IDT PCI Express 89HPES32NT24xG2, User Manual, Page: 123 / 744

IDT Switch Partition and Port Configuration
PES32NT24xG2 User Manual 5 - 23 January 30, 2013
Notes
Partition Reconfiguration Latency
The amount of time that switch takes to do a partition reconfiguration depends on the reconfiguration
actions. A partition reconfiguration action may involve partition state changes and/or port operating mode
changes.
– The latency to perform port operating mode changes is described in section Port Operating Mode
Change Latency on page 5-14.This latency defaults to 2 ms or 2.5 ms, depending on the port’s
operating mode change action (OMA).
– The latency to perform partition state changes is described in section Partition State Change
Latency on page 5-4. This latency is typically a few cycles, unless the partition state change has
the side-effect of causing port operating mode changes. For the latter case, the delay is as
described in the previous bullet.
System Notification of Partition Reconfiguration
A system may require software notification when a partition reconfiguration occurs. The
PES32NT24xG2 contains multiple mechanisms to accomplish this.
– If the reconfiguration is the result of a failover event, the failover may be signaled by the device
via the following mechanisms:
• Generation of an interrupt by the upstream port of the reconfigured partition. The interrupt may
be generated by the upstream port’s PCI-to-PCI bridge function or the NT function. Refer to
section Interrupts on page 10-4 and section Interrupts on page 14-20 respectively for details.
• Through the Event Signaling mechanism described in section Switch Events on page 16-1.
Alternatively, if the reconfiguration results in the addition, removal, or change in operating mode of the
upstream port associated with the partition, then the system may be notified of the reconfiguration by a link
down or link up event detected by the component upstream of the partition (i.e., the root or switch down-
stream port). This form of notification requires that the OMA field in the SWPORTxCTL register be set to
reset.
Finally, if the reconfiguration is done by a switch management agent, the agent can coordinate and
notify the reconfiguration using the global signals event mechanism described in section Global Signals on
page 16-4.