videomp.c

/*****************************************************************************

Copyright (c) 2012  Michal Necasek

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

*****************************************************************************/

/*
 * Windows NT Video Miniport for the VirtualBox/bochs/qemu SVGA adapter.
 * This miniport programs the hardware directly and does not use or require
 * the video BIOS or VBE.
 *
 * NB: This is not a "VGA compatible" miniport and standard VGA modes are
 * handled by the default VGA miniport.
 */

#include <miniport.h>
#include <ntddvdeo.h>
#include <video.h>
#include <stddef.h>

#include "videomp.h"
#include "boxv.h"

/* Accommodate incomplete DDK headers shipped with Open Watcom 1.9. */
#ifndef SIZE_OF_NT4_VIDEO_HW_INITIALIZATION_DATA

#define SIZE_OF_NT4_VIDEO_HW_INITIALIZATION_DATA    FIELD_OFFSET( VIDEO_HW_INITIALIZATION_DATA, HwStartDma )
#define SIZE_OF_W2K_VIDEO_HW_INITIALIZATION_DATA    FIELD_OFFSET( VIDEO_HW_INITIALIZATION_DATA, Reserved )
#define SIZE_OF_WXP_VIDEO_HW_INITIALIZATION_DATA    (SIZE_OF_W2K_VIDEO_HW_INITIALIZATION_DATA + sizeof( ULONG ))

#include <winerror.h>   /* This should really be dderror.h... */

#else

#include <dderror.h>

#endif

/* Number of PCI access ranges. */
#define NUM_PCI_RANGES      3

/* RGB color channel constants. */
typedef enum {
    CHANNEL_RED,
    CHANNEL_GREEN,
    CHANNEL_BLUE
} COLOR_CHANNEL;


#if defined( ALLOC_PRAGMA )
#pragma alloc_text( PAGE, DriverEntry )
#pragma alloc_text( PAGE, HwVidFindAdapter )
#pragma alloc_text( PAGE, HwVidInitialize )
#pragma alloc_text( PAGE, HwVidStartIO )
#endif


/* Calculate pitch based on scanline length and bit depth. */
static ULONG vmpPitchByBpp( ULONG Length, UCHAR Bpp )
{
    ULONG   ulPitch = 0;

    switch( Bpp ) {
    case 4:
        ulPitch = (Length + 1) / 2;
        break;
    case 8:
        ulPitch = Length;
        break;
    case 15:
    case 16:
        ulPitch = Length * 2;
        break;
    case 24:
        ulPitch = Length * 3;
        break;
    case 32:
        ulPitch = Length * 4;
        break;
    }
    return( ulPitch );
}


/* Validate a given mode and set the appropriate flag. Note that the
 * validation criteria are somewhat arbitrary.
 */
static void vmpValidateMode( PVIDEOMP_MODE Mode, ULONG FramebufLen )
{
    ULONG   ulModeMem;

    Mode->bValid = FALSE;

    do {
        /* Horizontal resolution should be divisible by 8. */
        if( Mode->HorzRes % 8)
            break;

        /* Validate memory requirements. */
        ulModeMem = vmpPitchByBpp( Mode->HorzRes, Mode->Bpp ) * Mode->VertRes;
        if( ulModeMem > FramebufLen )
            break;

        /* Passed all checks, mode is valid. */
        Mode->bValid = TRUE;
    } while( 0 );
}

/* Determine whether the supported adapter is present. Note that this
 * function is not allowed to change the state of the adapter!
 */
VP_STATUS HwVidFindAdapter( PVOID HwDevExt, PVOID HwContext, PWSTR ArgumentString,
                            PVIDEO_PORT_CONFIG_INFO ConfigInfo, PUCHAR Again )
{
    PHW_DEV_EXT             pExt = HwDevExt;
    PVOID                   *pVirtAddr;
    ULONG                   i;
    INT                     chip_id;
    VP_STATUS               status;
    ULONG                   cbVramSize;
    PWSTR                   pwszDesc;
    ULONG                   cbDesc;
#ifdef USE_GETACCESSRANGES
    VIDEO_ACCESS_RANGE      pciAccessRanges[NUM_PCI_RANGES];
    USHORT                  usVendorId = BOXV_PCI_VEN;
    USHORT                  usDeviceId = BOXV_PCI_DEV;
    ULONG                   ulSlot = 0;
#endif

    //@todo: The framebuffer address should not be hardcoded for non-PCI access
#define NUM_ACCESS_RANGES   2
    VIDEO_ACCESS_RANGE accessRanges[NUM_ACCESS_RANGES] = {
        /* StartLo     StartHi     Len       IO Vis Shr */
        { 0x000001CE, 0x00000000, 0x00000002, 1, 1, 0 },    /* I/O ports */
        { 0xE0000000, 0x00000000, 0x00400000, 0, 1, 0 }     /* Framebuffer */
    };

    VideoDebugPrint( (1, "videomp: HwVidFindAdapter\n") );

    /* Fail if the passed structure is smaller than the NT 3.1 version. */
    if( ConfigInfo->Length < offsetof( VIDEO_PORT_CONFIG_INFO, DmaChannel ) ) {
        return( ERROR_INVALID_PARAMETER );
    }

    /* Sadly, VideoPortGetAccessRanges was not present in NT 3.1. There is no
     * reasonably simple way to dynamically import port driver routines on
     * newer versions, so we'll just do without.
     */
#ifdef USE_GETACCESSRANGES
    /* If PCI is supported, query the bus for resource mappings. */
    if( ConfigInfo->AdapterInterfaceType == PCIBus ) {
        /* Ask for bus specific access ranges. */
        VideoPortZeroMemory( pciAccessRanges, sizeof( pciAccessRanges ) );
        status = VideoPortGetAccessRanges( HwDevExt, 0, NULL,
                                           NUM_PCI_RANGES, pciAccessRanges,
                                           &usVendorId, &usDeviceId, &ulSlot );
        if( status == NO_ERROR ) {
            VideoDebugPrint( (1, "videomp: Found adapter in PCI slot %d\n", ulSlot) );
            pExt->ulSlot = ulSlot;
            /* The framebuffer is in the first slot of the PCI ranges. Copy
             * the data into the access ranges we're going to request.
             */
            accessRanges[1].RangeStart  = pciAccessRanges[0].RangeStart;
            accessRanges[1].RangeLength = pciAccessRanges[0].RangeLength;
        } else {
            /* On NT versions without PCI support, we won't even attempt this.
             * So if we tried to query the PCI device and failed to find it,
             * it really isn't there and we have to give up.
             */
            VideoDebugPrint( (1, "videomp: PCI adapter not found\n") );
            return( ERROR_DEV_NOT_EXIST );
        }
    }
#endif

    /* Some versions of vga.sys trap accesses to ports 0x1CE-0x1CF used on
     * old ATI cards. On Windows 2000 and later we can report legacy
     * resources to resolve this conflict. On NT 4 and older, we use a hack
     * and claim other, non-conflicting ports.
     */
    if( PortVersion < VP_VER_W2K )
        accessRanges[0].RangeStart = RtlConvertUlongToLargeInteger( 0x1CC );

    /* Check for a conflict in case someone else claimed our resources. */
    status = VideoPortVerifyAccessRanges( HwDevExt, NUM_ACCESS_RANGES, accessRanges );
    if( status != NO_ERROR ) {
        return( status );
    }

    /* Indicate no emulator support. */
    ConfigInfo->NumEmulatorAccessEntries     = 0;
    ConfigInfo->EmulatorAccessEntries        = NULL;
    ConfigInfo->EmulatorAccessEntriesContext = 0;

    ConfigInfo->HardwareStateSize = 0;

    ConfigInfo->VdmPhysicalVideoMemoryAddress.LowPart  = 0;
    ConfigInfo->VdmPhysicalVideoMemoryAddress.HighPart = 0;
    ConfigInfo->VdmPhysicalVideoMemoryLength           = 0;

    /* Describe the framebuffer. We claimed the range already. */
    pExt->PhysicalFrameAddress = accessRanges[1].RangeStart;


    /*
     * Map all memory and I/O ranges into system virtual address space.
     * NB: The virtual addresses in the HwDevExt must match the number
     * and type of AccessRange entries.
     */
    pVirtAddr = &pExt->IoPorts;

    /* Attempt to claim and map the memory and I/O address ranges. */
    for( i = 0; i < NUM_ACCESS_RANGES; ++i, ++pVirtAddr ) {
        *pVirtAddr = VideoPortGetDeviceBase( pExt,
                                             accessRanges[i].RangeStart,
                                             accessRanges[i].RangeLength,
                                             accessRanges[i].RangeInIoSpace );
        if( *pVirtAddr == NULL ) {
            return( ERROR_INVALID_PARAMETER );
        }
    }

    /* Verify that supported hardware is present. */
    chip_id = BOXV_detect( pExt, &pExt->FramebufLen );
    if( !chip_id ) {
        /* If supported hardware was not found, free allocated resources. */
        pVirtAddr = &pExt->IoPorts;
        for( i = 0; i < NUM_ACCESS_RANGES; ++i, ++pVirtAddr )
            VideoPortFreeDeviceBase( pExt, *pVirtAddr );

        return( ERROR_DEV_NOT_EXIST );
    }

    /* We need to access VGA and other I/O ports. Fortunately the HAL doesn't
     * care at all how the I/O ports are or aren't mapped on x86 platforms.
     */
    pExt->IOAddrVGA = NULL;

    /* Only support one attached monitor. */
    pExt->NumMonitors = 1;

    /* Set up mode information. */
    pExt->CurrentModeNumber = 0;
    pExt->NumValidModes     = 0;

    for( i = 0; i < ulAllModes; ++i ) {
        vmpValidateMode( &VideoModes[i], pExt->FramebufLen );
        if( VideoModes[i].bValid )
            ++pExt->NumValidModes;
    }

    /* Only one adapter supported, no need to call us again. */
    *Again = 0;

    /* Report the hardware names via registry. */

#define TEMP_CHIP_NAME  L"bochs Mk II"
    pwszDesc = TEMP_CHIP_NAME;
    cbDesc   = sizeof( TEMP_CHIP_NAME );

    VideoPortSetRegistryParameters( pExt, L"HardwareInformation.ChipType",
                                    pwszDesc, cbDesc );

#define TEMP_DAC_NAME  L"Integrated DAC"
    pwszDesc = TEMP_DAC_NAME;
    cbDesc   = sizeof( TEMP_DAC_NAME );
    VideoPortSetRegistryParameters( pExt, L"HardwareInformation.DacType",
                                    pwszDesc, cbDesc );

#define TEMP_ADAPTER_NAME  L"VirtualBox/bochs"
    pwszDesc = TEMP_ADAPTER_NAME;
    cbDesc   = sizeof( TEMP_ADAPTER_NAME );
    VideoPortSetRegistryParameters( pExt, L"HardwareInformation.AdapterString",
                                    pwszDesc, cbDesc );

    cbVramSize = pExt->FramebufLen;
    VideoPortSetRegistryParameters( pExt, L"HardwareInformation.MemorySize",
                                    &cbVramSize, sizeof( ULONG ) );
    /* All is well. */
    return( NO_ERROR );
}


/* Perform one-time device initialization. Once this function has been
 * entered, the miniport may change adapter state.
 */
BOOLEAN HwVidInitialize( PVOID HwDevExt )
{
    VideoDebugPrint( (1, "videomp: HwVidInitialize\n") );
    return( TRUE );
}


/* Determine pixel mask given color depth and color channel. */
static ULONG vmpMaskByBpp( UCHAR Bpp, COLOR_CHANNEL Channel )
{
    ULONG   ulMask;

    switch( Bpp ) {
    case 24:
    case 32:
        ulMask = 0x00FF0000 >> (Channel * 8);
        break;
    case 15:
        ulMask = 0x00007C00 >> (Channel * 5);
        break;
    case 16:
        switch( Channel ) {
        case CHANNEL_RED:
            ulMask = 0x0000F800;
            break;
        case CHANNEL_GREEN:
            ulMask = 0x000007E0;
            break;
        case CHANNEL_BLUE:
            ulMask = 0x0000001F;
            break;
        }
        break;
    case 4:
    case 8:
    default:
        ulMask = 0;     /* Palettized modes don't have a mask. */
    }

    return( ulMask );
}

/* Fill out NT specific video mode information struct based on resolution
 * and color depth.
 */
static void vmpFillModeInfo( PVIDEO_MODE_INFORMATION ModeInfo, USHORT HRes, USHORT VRes, UCHAR Bpp)
{
    /* First the basic mode information. */
    ModeInfo->Length          = sizeof( VIDEO_MODE_INFORMATION );
    ModeInfo->ModeIndex       = 0;      /* Filled in later. */
    ModeInfo->VisScreenWidth  = HRes;   /* Horizontal resolution in pixels. */
    ModeInfo->VisScreenHeight = VRes;   /* Vertical resolution in pixels. */

    /* Assume no rounding is necessary. */
    ModeInfo->ScreenStride    = vmpPitchByBpp( HRes, Bpp );

    ModeInfo->NumberOfPlanes  = 1;      /* Always one plane - packed pixel only. */
    ModeInfo->BitsPerPlane    = Bpp;    /* Number of bits per pixel. */
    ModeInfo->Frequency       = 60;     /* Irrelevant; just make something up. */

    /* Screen size is made up, but should correspond to aspect ratio. */
    ModeInfo->XMillimeter     = 320;
    ModeInfo->YMillimeter     = ModeInfo->XMillimeter * VRes / HRes;

    /* The DAC always works with 8 bits per channel. */
    ModeInfo->NumberRedBits   = 8;      /* Red pixels in DAC. */
    ModeInfo->NumberGreenBits = 8;      /* Green pixels in DAC. */
    ModeInfo->NumberBlueBits  = 8;      /* Blue pixels in DAC. */

    /* Pixel mask depends on color depth. */
    ModeInfo->RedMask         = vmpMaskByBpp( Bpp, CHANNEL_RED );
    ModeInfo->GreenMask       = vmpMaskByBpp( Bpp, CHANNEL_GREEN );
    ModeInfo->BlueMask        = vmpMaskByBpp( Bpp, CHANNEL_BLUE );

    /* Mode attributes are only different for 8bpp modes. */
    ModeInfo->AttributeFlags      = VIDEO_MODE_GRAPHICS | VIDEO_MODE_COLOR;
    if( Bpp <= 8 )
        ModeInfo->AttributeFlags |= VIDEO_MODE_PALETTE_DRIVEN | VIDEO_MODE_MANAGED_PALETTE;

    /* Strictly speaking, the following don't need to be filled out. */
    ModeInfo->VideoMemoryBitmapWidth       = 0;
    ModeInfo->VideoMemoryBitmapHeight      = 0;
    ModeInfo->DriverSpecificAttributeFlags = 0;
}

/* Main I/O request handler routine. */
BOOLEAN HwVidStartIO( PVOID HwDevExt, PVIDEO_REQUEST_PACKET ReqPkt )
{
    PHW_DEV_EXT                         pExt = HwDevExt;
    VP_STATUS                           status = NO_ERROR;
    PVIDEO_MODE_INFORMATION             modeInfo;
    PVIDEO_MEMORY                       vidMem;
    PVIDEO_SHARE_MEMORY                 pShrMem;
    PVOID                               virtualAddress;
    ULONG                               inIoSpace;
    ULONG                               modeNumber;
    ULONG                               ulLen;
    ULONG                               i;

    VideoDebugPrint( (2, "videomp: HwVidStartIO: ") );

    /* Process the VRP. Required requests are handled first. */
    switch( ReqPkt->IoControlCode ) {
    case IOCTL_VIDEO_QUERY_NUM_AVAIL_MODES:
    {
        PVIDEO_NUM_MODES        numModes;

        VideoDebugPrint( (2, "QUERY_NUM_AVAIL_MODES\n") );
        if( ReqPkt->OutputBufferLength < sizeof( VIDEO_NUM_MODES ) ) {
            status = ERROR_INSUFFICIENT_BUFFER;
        } else {
            ReqPkt->StatusBlock->Information = sizeof( VIDEO_NUM_MODES );
            numModes = (PVIDEO_NUM_MODES)ReqPkt->OutputBuffer;
            numModes->ModeInformationLength = sizeof( VIDEO_MODE_INFORMATION );
            numModes->NumModes = pExt->NumValidModes;
        }
        break;
    }

    case IOCTL_VIDEO_QUERY_AVAIL_MODES:
        VideoDebugPrint( (2, "QUERY_AVAIL_MODES\n") );
        ulLen = pExt->NumValidModes * sizeof( VIDEO_MODE_INFORMATION );
        if( ReqPkt->OutputBufferLength < ulLen ) {
            status = ERROR_INSUFFICIENT_BUFFER;
        } else {
            ReqPkt->StatusBlock->Information = ulLen;
            modeInfo = ReqPkt->OutputBuffer;
            for( i = 0; i < ulAllModes; ++i ) {
                if( VideoModes[i].bValid ) {
                    vmpFillModeInfo( modeInfo, VideoModes[i].HorzRes,
                                     VideoModes[i].VertRes, VideoModes[i].Bpp );
                    modeInfo->ModeIndex = i; //VideoModes[i].modeInformation.ModeIndex;

                    modeInfo++;
                }
            }
        }
        break;

    case IOCTL_VIDEO_QUERY_CURRENT_MODE:
        VideoDebugPrint( (2, "QUERY_CURRENT_MODE\n") );
        if( ReqPkt->OutputBufferLength < sizeof( VIDEO_MODE_INFORMATION ) ) {
            status = ERROR_INSUFFICIENT_BUFFER;
        } else {
            ReqPkt->StatusBlock->Information = sizeof( VIDEO_MODE_INFORMATION );
            modeInfo  = ReqPkt->OutputBuffer;
            vmpFillModeInfo( modeInfo,
                             VideoModes[pExt->CurrentModeNumber].HorzRes,
                             VideoModes[pExt->CurrentModeNumber].VertRes,
                             VideoModes[pExt->CurrentModeNumber].Bpp );
            modeInfo->ModeIndex = pExt->CurrentModeNumber; //VideoModes[pExt->CurrentModeNumber].modeInformation.ModeIndex;
        }

        break;

    case IOCTL_VIDEO_SET_CURRENT_MODE:
        VideoDebugPrint( (2, "SET_CURRENT_MODE\n") );

        /* Ensure the mode is valid. */
        modeNumber = ((PVIDEO_MODE)(ReqPkt->InputBuffer))->RequestedMode;

        if( (modeNumber > ulAllModes) || (!VideoModes[modeNumber].bValid) ) {
            status = ERROR_INVALID_PARAMETER;
            break;
        }

        BOXV_ext_mode_set( pExt, VideoModes[modeNumber].HorzRes,
                           VideoModes[modeNumber].VertRes, VideoModes[modeNumber].Bpp,
                           VideoModes[modeNumber].HorzRes, VideoModes[modeNumber].VertRes );

        pExt->CurrentModeNumber = modeNumber;
        break;

    case IOCTL_VIDEO_RESET_DEVICE:
        VideoDebugPrint( (2, "RESET_DEVICE\n") );
	/* Not calling the following routine avoids some visual glitches. */
        /* BOXV_ext_disable( pExt ); */
        break;

    case IOCTL_VIDEO_MAP_VIDEO_MEMORY:
    {
        PVIDEO_MEMORY_INFORMATION           memInfo;

        VideoDebugPrint( (2, "MAP_VIDEO_MEMORY\n") );
        if( (ReqPkt->OutputBufferLength < sizeof( VIDEO_MEMORY_INFORMATION )) ||
            (ReqPkt->InputBufferLength < sizeof( VIDEO_MEMORY )) ) {

            status = ERROR_INSUFFICIENT_BUFFER;
            break;
        }

        ReqPkt->StatusBlock->Information =  sizeof( VIDEO_MEMORY_INFORMATION );

        vidMem    = (PVIDEO_MEMORY)ReqPkt->InputBuffer;
        memInfo   = ReqPkt->OutputBuffer;
        inIoSpace = FALSE;

        memInfo->VideoRamBase   = vidMem->RequestedVirtualAddress;
        memInfo->VideoRamLength = pExt->FramebufLen;

        status = VideoPortMapMemory( pExt, pExt->PhysicalFrameAddress,
                                     &memInfo->VideoRamLength, &inIoSpace,
                                     &memInfo->VideoRamBase );

        /* The framebuffer covers the entire video memory. */
        memInfo->FrameBufferBase   = memInfo->VideoRamBase;
        memInfo->FrameBufferLength = memInfo->VideoRamLength;
        break;
    }

    case IOCTL_VIDEO_UNMAP_VIDEO_MEMORY:
        VideoDebugPrint( (2, "UNMAP_VIDEO_MEMORY\n") );
        if( ReqPkt->InputBufferLength < sizeof( VIDEO_MEMORY ) ) {
            status = ERROR_INSUFFICIENT_BUFFER;
        } else {
            vidMem  = (PVIDEO_MEMORY)ReqPkt->InputBuffer;
            status = VideoPortUnmapMemory( pExt,
                                           vidMem->RequestedVirtualAddress,
                                           0 );
        }
        break;

    /* The following request is required for palettized modes. */
    case IOCTL_VIDEO_SET_COLOR_REGISTERS:
    {
        PVIDEO_CLUT     clutBuffer;

        VideoDebugPrint( (2, "SET_COLOR_REGISTERS\n") );
        clutBuffer = ReqPkt->InputBuffer;

        if( (ReqPkt->InputBufferLength < sizeof( VIDEO_CLUT ) - sizeof( ULONG )) ||
            (ReqPkt->InputBufferLength < sizeof( VIDEO_CLUT ) +
                    (sizeof( ULONG ) * (clutBuffer->NumEntries - 1)) ) ) {

            status = ERROR_INSUFFICIENT_BUFFER;
            break;
        }

        if( VideoModes[pExt->CurrentModeNumber].Bpp == 8 ) {
            BOXV_dac_set( pExt, clutBuffer->FirstEntry, clutBuffer->NumEntries,
                          clutBuffer->LookupTable );
        }
        break;
    }

    /* The following requests are optional. */
    case IOCTL_VIDEO_QUERY_POINTER_CAPABILITIES:
    {
        PVIDEO_POINTER_CAPABILITIES     ptrCaps = ReqPkt->OutputBuffer;

        VideoDebugPrint( (2, "QUERY_POINTER_CAPABILITIES\n") );
        if( ReqPkt->OutputBufferLength < sizeof( VIDEO_POINTER_CAPABILITIES ) ) {
            ReqPkt->StatusBlock->Information = 0;
            status = ERROR_INSUFFICIENT_BUFFER;
        }

        ptrCaps->Flags = 0;     /* Indicate no pointer support. */
        ptrCaps->MaxWidth = ptrCaps->MaxHeight = 0;
        /* Documentation and sample code disagree on whether no display
         * memory for cursor is indicated by 0 or -1.
         */
        ptrCaps->HWPtrBitmapStart = ptrCaps->HWPtrBitmapEnd = ~0;

        ReqPkt->StatusBlock->Information = sizeof( VIDEO_POINTER_CAPABILITIES );
        break;
    }

    /* The share/unshare IOCTLs are new for NT 3.51. */
    case IOCTL_VIDEO_SHARE_VIDEO_MEMORY:
    {
        PVIDEO_SHARE_MEMORY_INFORMATION     pShrMemInfo;
        PHYSICAL_ADDRESS                    shareAddress;
        ULONG                               sharedViewSize;

        VideoDebugPrint( (2, "SHARE_VIDEO_MEMORY\n") );
        if( (ReqPkt->OutputBufferLength < sizeof( VIDEO_SHARE_MEMORY_INFORMATION )) ||
            (ReqPkt->InputBufferLength < sizeof( VIDEO_MEMORY )) ) {

            status = ERROR_INSUFFICIENT_BUFFER;
            break;
        }

        pShrMem = ReqPkt->InputBuffer;

        if( (pShrMem->ViewOffset > pExt->FramebufLen) ||
            ((pShrMem->ViewOffset + pShrMem->ViewSize) > pExt->FramebufLen) ) {

            status = ERROR_INVALID_PARAMETER;
            break;
        }

        ReqPkt->StatusBlock->Information = sizeof( VIDEO_SHARE_MEMORY_INFORMATION );

        /* The input buffer is also the output buffer; remember the input. */
        virtualAddress = pShrMem->ProcessHandle;
        sharedViewSize = pShrMem->ViewSize;

        inIoSpace = FALSE;

        /* NB: ViewOffset is not being taken into account. */
        shareAddress.QuadPart = pExt->PhysicalFrameAddress.QuadPart;

        status = VideoPortMapMemory( pExt, shareAddress,
                                     &sharedViewSize, &inIoSpace,
                                     &virtualAddress );

        pShrMemInfo = ReqPkt->OutputBuffer;
        pShrMemInfo->SharedViewOffset = pShrMem->ViewOffset;
        pShrMemInfo->VirtualAddress   = virtualAddress;
        pShrMemInfo->SharedViewSize   = sharedViewSize;
        break;
    }

    case IOCTL_VIDEO_UNSHARE_VIDEO_MEMORY:
        VideoDebugPrint( (2, "UNSHARE_VIDEO_MEMORY\n") );
        if( ReqPkt->InputBufferLength < sizeof( VIDEO_SHARE_MEMORY ) ) {
            status = ERROR_INSUFFICIENT_BUFFER;
            break;
        }

        pShrMem = ReqPkt->InputBuffer;
        status = VideoPortUnmapMemory( pExt, pShrMem->RequestedVirtualAddress,
                                       pShrMem->ProcessHandle );
        break;


    /* The child state IOCTLs are new for NT 5.0 (Windows 2000). */
    case IOCTL_VIDEO_GET_CHILD_STATE:
    {
        PULONG      pChildIndex;
        PULONG      pChildState;

        VideoDebugPrint( (2, "GET_CHILD_STATE\n") );
        if( ReqPkt->InputBufferLength < sizeof( ULONG ) ||
            ReqPkt->OutputBufferLength < sizeof( ULONG ) ) {
            status = ERROR_INSUFFICIENT_BUFFER;
            break;
        }

        pChildIndex = ReqPkt->InputBuffer;
        pChildState = ReqPkt->OutputBuffer;

        /* Always say the child is active. */
        *pChildState = VIDEO_CHILD_ACTIVE;
        break;
    }

    /* Any other request is invalid and fails. */
    default:
        VideoDebugPrint( (1, "Unhandled IoControlCode %08x!\n", ReqPkt->IoControlCode) );
        status = ERROR_INVALID_FUNCTION;
        break;
    }

    ReqPkt->StatusBlock->Status = status;
    return( TRUE );
}

/* Validate support for a requested power state. */
VP_STATUS HwGetPowerState( PVOID HwDevExt, ULONG HwId,
                           PVIDEO_POWER_MANAGEMENT VideoPowerControl )
{
    VideoDebugPrint( (1, "videomp: HwGetPowerState\n") );
    return( NO_ERROR );
}

/* Set the device power state. */
VP_STATUS HwSetPowerState( PVOID HwDevExt, ULONG HwId,
                           PVIDEO_POWER_MANAGEMENT VideoPowerControl )
{
    VideoDebugPrint( (1, "videomp: HwSetPowerState\n") );
    return( NO_ERROR );
}

/* Return child device descriptors. In this case just a single monitor. */
VP_STATUS HwGetChildDesc( PVOID HwDevExt, PVIDEO_CHILD_ENUM_INFO ChildEnumInfo,
                          PVIDEO_CHILD_TYPE VideoChildType, PUCHAR pChildDescriptor,
                          PULONG UId, PULONG pUnused )
{
    PHW_DEV_EXT     pExt = HwDevExt;

    VideoDebugPrint( (1, "videomp: HwGetChildDesc\n") );

    if( ChildEnumInfo->ChildIndex > 0 ) {
        if( (int)ChildEnumInfo->ChildIndex <= pExt->NumMonitors ) {
            *VideoChildType = Monitor;
            *UId = ChildEnumInfo->ChildIndex;
            return( VIDEO_ENUM_MORE_DEVICES );
        }
    }

    return( ERROR_NO_MORE_DEVICES );
}

/* Reset the adapter into a VGA-compatible state. */
BOOLEAN HwVidResetHw( PVOID HwDevExt, ULONG Columns, ULONG Rows )
{
    PHW_DEV_EXT     pExt = HwDevExt;

    VideoDebugPrint( (1, "videomp: HwVidResetHw\n") );

    BOXV_ext_disable( pExt );
    /* Indicate that we didn't actually set the requested text mode. */
    return( FALSE );
}

/* Standard NT driver initialization entry point. */
ULONG DriverEntry( PVOID Context1, PVOID Context2 )
{
    VIDEO_HW_INITIALIZATION_DATA    hwInitData;
    ULONG                           status;

    VideoDebugPrint( (1, "videomp: DriverEntry\n") );

    /* Prepare the initialization structure. */
    VideoPortZeroMemory( &hwInitData, sizeof( VIDEO_HW_INITIALIZATION_DATA ) );
    hwInitData.HwInitDataSize = sizeof( VIDEO_HW_INITIALIZATION_DATA );

    /* Set up driver callbacks. */
    hwInitData.HwFindAdapter = HwVidFindAdapter;
    hwInitData.HwInitialize  = HwVidInitialize;
    hwInitData.HwStartIO     = HwVidStartIO;
    /* There's no interrupt or timer callback. */
    hwInitData.HwInterrupt   = NULL;
    hwInitData.HwTimer       = NULL;
    hwInitData.HwResetHw     = HwVidResetHw;

    /* Power and child device management callbacks were added in NT 5.0. */
    hwInitData.HwGetPowerState           = HwGetPowerState;
    hwInitData.HwSetPowerState           = HwSetPowerState;
    hwInitData.HwGetVideoChildDescriptor = HwGetChildDesc;

    /* Report legacy resources. */
    hwInitData.HwLegacyResourceList  = LegacyRanges;
    hwInitData.HwLegacyResourceCount = ulNumLegacyRanges;

    /* Report the device extension size. */
    hwInitData.HwDeviceExtensionSize = sizeof( HW_DEV_EXT );

    /* Refer to the CurrentControlSet\Services\xxx\Device0 registry key. */
    hwInitData.StartingDeviceNumber = 0;

    /* Later NT versions support PCI; recent versions ignore this entirely */
    hwInitData.AdapterInterfaceType = PCIBus;

    /* The PsGetVersion function was not available in NT 3.x. We therefore
     * implement a poor man's version detection by successively reducing the
     * HwInitDataSize until the video miniport (we hope) accepts it.
     */
    do {
        /* First try with NT 5.1 (Windows XP) structure size. */
        VideoDebugPrint( (1, "videomp: Trying DDI 5.1 HwInitDataSize\n") );
        hwInitData.HwInitDataSize = SIZE_OF_WXP_VIDEO_HW_INITIALIZATION_DATA;
        PortVersion = VP_VER_XP;
        status = VideoPortInitialize( Context1, Context2, &hwInitData, NULL );
        if( status != STATUS_REVISION_MISMATCH ) {
            /* If status is anything other than a version mismatch, don't
             * try calling VideoPortInitialize again. The call may have
             * succeeded, or it failed for some reason whe can't easily fix.
             */
            break;
        }

        /* Try the NT 5.0 (Windows 2000) structure size. */
        VideoDebugPrint( (1, "videomp: Trying DDI 5.0 HwInitDataSize\n") );
        hwInitData.HwInitDataSize = SIZE_OF_W2K_VIDEO_HW_INITIALIZATION_DATA;
        PortVersion = VP_VER_W2K;
        status = VideoPortInitialize( Context1, Context2, &hwInitData, NULL );
        if( status != STATUS_REVISION_MISMATCH ) {
            break;
        }

        /* Try the NT 4.0 (and also NT 3.51) structure size. */
        VideoDebugPrint( (1, "videomp: Trying DDI 4.0 HwInitDataSize\n") );
        hwInitData.HwInitDataSize = SIZE_OF_NT4_VIDEO_HW_INITIALIZATION_DATA;
        PortVersion = VP_VER_NT4;
        status = VideoPortInitialize( Context1, Context2, &hwInitData, NULL );
        if( status != STATUS_REVISION_MISMATCH ) {
            break;
        }

        /* Try the original NT 3.1/3.5 HwInitDataSize. No PCI support. */
        VideoDebugPrint( (1, "videomp: Trying DDI 3.1 HwInitDataSize\n") );
        hwInitData.HwInitDataSize = offsetof( VIDEO_HW_INITIALIZATION_DATA, HwResetHw );
        hwInitData.AdapterInterfaceType = Isa;
        PortVersion = VP_VER_NT31;
        status = VideoPortInitialize( Context1, Context2, &hwInitData, NULL );
    } while( 0 );
    VideoDebugPrint( (1, "videomp: VideoPortInitialize rc=%08x\n", status ) );
    return( status );
}