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>

3 files changed, 11 insertions, 3 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.c b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
index 0587b52a18bf..8cd9d8eec46e 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;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.h b/drivers/gpu/drm/exynos/exynos_drm_drv.h
index 002f2925106a..63c1422403d8 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.h
@@ -82,7 +82,6 @@ struct exynos_drm_overlay_ops {
  * @paddr: bus(accessed by dma) physical memory address to this overlay
  *              and this is physically continuous.
  * @vaddr: virtual memory addresss to this overlay.
- * @buf_off: start offset of framebuffer to be displayed.
  * @default_win: a window to be enabled.
  * @color_key: color key on or off.
  * @index_color: if using color key feature then this value would be used
@@ -111,7 +110,6 @@ struct exynos_drm_overlay {
         unsigned int pitch;
         dma_addr_t paddr;
         void __iomem *vaddr;
-        unsigned int buf_off;
 
         bool default_win;
         bool color_key;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
index 4366dc5032ef..1f4b3d1a7713 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
@@ -393,6 +393,10 @@ int exynos_drm_fbdev_reinit(struct drm_device *dev)
         if (!private)
                 return -EINVAL;
 
+        /*
+         * if all sub drivers were unloaded then num_connector is 0
+         * so at this time, the framebuffers also should be destroyed.
+         */
         if (!dev->mode_config.num_connector) {
                 exynos_drm_fbdev_fini(dev);
                 return 0;
@@ -429,7 +433,7 @@ int exynos_drm_fbdev_reinit(struct drm_device *dev)
                  * re-configure the fb helper. it means that this function
                  * has been called by the specific drivers.
                  */
-                return exynos_drm_fbdev_init(dev);
+                ret = exynos_drm_fbdev_init(dev);
         }
 
         return ret;