diff --git a/src/backends/meta-monitor-config-manager.c b/src/backends/meta-monitor-config-manager.c
index c99d31e54..8938f4e2c 100644
--- a/src/backends/meta-monitor-config-manager.c
+++ b/src/backends/meta-monitor-config-manager.c
@@ -410,6 +410,25 @@ is_lid_closed (MetaMonitorManager *monitor_manager)
     return meta_backend_is_lid_closed (backend);
 }
 
+gboolean
+meta_config_key_edid_sufficient_for_specs (GList *monitor_specs)
+{
+  GList *l;
+
+  for (l = monitor_specs; l && l->next; l = l->next)
+    {
+      MetaMonitorSpec *spec = l->data;
+      MetaMonitorSpec *spec_next = l->next->data;
+
+      if (meta_monitor_spec_equals (spec, spec_next, TRUE))
+        return FALSE;
+
+      /* XXX: Should we reject e.g. only 0 serial numbers? */
+    }
+
+  return TRUE;
+}
+
 MetaMonitorsConfigKey *
 meta_create_monitors_config_key_for_current_state (MetaMonitorManager *monitor_manager)
 {
@@ -439,7 +458,8 @@ meta_create_monitors_config_key_for_current_state (MetaMonitorManager *monitor_m
 
   config_key = g_new0 (MetaMonitorsConfigKey, 1);
   *config_key = (MetaMonitorsConfigKey) {
-    .monitor_specs = monitor_specs
+    .monitor_specs = monitor_specs,
+    .edid_sufficient = meta_config_key_edid_sufficient_for_specs (monitor_specs)
   };
 
   return config_key;
@@ -1356,7 +1376,8 @@ meta_monitors_config_key_new (GList *logical_monitor_configs,
 
   config_key = g_new0 (MetaMonitorsConfigKey, 1);
   *config_key = (MetaMonitorsConfigKey) {
-    .monitor_specs = monitor_specs
+    .monitor_specs = monitor_specs,
+    .edid_sufficient = meta_config_key_edid_sufficient_for_specs (monitor_specs)
   };
 
   return config_key;
diff --git a/src/backends/meta-monitor-config-manager.h b/src/backends/meta-monitor-config-manager.h
index 3875e04e9..207cec473 100644
--- a/src/backends/meta-monitor-config-manager.h
+++ b/src/backends/meta-monitor-config-manager.h
@@ -48,7 +48,9 @@ typedef struct _MetaLogicalMonitorConfig
 
 typedef struct _MetaMonitorsConfigKey
 {
+  /* monitor_specs needs to be sorted using meta_monitor_spec_compare. */
   GList *monitor_specs;
+  gboolean edid_sufficient;
 } MetaMonitorsConfigKey;
 
 typedef enum _MetaMonitorsConfigFlag
@@ -159,6 +161,9 @@ META_EXPORT_TEST
 gboolean meta_monitors_config_key_equal (gconstpointer config_key_a,
                                          gconstpointer config_key_b);
 
+META_EXPORT_TEST
+gboolean meta_config_key_edid_sufficient_for_specs (GList *monitor_specs);
+
 META_EXPORT_TEST
 void meta_monitors_config_key_free (MetaMonitorsConfigKey *config_key);
 
diff --git a/src/backends/meta-monitor-manager-private.h b/src/backends/meta-monitor-manager-private.h
index 20bb6b679..897454697 100644
--- a/src/backends/meta-monitor-manager-private.h
+++ b/src/backends/meta-monitor-manager-private.h
@@ -122,6 +122,7 @@ struct _MetaMonitorManager
   int screen_height;
 
   GList *monitors;
+  gboolean edid_sufficient;
 
   GList *logical_monitors;
   MetaLogicalMonitor *primary_logical_monitor;
diff --git a/src/backends/meta-monitor-manager.c b/src/backends/meta-monitor-manager.c
index b773d436f..b0e1c449c 100644
--- a/src/backends/meta-monitor-manager.c
+++ b/src/backends/meta-monitor-manager.c
@@ -2621,6 +2621,7 @@ rebuild_monitors (MetaMonitorManager *manager)
 {
   GList *gpus;
   GList *l;
+  GList *specs;
 
   if (manager->monitors)
     {
@@ -2659,6 +2660,15 @@ rebuild_monitors (MetaMonitorManager *manager)
             }
         }
     }
+
+  specs = NULL;
+  for (l = manager->monitors; l; l = l->next)
+    specs = g_list_prepend (specs, meta_monitor_get_spec (l->data));
+
+  specs = g_list_sort (specs,
+                       (GCompareFunc) meta_monitor_spec_compare);
+  manager->edid_sufficient = meta_config_key_edid_sufficient_for_specs (specs);
+  g_list_free (specs);
 }
 
 void
diff --git a/src/tests/monitor-store-unit-tests.c b/src/tests/monitor-store-unit-tests.c
index 4a73d89db..77810e2e7 100644
--- a/src/tests/monitor-store-unit-tests.c
+++ b/src/tests/monitor-store-unit-tests.c
@@ -108,7 +108,8 @@ create_config_key_from_expect (MonitorStoreTestConfiguration *expect_config)
 
   config_key = g_new0 (MetaMonitorsConfigKey, 1);
   *config_key = (MetaMonitorsConfigKey) {
-    .monitor_specs = monitor_specs
+    .monitor_specs = monitor_specs,
+    .edid_sufficient = meta_config_key_edid_sufficient_for_specs (monitor_specs)
   };
 
   return config_key;