Abstract: Systems and devices can include an upstream port, a downstream port, and a multilane link connecting the upstream port to the downstream port, the multilane link comprising a first link width. The upstream port or the downstream port can be configured to determine that the downstream port is to operate using a second link width, the second link width less than the first link width; transmit to the upstream port an indication of a last data block for the first link width across one or more lanes of the multilane link; cause a first set lanes to enter an idle state; and transmit data on a second set of lanes, the second set of lanes defining the second link width.

Abstract: Systems and devices can include forward error correction (FEC) logic to identify a correctable error in the first flit, and correct the correctable error using three error correcting code (ECC) groups. System and devices can also include an error log, the correctable error log to log a symbol number in the first flit corrected by each ECC group, and to log a magnitude of the correctable error corrected by each ECC group in the first flit; and a configuration register to log link error correlation, the link error correlation comprising a indication of one or more bits in error in the first flit.

Abstract: There is disclosed in an example an interconnect apparatus having: a root circuit; and a downstream circuit comprising at least one receiver; wherein the root circuit is operable to provide a margin test directive to the downstream circuit during a normal operating state; and the downstream circuit is operable to perform a margin test and provide a result report of the margin test to the root circuit. This may be performed in-band, for example in the L0 state. There is also disclosed a system comprising such an interconnect, and a method of performing margin testing.

Abstract: A physical layer (PHY) is coupled to a serial, differential link that is to include a number of lanes. The PHY includes a transmitter and a receiver to be coupled to each lane of the number of lanes. The transmitter coupled to each lane is configured to embed a clock with data to be transmitted over the lane, and the PHY periodically issues a blocking link state (BLS) request to cause an agent to enter a BLS to hold off link layer flit transmission for a duration.

Abstract: An interface for coupling an agent to a fabric supports a load/store interconnect protocol and includes a header channel implemented on a first subset of a plurality of physical lanes, the first subset of lanes including first lanes to carry a header of a packet based on the interconnect protocol and second lanes to carry metadata for the header. The interface additionally includes a data channel implemented on a separate second subset of the plurality of physical lanes, the second subset of lanes including third lanes to carry a payload of the packet and fourth lanes to carry metadata for the payload.

Abstract: Physical layer logic is provided that is to receive data on one or more data lanes of a physical link, receive a valid signal on another of the lanes of the physical link identifying that valid data is to follow assertion of the valid signal on the one or more data lanes, and receive a stream signal on another of the lanes of the physical link identifying a type of the data on the one or more data lanes.

Abstract: A port of a computing device is to connect to another device over a link and use equalization logic to perform equalization of the link at a plurality of different data rates. The equalization logic may identify that the other device supports bypassing a sequential equalization mode, determine a maximum data rate supported by the devices on the link, and participate in equalization of the link at the maximum supported data rate before equalizing the link at one or more other data rates lower than the maximum supported data rate in the plurality of data rates.

Abstract: A device includes a receiver to receive one or more training sequences during a training of a link, where the link connects two devices. The device may include agent logic to determine, from the one or more training sequences, a number of extension devices on the link between the two devices, and determine that the number of extension devices exceeds a threshold number. The device may include a transmitter to send a plurality of clock compensation ordered sets on the link based on determining that the number of extension devices exceeds a threshold number.

Abstract: Embodiments herein describe a FEC codec for generating a check byte for a message. The FEC codec includes a port encoder having a storage unit, a Galois field multiplier, and a sum unit. The storage unit stores a first staged result, which is accumulated based on previous sets of input bytes of the message for all clock cycles from a first clock cycle to a clock cycle immediately prior to the current clock cycle. The Galois field multiplier performs a Galois field multiplication of the first staged result and a power of the alpha to generate a Galois field product. The sum unit performs a Galois field addition on an internal input based on a consolidated byte for the current clock cycle and the Galois field product to generate a second staged result for subsequent use to generate the check byte. Other embodiments may be described and/or claimed.

Abstract: Aspects of the embodiments are directed to systems, methods, and devices that can activate forward error correction (FEC) based on the channel loss of a channel. The channel's loss can be characterized as a high loss channel if the channel loss exceeds a predetermined threshold value. For channels with high loss and for those that operate at high data rates (e.g., data rates commensurate with PCIe Gen 4 or Gen 5), FEC can be activated so that the channels can achieve higher data rates.

Abstract: A system and apparatus can include a first port configured to support a first link width; a second port configured to support a second link width, the second link width different from the first link width; and physical layer logic to receive from the first port a first data block arranged according to the first link width and frequency; create at least one second data block arranged according the second link width and frequency, the at least one second data block including data bytes from the first data block arranged sequentially in the at least one second data block; and transmit the at least one second data block to the second port.

Abstract: Systems and devices can include a first port of a first device coupled to a second port of a second device across a multi-lane link. The first port can augment a data block with error correcting code by distributing error correcting code evenly across each lane of the data block, wherein each lane of the data block includes a same number of error correcting code. The first port can transmit the data block with the per-lane error correcting code to the second port across the multi-lane link. The second port can determine error correcting code based on the error correcting code bits received in the data block, and perform error correction on the symbols of the data block based on the error correcting code received.

Abstract: A retimer device receives a first signal from a first device and regenerates the first signal to send to a second device. The retimer further receive a second signal from the second device and regenerates the second signal to send to the first device, where the first device includes a processor device. The retimer includes a sideband interface to connect to the first device and further includes protocol logic to monitor the first signal, determine that the first signal includes a pattern defined in a protocol to identify a protocol activity, and participate in performance of the protocol activity using the sideband interface.

Abstract: Systems and devices can include a physical layer (PHY) that includes a logical PHY to support multiple interconnect protocols. The logical PHY can include a first set of cyclic redundancy check (CRC) encoders corresponding to a first interconnect protocol, and a second set of CRC encoders corresponding to a second interconnect protocol. A multiplexer can direct data to the first set or the second set of CRC encoders based on a selected interconnect protocol. The logical PHY can include a first set of error correcting code (ECC) encoders corresponding to the first interconnect protocol and a second set of ECC encoders corresponding to the second interconnect protocol. The multiplexer can direct data to the first set or the second set of ECC encoders based on the selected interconnect protocol. In embodiments, different CRC/ECC combinations can be used based on the interconnect protocol and the link operational conditions.

Abstract: A system can include a host device that includes a downstream port and an endpoint device that includes an upstream port. A bidirectional multilane link can interconnect the downstream port and the upstream port. The downstream port can send a request to the upstream port across the bidirectional multilane link to change a number of active lanes in a first direction on the bidirectional multilane link, the request comprising an indication of a desired link width, receive an acknowledgment from the upstream port to change the number of active lanes on the bidirectional multilane link to the desired link width in the first direction, configure the bidirectional multilane link to operate using the desired link width, and send or receiving data to the upstream port using the desired link width. The change in link width can be asymmetrical (i.e., the upstream link width is different from the downstream link width).

Abstract: An interface couples a controller to a physical layer (PHY) block, where the interface includes a set of data pins comprising transmit data pins to send data to the PHY block and receive data pins to receive data from the PHY block. The interface further includes a particular set of pins to implement a message bus interface, where the controller is to send a write command to the PHY block over the message bus interface to write a value to at least one particular bit of a PHY message bus register, bits of the PHY message bus register are mapped to a set of control and status signals, and the particular bit is mapped to a recalibration request signal to request that the PHY block perform a recalibration.

Abstract: An apparatus is provided that includes a set of registers, and an interface of a computing block. The computing block includes one of a physical layer block or a media access control layer block. The interface includes one or more pins to transmit asynchronous signals, one or more pins to receive asynchronous signals, and a set of pins to communicate particular signals to access the set of registers, where a set of control and status signals of a defined interface are mapped to respective bits of the set of registers.

Abstract: Systems, methods, and devices can involve a host device that includes a root complex, a link, and an interconnect protocol stack coupled to a bus link. The interconnect protocol stack can include multiplexing logic to select one of a Peripheral Component Interconnect Express (PCIe) upper layer mode, or an accelerator link protocol upper layer mode, the PCIe upper layer mode or the accelerator link protocol upper layer mode to communicate over the link, and physical layer logic to determine one or more low latency features associated with one or both of the PCIe upper layer mode or the accelerator link protocol upper layer mode.

Abstract: Inter-die passive interconnects are lengthened while locating I/O circuitry away from die edge, such that passive interconnect length is agglomerated toward the die edge, and inter-die communication is expedited.

Abstract: A packet is identified at a port of a serial data link, and it is determined that the packet is associated with an error. Entry into an error recovery mode is initiated based on the determination that the packet is associated with the error. Entry into the error recovery mode can cause the serial data link to be forced down. In one aspect, forcing the data link down causes all subsequent inbound packets to be dropped and all pending outbound requests and completions to be aborted during the error recovery mode.