Abstract: A compositor for providing a pixel value corresponding to a current pixel is implemented on a chip. A desktop pixel logic circuit supplies a desktop pixel value. A cursor logic circuit supplies a cursor pixel value. A hardware icon logic circuit provides an icon pixel value by accessing an icon memory located on the compositor chip. The hardware icon logic circuit supports selectable magnification and color modes. Priority logic selects one of the icon pixel value, the desktop pixel value, and the cursor pixel value as the final pixel value. Whether the hardware icon is displayed can be controlled based on a hardware condition.

Abstract: Circuits, methods, and apparatus for slowing clock circuits on a graphics processor integrated circuit in order to reduce power dissipation. An exemplary embodiment of the present invention provides a graphics processor having two memory clocks, specifically, a switched memory clock and an unswitched memory clock. The switched memory clock frequency is reduced under specific conditions, while the unswitched memory clock frequency remains fixed. In a specific embodiment, the switched memory clock frequency is reduced when related graphics, display, scaler, and frame buffer circuits are not requesting data, or are such data requests can be delayed. Further refinements to the present invention provide circuits, methods, and apparatus for ensuring that the switched and unswitched memory clock signals remain in-phase and aligned with each other.

Abstract: A graphics processor or display device including a microcontroller that functions as a sequencer, a computer system including at least one such graphics processor or display device, and a microcontroller for use in such a graphics processor or display device. In preferred embodiments, the microcontroller functions as a sequencer for controlling the timing of power up and/or power down operations by one or both of a graphics processor and a display device. The microcontroller is implemented to exclude any capacity to handle interrupts and so can provide guaranteed timing, and is preferably implemented to be small, simple, and programmable, and to store a small number of programs. Each program consists of instructions belonging to a small instruction set, such as a set consisting of set and clear instructions (for overriding or overwriting specified register bits) and wait, release, and stop instructions.

Abstract: Circuits, methods, and apparatus for reducing power on a graphics processor integrated circuit by generating two memory clock signals, reducing the frequency of one under certain conditions, and maintaining the frequency of the other. To reduce skew and jitter between these two memory clocks, and to ensure that they remain in phase, a synchronizer circuit is used by an exemplary embodiment of the present invention. The synchronizer circuit is also useful as a general application clock generator.

Abstract: A computer system includes an integrated graphics subsystem and a graphics connector for attaching either an auxiliary graphics subsystem or a loopback card. A first bus connection communicates data from the computer system to the integrated graphics subsystem. With a loopback card in place, data travels from the integrated graphics subsystem back to the computer system via a second bus connection. When the auxiliary graphics subsystem is attached, the integrated graphics subsystem operates in a data forwarding mode. Data is communicated to the integrated graphics subsystem via the first bus connection. The integrated graphics subsystem then forwards data to the auxiliary graphics subsystem. A portion of the second bus connection communicates data from the auxiliary graphics subsystem back to the computer system. The auxiliary graphics subsystem communicates display information back to the integrated graphics subsystem, where it is used to control a display device.

Abstract: A programmable system for dithering video data. The system is operable in at least two user-selectable modes which can include a small kernel mode and a large kernel mode. In some embodiments, the system is operable in at least one mode in which it applies two or more kernels (each from a different kernel sequence) to each block of video words. Each kernel sequence repeats after a programmable number of the blocks (e.g., a programmable number of frames containing the blocks) have been dithered. The period of repetition is preferably programmable independently for each kernel sequence. The system preferably includes a frame counter for each kernel sequence. Each counter generates an interrupt when the number of frames of data dithered by kernels of the sequence has reached a predetermined value. In response to the interrupt, software can change the kernel sequence being applied. Typically, the system performs both truncation and dithering on words of video data.

Abstract: A system, method and computer program product are provided for performing depth testing and blending operations in a first mode and a second mode. In the first mode, a circuit processes a first number (m) of first pixels per clock cycle, each of the first pixels including both color values and depth values. In the second mode, the circuit processes a second number (n) of second pixels per clock cycle. Each of the second pixels includes the depth values and not the color values. Further, the second number (n) is greater than the first number (m).

Abstract: A graphics processor or display device including a microcontroller that functions as a sequencer, a computer system including at least one such graphics processor or display device, and a microcontroller for use in such a graphics processor or display device. In preferred embodiments, the microcontroller functions as a sequencer for controlling the timing of power up and/or power down operations by one or both of a graphics processor and a display device. The microcontroller is implemented to exclude any capacity to handle interrupts and so can provide guaranteed timing, and is preferably implemented to be small, simple, and programmable, and to store a small number of programs. Each program consists of instructions belonging to a small instruction set, such as a set consisting of set and clear instructions (for overriding or overwriting specified register bits) and wait, release, and stop instructions.

Abstract: A graphics processing system performs filtering of oversampled data during a scanout operation. Sample values are read from an oversampled frame buffer and filtered during scanout; the filtered color values (one per pixel) are provided to a display device without an intervening step of storing the filtered data in a frame buffer. In one embodiment, the filtering circuit includes a memory interface configured to read data values corresponding to sample points from a frame buffer containing the oversampled data; and a filter configured to receive the data values provided by the memory interface, to compute a pixel value from the data values, and to transmit the pixel value for displaying by a display device, wherein the filter computes the pixel value during a scanout operation.

Abstract: A system and method are provided for reducing the number of depth clear operations in a hardware graphics pipeline. Initially, a frame count is stored into a frame buffer associated with the hardware graphics pipeline. The stored frame count is associated with a pixel. A depth clear operation is then performed based at least in part on the frame count utilizing the hardware graphics pipeline.

Abstract: A compositor for providing a pixel value corresponding to a current pixel is implemented on a chip. A desktop pixel logic circuit supplies a desktop pixel value. A cursor logic circuit supplies a cursor pixel value. A hardware icon logic circuit provides an icon pixel value by accessing an icon memory located on the compositor chip. The hardware icon logic circuit supports selectable magnification and color modes. Priority logic selects one of the icon pixel value, the desktop pixel value, and the cursor pixel value as the final pixel value. Whether the hardware icon is displayed can be controlled based on a hardware condition.

Abstract: A graphics processing system performs filtering of oversampled data during a scanout operation. Sample values are read from an oversampled frame buffer and filtered during scanout; the filtered color values (one per pixel) are provided to a display device without an intervening step of storing the filtered data in a frame buffer. In one embodiment, the filtering circuit includes a memory interface configured to read data values corresponding to sample points from a frame buffer containing the oversampled data; and a filter configured to receive the data values provided by the memory interface, to compute a pixel value from the data values, and to transmit the pixel value for displaying by a display device, wherein the filter computes the pixel value during a scanout operation.