Modesetting

Modesetting refers to the process of setting display modes, such as resolution, color depth, and refresh rate, on a computer system. This is a fundamental aspect of graphical display management. In Linux systems, modesetting is often handled by the kernel's direct rendering manager (DRM) and the user-space graphics driver.

Historically, graphics drivers in Linux would interact directly with the hardware to set display modes. However, this approach had several drawbacks, including increased complexity and potential for instability. Modesetting emerged as a more modern and robust approach, aiming to decouple the hardware-specific details from the rest of the graphics stack.

With modesetting, the kernel DRM subsystem is responsible for managing the graphics hardware and configuring the display. The user-space graphics driver then interacts with the DRM interface to request specific display modes. This allows for a more streamlined and consistent way to manage graphics across different hardware and kernel versions. It also facilitates features like atomic modesetting, which enables changes to multiple display parameters simultaneously and atomically, reducing screen tearing and improving overall visual smoothness. The benefits of modesetting include improved stability, better support for modern graphics hardware, and a simplified driver development process.