Examples described herein relate to a graphics processing system that includes one or more integrated graphics systems and one or more discrete graphics systems. In some examples, an operating system (OS) or other software supports switching between image display data being provided from either an integrated graphics system or a discrete graphics system by configuring a multiplexer at runtime to output image data to a display. In some examples, a multiplexer is not used and interface supported messages are used to transfer image data from an integrated graphics system to a discrete graphics system and the discrete graphics system generates and outputs image data to a display. In some examples, interface supported messages are used to transfer image data from a discrete graphics system to an integrated graphics system and the integrated graphics system uses an overlay process to generate a composite image for output to a display.