steam-deck-tools/PowerControl/Options/Volume.cs

namespace PowerControl.Options
{
    public static class Volume
    {
        public static Menu.MenuItemWithOptions Instance = new Menu.MenuItemWithOptions()
        {
            Name = "Volume",
            Options = { 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 },
            CycleOptions = false,
            CurrentValue = delegate ()
            {
                try { return Helpers.AudioManager.GetMasterVolume(5.0); }
                catch (Exception) { return null; }
            },
            ApplyValue = delegate (object selected)
            {
                try
                {
                    Helpers.AudioManager.SetMasterVolumeMute(false);
                    Helpers.AudioManager.SetMasterVolume((int)selected);

                    return Helpers.AudioManager.GetMasterVolume(5.0);
                }
                catch (Exception)
                {
                    // In some cases MasterVolume device is missing
                    return null;
                }
            }
        };
    }
}