Abstract: A method and apparatus are described for facilitating proper ordering of peer-to-peer communications between bridged bus segments. According to one embodiment of the present invention a fence command is issued when a peer-to-peer communication between devices on separate bus segments connected on the same side of a bridge is detected. The fence command is inserted into a plurality of buffers in an I/O hub corresponding to the bus segments to force temporary ordering across all pipes of the I/O hub. The hub prohibits processing of subsequent commands from a buffer once a fence command has been read from that buffer until a corresponding fence command is read from all other buffers in the plurality of buffers therby assuring proper ordering of the peer-to-peer communication.

Abstract: In various embodiments, the present invention includes a method for receiving a transaction having first header information from a first peer device at a first agent of a coherent system, inserting second header information onto the transaction, and routing the transaction to a second peer device using the second header information. In one such embodiment, the first header may be a header of a first protocol and the second header may be of a different protocol that is used to tunnel the transaction through the coherent system.

Abstract: Systems and methods of processing write transactions provide for combining write transactions on an input/output (I/O) hub according to a protocol between the I/O hub and a processor. Data associated with the write transactions can be flushed to an I/O device without the need for proprietary software and specialized registers within the I/O device.

Abstract: To reduce prefetch overshoot when prefetching partial data sets along the path from input-output bus to system memory, a prefetch field is used to communicate the amount of data that a prefetching entity upstream may prefetch. Utilizing a prefetch field in such a manner reduces the fetching of unneeded data past the end of the requested data, resulting in overall increased system performance.

Abstract: A method of detecting synchronization errors during the transfer of data in which a transmitting agent sends to the receiving agent either: (a) data parity encoded with a data parity function when the transmitting agent encodes data in one or more clock signals, or (b) header parity encoded with a header parity function when the transmitting agent encodes header information in the one or more clock signals. A synchronization error condition is detected when the receiving agent either: (a) is configured to receive the data parity and actually receives the header parity, or (b) is configured to receive the header parity and actually receives the data parity.

Abstract: A point-to-point interconnection and communication architecture, protocol and related methods is presented.

Abstract: A point-to-point interconnection and communication architecture, protocol and related methods is presented.

Abstract: According to one embodiment, a computer comprises a central processing unit (CPU), a first hub agent, a first hub interface coupled to the first hub agent, and a second hub agent coupled to the first hub interface. The first and second hub agents operate at a first data clocking rate determined by exchanging data clocking rate capabilities.

Abstract: A method and apparatus are described for facilitating proper ordering of peer-to-peer communications between bridged bus segments. According to one embodiment of the present invention a fence command is issued when a peer-to-peer communication between devices on separate bus segments connected on the same side of a bridge is detected. The fence command is inserted into a plurality of buffers in an I/O hub corresponding to the bus segments to force temporary ordering across all pipes of the I/O hub. The hub prohibits processing of subsequent commands from a buffer once a fence command has been read from that buffer until a corresponding fence command is read from all other buffers in the plurality of buffers therby assuring proper ordering of the peer-to-peer communication.

Abstract: According to one embodiment, a computer comprises a central processing unit (CPU), a first hub agent, a first hub interface coupled to the first hub agent, and a second hub agent coupled to the first hub interface. The first and second hub agents operate at a first data clocking rate determined by exchanging data clocking rate capabilities.

Abstract: A requesting device and a completer device are coupled via a high-speed serial interface within a computer system. The requesting device transmits a packet for a request transaction to a completer device. The completer device checks for error conditions in the course of servicing the request. If an error condition is found then the completer device transmits a completion packet with a completion status of something other than successful. The completion packet includes a completer identification field. The requesting device records the completer identification value and indicates in a register that a completion packet has been received with a non-successful completion status.

Abstract: A method and apparatus for reducing flow control and minimizing interface acquisition latency in a hub interface is a method of transferring data between a control hub coupled to a hub interface which is coupled to an input-output hub including the following: Transferring the data in packets. Prioritizing isochronous transfers over asynchronous transfers. Limiting asynchronous transfers to 32 bytes per packet when an agent requests the hub interface, and limiting asynchronous transfers to 64 bytes per packet when no requests for the hub interface are recognized.

Abstract: An enhanced general input/output communication architecture, protocol and related methods are presented.

Abstract: An enhanced general input/output communication architecture, protocol and related methods are presented.

Abstract: An enhanced general input/output communication architecture, protocol and related methods are presented.

Abstract: A method of detecting synchronization errors during the transfer of data in which a transmitting agent sends to the receiving agent either: (a) data parity encoded with a data parity function when the transmitting agent encodes data in one or more clock signals, or (b) header parity encoded with a header parity function when the transmitting agent encodes header information in the one or more clock signals. A synchronization error condition is detected when the receiving agent either: (a) is configured to receive the data parity and actually receives the header parity, or (b) is configured to receive the header parity and actually receives the data parity.

Abstract: A transmitting device and a receiving device are coupled via a high-speed serial interface within a computer system. The transmitting device transmits a packet for a request transaction to a receiving device. The receiving device checks for error conditions. If an error condition exists and if the packet for the request transaction indicates that a completion is not expected by the transmitting device, an error message is delivered by the receiving device to the transmitting device.

Abstract: A transmitting device and a receiving device are coupled via a high-speed serial interface within a computer system. The transmitting device transmits a packet that includes a format field to partially specify the packet header format and a type field to specify a transaction type. The format field and the type field together specify the packet header format and the format field indicates the size of the packet header.

Abstract: A method of detecting synchronization errors during the transfer of data in which a transmitting agent sends to the receiving agent either: (a) data parity encoded with a data parity function when the transmitting agent encodes data in one or more clock signals, or (b) header parity encoded with a header parity function when the transmitting agent encodes header information in the one or more clock signals. A synchronization error condition is detected when the receiving agent either: (a) is configured to receive the data parity and actually receives the header parity, or (b) is configured to receive the header parity and actually receives the data parity.

Abstract: An enhanced general input/output communication architecture, protocol and related methods are presented.