I want to enable the home button in the Action bar. I'm using this code:

```
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
            actionbar.setHomeButtonEnabled(true);
            actionbar.setDisplayHomeAsUpEnabled(true);
}

```

In this I'm using `setHomeButtonEnabled` and `setDisplayHomeAsUpEnabled` to put a back mark at icon in ActionBar. If I use only `setDisplayHomeAsUpEnabled` then also will it work? Is there a need to set `setHomeButtonEnabled` to true?

What is the difference between the two?