IDT 89HPES64H16G2 User Manual page 89

IDT Switch Partitions
Notes
PES64H16G2 User Manual
Upstream port removal:
– A switch partition must initiate an exit from L0s on the transmitters of all downstream ports asso-
ciated with the partition if it detects an exit from L0s on the receiver of its upstream port.
– Removing an upstream port from a partition removes it from affecting the L0s ASPM state of
downstream ports of the source partition.
L1 ASPM
A switch upstream port is not allowed to initiate entry into L1 unless all of the downstream ports associ-
ated within the partition are in an L1 (or deeper) state. Refer to section Active State Power Management on
page 7-11 and to the PCI Express Base specification for details.
Downstream port removal:
– Removing a downstream port from a partition removes it from affecting the L1 ASPM state of
upstream port in the source partition.
Upstream port removal:
– Removing an upstream port from a partition has no effect on the L1 state of downstream ports
associated with the partition.
PME Synchronization
Removing a port from a partition has the affect of removing it from participation in PME synchronization
associated with the source partition. If PME synchronization is in progress, then PME synchronization
completes before the port (upstream or downstream) is removed from the partition.
For an upstream port, PME synchronization completes when the port aggregates PME_TO_Ack
messages from all downstream ports in the partition or when the upstream port abandons the aggregation.
For a downstream port, PME synchronization completes when the port notifies the upstream port of the
reception of a PME_TO_Ack message or a PME_TO_Ack timer timeout.
In this scenario, the OMCI field in the port's SWPORTxSTS register is set after the operating mode
change is requested, and the OMCC field in this same register is set after the PME synchronization has
finished and the operating mode change completes.
Bus Locking
Removing the upstream port from a partition immediately unlocks the partition. Removing a downstream
port that is locked has the effect of unlocking the partition. Removing a downstream port that is not locked
from a locked partition has no effect on the locked nature of the partition.
INTx Interrupt Signaling
Removing an upstream port from a partition has no effect on a partition since the interrupt state is asso-
ciated with the root located above the upstream port that is being removed. An INTx state change signalled
by a downstream port in the source partition has no effect on the upstream port as the latter is no longer
associated with the partition.
Removing a downstream port from a partition has the affect of removing all INTx virtual wire assertions
associated with the port (i.e., INTA, INTB, INTC and INTD from the port are negated).
Mode Change Effect on Destination Partition
A port operating mode change that results in a port being added to a partition has the following effect on
that partition (i.e., the "destination" partition). Some of the behaviors described below rely on the state of the
port. The state of the port and its corresponding configuration registers are determined by the OMA field as
described in section No Action Mode Change Behavior on page 6-14 through section Hot Reset Mode
Change Behavior on page 6-15.
Partition Hot Reset
See section Partition Hot Reset on page 5-9 for an overview of partition hot resets. The addition of an
upstream port that is initiating a hot reset (i.e., as the result of reception of TS1 ordered sets with the hot
reset bit set or DL_Down) has the effect of initiating a partition hot reset to the destination partition as
6 - 11 April 5, 2013