Study the source code of the modetest utility in the libdrm repository to see how to perform a mode set from scratch. 3. Graphics Request Analysis with Wireshark
Mesa is the heart of the open-source Linux graphics stack, providing the translation layer between APIs like OpenGL/Vulkan and the hardware. Hands On Projects For The Linux Graphics Subsystem
Follow tutorials like those found in the Hands-on Projects for the Linux Graphics Subsystem book, which details repainting screen pixels manually. 2. Basic DRM/KMS "Modetest" Application Study the source code of the modetest utility
Use Wireshark to analyze how graphics requests are dispatched from an application to the X Server or Wayland compositor. Hands On Projects For The Linux Graphics Subsystem