[mutter/wip/rstrode/rhel-8.0.0: 100/117] monitor-manager: Consider external layout before default linear config

[Ray Strode <halfline src gnome org>]

commit f3765bf412ed15f4e9dbef6a2390aeb3ddaf6738
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Jan 28 15:26:33 2016 +0100

    monitor-manager: Consider external layout before default linear config
    
    In case of no existing configuration, we use a default layout of
    aligning attached displays horizontally. This sidesteps any layout
    configuration that is done externally, for instance via xorg.conf,
    which is not desirable. Instead, base the initial configuration on
    the existing layout if it passes some sanity checks before falling
    back to the default linear config.

 src/backends/meta-monitor-config-manager.c | 77 ++++++++++++++++++++++++++++++
 src/backends/meta-monitor-config-manager.h |  1 +
 src/backends/meta-monitor-manager.c        | 19 ++++++++
 3 files changed, 97 insertions(+)
---
diff --git a/src/backends/meta-monitor-config-manager.c b/src/backends/meta-monitor-config-manager.c
index 197892bf2..585ee7034 100644
--- a/src/backends/meta-monitor-config-manager.c
+++ b/src/backends/meta-monitor-config-manager.c
@@ -559,6 +559,83 @@ create_preferred_logical_monitor_config (MetaMonitorManager          *monitor_ma
   return logical_monitor_config;
 }
 
+static MetaLogicalMonitorConfig *
+create_logical_monitor_config_from_output (MetaMonitorManager           *monitor_manager,
+                                           MetaMonitor                  *monitor,
+                                           MetaLogicalMonitorConfig     *primary_logical_monitor_config,
+                                           MetaLogicalMonitorLayoutMode  layout_mode)
+{
+    MetaOutput *output;
+    MetaCrtc *crtc;
+
+    output = meta_monitor_get_main_output (monitor);
+    crtc = meta_output_get_assigned_crtc (output);
+    return create_preferred_logical_monitor_config (monitor_manager,
+                                                    monitor,
+                                                    crtc->rect.x,
+                                                    crtc->rect.y,
+                                                    primary_logical_monitor_config,
+                                                    layout_mode);
+}
+
+MetaMonitorsConfig *
+meta_monitor_config_manager_create_current (MetaMonitorConfigManager *config_manager)
+{
+  MetaMonitorManager *monitor_manager = config_manager->monitor_manager;
+  GList *logical_monitor_configs;
+  MetaMonitor *primary_monitor;
+  MetaLogicalMonitorLayoutMode layout_mode;
+  MetaLogicalMonitorConfig *primary_logical_monitor_config;
+  GList *monitors;
+  GList *l;
+
+  if (meta_monitor_config_store_get_config_count (config_manager->config_store) > 0)
+    return NULL;
+
+  primary_monitor = find_primary_monitor (monitor_manager);
+  if (!primary_monitor || !meta_monitor_is_active (primary_monitor))
+    return NULL;
+
+  layout_mode = meta_monitor_manager_get_default_layout_mode (monitor_manager);
+
+  primary_logical_monitor_config =
+    create_logical_monitor_config_from_output (monitor_manager,
+                                               primary_monitor,
+                                               NULL,
+                                               layout_mode);
+
+  primary_logical_monitor_config->is_primary = TRUE;
+  logical_monitor_configs = g_list_append (NULL,
+                                           primary_logical_monitor_config);
+
+  monitors = meta_monitor_manager_get_monitors (monitor_manager);
+  for (l = monitors; l; l = l->next)
+    {
+      MetaMonitor *monitor = l->data;
+      MetaLogicalMonitorConfig *logical_monitor_config;
+
+      if (monitor == primary_monitor)
+        continue;
+
+      if (!meta_monitor_is_active (monitor))
+        continue;
+
+      logical_monitor_config =
+        create_logical_monitor_config_from_output (monitor_manager,
+                                                   monitor,
+                                                   primary_logical_monitor_config,
+                                                   layout_mode);
+
+      logical_monitor_configs = g_list_append (logical_monitor_configs,
+                                               logical_monitor_config);
+    }
+
+  return meta_monitors_config_new (monitor_manager,
+                                   logical_monitor_configs,
+                                   layout_mode,
+                                   META_MONITORS_CONFIG_FLAG_NONE);
+}
+
 MetaMonitorsConfig *
 meta_monitor_config_manager_create_linear (MetaMonitorConfigManager *config_manager)
 {
diff --git a/src/backends/meta-monitor-config-manager.h b/src/backends/meta-monitor-config-manager.h
index 269d8e1b7..c36df38e6 100644
--- a/src/backends/meta-monitor-config-manager.h
+++ b/src/backends/meta-monitor-config-manager.h
@@ -87,6 +87,7 @@ gboolean meta_monitor_config_manager_assign (MetaMonitorManager *manager,
 
 MetaMonitorsConfig * meta_monitor_config_manager_get_stored (MetaMonitorConfigManager *config_manager);
 
+MetaMonitorsConfig * meta_monitor_config_manager_create_current (MetaMonitorConfigManager *config_manager);
 MetaMonitorsConfig * meta_monitor_config_manager_create_linear (MetaMonitorConfigManager *config_manager);
 
 MetaMonitorsConfig * meta_monitor_config_manager_create_fallback (MetaMonitorConfigManager *config_manager);
diff --git a/src/backends/meta-monitor-manager.c b/src/backends/meta-monitor-manager.c
index 5bd34ad47..4503eb841 100644
--- a/src/backends/meta-monitor-manager.c
+++ b/src/backends/meta-monitor-manager.c
@@ -576,6 +576,25 @@ meta_monitor_manager_ensure_configured (MetaMonitorManager *manager)
       g_clear_object (&config);
     }
 
+  config = meta_monitor_config_manager_create_current (manager->config_manager);
+  if (config)
+    {
+      if (!meta_monitor_manager_apply_monitors_config (manager,
+                                                       config,
+                                                       method,
+                                                       &error))
+        {
+          g_clear_object (&config);
+          g_warning ("Failed to use current monitor configuration: %s",
+                     error->message);
+          g_clear_error (&error);
+        }
+      else
+        {
+          goto done;
+        }
+    }
+
   config = meta_monitor_config_manager_create_linear (manager->config_manager);
   if (config)
     {