好吧，好像真跟cpu数目有关:
int fb_show_logo(struct fb_info *info, int rotate)
{
int y;
y = fb_show_logo_line(info, rotate, fb_logo.logo, 0,
num_online_cpus());
y = fb_show_extra_logos(info, y, rotate);
return y;
}

static void fb_do_show_logo(struct fb_info *info, struct fb_image *image,
int rotate, unsigned int num)
{
unsigned int x;
if (rotate == FB_ROTATE_UR) {
for (x = 0;
x < num && image->dx + image->width <= info->var.xres;
x++) {
info->fbops->fb_imageblit(info, image);
image->dx += image->width + 8;
}
} else if (rotate == FB_ROTATE_UD) {
for (x = 0; x < num && image->dx >= 0; x++) {
info->fbops->fb_imageblit(info, image);
image->dx -= image->width + 8;
}
} else if (rotate == FB_ROTATE_CW) {
for (x = 0;
x < num && image->dy + image->height <= info->var.yres;
x++) {
info->fbops->fb_imageblit(info, image);
image->dy += image->height + 8;
}
} else if (rotate == FB_ROTATE_CCW) {
for (x = 0; x < num && image->dy >= 0; x++) {
info->fbops->fb_imageblit(info, image);
image->dy -= image->height + 8;
}
}
}