White Paper

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Table of contents

Executive Summary ................................................................................................................................2

Problem Statement................................................................................................................................. 2

Historical Evolution of PCI/PCI-Express Error Recovery (ER).........................................................................2

Why PCI/PCI-Express Error Recovery .......................................................................................................2

Types of Error Recovery..........................................................................................................................5

How PCI / PCI-Express Error Recovery Works ...........................................................................................6

Support of PCI/PCI-Express Error Handling and Error Recovery on HP-UX.....................................................8

Summary ..............................................................................................................................................8

References ............................................................................................................................................8

Glossary...............................................................................................................................................8

For more information

.............................................................................................................................................................. 10

PCI / PCI EXPRESS Error Recovery White Paper

Summary of content (11 pages)

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PCI / PCI EXPRESS Error Recovery White Paper Table of contents Executive Summary ................................................................................................................................2 Problem Statement................................................................................................................................. 2 Historical Evolution of PCI/PCI-Express Error Recovery (ER) .........................................................................
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Executive Summary In the context of software applications, Reliability, Availability, and Serviceability (RAS) mean failures in the underlying processes and hardware components must not cause any interruptions in the overall system operation. Service transactions are adversely impacted during system failure and performance is affected because of the service down time in the failed system.
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Figure 1: Without PCI Error Recovery PCI bus I/O Card 1 Status: Available HP-UX Server (Up and Running) I/O Card 2 Status: Available I/O Card 3 Status: Available and has encountered PCI error.
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Figure 2: With PCI Error Recovery PCI bus I/O Card 1 Status: Available HP-UX Server (Up and Running) I/O Card 2 Status: Available I/O Card 3 Status: Available and has encountered PCI error. Recovering I/O Card 3 using PCI Error Recovery I/O Card 1 Status: Available HP-UX Server (Up and Running) I/O Card 2 Status: Available PCI bus isolated I/O Card 3 Status: Driver suspended. Card not available due to PCI error.
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PCI ER decreases the frequency of crashes, service calls, & repair rates for PCI errors by a factor of 20 to 25 times. Without PCI error recovery, the entry-level system I/O errors account for more than 20% of all errors in the system. Tables below list the time taken by the PCI/PCIe cards to recover from PCI errors with the error recovery feature.
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Automatic error recovery On an HP-UX 11i v3 system, PCI errors are recovered automatically. If automatic recovery fails, users can attempt to manually recover* cards on hot-pluggable slots but cannot manually recover cards on non hot-pluggable slots. Note: The PCI Error recovery feature is neither supported on shared/switched hot-pluggable slots on HP-UX 11i v1, HP-UX 11i v2, and HP-UX 11i v3 Operating Environments, nor on Core IO on HP Superdome 2 platform.
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How PCI / PCI-Express Error Recovery Works When an I/O driver detects PCI bus parity errors, it reports the errors to Error Recovery Infrastructure and then to the core platform support module. Core PSM implements error recovery functionality using interfaces that are independent of the platform. This module verifies if the error is a device error or a bus error. If the error is a device error then the PSM ignores the error.
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and suspend the I/O modules in the error path. When this phase is completed, it is assumed that drivers have suspended all activities for the devices in the error path. On HP Superdome 2 platform system, during this phase the Health Checker Daemon is invoked to log and clear the errors. Release Phase: During this phase, the suspended I/O path is restored. It involves resuming the driver. If any I/O cards were left in a suspended state, the card will be replaced via a PCI OLR action.
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Support of PCI/PCI-Express Error Handling and Error Recovery on HP-UX PCI error handling and error recovery are supported only with some HP-UX version, I/O products and servers. For more information, see the support matrix available at the following location: http://www.hp.com/go/hpux-networking-docs under HP-UX 11i v3 I/O Cards category. There are several kernel tunables that can change the behavior of PCI error recovery operation.
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RC (Root Complex) An entity that includes a host bridge and one or more root ports. RP (Root Port) A PCI Express port on a root complex that maps a portion of the tree structured PCI Express I/O interconnect through an associated virtual PCI bridge. SoftFail mode The mode of operation of LBA, during which PCI errors does not cause an HPMC/MCA for PCI I/O errors during PIO read.
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For more information www.hp.com/go/hpux11i © Copyright 2008-2010 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein. Linux is a U.S.