distrib/sdl-1.2.12/src/video/Xext/Xxf86dga/XF86DGA2.c

/* $XFree86: xc/lib/Xxf86dga/XF86DGA2.c,v 1.18 2001/08/17 13:27:51 dawes Exp $ */
/*

Copyright (c) 1995  Jon Tombs
Copyright (c) 1995,1996  The XFree86 Project, Inc

*/

/* THIS IS NOT AN X CONSORTIUM STANDARD */

#ifdef __EMX__ /* needed here to override certain constants in X headers */
#define INCL_DOS
#define INCL_DOSIOCTL
#include <os2.h>
#endif

#define NEED_EVENTS
#define NEED_REPLIES

#include <X11/Xlibint.h>
#include "../extensions/xf86dga.h"
#include "../extensions/xf86dgastr.h"
#include "../extensions/Xext.h"
#include "../extensions/extutil.h"
#include <stdio.h>

#if defined(ENABLE_FBCON)  /* Needed for framebuffer console support */
#include <sys/ioctl.h>
#include <linux/fb.h>
#endif

/* If you change this, change the Bases[] array below as well */
#define MAX_HEADS 16

char *SDL_NAME(xdga_extension_name) = XF86DGANAME;

static XExtensionInfo _xdga_info_data;
static XExtensionInfo *xdga_info = &_xdga_info_data;

 
Bool SDL_NAME(XDGAMapFramebuffer)(int, char *, unsigned char*, CARD32, CARD32, CARD32);
void SDL_NAME(XDGAUnmapFramebuffer)(int);
unsigned char* SDL_NAME(XDGAGetMappedMemory)(int);

#define XDGACheckExtension(dpy,i,val) \
  XextCheckExtension (dpy, i, SDL_NAME(xdga_extension_name), val)

/*****************************************************************************
 *                                                                           *
 *			   private utility routines                          *
 *                                                                           *
 *****************************************************************************/

static int xdga_close_display(Display *dpy, XExtCodes *codes);
static Bool xdga_wire_to_event(Display *dpy, XEvent *event, xEvent *wire_ev);
static Status xdga_event_to_wire(Display *dpy, XEvent *event, xEvent *wire_ev);

static XExtensionHooks xdga_extension_hooks = {
    NULL,				/* create_gc */
    NULL,				/* copy_gc */
    NULL,				/* flush_gc */
    NULL,				/* free_gc */
    NULL,				/* create_font */
    NULL,				/* free_font */
    xdga_close_display,			/* close_display */
    xdga_wire_to_event,			/* wire_to_event */
    xdga_event_to_wire,			/* event_to_wire */
    NULL,				/* error */
    NULL,				/* error_string */
};

static XEXT_GENERATE_CLOSE_DISPLAY (xdga_close_display, xdga_info)


XEXT_GENERATE_FIND_DISPLAY (SDL_NAME(xdga_find_display), xdga_info, 
				   "XFree86-DGA", 
				   &xdga_extension_hooks, 
				   0, NULL)


static Status
xdga_event_to_wire(
  Display *dpy,
  XEvent *event,
  xEvent *wire_ev
){
    return True;
}

static Bool
xdga_wire_to_event(
  Display *dpy,
  XEvent *event,
  xEvent *wire_ev
){
  dgaEvent *wire = (dgaEvent *) wire_ev;
  SDL_NAME(XDGAButtonEvent) *bevent;
  SDL_NAME(XDGAKeyEvent) *kevent;
  SDL_NAME(XDGAMotionEvent) *mevent;
  XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);

  XDGACheckExtension (dpy, info, False);

  switch((wire->u.u.type & 0x7f) - info->codes->first_event) {
  case MotionNotify:
	mevent = (SDL_NAME(XDGAMotionEvent)*)event;
	mevent->type = wire->u.u.type & 0x7F;
	mevent->serial = _XSetLastRequestRead(dpy, (xGenericReply *)wire);
	mevent->display = dpy;
	mevent->screen = wire->u.event.screen;
	mevent->time = wire->u.event.time;
	mevent->state = wire->u.event.state;
	mevent->dx = wire->u.event.dx;
	mevent->dy = wire->u.event.dy;
	return True;
  case ButtonPress:
  case ButtonRelease:
	bevent = (SDL_NAME(XDGAButtonEvent)*)event;
	bevent->type = wire->u.u.type & 0x7F;
	bevent->serial = _XSetLastRequestRead(dpy, (xGenericReply *)wire);
	bevent->display = dpy;
	bevent->screen = wire->u.event.screen;
	bevent->time = wire->u.event.time;
	bevent->state = wire->u.event.state;
	bevent->button = wire->u.u.detail;
	return True;
  case KeyPress:
  case KeyRelease:
	kevent = (SDL_NAME(XDGAKeyEvent)*)event;
	kevent->type = wire->u.u.type & 0x7F;
	kevent->serial = _XSetLastRequestRead(dpy, (xGenericReply *)wire);
	kevent->display = dpy;
	kevent->screen = wire->u.event.screen;
	kevent->time = wire->u.event.time;
	kevent->state = wire->u.event.state;
	kevent->keycode = wire->u.u.detail;
	return True;
  }

  return False;
}


Bool SDL_NAME(XDGAQueryExtension) (
    Display *dpy,
    int *event_basep,
    int *error_basep
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);

    if (XextHasExtension(info)) {
	*event_basep = info->codes->first_event;
	*error_basep = info->codes->first_error;
	return True;
    } else {
	return False;
    }
}


Bool SDL_NAME(XDGAQueryVersion)(
    Display *dpy,
    int *majorVersion, 
    int *minorVersion
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGAQueryVersionReply rep;
    xXDGAQueryVersionReq *req;

    XDGACheckExtension (dpy, info, False);

    LockDisplay(dpy);
    GetReq(XDGAQueryVersion, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGAQueryVersion;
    if (!_XReply(dpy, (xReply *)&rep, 0, xFalse)) {
	UnlockDisplay(dpy);
	SyncHandle();
	return False;
    }
    *majorVersion = rep.majorVersion;
    *minorVersion = rep.minorVersion;
    UnlockDisplay(dpy);
    SyncHandle();
    if (*majorVersion >= 2)
    {
	int i, j;

	for (i = 0, j = info->codes->first_event;
	     i < XF86DGANumberEvents;
	     i++, j++) 
	{
	    XESetWireToEvent(dpy, j, xdga_wire_to_event);
	    XESetEventToWire(dpy, j, xdga_event_to_wire);
	}
	SDL_NAME(XDGASetClientVersion)(dpy);
    }
    return True;
}

Bool SDL_NAME(XDGASetClientVersion)(
    Display	*dpy
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGASetClientVersionReq *req;

    XDGACheckExtension (dpy, info, False);

    LockDisplay(dpy);
    GetReq(XDGASetClientVersion, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGASetClientVersion;
    req->major = XDGA_MAJOR_VERSION;
    req->minor = XDGA_MINOR_VERSION;
    UnlockDisplay(dpy);
    SyncHandle();
    return True;
}

Bool SDL_NAME(XDGAOpenFramebuffer)(
    Display	*dpy,
    int 	screen
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGAOpenFramebufferReply rep;
    xXDGAOpenFramebufferReq *req;
    char *deviceName = NULL;
    Bool ret;

    XDGACheckExtension (dpy, info, False);

    LockDisplay(dpy);
    GetReq(XDGAOpenFramebuffer, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGAOpenFramebuffer;
    req->screen = screen;
    if (!_XReply(dpy, (xReply *)&rep, 0, xFalse)) {
	UnlockDisplay(dpy);
	SyncHandle();
	return False;
    }

    if(rep.length) {
	deviceName = Xmalloc(rep.length << 2);
	_XRead(dpy, deviceName, rep.length << 2);
    }

    ret = SDL_NAME(XDGAMapFramebuffer)(screen, deviceName,
				(unsigned char*)(long)rep.mem1, 
				rep.size, rep.offset, rep.extra);

    if(deviceName)
	Xfree(deviceName);	

    UnlockDisplay(dpy);
    SyncHandle();
    return ret;
}

void SDL_NAME(XDGACloseFramebuffer)(
    Display	*dpy,
    int		screen
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGACloseFramebufferReq *req;

    XextSimpleCheckExtension (dpy, info, SDL_NAME(xdga_extension_name));

    SDL_NAME(XDGAUnmapFramebuffer)(screen);

    LockDisplay(dpy);
    GetReq(XDGACloseFramebuffer, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGACloseFramebuffer;
    req->screen = screen;
    UnlockDisplay(dpy);
    SyncHandle();
}



SDL_NAME(XDGAMode)* SDL_NAME(XDGAQueryModes)(
    Display *dpy,
    int screen,
    int *num
){
    XExtDisplayInfo *dinfo = SDL_NAME(xdga_find_display) (dpy);
    xXDGAQueryModesReply rep;
    xXDGAQueryModesReq *req;
    SDL_NAME(XDGAMode) *modes = NULL;

    *num = 0;

    XDGACheckExtension (dpy, dinfo, NULL);

    LockDisplay(dpy);
    GetReq(XDGAQueryModes, req);
    req->reqType = dinfo->codes->major_opcode;
    req->dgaReqType = X_XDGAQueryModes;
    req->screen = screen;

    if (_XReply(dpy, (xReply *)&rep, 0, xFalse)) {
	if(rep.length) {
	   xXDGAModeInfo info;
	   int i, size;
	   char *offset;

	   size = rep.length << 2;
	   size -= rep.number * sz_xXDGAModeInfo; /* find text size */
	   modes = (SDL_NAME(XDGAMode)*)Xmalloc((rep.number * sizeof(SDL_NAME(XDGAMode))) + size);
	   offset = (char*)(&modes[rep.number]); /* start of text */


	   if(modes) {	
	      for(i = 0; i < rep.number; i++) {
		_XRead(dpy, (char*)(&info), sz_xXDGAModeInfo);

		modes[i].num = info.num;
		modes[i].verticalRefresh = 
			(float)info.vsync_num / (float)info.vsync_den;
		modes[i].flags = info.flags;
		modes[i].imageWidth = info.image_width;
		modes[i].imageHeight = info.image_height;
		modes[i].pixmapWidth = info.pixmap_width;
		modes[i].pixmapHeight = info.pixmap_height;
		modes[i].bytesPerScanline = info.bytes_per_scanline;
		modes[i].byteOrder = info.byte_order;
		modes[i].depth = info.depth;
		modes[i].bitsPerPixel = info.bpp;
		modes[i].redMask = info.red_mask;
		modes[i].greenMask = info.green_mask;
		modes[i].blueMask = info.blue_mask;
		modes[i].visualClass = info.visual_class;
		modes[i].viewportWidth = info.viewport_width;
		modes[i].viewportHeight = info.viewport_height;
		modes[i].xViewportStep = info.viewport_xstep;
		modes[i].yViewportStep = info.viewport_ystep;
		modes[i].maxViewportX = info.viewport_xmax;
		modes[i].maxViewportY = info.viewport_ymax;
		modes[i].viewportFlags = info.viewport_flags;
		modes[i].reserved1 = info.reserved1;
		modes[i].reserved2 = info.reserved2;	

		_XRead(dpy, offset, info.name_size);
		modes[i].name = offset;
		offset += info.name_size;
	      }
	      *num = rep.number;
	   } else
		_XEatData(dpy, rep.length << 2);
	}
    }

    UnlockDisplay(dpy);
    SyncHandle();

    return modes;
}


SDL_NAME(XDGADevice) * 
SDL_NAME(XDGASetMode)(
    Display	*dpy,
    int		screen,
    int		mode
){
    XExtDisplayInfo *dinfo = SDL_NAME(xdga_find_display) (dpy);
    xXDGASetModeReply rep;
    xXDGASetModeReq *req;
    SDL_NAME(XDGADevice) *dev = NULL;
    Pixmap pid;

    XDGACheckExtension (dpy, dinfo, NULL);

    LockDisplay(dpy);
    GetReq(XDGASetMode, req);
    req->reqType = dinfo->codes->major_opcode;
    req->dgaReqType = X_XDGASetMode;
    req->screen = screen;
    req->mode = mode;
    req->pid = pid = XAllocID(dpy);
    
    if (_XReply(dpy, (xReply *)&rep, 0, xFalse)) {
	if(rep.length) {
	   xXDGAModeInfo info;
	   int size;

	   size = rep.length << 2;
	   size -= sz_xXDGAModeInfo; /* get text size */

	   dev = (SDL_NAME(XDGADevice)*)Xmalloc(sizeof(SDL_NAME(XDGADevice)) + size);
	    
	   if(dev) {
		_XRead(dpy, (char*)(&info), sz_xXDGAModeInfo);

		dev->mode.num = info.num;
		dev->mode.verticalRefresh = 
				(float)info.vsync_num / (float)info.vsync_den;
		dev->mode.flags = info.flags;
		dev->mode.imageWidth = info.image_width;
		dev->mode.imageHeight = info.image_height;
		dev->mode.pixmapWidth = info.pixmap_width;
		dev->mode.pixmapHeight = info.pixmap_height;
		dev->mode.bytesPerScanline = info.bytes_per_scanline;
		dev->mode.byteOrder = info.byte_order;
		dev->mode.depth = info.depth;
		dev->mode.bitsPerPixel = info.bpp;
		dev->mode.redMask = info.red_mask;
		dev->mode.greenMask = info.green_mask;
		dev->mode.blueMask = info.blue_mask;
		dev->mode.visualClass = info.visual_class;
		dev->mode.viewportWidth = info.viewport_width;
		dev->mode.viewportHeight = info.viewport_height;
		dev->mode.xViewportStep = info.viewport_xstep;
		dev->mode.yViewportStep = info.viewport_ystep;
		dev->mode.maxViewportX = info.viewport_xmax;
		dev->mode.maxViewportY = info.viewport_ymax;
		dev->mode.viewportFlags = info.viewport_flags;
		dev->mode.reserved1 = info.reserved1;
		dev->mode.reserved2 = info.reserved2;

		dev->mode.name = (char*)(&dev[1]);	
		_XRead(dpy, dev->mode.name, info.name_size);

		dev->pixmap = (rep.flags & XDGAPixmap) ? pid : 0;
		dev->data = SDL_NAME(XDGAGetMappedMemory)(screen);

		if(dev->data)
		    dev->data += rep.offset;
	   } 
	   /* not sure what to do if the allocation fails */
	}
    }

    UnlockDisplay(dpy);
    SyncHandle();

    return dev;
}


void SDL_NAME(XDGASetViewport)(
    Display	*dpy,
    int		screen,
    int		x,
    int		y,
    int		flags
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGASetViewportReq *req;

    XextSimpleCheckExtension (dpy, info, SDL_NAME(xdga_extension_name));

    LockDisplay(dpy);
    GetReq(XDGASetViewport, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGASetViewport;
    req->screen = screen;
    req->x = x;
    req->y = y;
    req->flags = flags;
    UnlockDisplay(dpy);
    SyncHandle();
}


void SDL_NAME(XDGAInstallColormap)(
    Display	*dpy,
    int		screen,
    Colormap	cmap
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGAInstallColormapReq *req;

    XextSimpleCheckExtension (dpy, info, SDL_NAME(xdga_extension_name));

    LockDisplay(dpy);
    GetReq(XDGAInstallColormap, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGAInstallColormap;
    req->screen = screen;
    req->cmap = cmap;
    UnlockDisplay(dpy);
    SyncHandle();
}

void SDL_NAME(XDGASelectInput)(
    Display	*dpy,
    int		screen,
    long	mask
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGASelectInputReq *req;

    XextSimpleCheckExtension (dpy, info, SDL_NAME(xdga_extension_name));

    LockDisplay(dpy);
    GetReq(XDGASelectInput, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGASelectInput;
    req->screen = screen;
    req->mask = mask;
    UnlockDisplay(dpy);
    SyncHandle();
}

void SDL_NAME(XDGAFillRectangle)(
    Display	*dpy,
    int		screen,
    int		x,
    int		y,
    unsigned int	width,
    unsigned int	height,
    unsigned long	color
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGAFillRectangleReq *req;

    XextSimpleCheckExtension (dpy, info, SDL_NAME(xdga_extension_name));

    LockDisplay(dpy);
    GetReq(XDGAFillRectangle, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGAFillRectangle;
    req->screen = screen;
    req->x = x;
    req->y = y;
    req->width = width;
    req->height = height;
    req->color = color;
    UnlockDisplay(dpy);
    SyncHandle();
}

void SDL_NAME(XDGACopyArea)(
    Display	*dpy,
    int		screen,
    int		srcx,
    int		srcy,
    unsigned int	width,
    unsigned int	height,
    int		dstx,
    int		dsty
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGACopyAreaReq *req;

    XextSimpleCheckExtension (dpy, info, SDL_NAME(xdga_extension_name));

    LockDisplay(dpy);
    GetReq(XDGACopyArea, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGACopyArea;
    req->screen = screen;
    req->srcx = srcx;
    req->srcy = srcy;
    req->width = width;
    req->height = height;
    req->dstx = dstx;
    req->dsty = dsty;
    UnlockDisplay(dpy);
    SyncHandle();
}

void SDL_NAME(XDGACopyTransparentArea)(
    Display	*dpy,
    int		screen,
    int		srcx,
    int		srcy,
    unsigned int	width,
    unsigned int	height,
    int		dstx,
    int		dsty,
    unsigned long key
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGACopyTransparentAreaReq *req;

    XextSimpleCheckExtension (dpy, info, SDL_NAME(xdga_extension_name));

    LockDisplay(dpy);
    GetReq(XDGACopyTransparentArea, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGACopyTransparentArea;
    req->screen = screen;
    req->srcx = srcx;
    req->srcy = srcy;
    req->width = width;
    req->height = height;
    req->dstx = dstx;
    req->dsty = dsty;
    req->key = key;
    UnlockDisplay(dpy);
    SyncHandle();
}


int SDL_NAME(XDGAGetViewportStatus)(
    Display *dpy,
    int screen 
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGAGetViewportStatusReply rep;
    xXDGAGetViewportStatusReq *req;
    int status = 0;

    XDGACheckExtension (dpy, info, 0);

    LockDisplay(dpy);
    GetReq(XDGAGetViewportStatus, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGAGetViewportStatus;
    req->screen = screen;
    if (!_XReply(dpy, (xReply *)&rep, 0, xFalse))
	status = rep.status;
    UnlockDisplay(dpy);
    SyncHandle();
    return status;
}

void SDL_NAME(XDGASync)(
    Display *dpy,
    int screen 
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGASyncReply rep;
    xXDGASyncReq *req;

    XextSimpleCheckExtension (dpy, info, SDL_NAME(xdga_extension_name));

    LockDisplay(dpy);
    GetReq(XDGASync, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGASync;
    req->screen = screen;
    _XReply(dpy, (xReply *)&rep, 0, xFalse);
    UnlockDisplay(dpy);
    SyncHandle();
}


void SDL_NAME(XDGAChangePixmapMode)(
    Display *dpy,
    int screen,
    int *x,
    int *y,
    int mode 
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGAChangePixmapModeReq *req;
    xXDGAChangePixmapModeReply rep;

    XextSimpleCheckExtension (dpy, info, SDL_NAME(xdga_extension_name));

    LockDisplay(dpy);
    GetReq(XDGAChangePixmapMode, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGAChangePixmapMode;
    req->screen = screen;
    req->x = *x;
    req->y = *y;
    req->flags = mode;
    _XReply(dpy, (xReply *)&rep, 0, xFalse);
    *x = rep.x;
    *y = rep.y;
    UnlockDisplay(dpy);
    SyncHandle();
}

Colormap SDL_NAME(XDGACreateColormap)(
    Display *dpy,
    int screen,
    SDL_NAME(XDGADevice) *dev,
    int	alloc
){
    XExtDisplayInfo *info = SDL_NAME(xdga_find_display) (dpy);
    xXDGACreateColormapReq *req;
    Colormap cid;

    XDGACheckExtension (dpy, info, -1);

    LockDisplay(dpy);
    GetReq(XDGACreateColormap, req);
    req->reqType = info->codes->major_opcode;
    req->dgaReqType = X_XDGACreateColormap;
    req->screen = screen;
    req->mode = dev->mode.num;
    req->alloc = alloc;
    cid = req->id = XAllocID(dpy);
    UnlockDisplay(dpy);
    SyncHandle();

    return cid;
}


void SDL_NAME(XDGAKeyEventToXKeyEvent)(
    SDL_NAME(XDGAKeyEvent)* dk, 
    XKeyEvent* xk
){
    xk->type = dk->type;
    xk->serial = dk->serial;
    xk->send_event = False;
    xk->display = dk->display;
    xk->window = RootWindow(dk->display, dk->screen);
    xk->root = xk->window;
    xk->subwindow = None;
    xk->time = dk->time;
    xk->x = xk->y = xk->x_root = xk->y_root = 0;
    xk->state = dk->state;
    xk->keycode = dk->keycode;
    xk->same_screen = True;
}

#include <X11/Xmd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#if defined(ISC) 
# define HAS_SVR3_MMAP
# include <sys/types.h>
# include <errno.h>

# include <sys/at_ansi.h>
# include <sys/kd.h>

# include <sys/sysmacros.h>
# include <sys/immu.h>
# include <sys/region.h>

# include <sys/mmap.h>
#else
# if !defined(Lynx)
#  if !defined(__EMX__)
#   include <sys/mman.h>
#  endif
# else
#  include <sys/types.h>
#  include <errno.h>
#  include <smem.h>
# endif
#endif
#include <sys/wait.h>
#include <signal.h>
#include <unistd.h>

#if defined(SVR4) && !defined(sun) && !defined(SCO325)
#define DEV_MEM "/dev/pmem"
#elif defined(SVR4) && defined(sun)
#define DEV_MEM "/dev/xsvc"
#else
#define DEV_MEM "/dev/mem"
#endif



typedef struct _DGAMapRec{
  unsigned char *physical;
  unsigned char *virtual;
  CARD32 size;
  int fd;
  int screen;
  struct _DGAMapRec *next;
} DGAMapRec, *DGAMapPtr;

static Bool
DGAMapPhysical(int, char*, unsigned char*, CARD32, CARD32, CARD32, DGAMapPtr); 
static void DGAUnmapPhysical(DGAMapPtr);

static DGAMapPtr _Maps = NULL;


unsigned char*
SDL_NAME(XDGAGetMappedMemory)(int screen)
{
    DGAMapPtr pMap = _Maps;
    unsigned char *pntr = NULL;

    while(pMap != NULL) {
	if(pMap->screen == screen) {
	    pntr = pMap->virtual;
	    break;
	}
	pMap = pMap->next;
    }

    return pntr;
}

Bool
SDL_NAME(XDGAMapFramebuffer)(
   int screen,
   char *name,			/* optional device name */
   unsigned char* base,		/* physical memory */
   CARD32 size,			/* size */
   CARD32 offset,		/* optional offset */
   CARD32 extra			/* optional extra data */
){
   DGAMapPtr pMap = _Maps;
   Bool result;
   
   /* is it already mapped ? */
   while(pMap != NULL) {
     if(pMap->screen == screen)
	return True;
     pMap = pMap->next;
   }

   if(extra & XDGANeedRoot) {
    /* we should probably check if we have root permissions and
       return False here */

   }

   pMap = (DGAMapPtr)Xmalloc(sizeof(DGAMapRec));

   result = DGAMapPhysical(screen, name, base, size, offset, extra, pMap);

   if(result) {
      pMap->next = _Maps;
      _Maps = pMap;
   } else 
      Xfree(pMap);
   
   return result;
}

void
SDL_NAME(XDGAUnmapFramebuffer)(int screen)
{
   DGAMapPtr pMap = _Maps;
   DGAMapPtr pPrev = NULL;

   /* is it already mapped */
    while(pMap != NULL) {
	if(pMap->screen == screen)
	    break;
	pPrev = pMap;
	pMap = pMap->next;
    }

    if(!pMap)
	return;

    DGAUnmapPhysical(pMap);

    if(!pPrev)
	_Maps = pMap->next;
    else
	pPrev->next = pMap->next;

    Xfree(pMap);
}


static Bool
DGAMapPhysical(
   int screen,
   char *name,			/* optional device name */
   unsigned char* base,		/* physical memory */
   CARD32 size,			/* size */
   CARD32 offset,		/* optional offset */
   CARD32 extra,		/* optional extra data */
   DGAMapPtr pMap
) {
#if defined(ISC) && defined(HAS_SVR3_MMAP)
    struct kd_memloc mloc;
#elif defined(__EMX__)
    APIRET rc;
    ULONG action;
    HFILE hfd;
#endif
  
    base += offset;

    pMap->screen = screen;
    pMap->physical = base;
    pMap->size = size;

#if defined(ISC) && defined(HAS_SVR3_MMAP)
    if ((pMap->fd = open("/dev/mmap", O_RDWR)) < 0)
	return False;
    mloc.vaddr = (char *)0;
    mloc.physaddr = (char *)base;
    mloc.length = size;
    mloc.ioflg=1;

    if ((pMap->virtual = (void *)ioctl(pMap->fd, MAP, &mloc)) == (void *)-1)
	return False;
#elif defined (__EMX__)
    /*
     * Dragon warning here! /dev/pmap$ is never closed, except on progam exit.
     * Consecutive calling of this routine will make PMAP$ driver run out
     * of memory handles. Some umap/close mechanism should be provided
     */

    rc = DosOpen("/dev/pmap$", &hfd, &action, 0, FILE_NORMAL, FILE_OPEN,
		 OPEN_ACCESS_READWRITE | OPEN_SHARE_DENYNONE, (PEAOP2)NULL);
    if (rc != 0)
	return False;
    {
	struct map_ioctl {
		union {
			ULONG phys;
			void* user;
		} a;
		ULONG size;
	} pmap,dmap;
	ULONG plen,dlen;
#define XFREE86_PMAP	0x76
#define PMAP_MAP	0x44

	pmap.a.phys = base;
	pmap.size = size;
	rc = DosDevIOCtl(hfd, XFREE86_PMAP, PMAP_MAP,
			 (PULONG)&pmap, sizeof(pmap), &plen,
			 (PULONG)&dmap, sizeof(dmap), &dlen);
	if (rc == 0) {
		pMap->virtual = dmap.a.user;
	}
   }
   if (rc != 0)
	return False;
#elif defined (Lynx)
    pMap->virtual = smem_create("XF86DGA", (char*)base, size, SM_READ|SM_WRITE);
#else
#ifndef MAP_FILE
#define MAP_FILE 0
#endif
    if (!name)
	    name = DEV_MEM;
    if ((pMap->fd = open(name, O_RDWR)) < 0)
#if defined(ENABLE_FBCON)
    { /* /dev/fb0 fallback added by Sam Lantinga <hercules@lokigames.com> */
        /* Try to fall back to /dev/fb on Linux - FIXME: verify the device */
        struct fb_fix_screeninfo finfo;

        if ((pMap->fd = open("/dev/fb0", O_RDWR)) < 0) {
            return False;
        }
        /* The useable framebuffer console memory may not be the whole
           framebuffer that X has access to. :-(
         */
        if ( ioctl(pMap->fd, FBIOGET_FSCREENINFO, &finfo) < 0 ) {
            close(pMap->fd);
            return False;
        }
        /* Warning: On PPC, the size and virtual need to be offset by:
           (((long)finfo.smem_start) -
           (((long)finfo.smem_start)&~(PAGE_SIZE-1)))
         */
        base = 0;
        size = pMap->size = finfo.smem_len;
    }
#else
	return False;
#endif
    pMap->virtual = mmap(NULL, size, PROT_READ | PROT_WRITE, 
			MAP_FILE | MAP_SHARED, pMap->fd, (off_t)base);
    if (pMap->virtual == (void *)-1)
	return False;
#endif

#if !defined(ISC) && !defined(HAS_SVR3_MMAP) && !defined(Lynx) \
	&& !defined(__EMX__)
    mprotect(pMap->virtual, size, PROT_READ | PROT_WRITE);
#endif

    return True;
}



static void
DGAUnmapPhysical(DGAMapPtr pMap)
{
#if !defined(ISC) && !defined(HAS_SVR3_MMAP) && !defined(Lynx) \
	&& !defined(__EMX__)
    mprotect(pMap->virtual,pMap->size, PROT_READ);
#elif defined(Lynx)
	/* XXX this doesn't allow enable after disable */
    smem_create(NULL, pMap->virtual, pMap->size, SM_DETACH);
    smem_remove("XF86DGA");
#endif


   /* We need to unmap and close too !!!!!!!!!!*/
}