D3COLD_REQUEST_PERST_DELAY callback function (wdm.h)

Enables the function device object (FDO) to convey its requirement for a fixed delay time between the PME_TO_Ack message is received at the PCI Express Downstream Port that originated the PME_Turn_Off message, and the time the platform asserts PERST# to the slot during the corresponding endpoint's or PCI Express Upstream Port's transition to D3cold while the system is in an ACPI operational state.

Syntax

D3COLD_REQUEST_PERST_DELAY D3coldRequestPerstDelay;

NTSTATUS D3coldRequestPerstDelay(
  [_In_reads_opt_(_Inexpressible_("varies"))] PVOID Context,
  [_In_]                                      ULONG DelayInMicroSeconds
)
{...}

Parameters

Context

The handle to the device.

[_In_] DelayInMicroSeconds

The delay in units of microsecond. The maximum value is 10000 microseconds.

Return value

Return STATUS_SUCCESS if the operation succeeds. Otherwise, return an appropriate NTSTATUS Values error code. For more information, see NTSTATUS Values.

Remarks

A device driver that successfully queries for the GUID_D3COLD_AUX_POWER_AND_TIMING_INTERFACE interface receives a pointer to a D3COLD_AUX_POWER_AND_TIMING_INTERFACE structure in which the driver sets the RequestPerstDelay member to a pointer to its implementation of the D3COLD_REQUEST_PERST_DELAY callback function.

• For a multi-function device, only Function 0 is allowed to call this routine.

• Function 0 must be in D0 when calling this routine.

Requirements