Hands On Projects For The Linux Graphics Subsystem ✯

Debugging and testing the Linux graphics subsystem can be a challenging and rewarding task.

Goal: Use checkpatch.pl and sparse to analyze a real DRM driver (e.g., panel-simple.c), then add a new display mode to the driver’s EDID fallback table.

Why it matters: Many embedded Linux projects (Raspberry Pi, i.MX, Allwinner) require custom display panel support. Modifying a DRM panel driver is a common real-world task.

Steps:

Goal: Build a working, bare-bones Wayland compositor (like a tiny version of Sway or Weston) using the wlroots library. It should be able to run a single terminal client.

Why it matters: Wayland compositors are the future of Linux display servers. This project demystifies how windows are managed, rendered, and input is handled. Hands On Projects For The Linux Graphics Subsystem

Prerequisites: libwayland-dev, libwlroots-dev (v0.16+), libxkbcommon, meson.

Architecture:

Minimal Implementation Outline (in C):

  • Set up a wlr_cursor with wlr_input_device (libinput) for mouse.
  • Run the main loop: wl_display_run(display).

    • Test: Run weston-terminal or foot inside your compositor. You should see a movable window.

    Advanced: Add keyboard handling (modifiers, keys to exit) and basic tiling layout. Debugging and testing the Linux graphics subsystem can

    The Linux graphics subsystem is often viewed as a terrifying labyrinth of acronyms: DRM, KMS, GEM, DRI, Mesa, VA-API, and Wayland. Most articles explain what these components are. This one is different. It is a project-based guide to touching the code, breaking things, fixing them, and understanding how pixels actually travel from your RAM to the screen.

    These projects assume you have a spare laptop, a virtual machine (with PCI passthrough for GPU acceleration), or a willingness to risk your display manager. Let’s get our hands dirty.

    Goal: Observe kernel graphics driver behavior in real time.

    Concepts:

    Task:

    Outcome: Deep insight into when modesetting, buffer flips, and GPU commands happen.

    Modify a simple Wayland client (e.g., weston-simple-shm) and trace round-trip from client writev() to kernel DRM atomic commit.

    Goal: Port the simple DRM client to use atomic modesetting API.

    Concepts:

    Task:

    Outcome: Future-proof code that matches modern kernel DRM practices.

    Render a rotating triangle directly on the display using GPU acceleration via EGL and GBM (Generic Buffer Management).