drm/exynos: check crtc's dpms mode at page flip

when page flip is requested, crtc's dpms mode should be on.
if not on, return -EINVAL so that it doesn't access hardware.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.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 8bd4d7ed964..07c5d2a0bdc 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_crtc.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
@@ -207,6 +207,12 @@ static int exynos_drm_crtc_page_flip(struct drm_crtc *crtc,
 
         DRM_DEBUG_KMS("%s\n", __FILE__);
 
+        /* when the page flip is requested, crtc's dpms should be on */
+        if (exynos_crtc->dpms > DRM_MODE_DPMS_ON) {
+                DRM_ERROR("failed page flip request.\n");
+                return -EINVAL;
+        }
+
         mutex_lock(&dev->struct_mutex);
 
         if (event) {