drm/exynos: fixed page flip issue.

with vblank_refcount = 1, there was the case that drm_vblank_put
is called by specific page flip function so this patch fixes the
issue.

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, 1 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
index 47961679c447..93846e810e38 100644
--- a/drivers/gpu/drm/exynos/exynos_mixer.c
+++ b/drivers/gpu/drm/exynos/exynos_mixer.c
@@ -712,7 +712,12 @@ static void mixer_finish_pageflip(struct drm_device *drm_dev, int crtc)
         }
 
         if (is_checked)
-                drm_vblank_put(drm_dev, crtc);
+                /*
+                 * call drm_vblank_put only in case that drm_vblank_get was
+                 * called.
+                 */
+                if (atomic_read(&drm_dev->vblank_refcount[crtc]) > 0)
+                        drm_vblank_put(drm_dev, crtc);
 
         spin_unlock_irqrestore(&drm_dev->event_lock, flags);
 }