Display data of a first type for a first display device is fetched from a first portion of a first buffer memory and display data of a second type is fetched from a first portion of a second buffer memory at a first time according to an arbitration control signal and then combined into display data for the first display device. Display data of the first type for the second display device is fetched from a second portion of the first buffer memory and display data of the second type for the second display device is fetched from a second portion of the second buffer memory at a second time according to the arbitration control signal, and then combined into display data for the second display device, which is multiplexed with the combined display data for the first display device into a single display data stream and output.