/*++

Copyright (c) 1996  Microsoft Corporation

Module Name:

    power.c

Abstract: NULL filter driver -- boilerplate code

Author:

    ervinp

Environment:

    Kernel mode

Revision History:


--*/

#include <WDM.H>

#include "filter.h"


#ifdef ALLOC_PRAGMA
    #ifdef HANDLE_DEVICE_USAGE
        #pragma alloc_text(PAGEPOWR, VA_Power)
    #endif // HANDLE_DEVICE_USAGE
#endif


NTSTATUS VA_Power(struct DEVICE_EXTENSION *devExt, PIRP irp)
/*++

Routine Description:

    Dispatch routine for Power IRPs (MajorFunction == IRP_MJ_Power)


    Note:
        If HANDLE_DEVICE_USAGE is defined     
     
           This function may or may not be locked down, depending on the lower
           device object and if the device is in the paging path, so we can't
           use the PAGED_CODE() macro.  Furthermore, we can't use PagedPool. 
           
        Otherwise

            This function is left locked down.        

Arguments:

    devExt - device extension for targetted device object
    irp - Io Request Packet

Return Value:

    NT status code

--*/
{
    PIO_STACK_LOCATION irpSp;
    NTSTATUS status;

    irpSp = IoGetCurrentIrpStackLocation(irp);

    TRACE(TL_PNP_WARNING,("VA_Power, minorFunc = %d ", (ULONG)irpSp->MinorFunction)); 


    switch (irpSp->MinorFunction){

        case IRP_MN_SET_POWER:

            switch (irpSp->Parameters.Power.Type) {

                case SystemPowerState:
                    /*
                     *  For system power states, just pass the IRP down.
                     */
                    break;

                case DevicePowerState:

                    switch (irpSp->Parameters.Power.State.DeviceState) {

                        case PowerDeviceD0:
                            /*
                             *  Resume from APM Suspend
                             *
                             *  Do nothing here; 
                             *  Send down the read IRPs in the completion
                             *  routine for this (the power) IRP.
                             */
                            break;

                        case PowerDeviceD1:
                        case PowerDeviceD2:
                        case PowerDeviceD3:
                            /*
                             *  Suspend
                             */
                            if (devExt->state == STATE_STARTED){
                                devExt->state = STATE_SUSPENDED;
                            }
                            break;

                    }
                    break;

            }
            break;

    }


    /*
     *  Send the IRP down the driver stack,
     *  using PoCallDriver (not IoCallDriver, as for non-power irps).
     */
    IncrementPendingActionCount(devExt);
    IoCopyCurrentIrpStackLocationToNext(irp);
    IoSetCompletionRoutine( irp, 
                            VA_PowerComplete, 
                            (PVOID)devExt,  // context
                            TRUE, 
                            TRUE, 
                            TRUE);
    status = PoCallDriver(devExt->topDevObj, irp);



    return status;
}


NTSTATUS VA_PowerComplete(
                            IN PDEVICE_OBJECT devObj, 
                            IN PIRP irp, 
                            IN PVOID context)
/*++

Routine Description:

      Completion routine for Power IRPs (MajorFunction == IRP_MJ_Power)

Arguments:

    devObj - targetted device object
    irp - Io Request Packet
    context - context value passed to IoSetCompletionRoutine by VA_Power

Return Value:

    NT status code

--*/
{
    PIO_STACK_LOCATION irpSp;
    struct DEVICE_EXTENSION *devExt = (struct DEVICE_EXTENSION *)context;

    ASSERT(devExt);
    ASSERT(devExt->signature == DEVICE_EXTENSION_SIGNATURE); 

    /*
     *  If the lower driver returned PENDING, mark our stack location as
     *  pending also.
     */
    if (irp->PendingReturned){
        IoMarkIrpPending(irp);
    }

    irpSp = IoGetCurrentIrpStackLocation(irp);
    ASSERT(irpSp->MajorFunction == IRP_MJ_POWER);

    if (NT_SUCCESS(irp->IoStatus.Status)){
        switch (irpSp->MinorFunction){

            case IRP_MN_SET_POWER:

                switch (irpSp->Parameters.Power.Type){

                    case DevicePowerState:
                        switch (irpSp->Parameters.Power.State.DeviceState){
                            case PowerDeviceD0:
                                if (devExt->state == STATE_SUSPENDED){
                                    devExt->state = STATE_STARTED;
                                }
                                break;
                        }
                        break;

                }
                break;
        }

    }
    
    
    /*
     *  Whether we are completing or relaying this power IRP,
     *  we must call PoStartNextPowerIrp.
     */
    PoStartNextPowerIrp(irp);

    /*
     *  Decrement the pendingActionCount, which we incremented in VA_Power.
     */
    DecrementPendingActionCount(devExt);

    return STATUS_SUCCESS;
}