According to an embodiment, the display device includes a touch controller, an image processor, and a display driver. The touch controller is configured to output touch event information corresponding to a touch signal received from a touch panel. The image processor is configured to determine whether a host is in a sleep mode or a normal mode, and to output mixed image data obtained by overlapping an image displayed on a display panel and a marker corresponding to the touch event information while a host is in the sleep mode. The display driver is configured to output pixel driving signals corresponding to the mixed image data to the display panel. The touch controller or image processor is further configured to determine whether a touch input of a user to the touch panel meets a predetermined condition, and if the predetermined condition is met, output a wake-up signal to the host.