In this chapter we gained some basic knowledge about the Linux kernel and its release strategy and the differences between the mainline kernel and the official Raspberry Pi Linux kernel. We also learned how to configure and compile the Linux kernel using a cross compiler. When changing the defconfig file within meta-raspberrypi, the kernel recipe requires some special treatment as compared to the normal Yocto Project procedure. This chapter demonstrated two examples of how this can be done. Later, we also went through some basic kernel configuration required for setting up two different touchscreens; this also included some basic understanding about device trees and how to configure the Raspberry Pi using 'them.

The chapter also covered some examples of how to run a Yocto-based image with a windowing system on the Raspberry Pi, using two different touchscreens: the Raspberry Pi 7 touchscreen and PiTFT 2.8 resistive touchscreen. In the last section of the chapter, we learned about how to run Qt applications built against an SDK generated using the Yocto Project, using a Raspberry Pi and the Raspberry Pi 7 touchscreen.

In the next chapter, we will learn how to contribute to the meta-raspberrypi project.