src/gallium/winsys/egl_xlib/egl_xlib.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28 /**
  29  * EGL / softpipe / xlib winsys module
  30  *
  31  * Authors: Brian Paul
  32  */
  33
  34
  35 #include <dlfcn.h>
  36 #include <X11/Xutil.h>
  37
  38 #include "pipe/p_compiler.h"
  39 #include "pipe/p_format.h"
  40 #include "pipe/p_state.h"
  41 #include "pipe/internal/p_winsys_screen.h"
  42 #include "util/u_memory.h"
  43 #include "softpipe/sp_winsys.h"
  44 #include "softpipe/sp_texture.h"
  45
  46 #include "eglconfig.h"
  47 #include "eglconfigutil.h"
  48 #include "eglcontext.h"
  49 #include "egldisplay.h"
  50 #include "egldriver.h"
  51 #include "eglglobals.h"
  52 #include "egllog.h"
  53 #include "eglsurface.h"
  54
  55 #include "state_tracker/st_public.h"
  56
  57 #include "sw_winsys.h"
  58
  59
  60 /** subclass of _EGLDriver */
  61 struct xlib_egl_driver
  62 {
  63    _EGLDriver Base;   /**< base class */
  64
  65    struct pipe_winsys *winsys;
  66    struct pipe_screen *screen;
  67 };
  68
  69
  70 /** subclass of _EGLContext */
  71 struct xlib_egl_context
  72 {
  73    _EGLContext Base;   /**< base class */
  74
  75    struct pipe_context *pipe;   /**< Gallium driver context */
  76    struct st_context *Context;  /**< Mesa/gallium state tracker context */
  77 };
  78
  79
  80 /** subclass of _EGLSurface */
  81 struct xlib_egl_surface
  82 {
  83    _EGLSurface Base;   /**< base class */
  84
  85    Display *Dpy;  /**< The X Display of the window */
  86    Window Win;    /**< The user-created window ID */
  87    GC Gc;
  88    XVisualInfo VisInfo;
  89
  90    struct pipe_winsys *winsys;
  91
  92    struct st_framebuffer *Framebuffer;
  93 };
  94
  95
  96 /** cast wrapper */
  97 static INLINE struct xlib_egl_driver *
  98 xlib_egl_driver(_EGLDriver *drv)
  99 {
 100    return (struct xlib_egl_driver *) drv;
 101 }
 102
 103
 104 static struct xlib_egl_surface *
 105 lookup_surface(EGLSurface surf)
 106 {
 107    _EGLSurface *surface = _eglLookupSurface(surf);
 108    return (struct xlib_egl_surface *) surface;
 109 }
 110
 111
 112 static struct xlib_egl_context *
 113 lookup_context(EGLContext surf)
 114 {
 115    _EGLContext *context = _eglLookupContext(surf);
 116    return (struct xlib_egl_context *) context;
 117 }
 118
 119
 120 static unsigned int
 121 bitcount(unsigned int n)
 122 {
 123    unsigned int bits;
 124    for (bits = 0; n > 0; n = n >> 1) {
 125       bits += (n & 1);
 126    }
 127    return bits;
 128 }
 129
 130
 131 /**
 132  * Create the EGLConfigs.  (one per X visual)
 133  */
 134 static void
 135 create_configs(_EGLDriver *drv, EGLDisplay dpy)
 136 {
 137    static const EGLint all_apis = (EGL_OPENGL_ES_BIT |
 138                                    EGL_OPENGL_ES2_BIT |
 139                                    EGL_OPENVG_BIT |
 140                                    EGL_OPENGL_BIT);
 141    _EGLDisplay *disp = _eglLookupDisplay(dpy);
 142    XVisualInfo *visInfo, visTemplate;
 143    int num_visuals, i;
 144
 145    /* get list of all X visuals, create an EGL config for each */
 146    visTemplate.screen = DefaultScreen(disp->Xdpy);
 147    visInfo = XGetVisualInfo(disp->Xdpy, VisualScreenMask,
 148                             &visTemplate, &num_visuals);
 149    if (!visInfo) {
 150       printf("egl_xlib.c: couldn't get any X visuals\n");
 151       abort();
 152    }
 153
 154    for (i = 0; i < num_visuals; i++) {
 155       _EGLConfig *config = calloc(1, sizeof(_EGLConfig));
 156       int id = i + 1;
 157       int rbits = bitcount(visInfo[i].red_mask);
 158       int gbits = bitcount(visInfo[i].green_mask);
 159       int bbits = bitcount(visInfo[i].blue_mask);
 160       int abits = bbits == 8 ? 8 : 0;
 161       int zbits = 24;
 162       int sbits = 8;
 163       int visid = visInfo[i].visualid;
 164 #if defined(__cplusplus) || defined(c_plusplus)
 165       int vistype = visInfo[i].c_class;
 166 #else
 167       int vistype = visInfo[i].class;
 168 #endif
 169
 170       _eglInitConfig(config, id);
 171       SET_CONFIG_ATTRIB(config, EGL_BUFFER_SIZE, rbits + gbits + bbits + abits);
 172       SET_CONFIG_ATTRIB(config, EGL_RED_SIZE, rbits);
 173       SET_CONFIG_ATTRIB(config, EGL_GREEN_SIZE, gbits);
 174       SET_CONFIG_ATTRIB(config, EGL_BLUE_SIZE, bbits);
 175       SET_CONFIG_ATTRIB(config, EGL_ALPHA_SIZE, abits);
 176       SET_CONFIG_ATTRIB(config, EGL_DEPTH_SIZE, zbits);
 177       SET_CONFIG_ATTRIB(config, EGL_STENCIL_SIZE, sbits);
 178       SET_CONFIG_ATTRIB(config, EGL_NATIVE_VISUAL_ID, visid);
 179       SET_CONFIG_ATTRIB(config, EGL_NATIVE_VISUAL_TYPE, vistype);
 180       SET_CONFIG_ATTRIB(config, EGL_NATIVE_RENDERABLE, EGL_FALSE);
 181       SET_CONFIG_ATTRIB(config, EGL_CONFORMANT, all_apis);
 182       SET_CONFIG_ATTRIB(config, EGL_RENDERABLE_TYPE, all_apis);
 183       SET_CONFIG_ATTRIB(config, EGL_SURFACE_TYPE, EGL_WINDOW_BIT);
 184
 185       _eglAddConfig(disp, config);
 186    }
 187 }
 188
 189
 190 /**
 191  * Called via eglInitialize(), drv->API.Initialize().
 192  */
 193 static EGLBoolean
 194 xlib_eglInitialize(_EGLDriver *drv, EGLDisplay dpy,
 195                    EGLint *minor, EGLint *major)
 196 {
 197    create_configs(drv, dpy);
 198
 199    drv->Initialized = EGL_TRUE;
 200
 201    /* we're supporting EGL 1.4 */
 202    *minor = 1;
 203    *major = 4;
 204
 205    return EGL_TRUE;
 206 }
 207
 208
 209 /**
 210  * Called via eglTerminate(), drv->API.Terminate().
 211  */
 212 static EGLBoolean
 213 xlib_eglTerminate(_EGLDriver *drv, EGLDisplay dpy)
 214 {
 215    return EGL_TRUE;
 216 }
 217
 218
 219 static _EGLProc
 220 xlib_eglGetProcAddress(const char *procname)
 221 {
 222    return (_EGLProc) st_get_proc_address(procname);
 223 }
 224
 225
 226 static void
 227 get_drawable_visual_info(Display *dpy, Drawable d, XVisualInfo *visInfo)
 228 {
 229    XWindowAttributes attr;
 230    XVisualInfo visTemp, *vis;
 231    int num_visuals;
 232
 233    XGetWindowAttributes(dpy, d, &attr);
 234
 235    visTemp.screen = DefaultScreen(dpy);
 236    visTemp.visualid = attr.visual->visualid;
 237    vis = XGetVisualInfo(dpy,
 238                         (VisualScreenMask | VisualIDMask),
 239                         &visTemp, &num_visuals);
 240    if (vis)
 241       *visInfo = *vis;
 242
 243    XFree(vis);
 244 }
 245
 246
 247
 248 /** Get size of given window */
 249 static Status
 250 get_drawable_size(Display *dpy, Drawable d, uint *width, uint *height)
 251 {
 252    Window root;
 253    Status stat;
 254    int xpos, ypos;
 255    unsigned int w, h, bw, depth;
 256    stat = XGetGeometry(dpy, d, &root, &xpos, &ypos, &w, &h, &bw, &depth);
 257    *width = w;
 258    *height = h;
 259    return stat;
 260 }
 261
 262
 263 static void
 264 check_and_update_buffer_size(struct xlib_egl_surface *surface)
 265 {
 266    uint width, height;
 267    get_drawable_size(surface->Dpy, surface->Win, &width, &height);
 268    st_resize_framebuffer(surface->Framebuffer, width, height);
 269    surface->Base.Width = width;
 270    surface->Base.Height = height;
 271 }
 272
 273
 274
 275 static void
 276 display_surface(struct pipe_winsys *pws,
 277                 struct pipe_surface *psurf,
 278                 struct xlib_egl_surface *xsurf)
 279 {
 280    struct softpipe_texture *spt = softpipe_texture(psurf->texture);
 281    XImage *ximage;
 282    void *data;
 283
 284    ximage = XCreateImage(xsurf->Dpy,
 285                          xsurf->VisInfo.visual,
 286                          xsurf->VisInfo.depth,
 287                          ZPixmap, 0,   /* format, offset */
 288                          NULL,         /* data */
 289                          0, 0,         /* size */
 290                          32,           /* bitmap_pad */
 291                          0);           /* bytes_per_line */
 292
 293
 294    assert(ximage->format);
 295    assert(ximage->bitmap_unit);
 296
 297    data = pws->buffer_map(pws, spt->buffer, 0);
 298
 299    /* update XImage's fields */
 300    ximage->data = data;
 301    ximage->width = psurf->width;
 302    ximage->height = psurf->height;
 303    ximage->bytes_per_line = spt->stride[psurf->level];
 304
 305    XPutImage(xsurf->Dpy, xsurf->Win, xsurf->Gc,
 306              ximage, 0, 0, 0, 0, psurf->width, psurf->height);
 307
 308    XSync(xsurf->Dpy, 0);
 309
 310    ximage->data = NULL;
 311    XDestroyImage(ximage);
 312
 313    pws->buffer_unmap(pws, spt->buffer);
 314 }
 315
 316
 317
 318 /** Display gallium surface in X window */
 319 static void
 320 flush_frontbuffer(struct pipe_winsys *pws,
 321                   struct pipe_surface *psurf,
 322                   void *context_private)
 323 {
 324    struct xlib_egl_surface *xsurf = (struct xlib_egl_surface *) context_private;
 325    display_surface(pws, psurf, xsurf);
 326 }
 327
 328
 329
 330 /**
 331  * Called via eglCreateContext(), drv->API.CreateContext().
 332  */
 333 static EGLContext
 334 xlib_eglCreateContext(_EGLDriver *drv, EGLDisplay dpy, EGLConfig config,
 335                       EGLContext share_list, const EGLint *attrib_list)
 336 {
 337    struct xlib_egl_driver *xdrv = xlib_egl_driver(drv);
 338    _EGLConfig *conf = _eglLookupConfig(drv, dpy, config);
 339    struct xlib_egl_context *ctx;
 340    struct st_context *share_ctx = NULL; /* XXX fix */
 341    __GLcontextModes visual;
 342
 343    ctx = CALLOC_STRUCT(xlib_egl_context);
 344    if (!ctx)
 345       return EGL_NO_CONTEXT;
 346
 347    /* let EGL lib init the common stuff */
 348    if (!_eglInitContext(drv, dpy, &ctx->Base, config, attrib_list)) {
 349       free(ctx);
 350       return EGL_NO_CONTEXT;
 351    }
 352
 353    /* API-dependent context creation */
 354    switch (ctx->Base.ClientAPI) {
 355    case EGL_OPENVG_API:
 356    case EGL_OPENGL_ES_API:
 357       _eglLog(_EGL_DEBUG, "Create Context for ES version %d\n",
 358               ctx->Base.ClientVersion);
 359       /* fall-through */
 360    case EGL_OPENGL_API:
 361       /* create a softpipe context */
 362       ctx->pipe = softpipe_create(xdrv->screen, xdrv->winsys, NULL);
 363       /* Now do xlib / state tracker inits here */
 364       _eglConfigToContextModesRec(conf, &visual);
 365       ctx->Context = st_create_context(ctx->pipe, &visual, share_ctx);
 366       break;
 367    default:
 368       _eglError(EGL_BAD_MATCH, "eglCreateContext(unsupported API)");
 369       free(ctx);
 370       return EGL_NO_CONTEXT;
 371    }
 372
 373    _eglSaveContext(&ctx->Base);
 374
 375    return _eglGetContextHandle(&ctx->Base);
 376 }
 377
 378
 379 static EGLBoolean
 380 xlib_eglDestroyContext(_EGLDriver *drv, EGLDisplay dpy, EGLContext ctx)
 381 {
 382    struct xlib_egl_context *context = lookup_context(ctx);
 383    if (context) {
 384       if (context->Base.IsBound) {
 385          context->Base.DeletePending = EGL_TRUE;
 386       }
 387       else {
 388          /* API-dependent clean-up */
 389          switch (context->Base.ClientAPI) {
 390          case EGL_OPENGL_ES_API:
 391             /* fall-through */
 392          case EGL_OPENGL_API:
 393             st_destroy_context(context->Context);
 394             break;
 395          default:
 396             assert(0);
 397          }
 398          free(context);
 399       }
 400       return EGL_TRUE;
 401    }
 402    else {
 403       _eglError(EGL_BAD_CONTEXT, "eglDestroyContext");
 404       return EGL_TRUE;
 405    }
 406 }
 407
 408
 409 /**
 410  * Called via eglMakeCurrent(), drv->API.MakeCurrent().
 411  */
 412 static EGLBoolean
 413 xlib_eglMakeCurrent(_EGLDriver *drv, EGLDisplay dpy,
 414                     EGLSurface draw, EGLSurface read, EGLContext ctx)
 415 {
 416    struct xlib_egl_context *context = lookup_context(ctx);
 417    struct xlib_egl_surface *draw_surf = lookup_surface(draw);
 418    struct xlib_egl_surface *read_surf = lookup_surface(read);
 419
 420    if (!_eglMakeCurrent(drv, dpy, draw, read, context))
 421       return EGL_FALSE;
 422
 423    st_make_current((context ? context->Context : NULL),
 424                    (draw_surf ? draw_surf->Framebuffer : NULL),
 425                    (read_surf ? read_surf->Framebuffer : NULL));
 426
 427    if (draw_surf)
 428       check_and_update_buffer_size(draw_surf);
 429    if (read_surf && read_surf != draw_surf)
 430       check_and_update_buffer_size(draw_surf);
 431
 432    return EGL_TRUE;
 433 }
 434
 435
 436 static enum pipe_format
 437 choose_color_format(const __GLcontextModes *visual)
 438 {
 439    if (visual->redBits == 8 &&
 440        visual->greenBits == 8 &&
 441        visual->blueBits == 8 &&
 442        visual->alphaBits == 8) {
 443       /* XXX this really also depends on the ordering of R,G,B,A */
 444       return PIPE_FORMAT_A8R8G8B8_UNORM;
 445    }
 446    else {
 447       assert(0);
 448       return PIPE_FORMAT_NONE;
 449    }
 450 }
 451
 452
 453 static enum pipe_format
 454 choose_depth_format(const __GLcontextModes *visual)
 455 {
 456    if (visual->depthBits > 0)
 457       return PIPE_FORMAT_S8Z24_UNORM;
 458    else
 459       return PIPE_FORMAT_NONE;
 460 }
 461
 462
 463 static enum pipe_format
 464 choose_stencil_format(const __GLcontextModes *visual)
 465 {
 466    if (visual->stencilBits > 0)
 467       return PIPE_FORMAT_S8Z24_UNORM;
 468    else
 469       return PIPE_FORMAT_NONE;
 470 }
 471
 472
 473 /**
 474  * Called via eglCreateWindowSurface(), drv->API.CreateWindowSurface().
 475  */
 476 static EGLSurface
 477 xlib_eglCreateWindowSurface(_EGLDriver *drv, EGLDisplay dpy, EGLConfig config,
 478                             NativeWindowType window, const EGLint *attrib_list)
 479 {
 480    struct xlib_egl_driver *xdrv = xlib_egl_driver(drv);
 481    _EGLDisplay *disp = _eglLookupDisplay(dpy);
 482    _EGLConfig *conf = _eglLookupConfig(drv, dpy, config);
 483
 484    struct xlib_egl_surface *surf;
 485    __GLcontextModes visual;
 486    uint width, height;
 487
 488    surf = CALLOC_STRUCT(xlib_egl_surface);
 489    if (!surf)
 490       return EGL_NO_SURFACE;
 491
 492    /* Let EGL lib init the common stuff */
 493    if (!_eglInitSurface(drv, dpy, &surf->Base, EGL_WINDOW_BIT,
 494                         config, attrib_list)) {
 495       free(surf);
 496       return EGL_NO_SURFACE;
 497    }
 498
 499    _eglSaveSurface(&surf->Base);
 500
 501    /*
 502     * Now init the Xlib and gallium stuff
 503     */
 504    surf->Win = (Window) window;  /* The X window ID */
 505    surf->Dpy = disp->Xdpy;  /* The X display */
 506    surf->Gc = XCreateGC(surf->Dpy, surf->Win, 0, NULL);
 507
 508    surf->winsys = xdrv->winsys;
 509
 510    _eglConfigToContextModesRec(conf, &visual);
 511    get_drawable_size(surf->Dpy, surf->Win, &width, &height);
 512    get_drawable_visual_info(surf->Dpy, surf->Win, &surf->VisInfo);
 513
 514    surf->Base.Width = width;
 515    surf->Base.Height = height;
 516
 517    /* Create GL statetracker framebuffer */
 518    surf->Framebuffer = st_create_framebuffer(&visual,
 519                                              choose_color_format(&visual),
 520                                              choose_depth_format(&visual),
 521                                              choose_stencil_format(&visual),
 522                                              width, height,
 523                                              (void *) surf);
 524
 525    st_resize_framebuffer(surf->Framebuffer, width, height);
 526
 527    return _eglGetSurfaceHandle(&surf->Base);
 528 }
 529
 530
 531 static EGLBoolean
 532 xlib_eglDestroySurface(_EGLDriver *drv, EGLDisplay dpy, EGLSurface surface)
 533 {
 534    struct xlib_egl_surface *surf = lookup_surface(surface);
 535    if (surf) {
 536       _eglHashRemove(_eglGlobal.Surfaces, (EGLuint) surface);
 537       if (surf->Base.IsBound) {
 538          surf->Base.DeletePending = EGL_TRUE;
 539       }
 540       else {
 541          XFreeGC(surf->Dpy, surf->Gc);
 542          st_unreference_framebuffer(surf->Framebuffer);
 543          free(surf);
 544       }
 545       return EGL_TRUE;
 546    }
 547    else {
 548       _eglError(EGL_BAD_SURFACE, "eglDestroySurface");
 549       return EGL_FALSE;
 550    }
 551 }
 552
 553
 554 static EGLBoolean
 555 xlib_eglSwapBuffers(_EGLDriver *drv, EGLDisplay dpy, EGLSurface draw)
 556 {
 557    /* error checking step: */
 558    if (!_eglSwapBuffers(drv, dpy, draw))
 559       return EGL_FALSE;
 560
 561    {
 562       struct xlib_egl_surface *xsurf = lookup_surface(draw);
 563       struct pipe_winsys *pws = xsurf->winsys;
 564       struct pipe_surface *psurf;
 565
 566       st_get_framebuffer_surface(xsurf->Framebuffer, ST_SURFACE_BACK_LEFT,
 567                                  &psurf);
 568
 569       st_notify_swapbuffers(xsurf->Framebuffer);
 570
 571       display_surface(pws, psurf, xsurf);
 572
 573       check_and_update_buffer_size(xsurf);
 574    }
 575
 576    return EGL_TRUE;
 577 }
 578
 579
 580 /**
 581  * Determine which API(s) is(are) present by looking for some specific
 582  * global symbols.
 583  */
 584 static EGLint
 585 find_supported_apis(void)
 586 {
 587    EGLint mask = 0;
 588    void *handle;
 589
 590    handle = dlopen(NULL, 0);
 591
 592    if (dlsym(handle, "st_api_OpenGL_ES1"))
 593       mask |= EGL_OPENGL_ES_BIT;
 594
 595    if (dlsym(handle, "st_api_OpenGL_ES2"))
 596       mask |= EGL_OPENGL_ES2_BIT;
 597
 598    if (dlsym(handle, "st_api_OpenGL"))
 599       mask |= EGL_OPENGL_BIT;
 600
 601    if (dlsym(handle, "st_api_OpenVG"))
 602       mask |= EGL_OPENVG_BIT;
 603
 604    dlclose(handle);
 605
 606    return mask;
 607 }
 608
 609
 610 /**
 611  * This is the main entrypoint into the driver.
 612  * Called by libEGL to instantiate an _EGLDriver object.
 613  */
 614 _EGLDriver *
 615 _eglMain(_EGLDisplay *dpy, const char *args)
 616 {
 617    struct xlib_egl_driver *xdrv;
 618
 619    _eglLog(_EGL_INFO, "Entering EGL/Xlib _eglMain(%s)", args);
 620
 621    xdrv = CALLOC_STRUCT(xlib_egl_driver);
 622    if (!xdrv)
 623       return NULL;
 624
 625    if (!dpy->Xdpy) {
 626       dpy->Xdpy = XOpenDisplay(NULL);
 627    }
 628
 629    _eglInitDriverFallbacks(&xdrv->Base);
 630    xdrv->Base.API.Initialize = xlib_eglInitialize;
 631    xdrv->Base.API.Terminate = xlib_eglTerminate;
 632    xdrv->Base.API.GetProcAddress = xlib_eglGetProcAddress;
 633    xdrv->Base.API.CreateContext = xlib_eglCreateContext;
 634    xdrv->Base.API.DestroyContext = xlib_eglDestroyContext;
 635    xdrv->Base.API.CreateWindowSurface = xlib_eglCreateWindowSurface;
 636    xdrv->Base.API.DestroySurface = xlib_eglDestroySurface;
 637    xdrv->Base.API.MakeCurrent = xlib_eglMakeCurrent;
 638    xdrv->Base.API.SwapBuffers = xlib_eglSwapBuffers;
 639
 640    xdrv->Base.ClientAPIsMask = find_supported_apis();
 641    if (xdrv->Base.ClientAPIsMask == 0x0) {
 642       /* the app isn't directly linked with any EGL-supprted APIs
 643        * (such as libGLESv2.so) so use an EGL utility to see what
 644        * APIs might be loaded dynamically on this system.
 645        */
 646       xdrv->Base.ClientAPIsMask = _eglFindAPIs();
 647    }
 648
 649    xdrv->Base.Name = "Xlib/softpipe";
 650
 651    /* create one winsys and use it for all contexts/surfaces */
 652    xdrv->winsys = create_sw_winsys();
 653    xdrv->winsys->flush_frontbuffer = flush_frontbuffer;
 654
 655    xdrv->screen = softpipe_create_screen(xdrv->winsys);
 656
 657    return &xdrv->Base;
 658 }
 659