From 45c5f557bd71f6104ed8563571cde772d0ab988c Mon Sep 17 00:00:00 2001
From: Ray Strode <rstrode@redhat.com>
Date: Sat, 12 Jan 2019 12:38:01 -0500
Subject: [PATCH] wayland: force X clients to redraw on resume

On nvidia, the textures backing Xwayland client window contents get
corrupted on suspend.  Xwayland currently doesn't handle this situation
itself.

For now, in order to work around this issue, send an empty output
change event to Xwayland.  This will cause it to force Expose events
to get sent to all clients and get them to redraw.
---
 .../native/meta-monitor-manager-kms.c         |  7 +++
 src/wayland/meta-wayland-outputs.c            | 47 +++++++++++++++++++
 src/wayland/meta-wayland-outputs.h            |  1 +
 3 files changed, 55 insertions(+)

diff --git a/src/backends/native/meta-monitor-manager-kms.c b/src/backends/native/meta-monitor-manager-kms.c
index 438069110..f9a9e1c6d 100644
--- a/src/backends/native/meta-monitor-manager-kms.c
+++ b/src/backends/native/meta-monitor-manager-kms.c
@@ -34,6 +34,7 @@
 #include "meta-crtc-kms.h"
 #include "meta-gpu-kms.h"
 #include "meta-output-kms.h"
+#include "wayland/meta-wayland-outputs.h"
 
 #include <string.h>
 #include <stdlib.h>
@@ -415,9 +416,15 @@ void
 meta_monitor_manager_kms_resume (MetaMonitorManagerKms *manager_kms)
 {
   MetaMonitorManager *manager = META_MONITOR_MANAGER (manager_kms);
+  ClutterBackend *clutter_backend = clutter_get_default_backend ();
+  CoglContext *cogl_context =
+    clutter_backend_get_cogl_context (clutter_backend);
 
   meta_monitor_manager_kms_connect_uevent_handler (manager_kms);
   handle_hotplug_event (manager);
+
+  if (cogl_has_feature (cogl_context, COGL_FEATURE_ID_UNSTABLE_TEXTURES))
+    meta_wayland_outputs_redraw (meta_wayland_compositor_get_default ());
 }
 
 static gboolean
diff --git a/src/wayland/meta-wayland-outputs.c b/src/wayland/meta-wayland-outputs.c
index bd0a3b1ff..56a8f8b19 100644
--- a/src/wayland/meta-wayland-outputs.c
+++ b/src/wayland/meta-wayland-outputs.c
@@ -452,6 +452,53 @@ meta_wayland_compositor_update_outputs (MetaWaylandCompositor *compositor,
   return new_table;
 }
 
+void
+meta_wayland_outputs_redraw (MetaWaylandCompositor *compositor)
+{
+  MetaMonitorManager *monitor_manager;
+  GList *logical_monitors, *l;
+
+  monitor_manager = meta_monitor_manager_get ();
+
+  logical_monitors =
+    meta_monitor_manager_get_logical_monitors (monitor_manager);
+
+  for (l = logical_monitors; l; l = l->next)
+    {
+      MetaLogicalMonitor *logical_monitor = l->data;
+      MetaWaylandOutput *wayland_output;
+      GList *iter;
+
+      if (logical_monitor->winsys_id == 0)
+        continue;
+
+      wayland_output =
+        g_hash_table_lookup (compositor->outputs,
+                             GSIZE_TO_POINTER (logical_monitor->winsys_id));
+
+      if (wayland_output == NULL)
+        continue;
+
+      /* Just output a "changes done" event for one of the outputs, with no actual changes.
+       * xwayland takes this as a cue to send expose events to all X clients.
+       */
+      for (iter = wayland_output->resources; iter; iter = iter->next)
+        {
+          struct wl_resource *resource = iter->data;
+          if (wl_resource_get_version (resource) >= WL_OUTPUT_DONE_SINCE_VERSION)
+            wl_output_send_done (resource);
+        }
+
+      for (iter = wayland_output->xdg_output_resources; iter; iter = iter->next)
+        {
+          struct wl_resource *xdg_output = iter->data;
+          zxdg_output_v1_send_done (xdg_output);
+        }
+
+      break;
+    }
+}
+
 static void
 on_monitors_changed (MetaMonitorManager    *monitors,
                      MetaWaylandCompositor *compositor)
diff --git a/src/wayland/meta-wayland-outputs.h b/src/wayland/meta-wayland-outputs.h
index e6b60d5fa..d8c648174 100644
--- a/src/wayland/meta-wayland-outputs.h
+++ b/src/wayland/meta-wayland-outputs.h
@@ -47,5 +47,6 @@ struct _MetaWaylandOutput
 };
 
 void meta_wayland_outputs_init (MetaWaylandCompositor *compositor);
+void meta_wayland_outputs_redraw (MetaWaylandCompositor *compositor);
 
 #endif /* META_WAYLAND_OUTPUTS_H */