How to create a filter condition autocomplete for entity reference field or normal?
you can change an exposed filter to Select List or Text Box using the following code..

function mymodule_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  if ($form_id == 'views_exposed_form') {
    $view = $form_state['view'];
    if ($view-&gt;name == 'my_view_machine_name' &amp;&amp; $view-&gt;current_display == 'display_name') {
        $options = array('your options');
        $form['your field name']['#type'] ='select'; //Use TEXTBOX for text field.
        $form['your field name']['#size'] = null;
        $form['your field name']['#default_value'] = '';
        $form['your field name']['#options'] = $options; //not needed for textbox
    }
  }
}


Another option is use Autocomplete Deluxe for References Module.

Hope this will help you..