【视频】显示器固定参数struct fb_fix_screeninfo中char id[16]说明

imx6q关于fb和video的设备信息

设备节点

root@myzr:/unit_tests# ls /dev/fb* -l
lrwxrwxrwx 1 root root      3 Jan  1  1970 /dev/fb -> fb0
crw-rw---- 1 root video 29, 0 Jan  1  1970 /dev/fb0
crw-rw---- 1 root video 29, 1 Jan  1  1970 /dev/fb1
crw-rw---- 1 root video 29, 2 Jan  1  1970 /dev/fb2
crw-rw---- 1 root video 29, 3 Jan  1  1970 /dev/fb3
crw-rw---- 1 root video 29, 4 Jan  1  1970 /dev/fb4
root@myzr:/unit_tests# ls /dev/video* -l
crw-rw---- 1 root video 81, 5 Jan  1  1970 /dev/video0
crw-rw---- 1 root video 81, 6 Jan  1  1970 /dev/video1
crw-rw---- 1 root video 81, 0 Jan  1  1970 /dev/video16
crw-rw---- 1 root video 81, 1 Jan  1  1970 /dev/video17
crw-rw---- 1 root video 81, 2 Jan  1  1970 /dev/video18
crw-rw---- 1 root video 81, 3 Jan  1  1970 /dev/video19
crw-rw---- 1 root video 81, 4 Jan  1  1970 /dev/video20
root@myzr:/unit_tests#

设备名字

root@myzr:~# cat /sys/class/graphics/fb0/name
DISP4 BG - DI1
root@myzr:~# cat /sys/class/graphics/fb1/name
DISP4 FG
root@myzr:~# cat /sys/class/graphics/fb2/name
DISP3 BG
root@myzr:~# cat /sys/class/graphics/fb3/name
DISP3 FG
root@myzr:~# cat /sys/class/graphics/fb4/name
DISP4 BG
root@myzr:~# cat /sys/class/video4linux/video0/name
Mxc Camera
root@myzr:~# cat /sys/class/video4linux/video1/name
Mxc Camera
root@myzr:~# cat /sys/class/video4linux/video16/name
DISP4 BG - DI1
root@myzr:~# cat /sys/class/video4linux/video17/name
DISP4 FG
root@myzr:~# cat /sys/class/video4linux/video18/name
DISP3 BG
root@myzr:~# cat /sys/class/video4linux/video19/name
DISP3 FG
root@myzr:~# cat /sys/class/video4linux/video20/name
DISP4 BG

fb与video的对应关系

fb0~fb4与video16~video20对应，共用相同的物理缓冲区
BG：background背景图层
FG：foreground前景图层，对应overlay遮盖层
即：fb0、fb2对应显示设备，fb1、fb3分贝对应它们的overlay层