Abstract: Machine-readable media, methods, and apparatus are described which order memory transactions to increase utilization of multiple memory channels. In some embodiments, a processor may determine an issue order for memory transactions based on the memory channels that are to service the memory transactions. In some embodiments, the processor attempts to obtain an issue order that minimizes or reduces the number of idle periods experienced by the memory channels. Further, the processor may issue the memory transactions to an external memory controller for servicing in the determined issue order.

Abstract: A memory controller hub includes a graphics subsystem adapted to perform graphics operations on data, and interface circuitry adapted selectively to couple the graphics subsystem to a local memory through electrical connectors and to couple the memory controller hub to a graphics controller through the electrical connectors.

Abstract: A transmitting device and a receiving device are coupled together via an interconnect. An electrical idle ordered set is received at the receiving device power management unit after having been transmitted by the transmitting device and received at the input pins of the receiving device and moving through the receiver logic pipeline. At the time the electrical idle ordered set has been recognized at the end of the receiver logic pipeline, the power management unit checks for activity on the interconnect. If there is no activity on the interconnect, then the power management unit causes the receiving device to enter a low power state where the receiver circuitry (input buffers) is turned off. If there is activity on the interconnect when the electrical idle ordered set is received at the power management unit, then the power management unit does not cause the receiver circuitry to be turned off.

Abstract: A number of symbols are received in a first integrated circuit (IC) device, where these symbols have been transmitted by a second IC device and are received over a serial point to point link. These symbols include a non-data sequence that has been inserted into a data sequence by the second device. The symbols are loaded into a buffer. The data sequence and some of the non-data sequence is unloaded from the buffer, according to a changing unload pointer. To prevent overflow of the buffer, and in response to detecting the non-data sequence, the unload pointer is changed by more than one entry so that a non-data symbol of the non-data sequence as loaded in the buffer is skipped while unloading from the buffer. In another embodiment, to prevent underflow of the buffer, the unload pointer is stalled at an entry of the buffer that contains a non-data symbol while unloading. Other embodiments are also described and claimed.

Abstract: A stream of bits are received in a first integrated circuit (IC) device, where the stream represents a sequence of symbols transmitted by a second IC device over a serial point to point link that couples the two devices. First and second M-bit sections of the stream are compared to a non-data symbol. The second M-bit section is offset by one bit in the stream relative to the first section. If there is a match between the first section and the non-data symbol, then a flag indicating symbol alignment is asserted. Each of multiple, consecutive, non overlapping M-bit sections that follow the first section are then to be treated as separate symbols. Other embodiments are also described and claimed.

Abstract: Multiple symbol sequences that have been transmitted in parallel using the same transmit clock over a serial point to point link are received. Each symbol sequence includes an instance of a first, non-data symbol. The multiple symbol sequences are buffered and the number of times an instance of a second, non-data symbol that occurs in one of the symbol sequences is changed. A first deskew process is performed, followed by a second deskew process. The first deskew process aligns an instance of the first non-data symbol in every one of the buffered symbol sequences. The second deskew process equalizes the number of instances of the second non-data symbol that follow an instance of the first non-data symbol in every one of the symbol sequences. Other embodiments are also described and claimed.

Abstract: Machine-readable media, methods, and apparatus are described which order memory transactions to increase utilization of multiple memory channels. In some embodiments, a processor may determine an issue order for memory transactions based on the memory channels that are to service the memory transactions. In some embodiments, the processor attempts to obtain an issue order that minimizes or reduces the number of idle periods experienced by the memory channels. Further, the processor may issue the memory transactions to an external memory controller for servicing in the determined issue order.

Abstract: A method and apparatus for performing a mid transaction refresh of DRAM and handling a suspend signal from a master. A timer is used to provide a refresh request at predetermined intervals. The refresh request is made to a DRAM state machine. The DRAM state machine performs a DRAM refresh responsive to the refresh request. The refresh is performed by manipulating the RAS and CAS signal while showing a master of the transaction a series of wait states.The suspend signal from the master is received by a DRAM state machine. The DRAM state machine will loop within its then current state as long as the suspend signal is asserted. The RAS, CAS and other control signals are maintained in the states existing when the suspend signal was asserted unless external signals (e.g., a refresh request) force a change in state of the control signals. At least one CAS state machine handles the assertion of CAS.