Abstract: In some embodiments, a system for communicating USB information via a non-USB extension medium is provided. The system comprises a downstream facing port device (DFP device). The DFP device is configured to receive, via the non-USB extension medium, an ACK IN packet addressed to a first endpoint while receiving DATA packets from a second endpoint. The DFP device is further configured to detect an end of transmission of the DATA packets from the second endpoint; determine a number of packets that can be received from the first endpoint during a remaining amount of time in a current bus interval; and transmit at least one synthetic ACK IN packet to the first endpoint based on the number of packets.

Abstract: In some embodiments, a system for communicating USB information via an extension medium is provided. The system comprises an upstream facing port device (UFP device) and a downstream facing port device (DFP device). The UFP device is communicatively coupled to a host device via a USB-compliant connection. The DFP device is communicatively coupled to at least one USB device via a USB-compliant connection and communicatively coupled to the UFP device via a non-USB extension medium. The DFP device is configured to receive, from the UFP device, an incoming request packet addressed to a first USB endpoint provided by a USB device; and hold transmission of an outgoing request packet based on the incoming request packet to the USB device in response to determining that a ping response packet has not yet been received from the first USB endpoint.

Abstract: A port device for use in a USB extension environment that couples a host device to one or more USB devices is provided. The port device includes a USB physical layer interface configured to be coupled to a USB device, a host device, or a USB hub device; a remote interface configured to be coupled to an extension medium; and an endpoint table. The port device includes logic that, in response to execution by the port device, causes the port device to perform actions comprising: receiving a first USB message addressed to a first endpoint; in response to determining that the endpoint table indicates that the first endpoint is active, providing the first USB message for transmission to the first endpoint; and in response to determining that the endpoint table indicates that the first endpoint is inactive, providing a synthetic USB message for transmission to the host device.

Abstract: In some embodiments, a system for communicating USB information via a non-USB extension medium is provided. The system comprises an upstream facing port device (UFP device) and a downstream facing port device (DFP device). The DFP device is configured to receive, from the UFP device via the extension medium, a first ACK IN packet addressed to a first endpoint and a second ACK IN packet addressed to a second endpoint after receiving the first ACK IN packet. In response to detecting that the USB-compliant connection is available, the DFP device compares a bInterval value for the first endpoint to a bInterval value for the second endpoint; and in response to determining that the bInterval value for the second endpoint is smaller than the bInterval value for the first endpoint, the DFP device transmits a synthetic ACK IN packet to the second endpoint based on the second ACK IN packet.

Abstract: In some embodiments, a system is provided for communicating USB information via an extension medium. The system comprises an upstream facing port device (UFP device) and a downstream facing port device (DFP device). The UFP device and the DFP device are communicatively coupled via a non-USB extension medium, and allow a host device communicatively coupled to the UFP device and a USB device communicatively coupled to the DFP device to communicate via USB-compliant techniques. In some embodiments, the DFP device generates synthetic request packets to request additional data packets from the USB device compared to those requested by the host device. In some embodiments, the DFP device is configured to store a request packet in a packet queue if the request packet is received from the UFP device while the DFP device is busy receiving a response to a previous synthetic request packet from the USB device.

Abstract: Techniques for generating bus interval messages by a downstream USB extension device in a USB extension environment are disclosed. The downstream USB extension device transmits a first outgoing bus interval message in response to receiving a first incoming bus interval message at a first time. An expected time of receipt of a second incoming bus interval message is determined based on the first time. The downstream USB extension device transmits a second outgoing bus interval message at a second time based on a difference between the reception time and the expected time of receipt if the second incoming bus interval message has been received at a reception time before the expected time of receipt. The downstream USB extension device transmits the second outgoing bus interval message at the expected time of receipt if the second incoming bus interval message has not been received before the expected time of receipt.

Abstract: In some embodiments, a system is provided for communicating USB information via an extension medium. The system comprises an upstream facing port device (UFP device) and a downstream facing port device (DFP device). The UFP device and the DFP device are communicatively coupled via a non-USB extension medium, and allow a host device communicatively coupled to the UFP device and a USB device communicatively coupled to the DFP device to communicate via USB-compliant techniques. In some embodiments, the DFP device generates synthetic request packets to request additional data packets from the USB device compared to those requested by the host device. In some embodiments, the DFP device is configured to store a request packet in a packet queue if the request packet is received from the UFP device while the DFP device is busy receiving a response to a previous synthetic request packet from the USB device.

Abstract: In providing USB communication functionality over a non-USB-compliant extension medium, increased latency and processing delays may be introduced, including during configuration of endpoints. In some embodiments of the present disclosure, an upstream facing port device (UFP device) and a downstream facing port device (DFP device) are used to extend USB communication across an extension medium. In some embodiments, the UFP device extracts information from packets sent between a host device and a USB device during configuration of an endpoint. In some embodiments, the UFP device sends a synthetic NRDY packet to the host device in response to a STATUS Transaction Packet to provide the UFP device and DFP device additional time to complete configuration for servicing the endpoint.

Abstract: In providing USB communication functionality over a non-USB-compliant extension medium, increased latency and processing delays may be introduced, including during configuration of endpoints. In some embodiments of the present disclosure, an upstream facing port device (UFP device) and a downstream facing port device (DFP device) are used to extend USB communication across an extension medium. In some embodiments, the UFP device extracts information from packets sent between a host device and a USB device during configuration of an endpoint. In some embodiments, the UFP device sends a synthetic NRDY packet to the host device in response to a STATUS Transaction Packet to provide the UFP device and DFP device additional time to complete configuration for servicing the endpoint.

Abstract: A method of managing communication between a host device and a USB device via a non-USB extension medium is provided. A downstream facing port device (DFP device) receives a data request packet that includes a first buffer count from an upstream facing port device (UFP device) via the non-USB extension medium. The DFP device determines a number of data packets to request from the USB device based on a free buffer count tracked by the DFP device that represents an amount of buffer space available on the UFP device. The DFP device generates a synthetic data request packet that includes a second buffer count based on the determined number of data packets to request from the USB device. The DFP device receives a set of data packets from the USB device responsive to the synthetic data request packet, and transmits the set of data packets to the UFP device.

Abstract: Techniques for generating bus interval messages by a downstream USB extension device in a USB extension environment are disclosed. The downstream USB extension device transmits a first outgoing bus interval message in response to receiving a first incoming bus interval message at a first time. An expected time of receipt of a second incoming bus interval message is determined based on the first time. The downstream USB extension device transmits a second outgoing bus interval message at a second time based on a difference between the reception time and the expected time of receipt if the second incoming bus interval message has been received at a reception time before the expected time of receipt. The downstream USB extension device transmits the second outgoing bus interval message at the expected time of receipt if the second incoming bus interval message has not been received before the expected time of receipt.

Abstract: A port device for use in a USB extension environment that couples a host device to one or more USB devices is provided. The port device includes a USB physical layer interface configured to be coupled to a USB device, a host device, or a USB hub device; a remote interface configured to be coupled to an extension medium; and an endpoint table. The port device includes logic that, in response to execution by the port device, causes the port device to perform actions comprising: receiving a first USB message addressed to a first endpoint; in response to determining that the endpoint table indicates that the first endpoint is active, providing the first USB message for transmission to the first endpoint; and in response to determining that the endpoint table indicates that the first endpoint is inactive, providing a synthetic USB message for transmission to the host device.

Abstract: An upstream facing port device (UFP device) and a downstream facing port device (DFP device) allow a host device and a USB device to conduct SuperSpeed communication via a non-USB compliant extension medium. In some embodiments, the UFP device helps overcome increased latency by generating synthetic packets to be transmitted to the DFP device in order to pre-fetch more data packets from the USB device than requested by the host device. In some embodiments, the DFP device adjusts service interval timing or caches data packets from the host device in order to compensate for the increased latency. In some embodiments, the DFP device transmits a synthetic acknowledgement packet to the UFP device to indicate a larger amount of free buffer space than is present on the USB device to help overcome the increased latency.

Abstract: In some embodiments, a system for communicating USB information via a non-USB extension medium is provided. The system comprises an upstream facing port device (UFP device) and a downstream facing port device (DFP device). The DFP device is configured to receive, from the UFP device via the extension medium, a first ACK IN packet addressed to a first endpoint and a second ACK IN packet addressed to a second endpoint after receiving the first ACK IN packet. In response to detecting that the USB-compliant connection is available, the DFP device compares a bInterval value for the first endpoint to a bInterval value for the second endpoint; and in response to determining that the bInterval value for the second endpoint is smaller than the bInterval value for the first endpoint, the DFP device transmits a synthetic ACK IN packet to the second endpoint based on the second ACK IN packet.

Abstract: In some embodiments, a system for communicating USB information via an extension medium is provided. The system comprises an upstream facing port device (UFP device) and a downstream facing port device (DFP device). The UFP device is communicatively coupled to a host device via a USB-compliant connection. The DFP device is communicatively coupled to at least one USB device via a USB-compliant connection and communicatively coupled to the UFP device via a non-USB extension medium. The DFP device is configured to receive, from the UFP device, an incoming request packet addressed to a first USB endpoint provided by a USB device; and hold transmission of an outgoing request packet based on the incoming request packet to the USB device in response to determining that a ping response packet has not yet been received from the first USB endpoint.

Abstract: In some embodiments, a system is provided for communicating USB information via an extension medium. The system comprises an upstream facing port device (UFP device) and a downstream facing port device (DFP device). The UFP device and the DFP device are communicatively coupled via a non-USB extension medium, and allow a host device communicatively coupled to the UFP device and a USB device communicatively coupled to the DFP device to communicate via USB-compliant techniques. In some embodiments, the DFP device generates synthetic request packets to request additional data packets from the USB device compared to those requested by the host device. In some embodiments, the DFP device is configured to store a request packet in a packet queue if the request packet is received from the UFP device while the DFP device is busy receiving a response to a previous synthetic request packet from the USB device.

Abstract: In providing USB communication functionality over a non-USB-compliant extension medium, increased latency and processing delays may be introduced, including during configuration of endpoints. In some embodiments of the present disclosure, an upstream facing port device (UFP device) and a downstream facing port device (DFP device) are used to extend USB communication across an extension medium. In some embodiments, the UFP device extracts information from packets sent between a host device and a USB device during configuration of an endpoint. In some embodiments, the UFP device sends a synthetic NRDY packet to the host device in response to a STATUS Transaction Packet to provide the UFP device and DFP device additional time to complete configuration for servicing the endpoint.

Abstract: An upstream facing port device (UFP device) and a downstream facing port device (DFP device) allow a host device and a USB device to conduct SuperSpeed communication via a non-USB compliant extension medium. In some embodiments, the UFP device helps overcome increased latency by generating synthetic packets to be transmitted to the DFP device in order to pre-fetch more data packets from the USB device than requested by the host device. In some embodiments, the DFP device adjusts service interval timing or caches data packets from the host device in order to compensate for the increased latency. In some embodiments, the DFP device transmits a synthetic acknowledgement packet to the UFP device to indicate a larger amount of free buffer space than is present on the USB device to help overcome the increased latency.

Abstract: An upstream facing port device (UFP device) and a downstream facing port device (DFP device) allow a host device and a USB device to conduct SuperSpeed communication via a non-USB compliant extension medium. In some embodiments, the UFP device helps overcome increased latency by generating synthetic packets to be transmitted to the DFP device in order to pre-fetch more data packets from the USB device than requested by the host device. In some embodiments, the DFP device adjusts service interval timing or caches data packets from the host device in order to compensate for the increased latency. In some embodiments, the DFP device transmits a synthetic acknowledgement packet to the UFP device to indicate a larger amount of free buffer space than is present on the USB device to help overcome the increased latency.

Abstract: An upstream facing port device (UFP device) and a downstream facing port device (DFP device) allow a host device and a USB device to conduct SuperSpeed communication via a non-USB compliant extension medium. In some embodiments, the UFP device helps overcome increased latency by generating synthetic packets to be transmitted to the DFP device in order to pre-fetch more data packets from the USB device than requested by the host device. In some embodiments, the DFP device adjusts service interval timing or caches data packets from the host device in order to compensate for the increased latency. In some embodiments, the DFP device transmits a synthetic acknowledgement packet to the UFP device to indicate a larger amount of free buffer space than is present on the USB device to help overcome the increased latency.