Abstract: An integrated circuit, in accordance with embodiments of the present technology, includes a plurality of engines, a plurality of engine level power gating (ELPG) controllers, and a power gating arbiter for implementing engine level power gating arbitration techniques. The power gating arbiter may receive requests from one or more ELPG controllers to turn on their respective engines or portions therein. The power gating arbiter prioritizes the request and sends an acknowledgment to a given ELPG controller to turn on or off its corresponding engine according to the prioritized predetermined order. After receiving the acknowledgement, the given ELPG controller turns on or off its corresponding engine and returns an indication to the power gating arbiter that the corresponding engine is turned on or off. The process may be iteratively repeated for each received request after receiving the indication from the previously serviced ELPG controller that its corresponding engine is turned on or off.

Abstract: A system and method are described for dynamically changing the size of a computer memory such as level 2 cache as used in a graphics processing unit. In an embodiment, a relatively large cache memory can be implemented in a computing system so as to meet the needs of memory intensive applications. But where cache utilization is reduced, the capacity of the cache can be reduced. In this way, power consumption is reduced by powering down a portion of the cache.

Abstract: Under some conditions, requests transmitted between different devices in a computing system may be blocked in a way that prevents the request from being processed, resulting in a deadlock condition. A skid buffer is used to allow additional requests to be queued in order to remove the blockage and end the deadlock condition. Once the deadlock condition is removed, the requests are processed and the additional buffer entries in the skid buffer are disabled.

Abstract: A system and method for communicating over a single virtual channel. The method includes reserving a first group of credits of a credit pool for a first traffic class and a second group of credits of the credit pool for a second traffic class. In addition, a first and second respective groups of tags are reserved from a tag pool for the first and second traffic class. A packet may then be selected from a first buffer for transmission over the virtual channel. The packet may include a traffic indicator of the first traffic class operable to allow the packet to pass a packet of the second traffic class from a second buffer. The method further includes sending the packet over the virtual channel and adjusting the first group of credits and the first group of tags based on having sent a packet of the first traffic class.

Abstract: An integrated circuit, in accordance with embodiments of the present technology, includes a plurality of engines, a plurality of engine level power gating (ELPG) controllers, and a power gating arbiter for implementing engine level power gating arbitration techniques. The power gating arbiter may receive requests from one or more ELPG controllers to turn on their respective engines or portions therein. The power gating arbiter prioritizes the request and sends an acknowledgment to a given ELPG controller to turn on or off its corresponding engine according to the prioritized predetermined order. After receiving the acknowledgement, the given ELPG controller turns on or off its corresponding engine and returns an indication to the power gating arbiter that the corresponding engine is turned on or off. The process may be iteratively repeated for each received request after receiving the indication from the previously serviced ELPG controller that its corresponding engine is turned on or off.

Abstract: A system and method for communicating over a single virtual channel. The method includes reserving a first group of credits of a credit pool for a first traffic class and a second group of credits of the credit pool for a second traffic class. In addition, a first and second respective groups of tags are reserved from a tag pool for the first and second traffic class. A packet may then be selected from a first buffer for transmission over the virtual channel. The packet may include a traffic indicator of the first traffic class operable to allow the packet to pass a packet of the second traffic class from a second buffer. The method further includes sending the packet over the virtual channel and adjusting the first group of credits and the first group of tags based on having sent a packet of the first traffic class.

Abstract: A system and method for increasing the yield of integrated circuits containing memory partitions the memory into regions and then independently tests each region to determine which, if any, of the memory regions contain one or more memory failures. The test results are stored for later retrieval. Prior to using the memory, software retrieves the test results and uses only the memory sections that contain no memory failures. A consequence of this approach is that integrated circuits containing memory that would have been discarded for containing memory failures now may be used. This approach also does not significantly impact die area.

Abstract: A bus permits the number of active serial data lanes of a data link to be re-negotiated in response to changes in bus bandwidth requirements. In one embodiment, one of the bus interfaces triggers a re-negotiation of link width and places a constraint on link width during the re-negotiation.

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 bus permits the number of active serial data lanes of a data link to be re-negotiated in response to changes in bus bandwidth requirements. In one embodiment, clock buffers not required to drive active data lanes are placed in an inactive state to reduce clock power dissipation.

Abstract: An arrangement provides for further power reduction where a system includes two or more electrical components that can be placed into two or more power consumption states. The arrangement can take advantage of existing circuitry to selectively disable certain state transition detectors to thereby provide additional power reduction.

Abstract: A bus permits the number of active serial data lanes of a data link to be re-negotiated in response to changes in bus bandwidth requirements. In one embodiment, one of the bus interfaces triggers a re-negotiation of link width and places a constraint on link width during the re-negotiation.

Abstract: A memory system and methods of operating the same that drastically increase the efficiency in memory use and allocation in graphics systems. In a graphics system using a tiled architecture, instead of pre-allocating a fixed amount of memory for each tile, the invention dynamically allocates varying amounts of memory per tile depending on the demand. In one embodiment all or a portion of the available memory is divided into smaller pages that are preferably equal in size. Memory allocation is done by page based on the amount of memory required for a given tile.

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 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 graphics processing subsystem uses system memory as its graphics memory for rendering and scanout of images. To prevent deadlock of the data bus, the graphics processing subsystem may use an alternate virtual channel of the data bus to access additional data from system memory needed to complete a write operation of a first data. In communicating with the system memory, a data packet including extended byte enable information allows the graphics processing subsystem to write large quantities of data with arbitrary byte masking to system memory. To leverage the high degree of two-dimensional locality of rendered image data, the graphics processing subsystem arranges image data in a tiled format in system memory. A tile translation unit converts image data virtual addresses to corresponding system memory addresses. The graphics processing subsystem reads image data from system memory and converts it into a display signal.

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 memory system and methods of operating the same that drastically increase the efficiency in memory use and allocation in graphics systems. In a graphics system using a tiled architecture, instead of pre-allocating a fixed amount of memory for each tile, the invention dynamically allocates varying amounts of memory per tile depending on the demand. In one embodiment all or a portion of the available memory is divided into smaller pages that are preferably equal in size. Memory allocation is done by page based on the amount of memory required for a given tile.

Abstract: A cache memory apparatus for graphics and other systems. The cache memory apparatus includes a cache memory having a first number of cache lines, each cache line addressable by a cache line address; a first plurality of storage elements coupled to a first address bus; and a second plurality of storage elements coupled to the first plurality of storage elements. The first plurality of storage elements holds a second number of cache line addresses, and the second plurality of storage elements holds a third number of cache line addresses.

Abstract: A computer graphics system splits vertex data into first and second streams and stores the streams in separate regions of memory. In a specific embodiment, the first stream includes positional data and the second stream includes non-positional color and texture data. A visibility subsystem uses only the first stream to perform visibility processing, thus reducing bandwidth requirement. The rendering system processes data from subsets, identified by the visibility subsystem, of both streams required to render the visible part of a scene.