1*4882a593SmuzhiyunFrame Buffer Library 2*4882a593Smuzhiyun==================== 3*4882a593Smuzhiyun 4*4882a593SmuzhiyunThe frame buffer drivers depend heavily on four data structures. These 5*4882a593Smuzhiyunstructures are declared in include/linux/fb.h. They are fb_info, 6*4882a593Smuzhiyunfb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. The last 7*4882a593Smuzhiyunthree can be made available to and from userland. 8*4882a593Smuzhiyun 9*4882a593Smuzhiyunfb_info defines the current state of a particular video card. Inside 10*4882a593Smuzhiyunfb_info, there exists a fb_ops structure which is a collection of 11*4882a593Smuzhiyunneeded functions to make fbdev and fbcon work. fb_info is only visible 12*4882a593Smuzhiyunto the kernel. 13*4882a593Smuzhiyun 14*4882a593Smuzhiyunfb_var_screeninfo is used to describe the features of a video card 15*4882a593Smuzhiyunthat are user defined. With fb_var_screeninfo, things such as depth 16*4882a593Smuzhiyunand the resolution may be defined. 17*4882a593Smuzhiyun 18*4882a593SmuzhiyunThe next structure is fb_fix_screeninfo. This defines the properties 19*4882a593Smuzhiyunof a card that are created when a mode is set and can't be changed 20*4882a593Smuzhiyunotherwise. A good example of this is the start of the frame buffer 21*4882a593Smuzhiyunmemory. This "locks" the address of the frame buffer memory, so that it 22*4882a593Smuzhiyuncannot be changed or moved. 23*4882a593Smuzhiyun 24*4882a593SmuzhiyunThe last structure is fb_monospecs. In the old API, there was little 25*4882a593Smuzhiyunimportance for fb_monospecs. This allowed for forbidden things such as 26*4882a593Smuzhiyunsetting a mode of 800x600 on a fix frequency monitor. With the new API, 27*4882a593Smuzhiyunfb_monospecs prevents such things, and if used correctly, can prevent a 28*4882a593Smuzhiyunmonitor from being cooked. fb_monospecs will not be useful until 29*4882a593Smuzhiyunkernels 2.5.x. 30*4882a593Smuzhiyun 31*4882a593SmuzhiyunFrame Buffer Memory 32*4882a593Smuzhiyun------------------- 33*4882a593Smuzhiyun 34*4882a593Smuzhiyun.. kernel-doc:: drivers/video/fbdev/core/fbmem.c 35*4882a593Smuzhiyun :export: 36*4882a593Smuzhiyun 37*4882a593SmuzhiyunFrame Buffer Colormap 38*4882a593Smuzhiyun--------------------- 39*4882a593Smuzhiyun 40*4882a593Smuzhiyun.. kernel-doc:: drivers/video/fbdev/core/fbcmap.c 41*4882a593Smuzhiyun :export: 42*4882a593Smuzhiyun 43*4882a593SmuzhiyunFrame Buffer Video Mode Database 44*4882a593Smuzhiyun-------------------------------- 45*4882a593Smuzhiyun 46*4882a593Smuzhiyun.. kernel-doc:: drivers/video/fbdev/core/modedb.c 47*4882a593Smuzhiyun :internal: 48*4882a593Smuzhiyun 49*4882a593Smuzhiyun.. kernel-doc:: drivers/video/fbdev/core/modedb.c 50*4882a593Smuzhiyun :export: 51*4882a593Smuzhiyun 52*4882a593SmuzhiyunFrame Buffer Macintosh Video Mode Database 53*4882a593Smuzhiyun------------------------------------------ 54*4882a593Smuzhiyun 55*4882a593Smuzhiyun.. kernel-doc:: drivers/video/fbdev/macmodes.c 56*4882a593Smuzhiyun :export: 57*4882a593Smuzhiyun 58*4882a593SmuzhiyunFrame Buffer Fonts 59*4882a593Smuzhiyun------------------ 60*4882a593Smuzhiyun 61*4882a593SmuzhiyunRefer to the file lib/fonts/fonts.c for more information. 62*4882a593Smuzhiyun 63