Patent ID: 8212826

Claim:
A computing device comprising: a system bus; a processor coupled to the system bus for executing instructions to test a video loopback cable; a graphics card including a graphics processing unit (GPU) coupled to the system bus; a video formatter card coupled to the system bus for formatting computer-generated video images, the video formatter card including a signal integrity evaluator (“SIE”) configured to identify a digitized video loopback cable coupling pixels from the graphics card to the video formatter card as an external agent affecting values of pixel data during transmission; and a cable test initiator in the graphics card being configured to send a test mode initiation signal to said signal integrity evaluator in the video formatter card via a sideband communications path in order to initiate testing of the digital video loopback cable to determine whether said digitized video cable is affecting said values, said cable test initiator being responsive to a command from said processor to test said digitized video cable, wherein said cable test initiator is further configured to send a test initiation signal to said GPU for generating pixel data having values selected to test said digitized video cable, said GPU being configured to send said pixel data to said signal integrity evaluator via said digitized video cable; wherein said signal integrity evaluator receiving the test mode initiation signal over the sideband communications path eliminates a requirement to disconnect said video loopback cable to apply test signals to perform testing, thereby providing for in-situ testing of said video loopback cable to determine whether said video loopback cable requires replacement and wherein said in-situ testing eliminates the graphics card as the source of data corruption.