--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/mozilla-bmo1744896.patch Sat Jan 08 10:41:19 2022 +0100
@@ -0,0 +1,43 @@
+diff -up firefox-95.0.2/widget/gtk/nsWindow.cpp.1744896 firefox-95.0.2/widget/gtk/nsWindow.cpp
+--- firefox-95.0.2/widget/gtk/nsWindow.cpp.1744896 2021-12-23 11:54:31.522539340 +0100
++++ firefox-95.0.2/widget/gtk/nsWindow.cpp 2021-12-23 11:55:56.070270174 +0100
+@@ -5765,6 +5765,17 @@ nsresult nsWindow::Create(nsIWidget* aPa
+ }
+ }
+ #endif
++#ifdef MOZ_WAYLAND
++ // Initialize the window specific VsyncSource early in order to avoid races
++ // with BrowserParent::UpdateVsyncParentVsyncSource().
++ // Only use for toplevel windows for now, see bug 1619246.
++ if (GdkIsWaylandDisplay() &&
++ StaticPrefs::widget_wayland_vsync_enabled_AtStartup() &&
++ mWindowType == eWindowType_toplevel) {
++ mWaylandVsyncSource = new WaylandVsyncSource();
++ MOZ_RELEASE_ASSERT(mWaylandVsyncSource);
++ }
++#endif
+
+ // We create input contexts for all containers, except for
+ // toplevel popup windows
+@@ -6077,19 +6088,12 @@ void nsWindow::ResumeCompositorFromCompo
+
+ void nsWindow::WaylandStartVsync() {
+ #ifdef MOZ_WAYLAND
+- // only use for toplevel windows for now - see bug 1619246
+- if (!GdkIsWaylandDisplay() ||
+- !StaticPrefs::widget_wayland_vsync_enabled_AtStartup() ||
+- mWindowType != eWindowType_toplevel) {
++ if (!mWaylandVsyncSource) {
+ return;
+ }
+
+ LOG("nsWindow::WaylandStartVsync() [%p]\n", (void*)this);
+
+- if (!mWaylandVsyncSource) {
+- mWaylandVsyncSource = new WaylandVsyncSource();
+- }
+-
+ WaylandVsyncSource::WaylandDisplay& display =
+ static_cast<WaylandVsyncSource::WaylandDisplay&>(
+ mWaylandVsyncSource->GetGlobalDisplay());
+