Lion won't detect TV display

so I upgraded to Lion on the first day...I had previously been using snow leopard and loved the fact that my Rocketfish MiniDP to HDMI dongle allowed me to project my screen to my Sharp HDTV

since the upgrade, my iMac will not recognize my HDTV as a display even when I go through the detect display option.

anyone else having this problem or have some advice for things I oculd try to get it moving?

Try reset of SMC.