Laravel雄辩的关系没有给我我想要的东西

im trying to figure out eloquent and having a hard time understand it, even tho ive tried to read up on it.

I have two tables: fs_festivals, and fs_bands.

fs_festivals: id, name

fs_bands: id, festival_id, name

So, one festival can have many bands, and one band belongs to a festival.

Band-model (Band.php)

class Band extends Eloquent implements UserInterface, RemindableInterface {

use UserTrait, RemindableTrait;

protected $fillable = array(
    'festival_id','name','note','bandak', 'bandakinfo','created_by','updated_by'
);

/**
 * The database table used by the model.
 *
 * @var string
 */
protected $table = 'fs_bands';

/**
 * The attributes excluded from the model's JSON form.
 *
 * @var array
 */
protected $hidden = array('password', 'remember_token');

public function festival() {
    return $this->belongsTo('Festival');
}

}

Festival-model (Festival.php):

class Festival extends Eloquent implements UserInterface, RemindableInterface {

use UserTrait, RemindableTrait;

protected $fillable = array(
    'name','year','info','slug', 'image','created_by','updated_by'
);

/**
 * The database table used by the model.
 *
 * @var string
 */
protected $table = 'fs_festivals';

/**
 * The attributes excluded from the model's JSON form.
 *
 * @var array
 */
protected $hidden = array('password', 'remember_token');

public function bands() {
    return $this->hasMany('Band');
}

}

In my controller:

    public function festivalHome() {
   $bands = Band::all();
    return View::make('fis.festivalhome')->with('bands',$bands);
}

And in my view:

Bands: 
@foreach($bands as $band)
{{ $band->name }}
@endforeach

This lists all bands in the fs_bands table. I only want to list those who are set with the festival_id of the current festival im working on (say festival_id='2'). How should i go about this?

Ive tried this (seeing what others have done),

@foreach($festival->$bands as $band)

But it gives me an error of

Undefined variable: festival

What am I doing wrong? Also I wonder, should I do something else instead of $bands = Band:all(); to list them by festival_id? That would be an option but something tells me that this should be done automatically with eloquent.

Controller:

public function festivalHome($id) {
      //$bands = Band::all();
      $festival = Festival::with('bands')->whereId($id)->first(); //it will load festival with all his bands 
      return View::make('fis.festivalhome')->with('festival',$festival);


      // or you can filter bands
      $bands = Band::whereHas('festival', function($query) use ($id){ 
                     $query->whereId($id);
               })->get(); //there will be only bands which will be on the festival

   }

And in your view:

@foreach($festival->bands as $band)
   {{ $band->name }}
@endforeach

 //or 
 @foreach($bands as $band)
   {{ $band->name }}
 @endforeach