1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.c b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
index db3decffc985..c200e4d71e3d 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_crtc.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
@@ -48,6 +48,8 @@ struct exynos_drm_crtc {
         unsigned int                    pipe;
         unsigned int                    dpms;
         enum exynos_crtc_mode           mode;
+        wait_queue_head_t               pending_flip_queue;
+        atomic_t                        pending_flip;
 };
 
 static void exynos_drm_crtc_dpms(struct drm_crtc *crtc, int mode)
@@ -61,6 +63,13 @@ static void exynos_drm_crtc_dpms(struct drm_crtc *crtc, int mode)
                 return;
         }
 
+        if (mode > DRM_MODE_DPMS_ON) {
+                /* wait for the completion of page flip. */
+                wait_event(exynos_crtc->pending_flip_queue,
+                                atomic_read(&exynos_crtc->pending_flip) == 0);
+                drm_vblank_off(crtc->dev, exynos_crtc->pipe);
+        }
+
         exynos_drm_fn_encoder(crtc, &mode, exynos_drm_encoder_crtc_dpms);
         exynos_crtc->dpms = mode;
 }
@@ -224,6 +233,7 @@ static int exynos_drm_crtc_page_flip(struct drm_crtc *crtc,
                 spin_lock_irq(&dev->event_lock);
                 list_add_tail(&event->base.link,
                                 &dev_priv->pageflip_event_list);
+                atomic_set(&exynos_crtc->pending_flip, 1);
                 spin_unlock_irq(&dev->event_lock);
 
                 crtc->fb = fb;
@@ -343,6 +353,8 @@ int exynos_drm_crtc_create(struct drm_device *dev, unsigned int nr)
 
         exynos_crtc->pipe = nr;
         exynos_crtc->dpms = DRM_MODE_DPMS_OFF;
+        init_waitqueue_head(&exynos_crtc->pending_flip_queue);
+        atomic_set(&exynos_crtc->pending_flip, 0);
         exynos_crtc->plane = exynos_plane_init(dev, 1 << nr, true);
         if (!exynos_crtc->plane) {
                 kfree(exynos_crtc);
@@ -397,6 +409,8 @@ void exynos_drm_crtc_finish_pageflip(struct drm_device *dev, int crtc)
 {
         struct exynos_drm_private *dev_priv = dev->dev_private;
         struct drm_pending_vblank_event *e, *t;
+        struct drm_crtc *drm_crtc = dev_priv->crtc[crtc];
+        struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(drm_crtc);
         unsigned long flags;
 
         DRM_DEBUG_KMS("%s\n", __FILE__);
@@ -412,6 +426,8 @@ void exynos_drm_crtc_finish_pageflip(struct drm_device *dev, int crtc)
                 list_del(&e->base.link);
                 drm_send_vblank_event(dev, -1, e);
                 drm_vblank_put(dev, crtc);
+                atomic_set(&exynos_crtc->pending_flip, 0);
+                wake_up(&exynos_crtc->pending_flip_queue);
         }
 
         spin_unlock_irqrestore(&dev->event_lock, flags);