Skip to content

Embedded Linux

Less Love for FOSS Qt Users

From Qt 5.15, The Qt Company make their offering a bit more inconvenient for FOSS users. They announced three changes:

  • A Qt account is mandatory to download binary Qt packages. The offline installer is not available to FOSS users any more.
  • LTS (long-term support) releases are not available to FOSS users, once the next minor or major release is out.
  • Small business pay 499 USD per year, if their yearly revenue is less than 100,000 USD and they have less than five employees.

What do these changes mean for the development of Qt embedded Linux systems under LGPLv3?

Read More »Less Love for FOSS Qt Users

Detecting Overdraw in QML HMIs with GammaRay

Overdraw happens when one QML item fully eclipses another QML item. The QML renderer always draws both items, although there is no need to draw the eclipsed item. You must help out the renderer by explicitly setting visible: false on the eclipsed item.

On embedded systems, heavy overdraw makes animations or flicking jerky. In the worst case, it freezes your HMI. Fortunately, the Qt experts at KDAB developed a tool, GammaRay, which makes detecting overdraw a piece of cake. I’ll show you how to build GammaRay, how to detect overdraw in the home screen of a harvester HMI, and how to fix the overdraw.

Read More »Detecting Overdraw in QML HMIs with GammaRay

Deploying Qt Projects to Embedded Devices with CMake

When you run a Qt project, QtCreator first deploys the project to a remote embedded Linux device via ssh and then runs the executable on the remote device. This feature enables nearly instant feedback how your Qt application works on the embedded device.

Deployment works fine with the INSTALLS variable of qmake. It does not work out of the box with the install functions of CMake. Fortunately, the Qt trolls provide a workaround. I’ll explain the workaround with an example CMakeLists.txt file.

Read More »Deploying Qt Projects to Embedded Devices with CMake

Yocto Builds with CROPS Containers

In a recent post Using Docker Containers for Yocto Builds, I suffered an episode of NIHS (not-invented-here syndrome). I wrote a Dockerfile for Yocto builds. Stefan Agner pointed out in his comment that the CROPS project provides ready-made containers for Linux distributions like Ubuntu, Fedora and others. The crops/poky-container enables us to start our first Yocto build within minutes.

Read More »Yocto Builds with CROPS Containers

Using Docker Containers for Yocto Builds

We want to build a custom Linux image with Yocto for the Raspberry Pi 3 model B (BCM2837). The Linux image contains a very simple Internet radio application using Qt 5.11 and the eglfs graphics backend. Our colleagues shall be able to repeat the build easily – now, in three years and even in ten years.

I’ll explain why Docker is an excellent choice to build custom Linux images and give you a step-by-step guide how to do it. At the end of the post, you will be able to run a simple Internet radio on a custom Linux image on a Raspberry Pi 3.

Read More »Using Docker Containers for Yocto Builds

Seminar “Open-Source Management in Software Supply Chains”

On 20 November 2018, the law firm Bird & Bird hosted a seminar about “Open-Source Management in Software Supply Chains – Effective and Consistent License Compliance” in their Frankfurt office. The seminar was organised by Miriam Ballhausen, who is Bird & Bird’s specialist in open-source Licensing.

The seminar offered the opportunity to meet two of Germany’s top lawyers for FOSS license compliance: Miriam Ballhausen and Catharina Maracke. If you have any questions about how to comply with FOSS licenses, Miriam and Catharina will give you invaluable counsel.

The roughly 25 attendees hailed from very different industries: automotive, agricultural, financial, medical, manufacturing and IT services. In late 2018, you cannot escape FOSS: Free open-source software has arrived in the mainstream.

Now, let me give you a summary of the four talks.
Read More »Seminar “Open-Source Management in Software Supply Chains”

Building Yocto Packages Manually with devshell

We must figure out why a Yocto package doesn’t work as expected. So, we must tweak the source code a bit here and there, cross-build the package for our ARM-based embedded Linux system and install some shared libraries from the package on the embedded Linux system. Of course, we want short turnaround times to try out our changes quickly. The bitbake task devshell will save our day.
Read More »Building Yocto Packages Manually with devshell