---补丁说明----
加入支持读取/dev/graphics/fb0 获得当前显示内容的功能，一般用于只能支持framebuffer框架的应用上；
使用方法
1. 打上补丁，更新固件；
2. 关闭hwc功能，调试过程可以通过下面命令配置：
	setprop sys.hwc.compose_policy 0
3. 通过下面命令测试：
	dd if=/dev/graphics/fb0 of=/data/fb0.bin
4. 将/data/fb0.bin导出来，通过7yuv软件可以查看当前显示的内容；

---补丁内容-----

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
index 5cbe6a0..6b486a9 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
@@ -100,6 +100,8 @@ rockchip_fb_alloc(struct drm_device *dev, struct drm_mode_fb_cmd2 *mode_cmd,
 {
 	struct rockchip_drm_fb *rockchip_fb;
 	struct rockchip_gem_object *rk_obj;
+	struct rockchip_drm_private *private = dev->dev_private;
+	struct drm_fb_helper *fb_helper = private->fbdev_helper;
 	int ret = 0;
 	int i;
 
@@ -125,6 +127,9 @@ rockchip_fb_alloc(struct drm_device *dev, struct drm_mode_fb_cmd2 *mode_cmd,
 			rk_obj = to_rockchip_obj(obj[i]);
 			rockchip_fb->dma_addr[i] = rk_obj->dma_addr;
 			rockchip_fb->kvaddr[i] = rk_obj->kvaddr;
+			private->fbdev_bo = &rk_obj->base;
+			if (fb_helper && fb_helper->fbdev)
+				fb_helper->fbdev->screen_base = rk_obj->kvaddr;
 		}
 #ifndef MODULE
 	} else if (logo) {
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fbdev.c b/drivers/gpu/drm/rockchip/rockchip_drm_fbdev.c
index 5bd8444..8cc7662 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_fbdev.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_fbdev.c
@@ -60,6 +60,8 @@ static struct fb_ops rockchip_drm_fbdev_ops = {
 	.fb_set_par	= drm_fb_helper_set_par,
 	.fb_blank	= drm_fb_helper_blank,
 	.fb_pan_display	= drm_fb_helper_pan_display,
+	.fb_read = drm_fb_helper_sys_read,
+	.fb_write = drm_fb_helper_sys_write,
 	.fb_setcmap	= drm_fb_helper_setcmap,
 	.fb_dmabuf_export	= rockchip_fbdev_get_dma_buf,
 };
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
index 273a52b..d2b9393 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
@@ -676,7 +676,7 @@ rockchip_gem_create_with_handle(struct drm_file *file_priv,
 	struct drm_gem_object *obj;
 	int ret;
 
-	rk_obj = rockchip_gem_create_object(drm, size, false, flags);
+	rk_obj = rockchip_gem_create_object(drm, size, true, flags);
 	if (IS_ERR(rk_obj))
 		return ERR_CAST(rk_obj);