From d79fe1960b4909455555f80de21eeaf3ec19d2d8 Mon Sep 17 00:00:00 2001
From: Benjamin Berg <bberg@redhat.com>
Date: Fri, 20 Dec 2019 14:17:46 +0100
Subject: [PATCH] monitor: Add flag whether EDID is sufficient to disambiguate
 monitors

If the EDID of the attached or stored monitor configurations contain
proper serial numbers, then we do not need to rely on the connector to
disambiguate them. Add a boolean to both MetaMonitorManager and
MetaMonitorsConfigKey to store this information.

https://gitlab.gnome.org/GNOME/mutter/issues/932
---
 src/backends/meta-monitor-config-manager.c  | 25 +++++++++++++++++++--
 src/backends/meta-monitor-config-manager.h  |  5 +++++
 src/backends/meta-monitor-manager-private.h |  1 +
 src/backends/meta-monitor-manager.c         | 10 +++++++++
 src/tests/monitor-store-unit-tests.c        |  3 ++-
 5 files changed, 41 insertions(+), 3 deletions(-)

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;