@@ -26,6 +26,7 @@
 #include <drm/drm_drv.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_fb_helper.h>
+#include <drm/drm_fourcc.h>
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_irq.h>

@@ -108,9 +109,51 @@ void mxsfb_disable_axi_clk(struct mxsfb_drm_private *mxsfb)
 		clk_disable_unprepare(mxsfb->clk_axi);
 }
 
+/**
+ * mxsfb_atomic_helper_check - validate state object
+ * @dev: DRM device
+ * @state: the driver state object
+ *
+ * On top of the drm imlementation drm_atomic_helper_check,
+ * check if the bpp is changed, if so, signal mode_changed,
+ * this will trigger disable/enable
+ *
+ * RETURNS:
+ * Zero for success or -errno
+ */
+static int mxsfb_atomic_helper_check(struct drm_device *dev,
+				     struct drm_atomic_state *state)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *new_state;
+	int i, ret;
+
+	ret = drm_atomic_helper_check(dev, state);
+	if (ret)
+		return ret;
+
+	for_each_new_crtc_in_state(state, crtc, new_state, i) {
+		struct drm_plane_state *primary_state;
+		int old_bpp = 0;
+		int new_bpp = 0;
+
+		if (!crtc->primary || !crtc->primary->old_fb)
+			continue;
+		primary_state =
+			drm_atomic_get_plane_state(state, crtc->primary);
+		if (!primary_state || !primary_state->fb)
+			continue;
+		old_bpp = crtc->primary->old_fb->format->depth;
+		new_bpp = primary_state->fb->format->depth;
+		if (old_bpp != new_bpp)
+			new_state->mode_changed = true;
+	}
+	return ret;
+}
+
 static const struct drm_mode_config_funcs mxsfb_mode_config_funcs = {
 	.fb_create		= drm_gem_fb_create,
-	.atomic_check		= drm_atomic_helper_check,
+	.atomic_check		= mxsfb_atomic_helper_check,
 	.atomic_commit		= drm_atomic_helper_commit,
 };