diff --git a/src/backends/native/meta-kms-crtc-private.h b/src/backends/native/meta-kms-crtc-private.h
index 79a5f0fe6..baf5f4099 100644
--- a/src/backends/native/meta-kms-crtc-private.h
+++ b/src/backends/native/meta-kms-crtc-private.h
@@ -42,8 +42,8 @@ MetaKmsResourceChanges meta_kms_crtc_update_state (MetaKmsCrtc *crtc);
 
 void meta_kms_crtc_disable (MetaKmsCrtc *crtc);
 
-MetaKmsResourceChanges meta_kms_crtc_predict_state (MetaKmsCrtc   *crtc,
-                                                    MetaKmsUpdate *update);
+void meta_kms_crtc_predict_state (MetaKmsCrtc   *crtc,
+                                  MetaKmsUpdate *update);
 
 uint32_t meta_kms_crtc_get_prop_id (MetaKmsCrtc     *crtc,
                                     MetaKmsCrtcProp  prop);
diff --git a/src/backends/native/meta-kms-crtc.c b/src/backends/native/meta-kms-crtc.c
index 707dfd4b8..ee9e19d2d 100644
--- a/src/backends/native/meta-kms-crtc.c
+++ b/src/backends/native/meta-kms-crtc.c
@@ -278,14 +278,13 @@ meta_kms_crtc_disable (MetaKmsCrtc *crtc)
   crtc->current_state.drm_mode = (drmModeModeInfo) { 0 };
 }
 
-MetaKmsResourceChanges
+void
 meta_kms_crtc_predict_state (MetaKmsCrtc   *crtc,
                              MetaKmsUpdate *update)
 {
   GList *mode_sets;
   GList *crtc_gammas;
   GList *l;
-  MetaKmsResourceChanges changes = META_KMS_RESOURCE_CHANGE_NONE;
 
   mode_sets = meta_kms_update_get_mode_sets (update);
   for (l = mode_sets; l; l = l->next)
@@ -338,11 +337,8 @@ meta_kms_crtc_predict_state (MetaKmsCrtc   *crtc,
       crtc->current_state.gamma.blue =
         g_memdup2 (gamma->blue, gamma->size * sizeof (uint16_t));
 
-      changes |= META_KMS_RESOURCE_CHANGE_GAMMA;
       break;
     }
-
-  return changes;
 }
 
 static void
diff --git a/src/backends/native/meta-kms-impl-device.c b/src/backends/native/meta-kms-impl-device.c
index 653a96f71..dc2ac31ef 100644
--- a/src/backends/native/meta-kms-impl-device.c
+++ b/src/backends/native/meta-kms-impl-device.c
@@ -923,12 +923,7 @@ meta_kms_impl_device_predict_states (MetaKmsImplDevice *impl_device,
   MetaKmsResourceChanges changes = META_KMS_RESOURCE_CHANGE_NONE;
   GList *l;
 
-  for (l = priv->crtcs; l; l = l->next)
-    {
-      MetaKmsCrtc *crtc = l->data;
-
-      changes |= meta_kms_crtc_predict_state (crtc, update);
-    }
+  g_list_foreach (priv->crtcs, (GFunc) meta_kms_crtc_predict_state, update);
 
   for (l = priv->connectors; l; l = l->next)
     {