[mutter] cursor-renderer/native: Handle GPU hotplug

[Jonas Ådahl <jadahl src gnome org>]

commit 8abdf16a3992e3332f2378ea7c65e6e251e418e0
Author: Pekka Paalanen <pekka paalanen collabora com>
Date:   Mon Feb 24 15:36:24 2020 +0200

    cursor-renderer/native: Handle GPU hotplug
    
    Listen for GPU hotplug events to initialize their cursor support.
    
    This fixes one reason for why DisplayLink devices may not be using a hardware
    cursor. Particularly, when a DisplayLink device is hotplugged for the first
    time such that EVDI creates a new DRM device node after gnome-shell has already
    started, we used to forget to initialize the cursor support.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/1097

 src/backends/native/meta-cursor-renderer-native.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
---
diff --git a/src/backends/native/meta-cursor-renderer-native.c 
b/src/backends/native/meta-cursor-renderer-native.c
index cf500f07c..b400a8740 100644
--- a/src/backends/native/meta-cursor-renderer-native.c
+++ b/src/backends/native/meta-cursor-renderer-native.c
@@ -2,6 +2,7 @@
 
 /*
  * Copyright (C) 2014 Red Hat
+ * Copyright 2020 DisplayLink (UK) Ltd.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
@@ -1626,6 +1627,13 @@ init_hw_cursor_support_for_gpu (MetaGpuKms *gpu_kms)
   cursor_renderer_gpu_data->cursor_height = height;
 }
 
+static void
+on_gpu_added_for_cursor (MetaBackend *backend,
+                         MetaGpuKms  *gpu_kms)
+{
+  init_hw_cursor_support_for_gpu (gpu_kms);
+}
+
 static void
 init_hw_cursor_support (MetaCursorRendererNative *cursor_renderer_native)
 {
@@ -1659,6 +1667,8 @@ meta_cursor_renderer_native_new (MetaBackend *backend)
   g_signal_connect_object (monitor_manager, "monitors-changed-internal",
                            G_CALLBACK (on_monitors_changed),
                            cursor_renderer_native, 0);
+  g_signal_connect (backend, "gpu-added",
+                    G_CALLBACK (on_gpu_added_for_cursor), NULL);
 
   priv->backend = backend;
   priv->hw_state_invalidated = TRUE;