static void adf_fbdev_fill_modelist(struct adf_fbdev *fbdev)
{
	struct drm_mode_modeinfo *modelist;
	struct fb_videomode fbmode;
	size_t n_modes, i;
	int ret = 0;

	n_modes = adf_interface_modelist(fbdev->intf, NULL, 0);
	modelist = kzalloc(sizeof(modelist[0]) * n_modes, GFP_KERNEL);
	if (!modelist) {
		dev_warn(fbdev->info->dev, "allocating new modelist failed; keeping old modelist\n");
		return;
	}
	adf_interface_modelist(fbdev->intf, modelist, n_modes);

	fb_destroy_modelist(&fbdev->info->modelist);

	for (i = 0; i < n_modes; i++) {
		adf_modeinfo_to_fb_videomode(&modelist[i], &fbmode);
		ret = fb_add_videomode(&fbmode, &fbdev->info->modelist);
		if (ret < 0)
			dev_warn(fbdev->info->dev, "adding mode %s to modelist failed: %d\n",
					modelist[i].name, ret);
	}

	kfree(modelist);
}
/**
 * adf_fbdev_open - default implementation of fbdev open op
 */
int adf_fbdev_open(struct fb_info *info, int user)
{
	struct adf_fbdev *fbdev = info->par;
	int ret;

	mutex_lock(&fbdev->refcount_lock);

	if (unlikely(fbdev->refcount == UINT_MAX)) {
		ret = -EMFILE;
		goto done;
	}

	if (!fbdev->refcount) {
		struct drm_mode_modeinfo mode;
		struct fb_videomode fbmode;
		struct adf_device *dev = adf_interface_parent(fbdev->intf);

		ret = adf_device_attach(dev, fbdev->eng, fbdev->intf);
		if (ret < 0 && ret != -EALREADY)
			goto done;

		ret = adf_fb_alloc(fbdev);
		if (ret < 0)
			goto done;

		adf_interface_current_mode(fbdev->intf, &mode);
		adf_modeinfo_to_fb_videomode(&mode, &fbmode);
		fb_videomode_to_var(&fbdev->info->var, &fbmode);

		adf_fbdev_set_format(fbdev, fbdev->default_format);
		adf_fbdev_fill_modelist(fbdev);
	}

	if (!fbdev_opened_once) {
		fbdev_opened_once = true;
	} else {
		ret = adf_fbdev_post(fbdev);
		if (ret < 0) {
			if (!fbdev->refcount)
				adf_fb_destroy(fbdev);
			goto done;
		}
	}

	fbdev->refcount++;
done:
	mutex_unlock(&fbdev->refcount_lock);
	return ret;
}
/**
 * adf_fbdev_open - default implementation of fbdev open op
 */
int adf_fbdev_open(struct fb_info *info, int user)
{
	struct adf_fbdev *fbdev = info->par;
	int ret;

	if (!fbdev->open) {
		struct drm_mode_modeinfo mode;
		struct fb_videomode fbmode;
		struct adf_device *dev = adf_interface_parent(fbdev->intf);

		ret = adf_device_attach(dev, fbdev->eng, fbdev->intf);
		if (ret < 0 && ret != -EALREADY)
			return ret;

		ret = adf_fb_alloc(fbdev);
		if (ret < 0)
			return ret;

		adf_interface_current_mode(fbdev->intf, &mode);
		adf_modeinfo_to_fb_videomode(&mode, &fbmode);
		fb_videomode_to_var(&fbdev->info->var, &fbmode);

		adf_fbdev_set_format(fbdev, fbdev->default_format);
		adf_fbdev_fill_modelist(fbdev);
	}

	ret = adf_fbdev_post(fbdev);
	if (ret < 0) {
		if (!fbdev->open)
			adf_fb_destroy(fbdev);
		return ret;
	}

	fbdev->open = true;
	return 0;
}