Sitecore MVC: Layout with Device Fall Back

GetLayoutRenderingWithFallback.cs

namespace Example
{   
    using System.Collections.Generic;
    using System.Linq;

    using Sitecore;
    using Sitecore.Data.Items;
    using Sitecore.Mvc.Extensions;
    using Sitecore.Mvc.Pipelines.Response.GetPageRendering;
    using Sitecore.Mvc.Presentation;

    public class GetLayoutRenderingWithFallback : GetLayoutRendering
    {
        protected override Rendering SelectLayoutRendering(List<Rendering> renderings, GetPageRenderingArgs args)
        {
            var result = base.SelectLayoutRendering(renderings, args);

            if (result != null)
            {
                return result;
            }

            var device = Context.Device;
            while (device != null)
            {
                var b = device.ValueOrDefault((DeviceItem d) => d.ID.ToGuid());
                foreach (var current in renderings.Where(current => current.DeviceId == b && current.RenderingType == "Layout"))
                {
                    // set fallback device as current.
                    Context.Device = device;
                    return current;
                }

                device = Context.Device.FallbackDevice;
            }

            return null;
        }
    }
}