frame-buffer.rst (2007B)
1Frame Buffer Library 2==================== 3 4The frame buffer drivers depend heavily on four data structures. These 5structures are declared in include/linux/fb.h. They are fb_info, 6fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. The last 7three can be made available to and from userland. 8 9fb_info defines the current state of a particular video card. Inside 10fb_info, there exists a fb_ops structure which is a collection of 11needed functions to make fbdev and fbcon work. fb_info is only visible 12to the kernel. 13 14fb_var_screeninfo is used to describe the features of a video card 15that are user defined. With fb_var_screeninfo, things such as depth 16and the resolution may be defined. 17 18The next structure is fb_fix_screeninfo. This defines the properties 19of a card that are created when a mode is set and can't be changed 20otherwise. A good example of this is the start of the frame buffer 21memory. This "locks" the address of the frame buffer memory, so that it 22cannot be changed or moved. 23 24The last structure is fb_monospecs. In the old API, there was little 25importance for fb_monospecs. This allowed for forbidden things such as 26setting a mode of 800x600 on a fix frequency monitor. With the new API, 27fb_monospecs prevents such things, and if used correctly, can prevent a 28monitor from being cooked. fb_monospecs will not be useful until 29kernels 2.5.x. 30 31Frame Buffer Memory 32------------------- 33 34.. kernel-doc:: drivers/video/fbdev/core/fbmem.c 35 :export: 36 37Frame Buffer Colormap 38--------------------- 39 40.. kernel-doc:: drivers/video/fbdev/core/fbcmap.c 41 :export: 42 43Frame Buffer Video Mode Database 44-------------------------------- 45 46.. kernel-doc:: drivers/video/fbdev/core/modedb.c 47 :internal: 48 49.. kernel-doc:: drivers/video/fbdev/core/modedb.c 50 :export: 51 52Frame Buffer Macintosh Video Mode Database 53------------------------------------------ 54 55.. kernel-doc:: drivers/video/fbdev/macmodes.c 56 :export: 57 58Frame Buffer Fonts 59------------------ 60 61Refer to the file lib/fonts/fonts.c for more information. 62