[Libdlo] udlfb flush on close (Was: Basic PNG and SVG display)

[Phil Endecott]

Phil Endecott wrote:
> if I open the device, write an image and close it, will your 
> driver flush to the hardware on the close?

Here's some code to do this:

static int dlfb_release(struct fb_info *info, int user) {
          struct dlfb_data *dev = info->par;
          image_blit(dev, 0, 0, info->var.xres,info->var.yres, info->screen_base);
          return 0;
}

static struct fb_ops dlfb_ops = {

          .fb_setcolreg   = dlfb_setcolreg,
          .fb_fillrect = dlfb_fillrect,
          .fb_copyarea = dlfb_copyarea,
          .fb_imageblit = dlfb_imageblit,
          .fb_mmap        = dlfb_mmap,
          .fb_ioctl       = dlfb_ioctl,
          .fb_release     = dlfb_release,
};


You can now do something like

# dd if=/bin/bash of=/dev/fb0 bs=1600 count=480

and see a load of rubbish on your screen.  (BTW, does anyone know how
to convert an image to 565 16-bit raw RGB?  I was expecting there to be
some pnmtorgb utility but I can't find one.  ImageMagick's convert will
convert to 24- or 32-bpp raw RGB, but AFAICT Roberto's code doesn't yet
support 24bpp.)

Now, how can we add double-buffering to that?

Phil.