If this happened after updating the PS3, you might try contacting their support. I don't know what their firmwares might have changed, or why it wouldn't work with our sets as a result.
I've had ongoing HDMI handshake issues with this TV and it seemed that a firmware upgrade fixed the problem for a while, but I recently updated my PS3 and now the problem is back. Samsung has taken the firmware off their website and I was wondering if anyone knows where it might be available. Thanks.