It's a figure of speech... asking "is it soup yet?" basically means "is it done yet?" I haven't met many people who use that particular expression, but I had an old boss who was from the Pittsburgh, PA, area who used that all the time. Apparently it was inspired by a 1970's era commercial for Lipton soup.[1]
We only had two channels... "off" and a channel full of snowy looking stuff that made a noise like kkkzzzzzzsshshshszzssshshshzzssshhshszzzsshshshzzsshshshszzzsshhhh...