IDT PCI Express 89HPES32NT24xG2, User Manual, Page: 480 / 744

IDT Proprietary Port Specific Registers
PES32NT24xG2 User Manual 21 - 32 January 30, 2013
Notes
Request Metering
RMCTL - Requester Metering Control (0x880)
15:14 Reserved RO 0x0 Reserved field
16 TSCTL RW 0x1
SWSticky
Timer Start Control.
Upon rejecting an L1 ASPM entry request from the link part-
ner, the switch port counts an amount of time equal to the
value in the MTL1ER field before detecting a new request.
This field selects the criteria for starting the timer.
0x0 - Timer starts counting when the port has issued a
PM_L1_Active_State_Nak TLP. Reception of
PM_L1_Active_State_Request DLLPs from the link
partner prior to the expiration of the timer result in the
timer being re-started.
0x1 - Timer starts counting when the port has issued a
PM_L1_Active_State_Nak TLP. Reception of
PM_L1_Active_State_Request DLLPs from the link
partner prior to the expiration of the timer are ignored.
Once the timer has expired, reception of an incoming
PM_L1_Active_State_Request DLLP will be treated as a
new request.
31:17 Reserved RO 0x0 Reserved field.
Bit
Field
Field
Name
Type Default
Value
Description
0 EN RW 0x0
SWSticky
Enable.
When this bit is set, request metering is enabled on the cor-
responding input port. Refer to section Request Metering
on page 4-11 for further details.
4:1 OVRFACTOR RW 0x2
SWSticky
Overhead Factor.
This field contains the overhead factor used in computing
the completion size estimate for memory read requests.
5 Reserved RO 0x0 Reserved field.
15:6 CNSTLIMIT RW 0x10
SWSticky
Constant Limit.
This field is used to control the algorithm used to compute
the completion size estimate for non-posted read requests
when request metering is enabled.
When the number of DWords required in completions to
service a non-posted read request is less than or equal to
the value in this field, then a constant completion size esti-
mate is used.
When the number of DWords required in completions to
service a non-posted read request is greater than the value
in this field, then the completion size estimate considers the
number of individual completion TLPs.
Bit
Field
Field
Name
Type Default
Value
Description