[PATCH 3/4] drm/exynos: check crtc's dpms mode at page flip

[Inki Dae]

when page flip is requested, crtc's dpms mode should be on.
if not on, return -EPERM so that the hardware can't be accessed.
if user requesed dpms off and next page flip then the hardware
can be accessed with dpms off to enable vblank so this patch
will prevent from accessing the hardware with dpms off.

Signed-off-by: Inki Dae <inki.dae at samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
---
 drivers/gpu/drm/exynos/exynos_drm_crtc.c |    6 ++++++
 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 8bd4d7e..5eda559 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 -EPERM;
+	}
+
 	mutex_lock(&dev->struct_mutex);
 
 	if (event) {
-- 
1.7.4.1