Kernel mode setting

Kernel Mode Setting

In order to work properly, a video card or graphics adapter must set a mode—a combination of screen resolution, color depth and refresh rate—that is within the range of values supported by itself and the attached display screen. This operation is called mode-setting, and it usually requires raw access to the graphics hardware—i.e. the ability to write to certain registers of the video card display controller. A mode-setting operation must be performed before starting to use the framebuffer, and also when the mode is required to change by an application or the user.