修改 fb_show_logo函数.
int fb_show_logo(struct fb_info *info)
{
u32 *palette = NULL, *saved_pseudo_palette = NULL;
// unsigned char *logo_new = NULL;
// struct fb_image image;
// int x;
unsigned char *logo_new = NULL, *border = NULL;
struct fb_image image, imageborder;
int x, xoffset;
int y, yoffset;
/* Return if the frame buffer is not mapped or suspended */
if (fb_logo.logo == NULL || info->state != FBINFO_STATE_RUNNING)
return 0;
image.depth = 8;
image.data = fb_logo.logo->data;
if (fb_logo.needs_cmapreset)
fb_set_logocmap(info, fb_logo.logo);
if (fb_logo.needs_truepalette ||
fb_logo.needs_directpalette) {
palette = kmalloc(256 * 4, GFP_KERNEL);
if (palette == NULL)
return 0;
if (fb_logo.needs_truepalette)
fb_set_logo_truepalette(info, fb_logo.logo, palette);
else
fb_set_logo_directpalette(info, fb_logo.logo, palette);
saved_pseudo_palette = info->pseudo_palette;
info->pseudo_palette = palette;
}
if (fb_logo.depth <= 4) {
logo_new = kmalloc(fb_logo.logo->width * fb_logo.logo->height,
GFP_KERNEL);
if (logo_new == NULL) {
if (palette)
kfree(palette);
if (saved_pseudo_palette)
info->pseudo_palette = saved_pseudo_palette;
return 0;
}
image.data = logo_new;
fb_set_logo(info, fb_logo.logo, logo_new, fb_logo.depth);
}
image.width = fb_logo.logo->width;
image.height = fb_logo.logo->height;
image.dy = 0;
//这段代码实现了重复左右边界直至屏幕两边
#if 0 //def CONFIG_LOGO_REPEAT_RIGHT
border = kmalloc(4 * fb_logo.logo->height, GFP_KERNEL);
if (border != NULL){
for (x = 0; x < fb_logo.logo->height; x++){ /* use x as y */
*((u32 *)border + x) = /* will repeat 4 pixels of the right side*/
*(u32 *)(image.data + (x+1)*fb_logo.logo->width - 4);
}
imageborder.depth = 8;
imageborder.data = border;
imageborder.width = 4;
imageborder.height = image.height;
imageborder.dy = 0;
for (x = 0; x < info->var.xres; x+=4){
imageborder.dx = x;
info->fbops->fb_imageblit(info, &imageborder);
}
kfree(border);
}
#endif
#if 0 //ndef CONFIG_CENTER_LOGO
xoffset = 0;
for (x = 0; x < num_online_cpus() * (fb_logo.logo->width + 8) &&
x <= info->var.xres-fb_logo.logo->width; x += (fb_logo.logo->width + 8)) {
image.dx = x;
info->fbops->fb_imageblit(info, &image);
}
#else //这段代码仅仅实现了X方向居中
xoffset = (info->var.xres - num_online_cpus() * (fb_logo.logo->width + 8))>>1;
yoffset = (info->var.yres - num_online_cpus() * (fb_logo.logo->height + 8))>>1;
if (xoffset<0) xoffset = 0;
if (yoffset<0) yoffset = 0;
#if 0//only-x
for (x = xoffset; x < num_online_cpus() * (fb_logo.logo->width + 8) + xoffset &&
x <= info->var.xres-fb_logo.logo->width+xoffset; x += (fb_logo.logo->width + 8)) {
image.dx = x;
info->fbops->fb_imageblit(info, &image);
}
#endif
#if 1// x-y //这段代码是实现X、Y居中的一部分，另外一部分是设置logo_lines。
for (x = xoffset,y=yoffset; \
x < num_online_cpus() * (fb_logo.logo->width + 8) + xoffset \
&& x <= info->var.xres - fb_logo.logo->width + xoffset \
&& y < num_online_cpus() * (fb_logo.logo->height + 8) + yoffset \
&& y <= info->var.yres - fb_logo.logo->height + yoffset;
x += (fb_logo.logo->width + 8), \
y += (fb_logo.logo->height +8) )
{
image.dx = x;
image.dy = y;
info->fbops->fb_imageblit(info, &image);
}
#endif
#endif
if (palette != NULL)
kfree(palette);
if (saved_pseudo_palette != NULL)
info->pseudo_palette = saved_pseudo_palette;
if (logo_new != NULL)
kfree(logo_new);
return fb_logo.logo->height;
}
drivers/video/console/fbcon.c
修改fbcon_prepare_logo函数中设置logo_lines的代码
int cols, int rows, int new_cols, int new_rows)
if (fb_get_color_depth(info) == 1)
erase &= ~0x400;
#ifdef CONFIG_CENTER_LOGO
logo_height = fb_prepare_logo(info);
logo_lines = (logo_height +((info->var.yres-logo_height)/2) + vc->vc_font.height - 1) /
vc->vc_font.height;
#else
logo_lines = (logo_height + vc->vc_font.height - 1) /
vc->vc_font.height;
#endif
经过修改后，重新编译内核，即可看到居中的LOGO了。
