backends: Check both input settings and mapper for tablet monitors

The upper layers (OSDs basically) want to know the monitor that a
tablet is currently assigned to, not the monitor just as configured
through settings.

This broke proper OSD positioning for display-attached tablets since
commit 87858a4e01d9, as the MetaInputMapper kicks in precisely when
there is no configured monitor for the given device.

Consulting both about the assigned output will make OSDs pop up
again in the right place.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/971

3 files changed, 83 insertions, 2 deletions

diff --git a/src/backends/meta-input-mapper-private.h b/src/backends/meta-input-mapper-private.h
index 34314577f..cdfdccde9 100644
--- a/src/backends/meta-input-mapper-private.h
+++ b/src/backends/meta-input-mapper-private.h
@@ -42,5 +42,8 @@ ClutterInputDevice *
 meta_input_mapper_get_logical_monitor_device (MetaInputMapper        *mapper,
                                               MetaLogicalMonitor     *logical_monitor,
                                               ClutterInputDeviceType  device_type);
+MetaLogicalMonitor *
+meta_input_mapper_get_device_logical_monitor (MetaInputMapper *mapper,
+                                              ClutterInputDevice *device);
 
 #endif /* META_INPUT_MAPPER_H */
diff --git a/src/backends/meta-input-mapper.c b/src/backends/meta-input-mapper.c
index 0e5a5f5c3..a241af3f5 100644
--- a/src/backends/meta-input-mapper.c
+++ b/src/backends/meta-input-mapper.c
@@ -675,3 +675,29 @@ meta_input_mapper_get_logical_monitor_device (MetaInputMapper        *mapper,
 
   return NULL;
 }
+
+MetaLogicalMonitor *
+meta_input_mapper_get_device_logical_monitor (MetaInputMapper    *mapper,
+                                              ClutterInputDevice *device)
+{
+  MetaMapperOutputInfo *output;
+  MetaLogicalMonitor *logical_monitor;
+  GHashTableIter iter;
+  GList *l;
+
+  g_hash_table_iter_init (&iter, mapper->output_devices);
+
+  while (g_hash_table_iter_next (&iter, (gpointer *) &logical_monitor,
+                                 (gpointer *) &output))
+    {
+      for (l = output->input_devices; l; l = l->next)
+        {
+          MetaMapperInputInfo *input = l->data;
+
+          if (input->device == device)
+            return logical_monitor;
+        }
+    }
+
+  return NULL;
+}
diff --git a/src/backends/meta-input-settings.c b/src/backends/meta-input-settings.c
index 73f4131fe..2028570c0 100644
--- a/src/backends/meta-input-settings.c
+++ b/src/backends/meta-input-settings.c
@@ -2064,6 +2064,44 @@ meta_input_settings_get_tablet_settings (MetaInputSettings  *settings,
   return info ? g_object_ref (info->settings) : NULL;
 }
 
+static ClutterInputDevice *
+find_grouped_pen (MetaInputSettings  *settings,
+                  ClutterInputDevice *device)
+{
+  MetaInputSettingsPrivate *priv;
+  GList *l, *devices;
+  ClutterInputDeviceType device_type;
+  ClutterInputDevice *pen = NULL;
+
+  device_type = clutter_input_device_get_device_type (device);
+
+  if (device_type == CLUTTER_TABLET_DEVICE ||
+      device_type == CLUTTER_PEN_DEVICE)
+    return device;
+
+  priv = meta_input_settings_get_instance_private (settings);
+  devices = clutter_seat_list_devices (priv->seat);
+
+  for (l = devices; l; l = l->next)
+    {
+      ClutterInputDevice *other_device = l->data;
+
+      device_type = clutter_input_device_get_device_type (other_device);
+
+      if ((device_type == CLUTTER_TABLET_DEVICE ||
+           device_type == CLUTTER_PEN_DEVICE) &&
+          clutter_input_device_is_grouped (device, other_device))
+        {
+          pen = other_device;
+          break;
+        }
+    }
+
+  g_list_free (devices);
+
+  return pen;
+}
+
 MetaLogicalMonitor *
 meta_input_settings_get_tablet_logical_monitor (MetaInputSettings  *settings,
                                                 ClutterInputDevice *device)
@@ -2075,13 +2113,27 @@ meta_input_settings_get_tablet_logical_monitor (MetaInputSettings  *settings,
   g_return_val_if_fail (META_IS_INPUT_SETTINGS (settings), NULL);
   g_return_val_if_fail (CLUTTER_IS_INPUT_DEVICE (device), NULL);
 
+  if (clutter_input_device_get_device_type (device) == CLUTTER_PAD_DEVICE)
+    {
+      device = find_grouped_pen (settings, device);
+      if (!device)
+        return NULL;
+    }
+
   priv = meta_input_settings_get_instance_private (settings);
   info = g_hash_table_lookup (priv->mappable_devices, device);
   if (!info)
     return NULL;
 
-  meta_input_settings_find_monitor (settings, info->settings, device,
-                                    NULL, &logical_monitor);
+  logical_monitor =
+    meta_input_mapper_get_device_logical_monitor (priv->input_mapper, device);
+
+  if (!logical_monitor)
+    {
+      meta_input_settings_find_monitor (settings, info->settings, device,
+                                        NULL, &logical_monitor);
+    }
+
   return logical_monitor;
 }