I have the option enabled for siri to work when i bring my phone to my ear, yet it only works if i hold the home button down. If i bring the phone to my ear and start talking nothing happens, the screen doesnt darken. I've tried it on the home screen, in safari, and in music app,without any luck. Ive also turned the phone on and off and turned the option on and off. is there anything else i can try?