From ad61347e9d92380fbbb4effd8a19349777d76715 Mon Sep 17 00:00:00 2001
From: Rui Matos <tiagomatos@gmail.com>
Date: Tue, 6 Oct 2015 21:16:18 +0200
Subject: [PATCH] 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.
---
 .../x11/meta-monitor-manager-xrandr.c         | 25 ++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/backends/x11/meta-monitor-manager-xrandr.c b/src/backends/x11/meta-monitor-manager-xrandr.c
index dbe3e4e3b..90a3952db 100644
--- a/src/backends/x11/meta-monitor-manager-xrandr.c
+++ b/src/backends/x11/meta-monitor-manager-xrandr.c
@@ -1058,6 +1058,24 @@ 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)
+    {
+      MetaOutput *output = l->data;
+
+      if (g_str_has_prefix (output->name, "VNC-"))
+        return TRUE;
+    }
+
+  return FALSE;
+}
+
 gboolean
 meta_monitor_manager_xrandr_handle_xevent (MetaMonitorManagerXrandr *manager_xrandr,
 					   XEvent                   *event)
@@ -1067,6 +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;
@@ -1078,7 +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)
-- 
2.17.0