Lsi Corporation

Lsi Logic Corporation

David T Uddenberg

William W Voorhees

Mark Slutz

Brian J Varney

Gabriel Leandro Romero

William J Schmitz

Methods and structure for determining compatibility between a pair of SAS devices for support of super-standard features of the devices. Features and aspects hereof provide for exchange of information between a first and second SAS device using SAS protocol in non-standard manners. The exchanges are designed to exchange information between compatible, enhanced device without causing protocol violation errors in either the first or second devices. The information exchanged represents super-standard features supported by each device. Mutually supported super-standard features are enabled for further communications between the devices. If no super-standard features are mutually supported or if the second device is non-enhanced, no super-standard features are enabled in further communications between the devices.

Methods and structure for identifying support for super-standard features in communications between serial attached SCSI devices

Method and structures provide for testing a SAS link during speed negotiation windows to determine success/failure in using a negotiated speed at one or more configured sets of speed options. For each device linked to a master SAS device, each possible set of speed options is configured; the device participates in a speed negotiation window operation with the current speed options configured. One or more SCSI requests are forwarded from the master device to the attached device. The SCSI requests may be non-destructive of data stored on the attached device. Results of the tests may be used to select a preferred speed for communication between the master device and that attached device. The speed options to be varied and tested may include: link speed; spread spectrum clocking for each SAS speed; type of supported spread spectrum clocking; and logical link rate in support of multiplexing.

Methods and structures for testing SAS-2 speed options in speed negotiation windows

Method and structures provide for testing a SAS link in association with participating in training windows to determine success/failure in using a negotiated speed using one or more configured sets of transceiver training options. For each device linked to a master SAS device, each possible set of transceiver training options is configured and one or more SCSI requests are forwarded from the master device to the attached device. The SCSI requests may be non-destructive of data stored on the attached device. Results of the tests may be used to select a preferred set of transceiver training options for communication between the master device and that attached device. The transceiver training options to be varied and tested may include: amplitude, slew rate, de-emphasis, and spread spectrum clocking.

Methods and structures for testing SAS transceiver training options in SAS-2 training windows

Methods and structures within a SAS expander for detecting link level errors in PHYs of a SAS expander to reduce overhead bandwidth utilization of SAS links between SAS initiators and SAS expanders. In one aspect hereof, a SAS expander self monitors the error status registers of its own PHYs over an internal path that does not use bandwidth of the attached SAS links. When a link level error is so detected the SAS expander may initiate actions and/or report the error to a SAS initiator to thereby reduce the potential for lost data integrity. Where multiple SAS expanders are configured in a SAS domain fabric, each expander may monitor its PHYs or one expander may be designated a master and monitor PHYs of all expanders in the fabric.

Methods and structure for detecting SAS link errors with minimal impact on SAS initiator and link bandwidth

Methods and structures within a SAS expander for testing SAS devices and other SAS expanders in the SAS domain. Testing devices and expanders in the domain by operations performed within a SAS expander in the domain relieves the burden of such processing in attached host systems and adds flexibility for scheduling processing for test operation of devices and expanders in the domain. In one aspect hereof, the testing may be performed by a master SAS expander configured in the domain. The SAS expander may initiate testing of devices following completion of the SAS discovery process. Testing may also be initiated in response to events in the SAS domain not typically detected by attached host systems.

Methods and structure for verifying domain functionality

Methods and structures within a SAS expander for initiating communication with one or more SAS initiators in a SAS domain to inform the initiators of sensed changes in the domain without the need for a full SAS Discovery process. In one aspect hereof, the expander may transmit a vendor unique BROADCAST primitive to inform SAS initiators that they should initiate a vendor unique SMP or SSP exchange with the expander to determine changes to the SAS domain. In another aspect hereof, the SAS initiator may respond as an SMP or SSP target device in response to initiation of vendor unique SMP or SSP exchanges by the expander. The expander may report to initiators regarding sensed changes in the domain and/or statistics regarding operation of the expander or other elements of the domain.

Methods and structure for SAS expander initiating communication to a SAS initiator to identify changes in the SAS domain

Methods and associated structure for utilizing multiple ports or PHYs comprising a SAS wide port to improve transmission bandwidth utilization for a single large I/O request. In one aspect hereof, a large I/O request is broken into a plurality of smaller I/O requests to be distributed over multiple PHYs or ports of a configured wide SAS port. The number of smaller I/O requests may be any number up to the maximum number of PHYs or ports comprising the SAS wide port. In another aspect hereof, the size of a large I/O request may be compared against a threshold value to determine whether the large request should be broken into smaller requests. The threshold value may be determined in accordance with features and aspects hereof either statically or dynamically based on workloads assigned to, and utilization of, the configured SAS wide port.

Methods and structure for improved transfer rate performance in a SAS wide port environment

Improved methods and structures for testing of SAS components, in situ, in a SAS domain. A first SAS component is adapted to generate stimuli such as error conditions to elicit a response to the error condition from a second SAS component coupled to the first in the intended SAS domain configuration. In one aspect, a SAS device controller generates stimuli applied to a SAS expander coupled thereto and verifies proper response from the SAS expander. In another aspect, a SAS expander generates stimuli applied to a SAS device controller coupled thereto and verifies proper response from the SAS device controller. Stimuli may be generated by custom circuits or firmware/software within the first component. Vendor specific SAS SMP transactions may be used to cause the first component to enter the special verification mode.

Methods and structure for testing responses from SAS device controllers or expanders

Systems and methods for analyzing data passing between an SAS/SATA device and a plurality of other devices are presented. A system includes a plurality of physical interfaces configured for passing data between the SAS/SATA device and the other devices. The system also includes a test interface, or test PHY, configured for coupling to the physical interfaces for analysis of the data passing through those physical interfaces. The test PHY may be integrally configured with the SAS/SATA device and may substantially minimize alteration of characteristic impedance caused by external analysis of the data. The system may also include a multiplexer for selectively coupling the PHYs to the test PHY.

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Colorado Springs, CO, United States of America

David T Uddenberg