What is DirectFB?
The graphics device on your computer is really just a big virtual drawing space in hardware with a defined set of calls to create picture changes. It has some functions to accelerate 2/3D drawing operations.
Generally these operations are implemented by the Xserver Driver which binds to the Abstracted VESAfb or actual device driver i.e. atidrv. However it is better to define an abstraction layer between the Xserver and the hardware driver; and this is what DirectFB does - in fact this is the same approach as DirectDraw2D in Windows.
