum number of participants is not reached, Bootlin will propose new dates or a full refund (including Eventbrite fees) if no new date works for the participant.

We guarantee that the maximum number of participants will be 12.

Dedicated online sessions

If you have enough people to train, such dedicated sessions can be a worthy alternative to public ones:

  • Flexible dates and daily durations, corresponding to the availability of your teams.
  • Confidentiality: freedom to ask questions that are related to your company’s projects and plans.
  • If time left, possibility to have knowledge sharing time with the instructor, that could go beyond the scope of the training course.
  • Language: possibility to have a session in French instead of in English.

Online seminar details

Each session will be given through Jitsi Meet, a Free Software solution that we are trying to promote. As a backup solution, we will also be able to Google Hangouts Meet. Each participant should have her or his own connection and computer (with webcam and microphone) and if possible headsets, to avoid echo issues between audio input and output. This is probably the best solution to allow each participant to ask questions and write comments in the chat window. We also support people connecting from the same conference room with suitable equipment.

Each participant is asked to connect 15 minutes before the session starts, to make sure her or his setup works (instructions will be sent before the event).

How to register

For online public sessions, use the EventBrite links in the above list of sessions to register one or several individuals.

To register an entire group (for dedicated sessions), please contact training@bootlin.com and tell us the type of session you are interested in. We will then send you a registration form to collect all the details we need to send you a quote.

You can also ask all your questions by calling +33 484 258 097.

Questions and answers

Q : Should I order hardware in advance, our hardware included in the training cost?
R : No, practical labs are replaced by technical demonstrations, so you will be able to follow the course without any hardware. However, you can still order the hardware by checking the “Shopping list” pages of presentation materials for each session. This way, between each session, you will be able to replay by yourself the labs demonstrated by your trainer, ask all your questions, and get help between sessions through our dedicated Matrix channel to reach your goals.

Q: Why just demos instead of practicing with real hardware?
A: We are not ready to support a sufficient number of participants doing practical labs remotely with real hardware. This is more complicated and time consuming than in real life. Hence, what we we’re proposing is to replace practical labs with practical demonstrations shown by the instructor. The instructor will go through the normal practical labs with the standard hardware that we’re using.

Q: Would it be possible to run practical labs on the QEMU emulator?
R: Yes, it’s coming. In the embedded Linux course, we are already offering instructions to run most practical labs on QEMU between the sessions, before the practical demos performed by the trainer. We should also be able to propose such instructions for our Yocto Project and Buildroot training courses in the next months. Such work is likely to take more time for our Linux kernel course, practical labs being closer to the hardware that we use.

Q: Why proposing half days instead of full days?
A: From our experience, it’s very difficult to stay focused on a new technical topic for an entire day without having periodic moments when you are active (which happens in our public and on-site sessions, in which we interleave lectures and practical labs). Hence, we believe that daily slots of 4 hours (with a small break in the middle) is a good solution, also leaving extra time for following up your normal work.

Yocto Project training course available on STM32MP1 platform

Back in May 2019, we announced the availability of our Embedded Linux system development course on the STMicroelectronics STM32MP1 platform, in addition to the already supported Microchip SAMA5D3 Xplained board.

In the context of our partnership with STMicroelectronics, we are now happy to announce the availability of our Yocto Project and OpenEmbedded development training also on the STM32MP1 platform for the practical labs. We now support either the BeagleBoneBlack Wireless or the STMicroelectronics STM32MP1 platforms for this training course.

The complete training materials are available: detailed agenda, slides and practical labs. The complete source code of the training materials is also available in our Github repository.

Bootlin Yocto course on STM32MP1
Slides of Bootlin’s Yocto course for the STM32MP1

This will hopefully help customers around the world to get started with using Yocto on the STM32MP1 system-on-chip. The Yocto experts at Bootlin are available to deliver this 3-day course anywhere in the world, at your location. The first edition of this new variant of the course is going to be given this week to one of our customers in Spain. Contact us if you’re interested by having this course organized at your location!

Yocto project and OpenEmbedded training updated to Krogoth

yocto

Continuing our efforts to keep our training materials up-to-date we just refreshed our Yocto project and OpenEmbedded training course to the latest Yocto project release, Krogoth (2.1.1). In addition to adapting our training labs to the Krogoth release, we improved our training materials to cover more aspects and new features.

The most important changes are:

  • New chapter about devtool, the new utility from the Yocto project to improve the developers’ workflow to integrate a package into the build system or to make patches to existing packages.
  • Improve the distro layers slides to add configuration samples and give advice on how to use these layers.
  • Add a part about quilt to easily patch already supported packages.
  • Explain in depth how file inclusions are handled by BitBake.
  • Improve the description about tasks by adding slides on how to write them in Python.

The updated training materials are available on our training page: agenda (PDF), slides (PDF) and labs (PDF).

Join our Yocto specialist Alexandre Belloni for the first public session of this improved training in Lyon (France) on October 19-21, 2016. We are also available to deliver this training worldwide at your site, contact us!