diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index 7a9f4768591e..265064c62d49 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -168,7 +168,7 @@ static int vc4_get_clock_select(struct drm_crtc *crtc)
 	struct drm_connector *connector;
 
 	drm_for_each_connector(connector, crtc->dev) {
-		if (connector && connector->state->crtc == crtc) {
+		if (connector->state->crtc == crtc) {
 			struct drm_encoder *encoder = connector->encoder;
 			struct vc4_encoder *vc4_encoder =
 				to_vc4_encoder(encoder);
@@ -401,7 +401,8 @@ static void vc4_crtc_atomic_flush(struct drm_crtc *crtc,
 		dlist_next++;
 
 		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),
-			  (u32 *)vc4_crtc->dlist - (u32 *)vc4->hvs->dlist);
+			  (u32 __iomem *)vc4_crtc->dlist -
+			  (u32 __iomem *)vc4->hvs->dlist);
 
 		/* Make the next display list start after ours. */
 		vc4_crtc->dlist_size -= (dlist_next - vc4_crtc->dlist);
@@ -591,14 +592,14 @@ static int vc4_crtc_bind(struct device *dev, struct device *master, void *data)
 	 * that will take too much.
 	 */
 	primary_plane = vc4_plane_init(drm, DRM_PLANE_TYPE_PRIMARY);
-	if (!primary_plane) {
+	if (IS_ERR(primary_plane)) {
 		dev_err(dev, "failed to construct primary plane\n");
 		ret = PTR_ERR(primary_plane);
 		goto err;
 	}
 
 	cursor_plane = vc4_plane_init(drm, DRM_PLANE_TYPE_CURSOR);
-	if (!cursor_plane) {
+	if (IS_ERR(cursor_plane)) {
 		dev_err(dev, "failed to construct cursor plane\n");
 		ret = PTR_ERR(cursor_plane);
 		goto err_primary;
diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 6e730605edcc..d5db9e0f3b73 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -259,7 +259,6 @@ static struct platform_driver vc4_platform_driver = {
 	.remove		= vc4_platform_drm_remove,
 	.driver		= {
 		.name	= "vc4-drm",
-		.owner	= THIS_MODULE,
 		.of_match_table = vc4_of_match,
 	},
 };
diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
index ab1673f672a4..8098c5b21ba4 100644
--- a/drivers/gpu/drm/vc4/vc4_hvs.c
+++ b/drivers/gpu/drm/vc4/vc4_hvs.c
@@ -75,10 +75,10 @@ void vc4_hvs_dump_state(struct drm_device *dev)
 	for (i = 0; i < 64; i += 4) {
 		DRM_INFO("0x%08x (%s): 0x%08x 0x%08x 0x%08x 0x%08x\n",
 			 i * 4, i < HVS_BOOTLOADER_DLIST_END ? "B" : "D",
-			 ((uint32_t *)vc4->hvs->dlist)[i + 0],
-			 ((uint32_t *)vc4->hvs->dlist)[i + 1],
-			 ((uint32_t *)vc4->hvs->dlist)[i + 2],
-			 ((uint32_t *)vc4->hvs->dlist)[i + 3]);
+			 readl((u32 __iomem *)vc4->hvs->dlist + i + 0),
+			 readl((u32 __iomem *)vc4->hvs->dlist + i + 1),
+			 readl((u32 __iomem *)vc4->hvs->dlist + i + 2),
+			 readl((u32 __iomem *)vc4->hvs->dlist + i + 3));
 	}
 }
 
diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c
index cdd8b10c0147..887f3caad0be 100644
--- a/drivers/gpu/drm/vc4/vc4_plane.c
+++ b/drivers/gpu/drm/vc4/vc4_plane.c
@@ -70,7 +70,7 @@ static bool plane_enabled(struct drm_plane_state *state)
 	return state->fb && state->crtc;
 }
 
-struct drm_plane_state *vc4_plane_duplicate_state(struct drm_plane *plane)
+static struct drm_plane_state *vc4_plane_duplicate_state(struct drm_plane *plane)
 {
 	struct vc4_plane_state *vc4_state;
 
@@ -97,8 +97,8 @@ struct drm_plane_state *vc4_plane_duplicate_state(struct drm_plane *plane)
 	return &vc4_state->base;
 }
 
-void vc4_plane_destroy_state(struct drm_plane *plane,
-			     struct drm_plane_state *state)
+static void vc4_plane_destroy_state(struct drm_plane *plane,
+				    struct drm_plane_state *state)
 {
 	struct vc4_plane_state *vc4_state = to_vc4_plane_state(state);
 
@@ -108,7 +108,7 @@ void vc4_plane_destroy_state(struct drm_plane *plane,
 }
 
 /* Called during init to allocate the plane's atomic state. */
-void vc4_plane_reset(struct drm_plane *plane)
+static void vc4_plane_reset(struct drm_plane *plane)
 {
 	struct vc4_plane_state *vc4_state;
 
@@ -157,6 +157,16 @@ static int vc4_plane_mode_set(struct drm_plane *plane,
 	int crtc_w = state->crtc_w;
 	int crtc_h = state->crtc_h;
 
+	if (state->crtc_w << 16 != state->src_w ||
+	    state->crtc_h << 16 != state->src_h) {
+		/* We don't support scaling yet, which involves
+		 * allocating the LBM memory for scaling temporary
+		 * storage, and putting filter kernels in the HVS
+		 * context.
+		 */
+		return -EINVAL;
+	}
+
 	if (crtc_x < 0) {
 		offset += drm_format_plane_cpp(fb->pixel_format, 0) * -crtc_x;
 		crtc_w += crtc_x;