src/gallium/drivers/svga/svga_screen.c

   1 /**********************************************************
   2  * Copyright 2008-2009 VMware, Inc.  All rights reserved.
   3  *
   4  * Permission is hereby granted, free of charge, to any person
   5  * obtaining a copy of this software and associated documentation
   6  * files (the "Software"), to deal in the Software without
   7  * restriction, including without limitation the rights to use, copy,
   8  * modify, merge, publish, distribute, sublicense, and/or sell copies
   9  * of the Software, and to permit persons to whom the Software is
  10  * furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  *
  24  **********************************************************/
  25
  26 #include "util/u_memory.h"
  27 #include "util/u_inlines.h"
  28 #include "util/u_string.h"
  29 #include "util/u_math.h"
  30
  31 #include "svga_winsys.h"
  32 #include "svga_public.h"
  33 #include "svga_context.h"
  34 #include "svga_format.h"
  35 #include "svga_screen.h"
  36 #include "svga_resource_texture.h"
  37 #include "svga_resource.h"
  38 #include "svga_debug.h"
  39
  40 #include "svga3d_shaderdefs.h"
  41
  42
  43 #ifdef DEBUG
  44 int SVGA_DEBUG = 0;
  45
  46 static const struct debug_named_value svga_debug_flags[] = {
  47    { "dma",      DEBUG_DMA, NULL },
  48    { "tgsi",     DEBUG_TGSI, NULL },
  49    { "pipe",     DEBUG_PIPE, NULL },
  50    { "state",    DEBUG_STATE, NULL },
  51    { "screen",   DEBUG_SCREEN, NULL },
  52    { "tex",      DEBUG_TEX, NULL },
  53    { "swtnl",    DEBUG_SWTNL, NULL },
  54    { "const",    DEBUG_CONSTS, NULL },
  55    { "viewport", DEBUG_VIEWPORT, NULL },
  56    { "views",    DEBUG_VIEWS, NULL },
  57    { "perf",     DEBUG_PERF, NULL },
  58    { "flush",    DEBUG_FLUSH, NULL },
  59    { "sync",     DEBUG_SYNC, NULL },
  60    { "cache",    DEBUG_CACHE, NULL },
  61    DEBUG_NAMED_VALUE_END
  62 };
  63 #endif
  64
  65 static const char *
  66 svga_get_vendor( struct pipe_screen *pscreen )
  67 {
  68    return "VMware, Inc.";
  69 }
  70
  71
  72 static const char *
  73 svga_get_name( struct pipe_screen *pscreen )
  74 {
  75    const char *build = "", *llvm = "", *mutex = "";
  76    static char name[100];
  77 #ifdef DEBUG
  78    /* Only return internal details in the DEBUG version:
  79     */
  80    build = "build: DEBUG;";
  81    mutex = "mutex: " PIPE_ATOMIC ";";
  82 #ifdef HAVE_LLVM
  83    llvm = "LLVM;";
  84 #endif
  85 #else
  86    build = "build: RELEASE;";
  87 #endif
  88
  89    util_snprintf(name, sizeof(name), "SVGA3D; %s %s %s", build, mutex, llvm);
  90    return name;
  91 }
  92
  93
  94
  95
  96 static float
  97 svga_get_paramf(struct pipe_screen *screen, enum pipe_capf param)
  98 {
  99    struct svga_screen *svgascreen = svga_screen(screen);
 100    struct svga_winsys_screen *sws = svgascreen->sws;
 101    SVGA3dDevCapResult result;
 102
 103    switch (param) {
 104    case PIPE_CAPF_MAX_LINE_WIDTH:
 105       /* fall-through */
 106    case PIPE_CAPF_MAX_LINE_WIDTH_AA:
 107       return 7.0;
 108
 109    case PIPE_CAPF_MAX_POINT_WIDTH:
 110       /* fall-through */
 111    case PIPE_CAPF_MAX_POINT_WIDTH_AA:
 112       return svgascreen->maxPointSize;
 113
 114    case PIPE_CAPF_MAX_TEXTURE_ANISOTROPY:
 115       if(!sws->get_cap(sws, SVGA3D_DEVCAP_MAX_TEXTURE_ANISOTROPY, &result))
 116          return 4.0;
 117       return result.u;
 118
 119    case PIPE_CAPF_MAX_TEXTURE_LOD_BIAS:
 120       return 15.0;
 121
 122    default:
 123       return 0;
 124    }
 125 }
 126
 127
 128 static int
 129 svga_get_param(struct pipe_screen *screen, enum pipe_cap param)
 130 {
 131    struct svga_screen *svgascreen = svga_screen(screen);
 132    struct svga_winsys_screen *sws = svgascreen->sws;
 133    SVGA3dDevCapResult result;
 134
 135    switch (param) {
 136    case PIPE_CAP_MAX_COMBINED_SAMPLERS:
 137       return 16;
 138    case PIPE_CAP_NPOT_TEXTURES:
 139       return 1;
 140    case PIPE_CAP_TWO_SIDED_STENCIL:
 141       return 1;
 142    case PIPE_CAP_ANISOTROPIC_FILTER:
 143       return 1;
 144    case PIPE_CAP_POINT_SPRITE:
 145       return 1;
 146    case PIPE_CAP_MAX_RENDER_TARGETS:
 147       if(!sws->get_cap(sws, SVGA3D_DEVCAP_MAX_RENDER_TARGETS, &result))
 148          return 1;
 149       if(!result.u)
 150          return 1;
 151       return MIN2(result.u, PIPE_MAX_COLOR_BUFS);
 152    case PIPE_CAP_OCCLUSION_QUERY:
 153       return 1;
 154    case PIPE_CAP_TIMER_QUERY:
 155       return 0;
 156    case PIPE_CAP_TEXTURE_SHADOW_MAP:
 157       return 1;
 158    case PIPE_CAP_TEXTURE_SWIZZLE:
 159       return 1;
 160
 161    case PIPE_CAP_MAX_TEXTURE_2D_LEVELS:
 162       {
 163          unsigned levels = SVGA_MAX_TEXTURE_LEVELS;
 164          if (sws->get_cap(sws, SVGA3D_DEVCAP_MAX_TEXTURE_WIDTH, &result))
 165             levels = MIN2(util_logbase2(result.u) + 1, levels);
 166          else
 167             levels = 12 /* 2048x2048 */;
 168          if (sws->get_cap(sws, SVGA3D_DEVCAP_MAX_TEXTURE_HEIGHT, &result))
 169             levels = MIN2(util_logbase2(result.u) + 1, levels);
 170          else
 171             levels = 12 /* 2048x2048 */;
 172          return levels;
 173       }
 174
 175    case PIPE_CAP_MAX_TEXTURE_3D_LEVELS:
 176       if (!sws->get_cap(sws, SVGA3D_DEVCAP_MAX_VOLUME_EXTENT, &result))
 177          return 8;  /* max 128x128x128 */
 178       return MIN2(util_logbase2(result.u) + 1, SVGA_MAX_TEXTURE_LEVELS);
 179
 180    case PIPE_CAP_MAX_TEXTURE_CUBE_LEVELS:
 181       /*
 182        * No mechanism to query the host, and at least limited to 2048x2048 on
 183        * certain hardware.
 184        */
 185       return MIN2(screen->get_param(screen, PIPE_CAP_MAX_TEXTURE_2D_LEVELS),
 186                   12 /* 2048x2048 */);
 187
 188    case PIPE_CAP_BLEND_EQUATION_SEPARATE: /* req. for GL 1.5 */
 189       return 1;
 190
 191    case PIPE_CAP_TGSI_FS_COORD_ORIGIN_UPPER_LEFT:
 192    case PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER:
 193       return 1;
 194    case PIPE_CAP_TGSI_FS_COORD_ORIGIN_LOWER_LEFT:
 195    case PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_INTEGER:
 196       return 0;
 197
 198    case PIPE_CAP_DEPTHSTENCIL_CLEAR_SEPARATE:
 199       return 1;
 200    case PIPE_CAP_MIXED_COLORBUFFER_FORMATS:
 201       return 0;
 202
 203    case PIPE_CAP_QUADS_FOLLOW_PROVOKING_VERTEX_CONVENTION:
 204       return 0;
 205
 206    case PIPE_CAP_VERTEX_COLOR_UNCLAMPED:
 207       return 1; /* The color outputs of vertex shaders are not clamped */
 208    case PIPE_CAP_VERTEX_COLOR_CLAMPED:
 209       return 0; /* The driver can't clamp vertex colors */
 210    case PIPE_CAP_FRAGMENT_COLOR_CLAMPED:
 211       return 0; /* The driver can't clamp fragment colors */
 212
 213    default:
 214       return 0;
 215    }
 216 }
 217
 218 static int svga_get_shader_param(struct pipe_screen *screen, unsigned shader, enum pipe_shader_cap param)
 219 {
 220    struct svga_screen *svgascreen = svga_screen(screen);
 221    struct svga_winsys_screen *sws = svgascreen->sws;
 222    SVGA3dDevCapResult result;
 223
 224    switch (shader)
 225    {
 226    case PIPE_SHADER_FRAGMENT:
 227       switch (param)
 228       {
 229       case PIPE_SHADER_CAP_MAX_INSTRUCTIONS:
 230       case PIPE_SHADER_CAP_MAX_ALU_INSTRUCTIONS:
 231       case PIPE_SHADER_CAP_MAX_TEX_INSTRUCTIONS:
 232       case PIPE_SHADER_CAP_MAX_TEX_INDIRECTIONS:
 233          return 512;
 234       case PIPE_SHADER_CAP_MAX_CONTROL_FLOW_DEPTH:
 235          return SVGA3D_MAX_NESTING_LEVEL;
 236       case PIPE_SHADER_CAP_MAX_INPUTS:
 237          return 10;
 238       case PIPE_SHADER_CAP_MAX_CONSTS:
 239          return 224;
 240       case PIPE_SHADER_CAP_MAX_CONST_BUFFERS:
 241          return 1;
 242       case PIPE_SHADER_CAP_MAX_TEMPS:
 243          if (!sws->get_cap(sws, SVGA3D_DEVCAP_MAX_FRAGMENT_SHADER_TEMPS, &result))
 244             return 32;
 245          return MIN2(result.u, SVGA3D_TEMPREG_MAX);
 246       case PIPE_SHADER_CAP_MAX_ADDRS:
 247       case PIPE_SHADER_CAP_INDIRECT_INPUT_ADDR:
 248          /*
 249           * Although PS 3.0 has some addressing abilities it can only represent
 250           * loops that can be statically determined and unrolled. Given we can
 251           * only handle a subset of the cases that the state tracker already
 252           * does it is better to defer loop unrolling to the state tracker.
 253           */
 254          return 0;
 255       case PIPE_SHADER_CAP_MAX_PREDS:
 256          return 1;
 257       case PIPE_SHADER_CAP_TGSI_CONT_SUPPORTED:
 258          return 1;
 259       case PIPE_SHADER_CAP_INDIRECT_OUTPUT_ADDR:
 260       case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:
 261       case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
 262          return 0;
 263       case PIPE_SHADER_CAP_SUBROUTINES:
 264          return 0;
 265       case PIPE_SHADER_CAP_INTEGERS:
 266          return 0;
 267       case PIPE_SHADER_CAP_MAX_TEXTURE_SAMPLERS:
 268          return 16;
 269       }
 270       break;
 271    case PIPE_SHADER_VERTEX:
 272       switch (param)
 273       {
 274       case PIPE_SHADER_CAP_MAX_INSTRUCTIONS:
 275       case PIPE_SHADER_CAP_MAX_ALU_INSTRUCTIONS:
 276          if (!sws->get_cap(sws, SVGA3D_DEVCAP_MAX_VERTEX_SHADER_INSTRUCTIONS, &result))
 277             return 512;
 278          return result.u;
 279       case PIPE_SHADER_CAP_MAX_TEX_INSTRUCTIONS:
 280       case PIPE_SHADER_CAP_MAX_TEX_INDIRECTIONS:
 281          /* XXX: until we have vertex texture support */
 282          return 0;
 283       case PIPE_SHADER_CAP_MAX_CONTROL_FLOW_DEPTH:
 284          return SVGA3D_MAX_NESTING_LEVEL;
 285       case PIPE_SHADER_CAP_MAX_INPUTS:
 286          return 16;
 287       case PIPE_SHADER_CAP_MAX_CONSTS:
 288          return 256;
 289       case PIPE_SHADER_CAP_MAX_CONST_BUFFERS:
 290          return 1;
 291       case PIPE_SHADER_CAP_MAX_TEMPS:
 292          if (!sws->get_cap(sws, SVGA3D_DEVCAP_MAX_VERTEX_SHADER_TEMPS, &result))
 293             return 32;
 294          return MIN2(result.u, SVGA3D_TEMPREG_MAX);
 295       case PIPE_SHADER_CAP_MAX_ADDRS:
 296          return 1;
 297       case PIPE_SHADER_CAP_MAX_PREDS:
 298          return 1;
 299       case PIPE_SHADER_CAP_TGSI_CONT_SUPPORTED:
 300          return 1;
 301       case PIPE_SHADER_CAP_INDIRECT_INPUT_ADDR:
 302       case PIPE_SHADER_CAP_INDIRECT_OUTPUT_ADDR:
 303          return 1;
 304       case PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR:
 305          return 0;
 306       case PIPE_SHADER_CAP_INDIRECT_CONST_ADDR:
 307          return 1;
 308       case PIPE_SHADER_CAP_SUBROUTINES:
 309          return 0;
 310       case PIPE_SHADER_CAP_INTEGERS:
 311          return 0;
 312       default:
 313          break;
 314       }
 315       break;
 316    default:
 317       break;
 318    }
 319    return 0;
 320 }
 321
 322
 323 static boolean
 324 svga_is_format_supported( struct pipe_screen *screen,
 325                           enum pipe_format format,
 326                           enum pipe_texture_target target,
 327                           unsigned sample_count,
 328                           unsigned tex_usage)
 329 {
 330    struct svga_screen *ss = svga_screen(screen);
 331    SVGA3dSurfaceFormat svga_format;
 332    SVGA3dSurfaceFormatCaps caps;
 333    SVGA3dSurfaceFormatCaps mask;
 334
 335    assert(tex_usage);
 336
 337    if (sample_count > 1) {
 338       return FALSE;
 339    }
 340
 341    svga_format = svga_translate_format(ss, format, tex_usage);
 342    if (svga_format == SVGA3D_FORMAT_INVALID) {
 343       return FALSE;
 344    }
 345
 346    /*
 347     * Override host capabilities, so that we end up with the same
 348     * visuals for all virtual hardware implementations.
 349     */
 350
 351    if (tex_usage & PIPE_BIND_DISPLAY_TARGET) {
 352       switch (svga_format) {
 353       case SVGA3D_A8R8G8B8:
 354       case SVGA3D_X8R8G8B8:
 355       case SVGA3D_R5G6B5:
 356          break;
 357
 358       /* Often unsupported/problematic. This means we end up with the same
 359        * visuals for all virtual hardware implementations.
 360        */
 361       case SVGA3D_A4R4G4B4:
 362       case SVGA3D_A1R5G5B5:
 363          return FALSE;
 364
 365       default:
 366          return FALSE;
 367       }
 368    }
 369
 370    /*
 371     * Query the host capabilities.
 372     */
 373
 374    svga_get_format_cap(ss, svga_format, &caps);
 375
 376    mask.value = 0;
 377    if (tex_usage & PIPE_BIND_RENDER_TARGET) {
 378       mask.offscreenRenderTarget = 1;
 379    }
 380    if (tex_usage & PIPE_BIND_DEPTH_STENCIL) {
 381       mask.zStencil = 1;
 382    }
 383    if (tex_usage & PIPE_BIND_SAMPLER_VIEW) {
 384       mask.texture = 1;
 385    }
 386
 387    return (caps.value & mask.value) == mask.value;
 388 }
 389
 390
 391 static void
 392 svga_fence_reference(struct pipe_screen *screen,
 393                      struct pipe_fence_handle **ptr,
 394                      struct pipe_fence_handle *fence)
 395 {
 396    struct svga_winsys_screen *sws = svga_screen(screen)->sws;
 397    sws->fence_reference(sws, ptr, fence);
 398 }
 399
 400
 401 static boolean
 402 svga_fence_signalled(struct pipe_screen *screen,
 403                      struct pipe_fence_handle *fence)
 404 {
 405    struct svga_winsys_screen *sws = svga_screen(screen)->sws;
 406    return sws->fence_signalled(sws, fence, 0) == 0;
 407 }
 408
 409
 410 static boolean
 411 svga_fence_finish(struct pipe_screen *screen,
 412                   struct pipe_fence_handle *fence,
 413                   uint64_t timeout)
 414 {
 415    struct svga_winsys_screen *sws = svga_screen(screen)->sws;
 416
 417    SVGA_DBG(DEBUG_DMA|DEBUG_PERF, "%s fence_ptr %p\n",
 418             __FUNCTION__, fence);
 419
 420    return sws->fence_finish(sws, fence, 0) == 0;
 421 }
 422
 423
 424 static void
 425 svga_destroy_screen( struct pipe_screen *screen )
 426 {
 427    struct svga_screen *svgascreen = svga_screen(screen);
 428
 429    svga_screen_cache_cleanup(svgascreen);
 430
 431    pipe_mutex_destroy(svgascreen->swc_mutex);
 432    pipe_mutex_destroy(svgascreen->tex_mutex);
 433
 434    svgascreen->sws->destroy(svgascreen->sws);
 435
 436    FREE(svgascreen);
 437 }
 438
 439
 440 /**
 441  * Create a new svga_screen object
 442  */
 443 struct pipe_screen *
 444 svga_screen_create(struct svga_winsys_screen *sws)
 445 {
 446    struct svga_screen *svgascreen;
 447    struct pipe_screen *screen;
 448    SVGA3dDevCapResult result;
 449    boolean use_vs30, use_ps30;
 450
 451 #ifdef DEBUG
 452    SVGA_DEBUG = debug_get_flags_option("SVGA_DEBUG", svga_debug_flags, 0 );
 453 #endif
 454
 455    svgascreen = CALLOC_STRUCT(svga_screen);
 456    if (!svgascreen)
 457       goto error1;
 458
 459    svgascreen->debug.force_level_surface_view =
 460       debug_get_bool_option("SVGA_FORCE_LEVEL_SURFACE_VIEW", FALSE);
 461    svgascreen->debug.force_surface_view =
 462       debug_get_bool_option("SVGA_FORCE_SURFACE_VIEW", FALSE);
 463    svgascreen->debug.force_sampler_view =
 464       debug_get_bool_option("SVGA_FORCE_SAMPLER_VIEW", FALSE);
 465    svgascreen->debug.no_surface_view =
 466       debug_get_bool_option("SVGA_NO_SURFACE_VIEW", FALSE);
 467    svgascreen->debug.no_sampler_view =
 468       debug_get_bool_option("SVGA_NO_SAMPLER_VIEW", FALSE);
 469
 470    screen = &svgascreen->screen;
 471
 472    screen->destroy = svga_destroy_screen;
 473    screen->get_name = svga_get_name;
 474    screen->get_vendor = svga_get_vendor;
 475    screen->get_param = svga_get_param;
 476    screen->get_shader_param = svga_get_shader_param;
 477    screen->get_paramf = svga_get_paramf;
 478    screen->is_format_supported = svga_is_format_supported;
 479    screen->context_create = svga_context_create;
 480    screen->fence_reference = svga_fence_reference;
 481    screen->fence_signalled = svga_fence_signalled;
 482    screen->fence_finish = svga_fence_finish;
 483    svgascreen->sws = sws;
 484
 485    svga_init_screen_resource_functions(svgascreen);
 486
 487    if (sws->get_hw_version) {
 488       svgascreen->hw_version = sws->get_hw_version(sws);
 489    } else {
 490       svgascreen->hw_version = SVGA3D_HWVERSION_WS65_B1;
 491    }
 492
 493    use_ps30 =
 494       sws->get_cap(sws, SVGA3D_DEVCAP_FRAGMENT_SHADER_VERSION, &result) &&
 495       result.u >= SVGA3DPSVERSION_30 ? TRUE : FALSE;
 496
 497    use_vs30 =
 498       sws->get_cap(sws, SVGA3D_DEVCAP_VERTEX_SHADER_VERSION, &result) &&
 499       result.u >= SVGA3DVSVERSION_30 ? TRUE : FALSE;
 500
 501    /* we require Shader model 3.0 or later */
 502    if (!use_ps30 || !use_vs30)
 503       goto error2;
 504
 505    /*
 506     * The D16, D24X8, and D24S8 formats always do an implicit shadow compare
 507     * when sampled from, where as the DF16, DF24, and D24S8_INT do not.  So
 508     * we prefer the later when available.
 509     *
 510     * This mimics hardware vendors extensions for D3D depth sampling. See also
 511     * http://aras-p.info/texts/D3D9GPUHacks.html
 512     */
 513
 514    {
 515       boolean has_df16, has_df24, has_d24s8_int;
 516       SVGA3dSurfaceFormatCaps caps;
 517       SVGA3dSurfaceFormatCaps mask;
 518       mask.value = 0;
 519       mask.zStencil = 1;
 520       mask.texture = 1;
 521
 522       svgascreen->depth.z16 = SVGA3D_Z_D16;
 523       svgascreen->depth.x8z24 = SVGA3D_Z_D24X8;
 524       svgascreen->depth.s8z24 = SVGA3D_Z_D24S8;
 525
 526       svga_get_format_cap(svgascreen, SVGA3D_Z_DF16, &caps);
 527       has_df16 = (caps.value & mask.value) == mask.value;
 528
 529       svga_get_format_cap(svgascreen, SVGA3D_Z_DF24, &caps);
 530       has_df24 = (caps.value & mask.value) == mask.value;
 531
 532       svga_get_format_cap(svgascreen, SVGA3D_Z_D24S8_INT, &caps);
 533       has_d24s8_int = (caps.value & mask.value) == mask.value;
 534
 535       /* XXX: We might want some other logic here.
 536        * Like if we only have d24s8_int we should
 537        * emulate the other formats with that.
 538        */
 539       if (has_df16) {
 540          svgascreen->depth.z16 = SVGA3D_Z_DF16;
 541       }
 542       if (has_df24) {
 543          svgascreen->depth.x8z24 = SVGA3D_Z_DF24;
 544       }
 545       if (has_d24s8_int) {
 546          svgascreen->depth.s8z24 = SVGA3D_Z_D24S8_INT;
 547       }
 548    }
 549
 550    if (!sws->get_cap(sws, SVGA3D_DEVCAP_MAX_POINT_SIZE, &result)) {
 551       svgascreen->maxPointSize = 1.0F;
 552    } else {
 553       /* Keep this to a reasonable size to avoid failures in
 554        * conform/pntaa.c:
 555        */
 556       svgascreen->maxPointSize = MIN2(result.f, 80.0f);
 557    }
 558
 559    pipe_mutex_init(svgascreen->tex_mutex);
 560    pipe_mutex_init(svgascreen->swc_mutex);
 561
 562    svga_screen_cache_init(svgascreen);
 563
 564    return screen;
 565 error2:
 566    FREE(svgascreen);
 567 error1:
 568    return NULL;
 569 }
 570
 571 struct svga_winsys_screen *
 572 svga_winsys_screen(struct pipe_screen *screen)
 573 {
 574    return svga_screen(screen)->sws;
 575 }
 576
 577 #ifdef DEBUG
 578 struct svga_screen *
 579 svga_screen(struct pipe_screen *screen)
 580 {
 581    assert(screen);
 582    assert(screen->destroy == svga_destroy_screen);
 583    return (struct svga_screen *)screen;
 584 }
 585 #endif