Merge change 24493 into eclair

#include <sys/mman.h>

/* TODO:

** - grab the current buffer, not the first buffer

** - sync with vsync to avoid tearing

*/

void framebuffer_service(int fd, void *cookie)

{

    struct fb_var_screeninfo vinfo;

    int fb;

    void *ptr = MAP_FAILED;

    char x;

    int fb, offset;

    char x[256];

    unsigned fbinfo[4];

    unsigned i, bytespp;

    fb = open("/dev/graphics/fb0", O_RDONLY);

    if(fb < 0) goto done;

    if(ioctl(fb, FBIOGET_VSCREENINFO, &vinfo) < 0) goto done;

    fcntl(fb, F_SETFD, FD_CLOEXEC);

    fbinfo[0] = 16;

    fbinfo[1] = vinfo.xres * vinfo.yres * 2;

    bytespp = vinfo.bits_per_pixel / 8;

    fbinfo[0] = vinfo.bits_per_pixel;

    fbinfo[1] = vinfo.xres * vinfo.yres * bytespp;

    fbinfo[2] = vinfo.xres;

    fbinfo[3] = vinfo.yres;

    ptr = mmap(0, fbinfo[1], PROT_READ, MAP_SHARED, fb, 0);

    if(ptr == MAP_FAILED) goto done;

    /* HACK: for several of our 3d cores a specific alignment

     * is required so the start of the fb may not be an integer number of lines

     * from the base.  As a result we are storing the additional offset in

     * xoffset. This is not the correct usage for xoffset, it should be added

     * to each line, not just once at the beginning */

    offset = vinfo.xoffset * bytespp;

    offset += vinfo.xres * vinfo.yoffset * bytespp;

    if(writex(fd, fbinfo, sizeof(unsigned) * 4)) goto done;

    if(writex(fd, fbinfo, sizeof(fbinfo))) goto done;

    for(;;) {

        if(readx(fd, &x, 1)) goto done;

        if(writex(fd, ptr, fbinfo[1])) goto done;

    lseek(fb, offset, SEEK_SET);

    for(i = 0; i < fbinfo[1]; i += 256) {

      if(readx(fb, &x, 256)) goto done;

      if(writex(fd, &x, 256)) goto done;

    }

    if(readx(fb, &x, fbinfo[1] % 256)) goto done;

    if(writex(fd, &x, fbinfo[1] % 256)) goto done;

done:

    if(ptr != MAP_FAILED) munmap(ptr, fbinfo[1]);

    if(fb >= 0) close(fb);

    close(fd);

}