This is a first start for some documentation about frame buffer deviceinternals.Geert Uytterhoeven <geert@linux-m68k.org>, 21 July 1998--------------------------------------------------------------------------------	    ***  STRUCTURES USED BY THE FRAME BUFFER DEVICE API  ***The following structures play a role in the game of frame buffer devices. Theyare defined in <linux/fb.h>.1. Outside the kernel (user space)  - struct fb_fix_screeninfo    Device independent unchangeable information about a frame buffer device and    a specific video mode. This can be obtained using the FBIOGET_FSCREENINFO    ioctl.  - struct fb_var_screeninfo    Device independent changeable information about a frame buffer device and a    specific video mode. This can be obtained using the FBIOGET_VSCREENINFO    ioctl, and updated with the FBIOPUT_VSCREENINFO ioctl. If you want to pan    the screen only, you can use the FBIOPAN_DISPLAY ioctl.  - struct fb_cmap    Device independent colormap information. You can get and set the colormap    using the FBIOGETCMAP and FBIOPUTCMAP ioctls.2. Inside the kernel  - struct fb_info    Generic information, API and low level information about a specific frame    buffer device instance (slot number, board address, ...).  - struct `par'    Device dependent information that uniquely defines the video mode for this    particular piece of hardware.  - struct display    Interface between the frame buffer device and the console driver.--------------------------------------------------------------------------------	    ***  VISUALS USED BY THE FRAME BUFFER DEVICE API  ***Monochrome (FB_VISUAL_MONO01 and FB_VISUAL_MONO10)-------------------------------------------------Each pixel is either black or white.Pseudo color (FB_VISUAL_PSEUDOCOLOR and FB_VISUAL_STATIC_PSEUDOCOLOR)---------------------------------------------------------------------The whole pixel value is fed through a programmable lookup table that has onecolor (including red, green, and blue intensities) for each possible pixelvalue, and that color is displayed.True color (FB_VISUAL_TRUECOLOR)--------------------------------The pixel value is broken up into red, green, and blue fields.Direct color (FB_VISUAL_DIRECTCOLOR)------------------------------------The pixel value is broken up into red, green, and blue fields, each of which are looked up in separate red, green, and blue lookup tables.Grayscale displays------------------Grayscale and static grayscale are special variants of pseudo color and staticpseudo color, where the red, green and blue components are always equal toeach other.