Usually when the white light is on without any image on the screen it could be the HDMI cable but could also be the HDMI port. The port can get damaged but plugging/unplugging the HDMI cable, it is possible maybe one of the pins got bent, you can shine a light at the port with some magnification and make sure all the pins are lying flat. If there is a bent ping you might be able to bend it back but be very, very gentle. Otherwise if you are using a known good cable and all the pins look ok, I would change the HDMI port next.