drm_fbdev_cma_hotplug_event(imxdrm->fbhelper);
 }
 
+static int imx_drm_atomic_check(struct drm_device *dev,
+                               struct drm_atomic_state *state)
+{
+       int ret;
+
+       ret = drm_atomic_helper_check_modeset(dev, state);
+       if (ret)
+               return ret;
+
+       ret = drm_atomic_helper_check_planes(dev, state);
+       if (ret)
+               return ret;
+
+       /*
+        * Check modeset again in case crtc_state->mode_changed is
+        * updated in plane's ->atomic_check callback.
+        */
+       ret = drm_atomic_helper_check_modeset(dev, state);
+       if (ret)
+               return ret;
+
+       return ret;
+}
+
 static const struct drm_mode_config_funcs imx_drm_mode_config_funcs = {
        .fb_create = drm_fb_cma_create,
        .output_poll_changed = imx_drm_output_poll_changed,
-       .atomic_check = drm_atomic_helper_check,
+       .atomic_check = imx_drm_atomic_check,
        .atomic_commit = drm_atomic_helper_commit,
 };
 
 
                return -EINVAL;
 
        /*
-        * since we cannot touch active IDMAC channels, we do not support
-        * resizing the enabled plane or changing its format
+        * We support resizing active plane or changing its format by
+        * forcing CRTC mode change in plane's ->atomic_check callback
+        * and disabling all affected active planes in CRTC's ->atomic_disable
+        * callback.  The planes will be reenabled in plane's ->atomic_update
+        * callback.
         */
        if (old_fb && (state->src_w != old_state->src_w ||
                              state->src_h != old_state->src_h ||
                              fb->pixel_format != old_fb->pixel_format))
-               return -EINVAL;
+               crtc_state->mode_changed = true;
 
        eba = drm_plane_state_to_eba(state);
 
                return -EINVAL;
 
        if (old_fb && fb->pitches[0] != old_fb->pitches[0])
-               return -EINVAL;
+               crtc_state->mode_changed = true;
 
        switch (fb->pixel_format) {
        case DRM_FORMAT_YUV420:
                        return -EINVAL;
 
                if (old_fb && old_fb->pitches[1] != fb->pitches[1])
-                       return -EINVAL;
+                       crtc_state->mode_changed = true;
        }
 
        return 0;