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Linux frame buffer

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Figure 11.

CLCD selection from menu config - 2

6.3

User level perspective of CLCD

As we already know, a frame buffer device is a memory device like /dev/mem and it has the

same features. You can read it, write it, seek to some location in it and mmap() it (the main

usage). The difference is just that the memory that appears in the special file is not the

whole memory, but the frame buffer of the video hardware.

6.3.1

Data structures for user level

It is essential to understand the following three structures, they are used by all frame buffer

user applications.

1.

Variable information pertaining to the video card is held in struct fb_var_screeninfo.

This structure contains fields such as the X-resolution, Y-resolution, bits required to