path: root/src/dummy_driver.c

/* $XFree86: xc/programs/Xserver/hw/xfree86/drivers/dummy/dummy_driver.c,v 1.5tsi Exp $ */

/*
 * Copyright 2002, SuSE Linux AG, Author: Egbert Eich
 */

/* All drivers should typically include these */
#include "xf86.h"
#include "xf86_OSproc.h"
#include "xf86_ansic.h"

/* This is used for module versioning */
#include "xf86Version.h"

/* All drivers initialising the SW cursor need this */
#include "mipointer.h"

/* All drivers implementing backing store need this */
#include "mibstore.h"

/* All drivers using the mi colormap manipulation need this */
#include "micmap.h"

/* identifying atom needed by magnifiers */
#include <X11/Xatom.h>
#include "property.h"

#include "xf86cmap.h"

#include "xf86fbman.h"

#include "fb.h"

#include "picturestr.h"

#include "xf86xv.h"
#include <X11/extensions/Xv.h>

/*
 * Driver data structures.
 */
#include "dummy.h"

/* These need to be checked */
#include <X11/X.h>
#include <X11/Xproto.h>
#include "scrnintstr.h"
#include "servermd.h"
#ifdef XFreeXDGA
#define _XF86DGA_SERVER_
#include <X11/extensions/xf86dgastr.h>
#endif

/* Mandatory functions */
static const OptionInfoRec *	DUMMYAvailableOptions(int chipid, int busid);
static void     DUMMYIdentify(int flags);
static Bool     DUMMYProbe(DriverPtr drv, int flags);
static Bool     DUMMYPreInit(ScrnInfoPtr pScrn, int flags);
static Bool     DUMMYScreenInit(int Index, ScreenPtr pScreen, int argc,
                                  char **argv);
static Bool     DUMMYEnterVT(int scrnIndex, int flags);
static void     DUMMYLeaveVT(int scrnIndex, int flags);
static Bool     DUMMYCloseScreen(int scrnIndex, ScreenPtr pScreen);
static Bool     DUMMYCreateWindow(WindowPtr pWin);
static void     DUMMYFreeScreen(int scrnIndex, int flags);
static ModeStatus DUMMYValidMode(int scrnIndex, DisplayModePtr mode,
                                 Bool verbose, int flags);
static Bool	DUMMYSaveScreen(ScreenPtr pScreen, int mode);

/* Internally used functions */
static Bool     dummyModeInit(ScrnInfoPtr pScrn, DisplayModePtr mode);
static void	dummySave(ScrnInfoPtr pScrn);
static void	dummyRestore(ScrnInfoPtr pScrn, Bool restoreText);
static Bool	dummyDriverFunc(ScrnInfoPtr pScrn, xorgDriverFuncOp op,
				pointer ptr);


/* static void     DUMMYDisplayPowerManagementSet(ScrnInfoPtr pScrn, */
/* 				int PowerManagementMode, int flags); */

#define VERSION 4000
#define DUMMY_NAME "DUMMY"
#define DUMMY_DRIVER_NAME "dummy"

#define DUMMY_MAJOR_VERSION 0
#define DUMMY_MINOR_VERSION 1
#define DUMMY_PATCHLEVEL 0

/*
 * This is intentionally screen-independent.  It indicates the binding
 * choice made in the first PreInit.
 */
static int pix24bpp = 0;


/*
 * This contains the functions needed by the server after loading the driver
 * module.  It must be supplied, and gets passed back by the SetupProc
 * function in the dynamic case.  In the static case, a reference to this
 * is compiled in, and this requires that the name of this DriverRec be
 * an upper-case version of the driver name.
 */

_X_EXPORT DriverRec DUMMY = {
    VERSION,
    DUMMY_DRIVER_NAME,
    DUMMYIdentify,
    DUMMYProbe,
    DUMMYAvailableOptions,
    NULL,
    0,
    dummyDriverFunc
};

static SymTabRec DUMMYChipsets[] = {
    { DUMMY_CHIP,   "dummy" },
    { -1,		 NULL }
};

typedef enum {
    OPTION_SW_CURSOR
} DUMMYOpts;

static const OptionInfoRec DUMMYOptions[] = {
    { OPTION_SW_CURSOR,	"SWcursor",	OPTV_BOOLEAN,	{0}, FALSE },
    { -1,                  NULL,           OPTV_NONE,	{0}, FALSE }
};


/*
 * List of symbols from other modules that this module references.  This
 * list is used to tell the loader that it is OK for symbols here to be
 * unresolved providing that it hasn't been told that they haven't been
 * told that they are essential via a call to xf86LoaderReqSymbols() or
 * xf86LoaderReqSymLists().  The purpose is this is to avoid warnings about
 * unresolved symbols that are not required.
 */

static const char *fbSymbols[] = {
    "fbPictureInit",
    "fbScreenInit",
    NULL
};

static const char *ramdacSymbols[] = {
    "xf86CreateCursorInfoRec",
    "xf86DestroyCursorInfoRec",
    "xf86InitCursor",
    NULL
};


#ifdef XFree86LOADER

static MODULESETUPPROTO(dummySetup);

static XF86ModuleVersionInfo dummyVersRec =
{
	"dummy",
	MODULEVENDORSTRING,
	MODINFOSTRING1,
	MODINFOSTRING2,
	XORG_VERSION_CURRENT,
	DUMMY_MAJOR_VERSION, DUMMY_MINOR_VERSION, DUMMY_PATCHLEVEL,
	ABI_CLASS_VIDEODRV,
	ABI_VIDEODRV_VERSION,
	MOD_CLASS_VIDEODRV,
	{0,0,0,0}
};

/*
 * This is the module init data.
 * Its name has to be the driver name followed by ModuleData
 */
_X_EXPORT XF86ModuleData dummyModuleData = { &dummyVersRec, dummySetup, NULL };

static pointer
dummySetup(pointer module, pointer opts, int *errmaj, int *errmin)
{
    static Bool setupDone = FALSE;

    if (!setupDone) {
	setupDone = TRUE;
        xf86AddDriver(&DUMMY, module, HaveDriverFuncs);

	/*
	 * Modules that this driver always requires can be loaded here
	 * by calling LoadSubModule().
	 */

	/*
	 * Tell the loader about symbols from other modules that this module
	 * might refer to.
	 */
	LoaderRefSymLists(fbSymbols, ramdacSymbols, NULL);
	/*
	 * The return value must be non-NULL on success even though there
	 * is no TearDownProc.
	 */
	return (pointer)1;
    } else {
	if (errmaj) *errmaj = LDR_ONCEONLY;
	return NULL;
    }
}

#endif /* XFree86LOADER */

static Bool
DUMMYGetRec(ScrnInfoPtr pScrn)
{
    /*
     * Allocate a DUMMYRec, and hook it into pScrn->driverPrivate.
     * pScrn->driverPrivate is initialised to NULL, so we can check if
     * the allocation has already been done.
     */
    if (pScrn->driverPrivate != NULL)
	return TRUE;

    pScrn->driverPrivate = xnfcalloc(sizeof(DUMMYRec), 1);

    if (pScrn->driverPrivate == NULL)
	return FALSE;
        return TRUE;
}

static void
DUMMYFreeRec(ScrnInfoPtr pScrn)
{
    if (pScrn->driverPrivate == NULL)
	return;
    xfree(pScrn->driverPrivate);
    pScrn->driverPrivate = NULL;
}

static const OptionInfoRec *
DUMMYAvailableOptions(int chipid, int busid)
{
    return DUMMYOptions;
}

/* Mandatory */
static void
DUMMYIdentify(int flags)
{
    xf86PrintChipsets(DUMMY_NAME, "Driver for Dummy chipsets",
			DUMMYChipsets);
}

/* Mandatory */
static Bool
DUMMYProbe(DriverPtr drv, int flags)
{
    Bool foundScreen = FALSE;
    int numDevSections, numUsed;
    GDevPtr *devSections;
    int i;

    if (flags & PROBE_DETECT)
	return FALSE;
    /*
     * Find the config file Device sections that match this
     * driver, and return if there are none.
     */
    if ((numDevSections = xf86MatchDevice(DUMMY_DRIVER_NAME,
					  &devSections)) <= 0) {
	return FALSE;
    }

    numUsed = numDevSections;

    if (numUsed > 0) {

	for (i = 0; i < numUsed; i++) {
	    ScrnInfoPtr pScrn = NULL;
	    int entityIndex = 
		xf86ClaimNoSlot(drv,DUMMY_CHIP,devSections[i],TRUE);
	    /* Allocate a ScrnInfoRec and claim the slot */
	    if ((pScrn = xf86AllocateScreen(drv,0 ))) {
		   xf86AddEntityToScreen(pScrn,entityIndex);
		    pScrn->driverVersion = VERSION;
		    pScrn->driverName    = DUMMY_DRIVER_NAME;
		    pScrn->name          = DUMMY_NAME;
		    pScrn->Probe         = DUMMYProbe;
		    pScrn->PreInit       = DUMMYPreInit;
		    pScrn->ScreenInit    = DUMMYScreenInit;
		    pScrn->SwitchMode    = DUMMYSwitchMode;
		    pScrn->AdjustFrame   = DUMMYAdjustFrame;
		    pScrn->EnterVT       = DUMMYEnterVT;
		    pScrn->LeaveVT       = DUMMYLeaveVT;
		    pScrn->FreeScreen    = DUMMYFreeScreen;
		    pScrn->ValidMode     = DUMMYValidMode;

		    foundScreen = TRUE;
	    }
	}
    }    
    return foundScreen;
}

# define RETURN \
    { DUMMYFreeRec(pScrn);\
			    return FALSE;\
					     }

/* Mandatory */
Bool
DUMMYPreInit(ScrnInfoPtr pScrn, int flags)
{
    ClockRangePtr clockRanges;
    int i;
    DUMMYPtr dPtr;
    int maxClock = 230000;
    GDevPtr device = xf86GetEntityInfo(pScrn->entityList[0])->device;

    if (flags & PROBE_DETECT) 
	return TRUE;
    
    /* Allocate the DummyRec driverPrivate */
    if (!DUMMYGetRec(pScrn)) {
	return FALSE;
    }
    
    dPtr = DUMMYPTR(pScrn);

    pScrn->chipset = (char *)xf86TokenToString(DUMMYChipsets,
					       DUMMY_CHIP);

    xf86DrvMsg(pScrn->scrnIndex, X_INFO, "Chipset is a DUMMY\n");
    
    pScrn->monitor = pScrn->confScreen->monitor;

    if (!xf86SetDepthBpp(pScrn, 0, 0, 0,  Support24bppFb | Support32bppFb))
	return FALSE;
    else {
	/* Check that the returned depth is one we support */
	switch (pScrn->depth) {
	case 8:
	case 15:
	case 16:
	case 24:
	    break;
	default:
	    xf86DrvMsg(pScrn->scrnIndex, X_ERROR,
		       "Given depth (%d) is not supported by this driver\n",
		       pScrn->depth);
	    return FALSE;
	}
    }

    xf86PrintDepthBpp(pScrn);
    if (pScrn->depth == 8)
	pScrn->rgbBits = 8;

    /* Get the depth24 pixmap format */
    if (pScrn->depth == 24 && pix24bpp == 0)
	pix24bpp = xf86GetBppFromDepth(pScrn, 24);

    /*
     * This must happen after pScrn->display has been set because
     * xf86SetWeight references it.
     */
    if (pScrn->depth > 8) {
	/* The defaults are OK for us */
	rgb zeros = {0, 0, 0};

	if (!xf86SetWeight(pScrn, zeros, zeros)) {
	    return FALSE;
	} else {
	    /* XXX check that weight returned is supported */
	    ;
	}
    }

    if (!xf86SetDefaultVisual(pScrn, -1)) 
	return FALSE;

    if (pScrn->depth > 1) {
	Gamma zeros = {0.0, 0.0, 0.0};

	if (!xf86SetGamma(pScrn, zeros))
	    return FALSE;
    }

    xf86CollectOptions(pScrn, device->options);
    /* Process the options */
    if (!(dPtr->Options = xalloc(sizeof(DUMMYOptions))))
	return FALSE;
    memcpy(dPtr->Options, DUMMYOptions, sizeof(DUMMYOptions));

    xf86ProcessOptions(pScrn->scrnIndex, pScrn->options, dPtr->Options);

    xf86GetOptValBool(dPtr->Options, OPTION_SW_CURSOR,&dPtr->swCursor);

    if (device->videoRam != 0) {
	pScrn->videoRam = device->videoRam;
	xf86DrvMsg(pScrn->scrnIndex, X_CONFIG, "VideoRAM: %d kByte\n",
		   pScrn->videoRam);
    } else {
	pScrn->videoRam = 4096;
	xf86DrvMsg(pScrn->scrnIndex, X_PROBED, "VideoRAM: %d kByte\n",
		   pScrn->videoRam);
    }
    
    if (device->dacSpeeds[0] != 0) {
	maxClock = device->dacSpeeds[0];
	xf86DrvMsg(pScrn->scrnIndex, X_CONFIG, "Max Clock: %d kHz\n",
		   maxClock);
    } else {
	xf86DrvMsg(pScrn->scrnIndex, X_PROBED, "Max Clock: %d kHz\n",
		   maxClock);
    }

    pScrn->progClock = TRUE;
    /*
     * Setup the ClockRanges, which describe what clock ranges are available,
     * and what sort of modes they can be used for.
     */
    clockRanges = (ClockRangePtr)xnfcalloc(sizeof(ClockRange), 1);
    clockRanges->next = NULL;
    clockRanges->ClockMulFactor = 1;
    clockRanges->minClock = 11000;   /* guessed §§§ */
    clockRanges->maxClock = 300000;
    clockRanges->clockIndex = -1;		/* programmable */
    clockRanges->interlaceAllowed = TRUE; 
    clockRanges->doubleScanAllowed = TRUE;

    /* Subtract memory for HW cursor */


    {
	int apertureSize = (pScrn->videoRam * 1024);
	i = xf86ValidateModes(pScrn, pScrn->monitor->Modes,
			      pScrn->display->modes, clockRanges,
			      NULL, 256, 2048,(8 * pScrn->bitsPerPixel),
			      128, 2048, pScrn->display->virtualX,
			      pScrn->display->virtualY, apertureSize,
			      LOOKUP_BEST_REFRESH);

       if (i == -1)
           RETURN;
    }

    /* Prune the modes marked as invalid */
    xf86PruneDriverModes(pScrn);

    if (i == 0 || pScrn->modes == NULL) {
	xf86DrvMsg(pScrn->scrnIndex, X_ERROR, "No valid modes found\n");
	RETURN;
    }

    /*
     * Set the CRTC parameters for all of the modes based on the type
     * of mode, and the chipset's interlace requirements.
     *
     * Calling this is required if the mode->Crtc* values are used by the
     * driver and if the driver doesn't provide code to set them.  They
     * are not pre-initialised at all.
     */
    xf86SetCrtcForModes(pScrn, 0); 
 
    /* Set the current mode to the first in the list */
    pScrn->currentMode = pScrn->modes;

    /* Print the list of modes being used */
    xf86PrintModes(pScrn);

    /* If monitor resolution is set on the command line, use it */
    xf86SetDpi(pScrn, 0, 0);

    if (xf86LoadSubModule(pScrn, "fb") == NULL) {
	RETURN;
    }
    xf86LoaderReqSymLists(fbSymbols, NULL);

    if (!dPtr->swCursor) {
	if (!xf86LoadSubModule(pScrn, "ramdac"))
	    RETURN;
	xf86LoaderReqSymLists(ramdacSymbols, NULL);
    }
    
    /* We have no contiguous physical fb in physical memory */
    pScrn->memPhysBase = 0;
    pScrn->fbOffset = 0;

    return TRUE;
}
#undef RETURN

/* Mandatory */
static Bool
DUMMYEnterVT(int scrnIndex, int flags)
{
    ScrnInfoPtr pScrn = xf86Screens[scrnIndex];
    
    /* Should we re-save the text mode on each VT enter? */
    if(!dummyModeInit(pScrn, pScrn->currentMode))
      return FALSE;

    DUMMYAdjustFrame(pScrn->scrnIndex, pScrn->frameX0, pScrn->frameY0, 0);    

    return TRUE;
}

/* Mandatory */
static void
DUMMYLeaveVT(int scrnIndex, int flags)
{
    ScrnInfoPtr pScrn = xf86Screens[scrnIndex];
    dummyRestore(pScrn, TRUE);
}

static void
DUMMYLoadPalette(
   ScrnInfoPtr pScrn,
   int numColors,
   int *indices,
   LOCO *colors,
   VisualPtr pVisual
){
   int i, index, shift, Gshift;
   DUMMYPtr dPtr = DUMMYPTR(pScrn);

   switch(pScrn->depth) {
   case 15:	
	shift = Gshift = 1;
	break;
   case 16:
	shift = 0; 
        Gshift = 0;
	break;
   default:
	shift = Gshift = 0;
	break;
   }

   for(i = 0; i < numColors; i++) {
       index = indices[i];
       dPtr->colors[index].red = colors[index].red << shift;
       dPtr->colors[index].green = colors[index].green << Gshift;
       dPtr->colors[index].blue = colors[index].blue << shift;
   } 

}

static ScrnInfoPtr DUMMYScrn; /* static-globalize it */

/* Mandatory */
static Bool
DUMMYScreenInit(int scrnIndex, ScreenPtr pScreen, int argc, char **argv)
{
    ScrnInfoPtr pScrn;
    DUMMYPtr dPtr;
    int ret;
    VisualPtr visual;
    
    /*
     * we need to get the ScrnInfoRec for this screen, so let's allocate
     * one first thing
     */
    pScrn = xf86Screens[pScreen->myNum];
    dPtr = DUMMYPTR(pScrn);
    DUMMYScrn = pScrn;


    if (!(dPtr->FBBase = xalloc(pScrn->videoRam * 1024)))
	return FALSE;
    
    /*
     * next we save the current state and setup the first mode
     */
    dummySave(pScrn);
    
    if (!dummyModeInit(pScrn,pScrn->currentMode))
	return FALSE;
    DUMMYAdjustFrame(scrnIndex, pScrn->frameX0, pScrn->frameY0, 0);

    /*
     * Reset visual list.
     */
    miClearVisualTypes();
    
    /* Setup the visuals we support. */
    
    if (!miSetVisualTypes(pScrn->depth,
      		      miGetDefaultVisualMask(pScrn->depth),
		      pScrn->rgbBits, pScrn->defaultVisual))
         return FALSE;

    if (!miSetPixmapDepths ()) return FALSE;

    /*
     * Call the framebuffer layer's ScreenInit function, and fill in other
     * pScreen fields.
     */
    ret = fbScreenInit(pScreen, dPtr->FBBase,
			    pScrn->virtualX, pScrn->virtualY,
			    pScrn->xDpi, pScrn->yDpi,
			    pScrn->displayWidth, pScrn->bitsPerPixel);
    if (!ret)
	return FALSE;

    if (pScrn->depth > 8) {
        /* Fixup RGB ordering */
        visual = pScreen->visuals + pScreen->numVisuals;
        while (--visual >= pScreen->visuals) {
	    if ((visual->class | DynamicClass) == DirectColor) {
		visual->offsetRed = pScrn->offset.red;
		visual->offsetGreen = pScrn->offset.green;
		visual->offsetBlue = pScrn->offset.blue;
		visual->redMask = pScrn->mask.red;
		visual->greenMask = pScrn->mask.green;
		visual->blueMask = pScrn->mask.blue;
	    }
	}
    }
    
    /* must be after RGB ordering fixed */
    fbPictureInit(pScreen, 0, 0);

    xf86SetBlackWhitePixels(pScreen);

    DUMMYDGAInit(pScreen);
    
    if (dPtr->swCursor)
	xf86DrvMsg(scrnIndex, X_CONFIG, "Using Software Cursor.\n");

    {

	 
	BoxRec AvailFBArea;
	int lines = pScrn->videoRam * 1024 /
	    (pScrn->displayWidth * (pScrn->bitsPerPixel >> 3));
	AvailFBArea.x1 = 0;
	AvailFBArea.y1 = 0;
	AvailFBArea.x2 = pScrn->displayWidth;
	AvailFBArea.y2 = lines;
	xf86InitFBManager(pScreen, &AvailFBArea); 
	
	xf86DrvMsg(pScrn->scrnIndex, X_INFO, 
		   "Using %i scanlines of offscreen memory \n"
		   , lines - pScrn->virtualY);
    }

    miInitializeBackingStore(pScreen);
    xf86SetBackingStore(pScreen);
    xf86SetSilkenMouse(pScreen);
	
    /* Initialise cursor functions */
    miDCInitialize (pScreen, xf86GetPointerScreenFuncs());


    if (!dPtr->swCursor) {
      /* HW cursor functions */
      if (!DUMMYCursorInit(pScreen)) {
	  xf86DrvMsg(scrnIndex, X_ERROR,
		     "Hardware cursor initialization failed\n");
	  return FALSE;
      }
    }
    
    /* Initialise default colourmap */
    if(!miCreateDefColormap(pScreen))
	return FALSE;

    if (!xf86HandleColormaps(pScreen, 256, pScrn->rgbBits,
                         DUMMYLoadPalette, NULL, 
                         CMAP_PALETTED_TRUECOLOR 
			     | CMAP_RELOAD_ON_MODE_SWITCH))
	return FALSE;

/*     DUMMYInitVideo(pScreen); */

    pScreen->SaveScreen = DUMMYSaveScreen;

    
    /* Wrap the current CloseScreen function */
    dPtr->CloseScreen = pScreen->CloseScreen;
    pScreen->CloseScreen = DUMMYCloseScreen;

    /* Wrap the current CreateWindow function */
    dPtr->CreateWindow = pScreen->CreateWindow;
    pScreen->CreateWindow = DUMMYCreateWindow;

    /* Report any unused options (only for the first generation) */
    if (serverGeneration == 1) {
	xf86ShowUnusedOptions(pScrn->scrnIndex, pScrn->options);
    }

    return TRUE;
}

/* Mandatory */
Bool
DUMMYSwitchMode(int scrnIndex, DisplayModePtr mode, int flags)
{
    return dummyModeInit(xf86Screens[scrnIndex], mode);
}

/* Mandatory */
void
DUMMYAdjustFrame(int scrnIndex, int x, int y, int flags)
{
    ScrnInfoPtr pScrn;
    int Base; 

    pScrn = xf86Screens[scrnIndex];

    Base = (y * pScrn->displayWidth + x) >> 2;

    /* Scale Base by the number of bytes per pixel. */
    switch (pScrn->depth) {
    case  8 :
	break;
    case 15 :
    case 16 :
	Base *= 2;
	break;
    case 24 :
	Base *= 3;
	break;
    default :
	break;
    }
}

/* Mandatory */
static Bool
DUMMYCloseScreen(int scrnIndex, ScreenPtr pScreen)
{
    ScrnInfoPtr pScrn = xf86Screens[scrnIndex];
    DUMMYPtr dPtr = DUMMYPTR(pScrn);

    if(pScrn->vtSema){
 	dummyRestore(pScrn, TRUE);
	xfree(dPtr->FBBase);
    }

    if (dPtr->CursorInfo)
	xf86DestroyCursorInfoRec(dPtr->CursorInfo);

    pScrn->vtSema = FALSE;
    pScreen->CloseScreen = dPtr->CloseScreen;
    return (*pScreen->CloseScreen)(scrnIndex, pScreen);
}

/* Optional */
static void
DUMMYFreeScreen(int scrnIndex, int flags)
{
    DUMMYFreeRec(xf86Screens[scrnIndex]);
}

static Bool
DUMMYSaveScreen(ScreenPtr pScreen, int mode)
{
    ScrnInfoPtr pScrn = NULL;
    DUMMYPtr dPtr;

    if (pScreen != NULL) {
	pScrn = xf86Screens[pScreen->myNum];
	dPtr = DUMMYPTR(pScrn);

	dPtr->screenSaver = xf86IsUnblank(mode);
    } 
    return TRUE;
}

/* Optional */
static ModeStatus
DUMMYValidMode(int scrnIndex, DisplayModePtr mode, Bool verbose, int flags)
{
    return(MODE_OK);
}

static void
dummySave(ScrnInfoPtr pScrn)
{
}

static void 
dummyRestore(ScrnInfoPtr pScrn, Bool restoreText)
{
}
    
static Bool
dummyModeInit(ScrnInfoPtr pScrn, DisplayModePtr mode)
{
    dummyRestore(pScrn, FALSE);
    
    return(TRUE);
}


Atom VFB_PROP  = 0;
#define  VFB_PROP_NAME  "VFB_IDENT"



static Bool
DUMMYCreateWindow(WindowPtr pWin)
{
    DUMMYPtr dPtr = DUMMYPTR(DUMMYScrn);
    WindowPtr pWinRoot;
    int ret;
	
    ret = dPtr->CreateWindow(pWin);
    if(ret != TRUE)
	return(ret);
	
    if(dPtr->prop == FALSE) {
        pWinRoot = WindowTable[DUMMYScrn->pScreen->myNum];
        if (! ValidAtom(VFB_PROP))
            VFB_PROP = MakeAtom(VFB_PROP_NAME, strlen(VFB_PROP_NAME), 1);

        ret = ChangeWindowProperty(pWinRoot, VFB_PROP, XA_STRING, 
		8, PropModeReplace, (int)4, (pointer)"TRUE", FALSE);
	if( ret != Success)
		ErrorF("Could not set VFB root window property");
        dPtr->prop = TRUE;

	return TRUE;
    }
    return TRUE;
}


static Bool
dummyDriverFunc(ScrnInfoPtr pScrn, xorgDriverFuncOp op, pointer ptr)
{
    CARD32 *flag;
    
    switch (op) {
	case GET_REQUIRED_HW_INTERFACES:
	    flag = (CARD32*)ptr;
	    (*flag) = 0;
	    return TRUE;
	default:
	    return FALSE;
    }
}