Determining whether video display interfaces are coupled to terminations

An apparatus comprising:

• a plurality of current output digital-to-analog converters (DACs) coupled to video communication lines;
• a comparator having a first input coupled to a given video communication line of the plurality of video communication lines, a second input, and an output to provide a comparison signal representing a comparison of the first input to the second input;
• and
• a video display interface, wherein the video display interface comprises a controller to:
• determine whether near end terminations are coupled to the plurality of video communication lines;
• in response to determining that the near end terminations are not coupled to the plurality of video communication lines, disable the plurality of current output DACs;
• and
• in response to determining that the near end terminations are coupled to the plurality of video communication lines:
• determine whether a video output of the video display interface is used;
• and
• in response to determining that the video output of the video display controller is used:
• control a given current output DAC of the plurality of current output DACs to provide a plurality of different currents at different times to the given video communication line to cause the comparison signal to exhibit a response thereto;
• and
• based on the response of the comparison signal, determine whether the video communication lines are coupled to far end terminations.

A computer system comprising:

• a plurality of central processing units (CPUs);
• a system memory;
• and
• a baseboard management controller comprising a video display interface, wherein the video display interface comprises:
• a plurality of digital-to-analog converters (DACs) coupled to video communication lines, wherein the plurality of DACs comprise a given DAC, and the video communication lines comprise a given video communication line;
• a comparator comprising a first input coupled to a voltage of a given video communication line of the video communication lines, a second input coupled to a threshold and an output;
• and
• a controller to:
• control the given DAC to provide a plurality of different currents to the given video communication line to cause a corresponding response of the output of the comparator;
• and
• based on the response of the output of the comparator, determine whether the video communication lines are coupled to cable-based far end terminations.