Functional Overview
PLX Technology, Inc.
4.2.2
Interrupts
Generated interrupts are INTx Interrupt message-type (compatible with the PCI r2.3-defined Interrupt
signals) or Message Signaled Interrupts (MSI), when enabled. MSI and INTx are mutually exclusive;
either can be enabled in a system (depending on which interrupt type the system software supports), but
never both. [Refer to the Message Signaled Interrupt Capability register (offset 48h) and Command
register Interrupt Disable bit (offset 04h[10]).] The PEX 8532 does not convert received INTx messages
to MSI messages.
Refer to Chapter 6, “Interrupts,” for complete details.
4.2.2.1
4.2.2.2
Interrupt Sources or Events
The PEX 8532-generated interrupt/message sources include:
• Hot Plug events
• Device-specific error events
• INTx
INTx Switch Mapping
The PEX 8532 remaps and collapses the INTx virtual wires, based on downstream port Device Number
and received INTx message Requester ID Device Number. Each virtual PCI-to-PCI bridge
of a downstream port specifies the Port Number associated with the INTx (Interrupt) messages received
or generated, and forwards the interrupt messages in the upstream direction. Refer to Section 6.2.1,
“INTx-Type Interrupt Message Remapping and Collapsing,” for interrupt routing information.
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ExpressLane PEX 8532AA/BA/BB/BC 8-Port/32-Lane Versatile PCI Express Switch Data Book
Copyright © 2007 by PLX Technology, Inc. All Rights Reserved – Version 1.6
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