Polarity synchronization method and apparatus for video signals in a computer system

A method and apparatus for automatically synchronizing the polarity of video signals generated by a graphics controller card to a display monitor is described. The present invention includes hardware circuitry comprising a storage unit, a detection unit, a selection unit that store, detect, and select input video signals, particularly a vertical and a horizontal synchronization signals, with the same or different polarity that are received from the graphics controller to a display monitor. The present invention synchronizes the polarity of input vertical and horizontal synchronization signals from the graphics controller prior to transmitting the sync signals to the display monitor. The detect and selection circuits of the present invention enable polarity of input sync signals to be synchronized without the use of software as practiced in the prior art.