Hands On Projects For The Linux Graphics Subsystem !exclusive! ✦ Direct

Now go make your screen glitch in interesting ways.

gcc kms_hello.c -ldrm -o kms_hello sudo chvt 2 # Switch to a free VT sudo ./kms_hello Add libinput to read mouse events and move a rectangle around the screen. Congratulations, you just wrote a micro-compositor. Project 2: Intercept and Inspect GEM Buffer Handles Goal: Trace which process is leaking GPU memory by hooking into the Graphics Execution Manager (GEM) via ftrace or a custom LD_PRELOAD library. Hands On Projects For The Linux Graphics Subsystem

#include <stdio.h> #include <fcntl.h> #include <unistd.h> #include <sys/mman.h> #include <drm_fourcc.h> #include <xf86drm.h> #include <xf86drmMode.h> int main() ((y * 255 / create.height) << 8); Now go make your screen glitch in interesting ways

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. Project 2: Intercept and Inspect GEM Buffer Handles

Once you’ve fixed a bug in your tinkering, send a patch to the dri-devel mailing list. The maintainers are harsh but fair – and desperately need people who have actually run their code on real hardware.

drmModeSetCrtc(fd, enc->crtc_id, fb_id, 0, 0, &conn->connector_id, 1, &crtc->mode); sleep(5); // Watch your gradient // Cleanup omitted for brevity