31

0h

RW

Disable scheduler direct transition from IDLE to NO requirement (DIS_​SDT_​IDL_​NR)

0: (default) allow scheduler direct transition from IDLE to NO requirement
1: Disable scheduler direct transition from IDLE to NO requirement

30

0h

RW

XHCI LTR Transition Policy (XLTRTP) (LTR_​TRANS_​POL)

When 0, the LTR messaging state machine transitions through High Med Low Active states
assuming enough latency is available for each transition.
When 1, LTR messaging state machine transitions from High, Medium, or Low LTR states to
Active state upon the Alarm Timer timeout and stays in Active until the next service boundary.

29

0h

RO

Reserved

28

0h

RW

XHCI LTR Active Enable (XLTRAE) (XLTRAE)

0: The Power Scheduler will not request an LTR message on a transition to ACTIVE.
1: The Power Scheduler will request an LTR message on a transition to ACTIVE.

27

0h

RW

Power Scheduler Local Clock Gating Enable (PWRLCGE) (PWRLCGE)

0: Power Scheduler does not use local clock gating
1: Power Scheduler's local clock gating enabled.
Note: This functionality is no longer required. This LCG existed previous to the inclusion of Aux clock gating.

26

0h

RW

LTR EVM Hysteresis Max Count (LTR_​HYS_​MAX)

Power Scheduler's Periodic IDLE residency before we assert Periodic Complete
0: Hysteresis set to 127 clock ticks. (.64us)
1: Hysteresis set to 31 clock ticks (.16us)

25

0h

RW

Enable USB2 Port L0 LTV based on active async (EN_​USB2_​LTV_​U0_​PORT_​ASYNC_​ACTIVE)

0 - USB2 Port L0 LTV is used regardless of whether there is active async EPs being present or not (Legacy mode)

1 - USB2 LTR L0 LTV is used only when there is active async EPs being present on that port. In the absence of active async EPs on given port, the L0 LTR value is NoRequirement for that port.

24

1h

RW

XHCI LTR Enable (XLTRE)

This bit must be set to enable LTV messaging from XHCI to the PMC.

23:12

400h

RW

Periodic Active LTV (PA_​LTV)

23:22 Latency Scale
00b : Reserved
01b : Latency Value to be multiplied by 1024
10b : Latency Value to be multiplied by 32,768
11b : Latency Value to be multiplied by 1,048,576

21:12 Latency Value (ns)

Defaults to 0 micro seconds

11:0

c01h

RW

USB2 Port L0 LTV (USB2_​PL0_​LTV)

11:10 Latency Scale
00b : Reserved
01b : Latency Value to be multiplied by 1024
10b : Latency Value to be multiplied by 32,768
11b : Latency Value to be multiplied by 1,048,576

9:0 Latency Value (ns)

Defaults to 128 Micro Seconds