diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
index 1e78d57..c3dad66 100644
--- a/drivers/gpu/drm/exynos/exynos_mixer.c
+++ b/drivers/gpu/drm/exynos/exynos_mixer.c
@@ -93,12 +93,25 @@ static const uint32_t vp_formats[] = {
 	DRM_FORMAT_NV21,
 };
 
+/*
+ * Mixer context structure.
+ *
+ * @crtc: The HDMI CRTC attached to the mixer.
+ * @planes: Array of plane objects for each of the mixer windows.
+ * @active_windows: Cache of the mixer's hardware state.
+ *       Tracks which mixer windows are active/inactive.
+ * @pipe: The CRTC index.
+ * @flags: Bitfield build from the mixer_flag_bits enumerator.
+ * @mixer_resources: A struct containing registers, clocks, etc.
+ * @mxr_ver: The hardware revision/version of the mixer.
+ */
 struct mixer_context {
 	struct platform_device *pdev;
 	struct device		*dev;
 	struct drm_device	*drm_dev;
 	struct exynos_drm_crtc	*crtc;
 	struct exynos_drm_plane	planes[MIXER_WIN_NR];
+	unsigned long		active_windows;
 	int			pipe;
 	unsigned long		flags;
 
@@ -418,37 +431,68 @@ static void mixer_cfg_rgb_fmt(struct mixer_context *ctx, unsigned int height)
 	mixer_reg_writemask(res, MXR_CFG, val, MXR_CFG_RGB_FMT_MASK);
 }
 
-static void mixer_cfg_layer(struct mixer_context *ctx, unsigned int win,
-			    unsigned int priority, bool enable)
+static void mixer_cfg_layer(struct mixer_context *ctx)
 {
 	struct mixer_resources *res = &ctx->mixer_res;
-	u32 val = enable ? ~0 : 0;
-
-	switch (win) {
-	case 0:
-		mixer_reg_writemask(res, MXR_CFG, val, MXR_CFG_GRP0_ENABLE);
-		mixer_reg_writemask(res, MXR_LAYER_CFG,
-				    MXR_LAYER_CFG_GRP0_VAL(priority),
-				    MXR_LAYER_CFG_GRP0_MASK);
-		break;
-	case 1:
-		mixer_reg_writemask(res, MXR_CFG, val, MXR_CFG_GRP1_ENABLE);
-		mixer_reg_writemask(res, MXR_LAYER_CFG,
-				    MXR_LAYER_CFG_GRP1_VAL(priority),
-				    MXR_LAYER_CFG_GRP1_MASK);
+	unsigned int win;
 
-		break;
-	case VP_DEFAULT_WIN:
-		if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags)) {
-			vp_reg_writemask(res, VP_ENABLE, val, VP_ENABLE_ON);
-			mixer_reg_writemask(res, MXR_CFG, val,
-				MXR_CFG_VP_ENABLE);
-			mixer_reg_writemask(res, MXR_LAYER_CFG,
-					    MXR_LAYER_CFG_VP_VAL(priority),
-					    MXR_LAYER_CFG_VP_MASK);
+	struct exynos_drm_plane_state *state;
+	struct drm_framebuffer *fb;
+	unsigned int priority;
+	u32 mxr_cfg = 0, mxr_layer_cfg = 0, vp_enable = 0;
+	bool enable;
+
+	for (win = 0; win < MIXER_WIN_NR; ++win) {
+		state = to_exynos_plane_state(ctx->planes[win].base.state);
+		fb = state->fb;
+
+		priority = state->base.normalized_zpos + 1;
+		enable = test_bit(win, &ctx->active_windows);
+
+		if (!enable)
+			continue;
+
+		switch (win) {
+		case 0:
+			mxr_cfg |=  MXR_CFG_GRP0_ENABLE;
+			mxr_layer_cfg |= MXR_LAYER_CFG_GRP0_VAL(priority);
+			break;
+
+		case 1:
+			mxr_cfg |=  MXR_CFG_GRP1_ENABLE;
+			mxr_layer_cfg |= MXR_LAYER_CFG_GRP1_VAL(priority);
+			break;
+
+		case VP_DEFAULT_WIN:
+			vp_enable = VP_ENABLE_ON;
+			mxr_cfg |=  MXR_CFG_VP_ENABLE;
+			mxr_layer_cfg |= MXR_LAYER_CFG_VP_VAL(priority);
+			break;
+		}
+
+		if (!fb)
+			continue;
+
+		/*
+		 * TODO: Don't enable alpha blending for the bottom window.
+		 */
+		switch (win) {
+		case 0:
+		case 1:
+			mixer_cfg_gfx_blend(ctx, win, is_alpha_format(fb->pixel_format));
+			break;
+
+		case VP_DEFAULT_WIN:
+			mixer_cfg_vp_blend(ctx);
+			break;
 		}
-		break;
 	}
+
+	if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags))
+		vp_reg_writemask(res, VP_ENABLE, vp_enable, VP_ENABLE_ON);
+
+	mixer_reg_writemask(res, MXR_CFG, mxr_cfg, MXR_CFG_ENABLE_MASK);
+	mixer_reg_writemask(res, MXR_LAYER_CFG, mxr_layer_cfg, MXR_LAYER_CFG_MASK);
 }
 
 static void mixer_run(struct mixer_context *ctx)
@@ -478,7 +522,6 @@ static void vp_video_buffer(struct mixer_context *ctx,
 	struct drm_display_mode *mode = &state->base.crtc->state->adjusted_mode;
 	struct mixer_resources *res = &ctx->mixer_res;
 	struct drm_framebuffer *fb = state->fb;
-	unsigned int priority = state->base.normalized_zpos + 1;
 	unsigned long flags;
 	dma_addr_t luma_addr[2], chroma_addr[2];
 	bool tiled_mode = false;
@@ -563,8 +606,6 @@ static void vp_video_buffer(struct mixer_context *ctx,
 
 	mixer_cfg_scan(ctx, mode->vdisplay);
 	mixer_cfg_rgb_fmt(ctx, mode->vdisplay);
-	mixer_cfg_layer(ctx, plane->index, priority, true);
-	mixer_cfg_vp_blend(ctx);
 	mixer_run(ctx);
 
 	spin_unlock_irqrestore(&res->reg_slock, flags);
@@ -588,7 +629,6 @@ static void mixer_graph_buffer(struct mixer_context *ctx,
 	struct drm_display_mode *mode = &state->base.crtc->state->adjusted_mode;
 	struct mixer_resources *res = &ctx->mixer_res;
 	struct drm_framebuffer *fb = state->fb;
-	unsigned int priority = state->base.normalized_zpos + 1;
 	unsigned long flags;
 	unsigned int win = plane->index;
 	unsigned int x_ratio = 0, y_ratio = 0;
@@ -680,8 +720,6 @@ static void mixer_graph_buffer(struct mixer_context *ctx,
 
 	mixer_cfg_scan(ctx, mode->vdisplay);
 	mixer_cfg_rgb_fmt(ctx, mode->vdisplay);
-	mixer_cfg_layer(ctx, win, priority, true);
-	mixer_cfg_gfx_blend(ctx, win, is_alpha_format(fb->pixel_format));
 
 	/* layer update mandatory for mixer 16.0.33.0 */
 	if (ctx->mxr_ver == MXR_VER_16_0_33_0 ||
@@ -726,9 +764,6 @@ static void mixer_win_reset(struct mixer_context *ctx)
 	mixer_reg_writemask(res, MXR_STATUS, MXR_STATUS_16_BURST,
 		MXR_STATUS_BURST_MASK);
 
-	/* reset default layer priority */
-	mixer_reg_write(res, MXR_LAYER_CFG, 0);
-
 	/* setting background color */
 	mixer_reg_write(res, MXR_BG_COLOR0, 0x008080);
 	mixer_reg_write(res, MXR_BG_COLOR1, 0x008080);
@@ -740,11 +775,9 @@ static void mixer_win_reset(struct mixer_context *ctx)
 		vp_default_filter(res);
 	}
 
-	/* disable all layers */
-	mixer_reg_writemask(res, MXR_CFG, 0, MXR_CFG_GRP0_ENABLE);
-	mixer_reg_writemask(res, MXR_CFG, 0, MXR_CFG_GRP1_ENABLE);
-	if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags))
-		mixer_reg_writemask(res, MXR_CFG, 0, MXR_CFG_VP_ENABLE);
+	/* disable all layers and reset layer priority to default */
+	ctx->active_windows = 0;
+	mixer_cfg_layer(ctx);
 
 	spin_unlock_irqrestore(&res->reg_slock, flags);
 }
@@ -994,32 +1027,36 @@ static void mixer_update_plane(struct exynos_drm_crtc *crtc,
 		vp_video_buffer(mixer_ctx, plane);
 	else
 		mixer_graph_buffer(mixer_ctx, plane);
+
+	__set_bit(plane->index, &mixer_ctx->active_windows);
 }
 
 static void mixer_disable_plane(struct exynos_drm_crtc *crtc,
 				struct exynos_drm_plane *plane)
 {
 	struct mixer_context *mixer_ctx = crtc->ctx;
-	struct mixer_resources *res = &mixer_ctx->mixer_res;
-	unsigned long flags;
 
 	DRM_DEBUG_KMS("win: %d\n", plane->index);
 
 	if (!test_bit(MXR_BIT_POWERED, &mixer_ctx->flags))
 		return;
 
-	spin_lock_irqsave(&res->reg_slock, flags);
-	mixer_cfg_layer(mixer_ctx, plane->index, 0, false);
-	spin_unlock_irqrestore(&res->reg_slock, flags);
+	__clear_bit(plane->index, &mixer_ctx->active_windows);
 }
 
 static void mixer_atomic_flush(struct exynos_drm_crtc *crtc)
 {
 	struct mixer_context *mixer_ctx = crtc->ctx;
+	struct mixer_resources *res = &mixer_ctx->mixer_res;
+	unsigned long flags;
 
 	if (!test_bit(MXR_BIT_POWERED, &mixer_ctx->flags))
 		return;
 
+	spin_lock_irqsave(&res->reg_slock, flags);
+	mixer_cfg_layer(mixer_ctx);
+	spin_unlock_irqrestore(&res->reg_slock, flags);
+
 	mixer_vsync_set_update(mixer_ctx, true);
 }
 
@@ -1053,6 +1090,8 @@ static void mixer_enable(struct exynos_drm_crtc *crtc)
 static void mixer_disable(struct exynos_drm_crtc *crtc)
 {
 	struct mixer_context *ctx = crtc->ctx;
+	struct mixer_resources *res = &ctx->mixer_res;
+	unsigned long flags;
 	int i;
 
 	if (!test_bit(MXR_BIT_POWERED, &ctx->flags))
@@ -1064,6 +1103,10 @@ static void mixer_disable(struct exynos_drm_crtc *crtc)
 	for (i = 0; i < MIXER_WIN_NR; i++)
 		mixer_disable_plane(crtc, &ctx->planes[i]);
 
+	spin_lock_irqsave(&res->reg_slock, flags);
+	mixer_cfg_layer(ctx);
+	spin_unlock_irqrestore(&res->reg_slock, flags);
+
 	exynos_drm_pipe_clk_enable(crtc, false);
 
 	pm_runtime_put(ctx->dev);
diff --git a/drivers/gpu/drm/exynos/regs-mixer.h b/drivers/gpu/drm/exynos/regs-mixer.h
index 7f22df5..728a18e 100644
--- a/drivers/gpu/drm/exynos/regs-mixer.h
+++ b/drivers/gpu/drm/exynos/regs-mixer.h
@@ -100,6 +100,7 @@
 #define MXR_CFG_GRP1_ENABLE		(1 << 5)
 #define MXR_CFG_GRP0_ENABLE		(1 << 4)
 #define MXR_CFG_VP_ENABLE		(1 << 3)
+#define MXR_CFG_ENABLE_MASK		(0x7 << 3)
 #define MXR_CFG_SCAN_INTERLACE		(0 << 2)
 #define MXR_CFG_SCAN_PROGRESSIVE	(1 << 2)
 #define MXR_CFG_SCAN_NTSC		(0 << 1)
@@ -151,6 +152,7 @@
 #define MXR_LAYER_CFG_GRP0_MASK		MXR_LAYER_CFG_GRP0_VAL(~0)
 #define MXR_LAYER_CFG_VP_VAL(x)		MXR_MASK_VAL(x, 3, 0)
 #define MXR_LAYER_CFG_VP_MASK		MXR_LAYER_CFG_VP_VAL(~0)
+#define MXR_LAYER_CFG_MASK		0xFFF
 
 #endif /* SAMSUNG_REGS_MIXER_H */
 
