IDT 89HPES64H16G2 User Manual page 91

IDT Switch Partitions
Notes
PES64H16G2 User Manual
Upstream port addition:
– 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. See the
PCI Express Base specification for details.
– Adding an upstream port to a partition causes it to affect the L0s ASPM state of downstream ports
in the destination partition.
If an upstream port whose receiver is in L0s is added to a switch partition, then an entry to L0s
is initiated on the transmitter of all downstream ports in L0 per the rules described in section
Active State Power Management on page 7-11.
If an upstream port whose receiver is in L0 is added to a switch partition, then an exit from L0s
is initiated on the transmitter of all downstream ports that are in L0s.
– Adding an upstream port to a partition causes the added port to be affected by the L0s ASPM state
of downstream ports in the destination partition.
For example, if an upstream port whose transmitter is in L0 is added to a switch partition
whose downstream ports are in L0s, then an entry to L0s is initiated on the port's transmitter
per the rules described in section Active State Power Management on page 7-11.
Also, if an upstream port whose transmitter is in L0s is added to a switch partition whose
downstream ports are in L0, then an exit from L0s is initiated on the port's transmitter.
L1 ASPM
Downstream port addition:
– A switch upstream port is not allowed to initiate entry into L1 unless all of the downstream ports
associated with the partition are in an L1 (or deeper) state. See section Active State Power
Management on page 7-11 and to the PCI Express Base specification for details.
– Adding a downstream port to a partition causes it to affect the L1 ASPM initiation of the upstream
port.
For example, if a downstream port in L0 is added to a switch partition whose upstream port is
in L1 ASPM, then an exit from L1 is initiated on the upstream port.
– Adding a downstream port to a partition causes the added port to be affected by the ASPM state
of the upstream port in the destination partition.
For example, if a downstream port in L1 ASPM is added to a switch partition whose upstream
port is in L0, then an exit from L1 is initiated on the added port.
Upstream port addition:
– Adding an upstream port to a partition causes it to affect the L1 ASPM state of downstream ports
in the destination partition.
For example, if an upstream port in L0 is added to a switch partition, then an exit from L1 is
initiated on all downstream ports in L1 ASPM.
– Adding an upstream port to a partition where all downstream ports are in L1 ASPM causes the
upstream port to enter the L1 ASPM state per the rules described in section Active State Power
Management on page 7-11.
PME Synchronization
If PME synchronization is in progress then the port being added must be a downstream port. This down-
stream port being added does not participate in PME synchronization in progress within the destination
partition. The added downstream port participates in PME synchronization initiated within the destination
partition after the addition of the port has been completed.
Bus Locking
If the destination partition is bus locked, then the port being added must be a downstream port. By the
nature that the port is added to a locked partition, it cannot be one of the two locked ports. Adding a down-
stream port to a partition that is locked causes it to adopt the locked behavior associated with the destina-
tion partition. The port blocks all requests from being propagated to either of the locked ports, except for
requests which map to non-VC0 on the egress port.
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