cakephp validation from both model and controller


I have given validation in model. Also, I have given some validation in controller for checking the captcha code. After that, the application is not displaying the model validation errors. If I comment the controller code, model validation is working fine and displaying the errors. Both not working..

Model code (sample)

class User extends AppModel {

var $name = 'User';

var $validate = array(
    'username' => 'notempty',
    'firstname' => 'notempty'


Controller code

if (!empty($this->data)) {

$captcha = $this->Session->read('CAPTCHA_CODE');

if (strtolower($captcha) != strtolower($this->data['User']['captcha']))
    $this->User->invalidate('captcha', __('Sorry, your entry did not match', true));

if ($this->User->save($this->data, array('validate' => 'only')))
    if ($this->User->save($this->data, array('validate' => 'false'))) {
        $this->Session->setFlash(__('Registered successfully', true));
}else {
    $this->Session->setFlash(__('Please, try again.', true));


I have replaced the "if ($this->User->save($this->data, array('validate' => 'only')))" line with if ($this->User->validates()), then also it is not working.

please help