drm/exynos: added comments and code clean.

this patch adds the following comments and code clean.
- add comment of exynos_drm_crtc_apply() call at page flip time.
- add comment that when exynos_drm_fbdev_reinit() is called,
  why num_connector is 0 and also the framebuffers should be destroyed.
- remove buf_off member from struct exynos_drm_overlay because this member
  isn't used anymore.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.c b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
index 0587b52..8cd9d8e 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_crtc.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
@@ -279,6 +279,12 @@ static int exynos_drm_crtc_page_flip(struct drm_crtc *crtc,
 			goto out;
 		}
 
+		/*
+		 * the values related to a buffer of the drm framebuffer
+		 * to be applied should be set at here. because these values
+		 * first, is set to shadow registers and then to
+		 * real registers at vsync front porch period.
+		 */
 		exynos_drm_crtc_apply(crtc);
 
 		dev_priv->pageflip_event = true;