[mutter/wip/rstrode/rhel-8.0.0: 98/117] monitor-manager-xrandr: Work around spurious hotplugs on Xvnc

[Ray Strode <halfline src gnome org>]

commit 064788cbc94e8600963384d81847627ae076eea4
Author: Rui Matos <tiagomatos gmail com>
Date:   Tue Oct 6 21:16:18 2015 +0200

    monitor-manager-xrandr: Work around spurious hotplugs on Xvnc
    
    Xvnc turns its outputs off/on on every mode set which makes us believe
    there was an hotplug when there actually wasn't. Work around this by
    requiring new randr configuration timestamps to be ahead of the last
    set timestamp by at least 100 ms for us to consider them an actual
    hotplug.

 src/backends/x11/meta-monitor-manager-xrandr.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)
---
diff --git a/src/backends/x11/meta-monitor-manager-xrandr.c b/src/backends/x11/meta-monitor-manager-xrandr.c
index e438d8f98..c6eb4b6aa 100644
--- a/src/backends/x11/meta-monitor-manager-xrandr.c
+++ b/src/backends/x11/meta-monitor-manager-xrandr.c
@@ -1063,6 +1063,19 @@ meta_monitor_manager_xrandr_class_init (MetaMonitorManagerXrandrClass *klass)
     g_quark_from_static_string ("-meta-monitor-xrandr-data");
 }
 
+static gboolean
+is_xvnc (MetaMonitorManager *manager)
+{
+  MetaMonitorManagerXrandr *manager_xrandr = META_MONITOR_MANAGER_XRANDR (manager);
+  GList *l;
+
+  for (l = meta_gpu_get_outputs (manager_xrandr->gpu); l; l = l->next)
+    if (g_str_has_prefix (((MetaOutput *)l->data)->name, "VNC-"))
+      return TRUE;
+
+  return FALSE;
+}
+
 gboolean
 meta_monitor_manager_xrandr_handle_xevent (MetaMonitorManagerXrandr *manager_xrandr,
                                           XEvent                   *event)
@@ -1072,6 +1085,7 @@ meta_monitor_manager_xrandr_handle_xevent (MetaMonitorManagerXrandr *manager_xra
   XRRScreenResources *resources;
   gboolean is_hotplug;
   gboolean is_our_configuration;
+  unsigned int timestamp;
 
   if ((event->type - manager_xrandr->rr_event_base) != RRScreenChangeNotify)
     return FALSE;
@@ -1083,7 +1097,11 @@ meta_monitor_manager_xrandr_handle_xevent (MetaMonitorManagerXrandr *manager_xra
   gpu_xrandr = META_GPU_XRANDR (manager_xrandr->gpu);
   resources = meta_gpu_xrandr_get_resources (gpu_xrandr);
 
-  is_hotplug = resources->timestamp < resources->configTimestamp;
+  timestamp = resources->timestamp;
+  if (is_xvnc (manager))
+    timestamp += 100;
+
+  is_hotplug = (timestamp < resources->configTimestamp);
   is_our_configuration = (resources->timestamp ==
                           manager_xrandr->last_xrandr_set_timestamp);
   if (is_hotplug)