From 35c9280fb6cc22170b952a1924237365dbcca89a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Fri, 11 Aug 2017 15:21:36 +0800
Subject: [PATCH] monitor-manager: Try to restore previous config before
 regenerating

When opening a laptop lid, one will likely want to restore the
configuration one had prior to closing it, so when ensuring monitor
configuration, first try to see if the previously set configuration is
both complete (all connected monitors are configured) and applicable
(it is a valid configuration) and only try to generate a new from
scratch if that failed.

https://bugzilla.gnome.org/show_bug.cgi?id=777732
---
 src/backends/meta-monitor-manager.c | 67 +++++++++++++++++++++++++++++
 src/tests/monitor-unit-tests.c      | 25 +++--------
 2 files changed, 73 insertions(+), 19 deletions(-)

diff --git a/src/backends/meta-monitor-manager.c b/src/backends/meta-monitor-manager.c
index b13926299..aa945a45a 100644
--- a/src/backends/meta-monitor-manager.c
+++ b/src/backends/meta-monitor-manager.c
@@ -71,6 +71,10 @@ G_DEFINE_ABSTRACT_TYPE_WITH_CODE (MetaMonitorManager, meta_monitor_manager, META
 
 static void initialize_dbus_interface (MetaMonitorManager *manager);
 
+static gboolean
+meta_monitor_manager_is_config_complete (MetaMonitorManager *manager,
+                                         MetaMonitorsConfig *config);
+
 static void
 meta_monitor_manager_init (MetaMonitorManager *manager)
 {
@@ -529,6 +533,31 @@ meta_monitor_manager_ensure_configured (MetaMonitorManager *manager)
         }
     }
 
+  config = meta_monitor_config_manager_get_previous (manager->config_manager);
+  if (config)
+    {
+      config = g_object_ref (config);
+
+      if (meta_monitor_manager_is_config_complete (manager, config))
+        {
+          if (!meta_monitor_manager_apply_monitors_config (manager,
+                                                           config,
+                                                           method,
+                                                           &error))
+            {
+              g_warning ("Failed to use suggested monitor configuration: %s",
+                         error->message);
+              g_clear_error (&error);
+            }
+          else
+            {
+              goto done;
+            }
+        }
+
+      g_clear_object (&config);
+    }
+
   config = meta_monitor_config_manager_create_linear (manager->config_manager);
   if (config)
     {
@@ -1494,6 +1523,44 @@ meta_monitor_manager_is_config_applicable (MetaMonitorManager *manager,
   return TRUE;
 }
 
+static gboolean
+meta_monitor_manager_is_config_complete (MetaMonitorManager *manager,
+                                         MetaMonitorsConfig *config)
+{
+  GList *l;
+  unsigned int configured_monitor_count = 0;
+  unsigned int expected_monitor_count = 0;
+
+  for (l = config->logical_monitor_configs; l; l = l->next)
+    {
+      MetaLogicalMonitorConfig *logical_monitor_config = l->data;
+      GList *k;
+
+      for (k = logical_monitor_config->monitor_configs; k; k = k->next)
+        configured_monitor_count++;
+    }
+
+  for (l = manager->monitors; l; l = l->next)
+    {
+      MetaMonitor *monitor = l->data;
+
+      if (meta_monitor_is_laptop_panel (monitor))
+        {
+          if (!meta_monitor_manager_is_lid_closed (manager))
+            expected_monitor_count++;
+        }
+      else
+        {
+          expected_monitor_count++;
+        }
+    }
+
+  if (configured_monitor_count != expected_monitor_count)
+    return FALSE;
+
+  return meta_monitor_manager_is_config_applicable (manager, config, NULL);
+}
+
 static MetaMonitor *
 find_monitor_from_connector (MetaMonitorManager *manager,
                              char               *connector)
diff --git a/src/tests/monitor-unit-tests.c b/src/tests/monitor-unit-tests.c
index 6a8626bca..53455c1f7 100644
--- a/src/tests/monitor-unit-tests.c
+++ b/src/tests/monitor-unit-tests.c
@@ -2281,33 +2281,20 @@ meta_test_monitor_lid_switch_config (void)
   meta_monitor_manager_test_set_is_lid_closed (monitor_manager_test, FALSE);
   meta_monitor_manager_lid_is_closed_changed (monitor_manager);
 
-  test_case.expect.n_logical_monitors = 2;
-  test_case.expect.screen_width = 1024 * 2;
-  test_case.expect.monitors[0].current_mode = 0;
-
-  test_case.expect.crtcs[0].current_mode = 0;
-  test_case.expect.crtcs[1].current_mode = 0;
-
-  /*
-   * FIXME: The above expectation is correct, but MetaMonitorConfigManager
-   * doesn't support restoring previous configurations yet, so it'll
-   * pick keep the external monitor as primary and put it first.
-   */
   test_case.expect.logical_monitors[0] = (MonitorTestCaseLogicalMonitor) {
-    .monitors = { 1 },
+    .monitors = { 0 },
     .n_monitors = 1,
     .layout = {.x = 0, .y = 0, .width = 1024, .height = 768 },
     .scale = 1
   };
-  test_case.expect.logical_monitors[1] = (MonitorTestCaseLogicalMonitor) {
-    .monitors = { 0 },
-    .n_monitors = 1,
-    .layout = {.x = 1024, .y = 0, .width = 1024, .height = 768 },
-    .scale = 1
-  };
   test_case.expect.n_logical_monitors = 2;
+  test_case.expect.screen_width = 1024 * 2;
+  test_case.expect.monitors[0].current_mode = 0;
   test_case.expect.primary_logical_monitor = 0;
 
+  test_case.expect.crtcs[0].current_mode = 0;
+  test_case.expect.crtcs[1].current_mode = 0;
+
   check_monitor_configuration (&test_case);
 }