在linux下如何启用framebuffer

3、测试framebuffer的例子如下:

#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>

int main()
{
int fbfd = 0;
struct fb_var_screeninfo vinfo;
struct fb_fix_screeninfo finfo;
long int screensize = 0;
char *fbp = 0;
int x = 0, y = 0,i;
long int location = 0;

/* Open the file for reading and writing */
fbfd = open("/dev/fb0", O_RDWR);
if (!fbfd) {
printf("Error: cannot open framebuffer device.\n");
exit(1);
}
printf("The framebuffer device was opened successfully.\n");

/* Get fixed screen information */
if (ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {
printf("Error reading fixed information.\n");
exit(2);
}

/* Get variable screen information */
if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
printf("Error reading variable information.\n");
exit(3);
}

/* Figure out the size of the screen in bytes */
screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;

/* Map the device to memory */
fbp = (char *)mmap(0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED,

fbfd, 0);
if ((int)fbp == -1) { printf("Error: failed to map
framebuffer device to memory.\n"); exit(4);
}
printf("The framebuffer device was mapped to memory successfully.\n");

x = 100; y = 100; /* Where we are going to put the pixel */

/* Figure out where in memory to put the pixel */
location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) +
(y+vinfo.yoffset) * finfo.line_length;

for(i=0;i<400;i++)

{

*(fbp + location+i) = 100; /* Some blue */
*(fbp + location +i+ 1) = 15; /* A little green */
*(fbp + location +i+ 2) = 200; /* A lot of red */
*(fbp + location +i+3) = 0; /* No transparency */

}

munmap(fbp, screensize);
close(fbfd);
return 0;
}

4、关于fbset工具。这是一个可以查看和设置framebuffer的工具。

5、一篇有用的参考文献：

   http://bbs.linuxsir.org/showthread.php?t=211427