--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -4417,16 +4417,18 @@ pref("layers.tile-height", 256);
 pref("layers.max-active", -1);
 // If this is set the tile size will only be treated as a suggestion.
 // On B2G we will round this to the stride of the underlying allocation.
 // On any platform we may later use the screen size and ignore
 // tile-width/tile-height entirely. Its recommended to turn this off
 // if you change the tile size.
 pref("layers.tiles.adjust", true);
 
+// Set the default values, and then override per-platform as needed
+pref("layers.offmainthreadcomposition.force-disabled", false);
 // Compositor target frame rate. NOTE: If vsync is enabled the compositor
 // frame rate will still be capped.
 // -1 -> default (match layout.frame_rate or 60 FPS)
 // 0  -> full-tilt mode: Recomposite even if not transaction occured.
 pref("layers.offmainthreadcomposition.frame-rate", -1);
 
 #ifdef XP_MACOSX
 pref("layers.enable-tiles", true);