Interposed graphics device driver module processing function requests within module in standard mode, and passing function requests to specialized mode device driver in specialized mode

Abstract

A module is interposed between the operating system and/or applications of a data processing system and the device driver for a graphics adapter within the data processing system. The interposed module may selectively intercept all graphics device driver function requests or simply pass such requests to a device driver supporting specialized (e.g., non-VGA) graphics modes. Standard (e.g., VGA) graphics mode(s) device driver support is accessible to the interposed module. When a specialized graphics mode is selected, the interposed is inactive and passes graphics function requests to the specialized device driver. When a standard graphics mode is selected, the interposed module is active and intercepts all graphics function requests, processing such request with available standard graphics mode support. Change of the graphics mode from standard to specialized or vice versa results in the interposed module changing from active to inactive or vice versa. Requests to set the graphics mode are similarly passed to the specialized device driver or processed by the interposed module depending on whether a standard or specialized graphics mode is requests. Initialization and termination function requests are both passed to the specialized device driver and processed by the interposed module. The interposed module is preferably implemented in accordance with the GRADD architecture model, with the interposed module implemented as a variant of a GRADD filter.