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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263Frame Buffer Library====================
The frame buffer drivers depend heavily on four data structures. Thesestructures are declared in include/linux/fb.h. They are fb_info,fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. The lastthree can be made available to and from userland.
fb_info defines the current state of a particular video card. Insidefb_info, there exists a fb_ops structure which is a collection ofneeded functions to make fbdev and fbcon work. fb_info is only visibleto the kernel.
fb_var_screeninfo is used to describe the features of a video cardthat are user defined. With fb_var_screeninfo, things such as depthand the resolution may be defined.
The next structure is fb_fix_screeninfo. This defines the propertiesof a card that are created when a mode is set and can't be changedotherwise. A good example of this is the start of the frame buffermemory. This "locks" the address of the frame buffer memory, so that itcannot be changed or moved.
The last structure is fb_monospecs. In the old API, there was littleimportance for fb_monospecs. This allowed for forbidden things such assetting a mode of 800x600 on a fix frequency monitor. With the new API,fb_monospecs prevents such things, and if used correctly, can prevent amonitor from being cooked. fb_monospecs will not be useful untilkernels 2.5.x.
Frame Buffer Memory-------------------
.. kernel-doc:: drivers/video/fbdev/core/fbmem.c :export:
Frame Buffer Colormap---------------------
.. kernel-doc:: drivers/video/fbdev/core/fbcmap.c :export:
Frame Buffer Video Mode Database--------------------------------
.. kernel-doc:: drivers/video/fbdev/core/modedb.c :internal:
.. kernel-doc:: drivers/video/fbdev/core/modedb.c :export:
Frame Buffer Macintosh Video Mode Database------------------------------------------
.. kernel-doc:: drivers/video/fbdev/macmodes.c :export:
Frame Buffer Fonts------------------
Refer to the file lib/fonts/fonts.c for more information.