Arm Limited

Jon Erik Oterhals

Lars Ericsson

Daren Croxford

Jørn Nystad

Eivind Liland

Tom Cooksey

Daren Croxdord

In a compositing window system, as a respective version of the window for an application is written into a window buffer, a corresponding set of per tile signatures indicative of the content of each respective tile in the window buffer is generated and stored. When an updated version of the window is stored into a window buffer, the set of signature values for the updated version is compared to the set of signature values for the previous version in the window buffer to determine which tiles' content has changed. The set of tiles found to have changed is used to generate a set of regions for a window compositor to write to a window in a display frame buffer to update the window in the display frame buffer to display the new version of the window.

Methods of and apparatus for displaying windows on a display

A transaction elimination hardware unit controls the writing to a frame buffer in a memory of tiles generated by a tile-based graphics processor. The transaction elimination hardware unit has a signature generator that generates a signature representative of the content of the tile for each tile. A signature comparator then compares the signature of a new tile received from the graphics processor with the signatures of one or more tiles already stored in the frame buffer to see if the signatures match. If the signatures do not match, then the signature comparator controls a write controller to write the new tile to the frame buffer. On the other hand, if the signatures match, then no data is written to the frame buffer and the existing tile is allowed to remain in the frame buffer. In this way, a tile is only written to the frame buffer if it is found by the signature comparison to differ from the tile or tiles that are already stored in the frame buffer that it is compared with.

Graphics processing system

A graphics processorincludes after its tile rendering logic, a transaction elimination unitthat includes data block generation logicand block comparison logic. The block generation logicgenerates data blocks from the rendered tiles produced by the tile rendering logic. The data blocks are then stored in buffers. Comparison logicthen compares a new data block with the previous data block (which will already be stored in the buffers), and generates an output metadata bit indicating whether the blocks can be considered to be the same or not, on the basis of the comparison. The meta-data output bits are stored appropriately in a meta-data bitmapin main memorythat is associated with the output data array in question. If the blocks are determined to be different by the comparison logic then the new data block is written from the buffersto the frame bufferin the main memory. On the other hand, if the two blocks are considered to be similar to each other, the new block is not written into the data array in the frame buffer

Graphics processing systems

A display controller reads blocks of data from a frame buffer and stores them in a local memory buffer of the display controller before outputting the blocks of data to a display. The display controller uses similarity meta-data associated with the output frame in the frame buffer to determine whether a new block of data to be processed for display is similar to a block of data already stored in the local memory of the display controller or not. If it is determined that the data block to be processed is similar to a data block already stored in the local buffer of the display controller, the display controller does not read a new data block from the frame buffer but instead provides the existing data block in its buffer to the display.

Growing community of inventors

Trondheim, Norway

Jon Erik Oterhals