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PCI_EXPRESS_LINK_CONTROL_REGISTER union (ntddk.h)

  • Article

The PCI_EXPRESS_LINK_CONTROL_REGISTER structure describes a PCI Express (PCIe) link control register of a PCIe capability structure.

Syntax

typedef union _PCI_EXPRESS_LINK_CONTROL_REGISTER {
  struct {
    USHORT ActiveStatePMControl  :2;
    USHORT Rsvd1  :1;
    USHORT ReadCompletionBoundary  :1;
    USHORT LinkDisable  :1;
    USHORT RetrainLink  :1;
    USHORT CommonClockConfig  :1;
    USHORT ExtendedSynch  :1;
    USHORT EnableClockPowerManagement  :1;
    USHORT Rsvd2  :7;
  };
  USHORT AsUSHORT;
} PCI_EXPRESS_LINK_CONTROL_REGISTER, *PPCI_EXPRESS_LINK_CONTROL_REGISTER;

Members

DUMMYSTRUCTNAME

DUMMYSTRUCTNAME.ActiveStatePMControl

The level of active state power management that is enabled on the PCIe link. Possible values are:

Value Description
L0sAndL1EntryDisabled L0s and L1 are both disabled.
L0sEntryEnabled L0s is enabled.
L1EntryEnabled L1 is enabled.
L0sAndL1EntryEnabled L0s and L1 are both enabled.

DUMMYSTRUCTNAME.Rsvd1

Reserved.

DUMMYSTRUCTNAME.ReadCompletionBoundary

The read completion boundary (RCB) value for the root port or the root port upstream from the endpoint. If the bit is clear, the RCB is 64 byte. If the bit is set, the RCB is 128 byte. This member is not applicable for switch ports.

DUMMYSTRUCTNAME.LinkDisable

A single bit that indicates that the link is disabled. This member is not applicable for endpoint devices, PCIe-to-PCI or PCI-X bridges, and upstream ports of switches.

DUMMYSTRUCTNAME.RetrainLink

A single bit that is used to initiate retraining of the link. Reads of this bit always return zero. This member is not applicable for endpoint devices, PCIe-to-PCI or PCI-X bridges, and upstream ports of switches.

DUMMYSTRUCTNAME.CommonClockConfig

A single bit that indicates that this component and the component at the opposite end of the link are operating with a distributed common reference clock. If this bit is clear, this component and the component at the opposite end of the link are operating with an asynchronous reference clock.

DUMMYSTRUCTNAME.ExtendedSynch

A single bit that indicates that additional ordered sets are transmitted when exiting the L0s state and when in the recovery state.

DUMMYSTRUCTNAME.EnableClockPowerManagement

A single bit that indicates that clock power management is enabled.

DUMMYSTRUCTNAME.Rsvd2

Reserved.

AsUSHORT

A USHORT representation of the contents of the PCI_EXPRESS_LINK_CONTROL_REGISTER structure.

Remarks

The PCI_EXPRESS_LINK_CONTROL_REGISTER structure is available in Windows Server 2008 and later versions of Windows.

A PCI_EXPRESS_LINK_CONTROL_REGISTER structure is contained in the PCI_EXPRESS_CAPABILITY_REGISTER structure.

Requirements

Requirement Value
Header ntddk.h (include Ntddk.h, Miniport.h)

See also

PCI_EXPRESS_CAPABILITY_REGISTER

PCI_EXPRESS_LINK_CONTROL_2_REGISTER