diff --git a/drivers/gpu/drm/exynos/exynos_drm_hdmi.c b/drivers/gpu/drm/exynos/exynos_drm_hdmi.c
index 437fb947e46d..b9b27265d0b1 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_hdmi.c
@@ -344,7 +344,7 @@ static void drm_mixer_commit(struct device *subdrv_dev, int zpos)
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
 
-	if (win < 0 || win > MIXER_WIN_NR) {
+	if (win < 0 || win >= MIXER_WIN_NR) {
 		DRM_ERROR("mixer window[%d] is wrong\n", win);
 		return;
 	}
@@ -362,7 +362,7 @@ static void drm_mixer_disable(struct device *subdrv_dev, int zpos)
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
 
-	if (win < 0 || win > MIXER_WIN_NR) {
+	if (win < 0 || win >= MIXER_WIN_NR) {
 		DRM_ERROR("mixer window[%d] is wrong\n", win);
 		return;
 	}
diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
index 7c197d3820c5..3658e0743487 100644
--- a/drivers/gpu/drm/exynos/exynos_mixer.c
+++ b/drivers/gpu/drm/exynos/exynos_mixer.c
@@ -742,7 +742,7 @@ static void mixer_win_mode_set(void *ctx,
 	if (win == DEFAULT_ZPOS)
 		win = MIXER_DEFAULT_WIN;
 
-	if (win < 0 || win > MIXER_WIN_NR) {
+	if (win < 0 || win >= MIXER_WIN_NR) {
 		DRM_ERROR("mixer window[%d] is wrong\n", win);
 		return;
 	}