A display system includes a host apparatus having a video interface circuit and a display apparatus operated by feed of a video image and power from the host apparatus, and also has a communication function for receiving and transmitting data between the host apparatus and the display apparatus. In the display system, the display apparatus transmits power consumption data thereof stored in an EEPROM to the host apparatus and processes the power consumption data thereof which is received by the host apparatus, thus controlling power of the display system including the host apparatus and the display apparatus.