src/gallium/drivers/svga/svga_resource_buffer_upload.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 "svga_cmd.h"
  27
  28 #include "pipe/p_state.h"
  29 #include "pipe/p_defines.h"
  30 #include "util/u_inlines.h"
  31 #include "os/os_thread.h"
  32 #include "util/u_math.h"
  33 #include "util/u_memory.h"
  34
  35 #include "svga_context.h"
  36 #include "svga_screen.h"
  37 #include "svga_resource_buffer.h"
  38 #include "svga_resource_buffer_upload.h"
  39 #include "svga_winsys.h"
  40 #include "svga_debug.h"
  41
  42
  43 #define MAX_DMA_SIZE (4 * 1024 * 1024)
  44
  45
  46 /**
  47  * Allocate a winsys_buffer (ie. DMA, aka GMR memory).
  48  *
  49  * It will flush and retry in case the first attempt to create a DMA buffer
  50  * fails, so it should not be called from any function involved in flushing
  51  * to avoid recursion.
  52  */
  53 struct svga_winsys_buffer *
  54 svga_winsys_buffer_create( struct svga_context *svga,
  55                            unsigned alignment,
  56                            unsigned usage,
  57                            unsigned size )
  58 {
  59    struct svga_screen *svgascreen = svga_screen(svga->pipe.screen);
  60    struct svga_winsys_screen *sws = svgascreen->sws;
  61    struct svga_winsys_buffer *buf;
  62
  63    /* XXX this shouldn't be a hard-coded number; it should be queried
  64     * somehow.
  65     */
  66    if (size > MAX_DMA_SIZE) {
  67       return NULL;
  68    }
  69
  70    /* Just try */
  71    buf = sws->buffer_create(sws, alignment, usage, size);
  72    if(!buf) {
  73
  74       SVGA_DBG(DEBUG_DMA|DEBUG_PERF, "flushing screen to find %d bytes GMR\n",
  75                size);
  76
  77       /* Try flushing all pending DMAs */
  78       svga_context_flush(svga, NULL);
  79       buf = sws->buffer_create(sws, alignment, usage, size);
  80    }
  81
  82    return buf;
  83 }
  84
  85
  86 void
  87 svga_buffer_destroy_hw_storage(struct svga_screen *ss, struct svga_buffer *sbuf)
  88 {
  89    struct svga_winsys_screen *sws = ss->sws;
  90
  91    assert(!sbuf->map.count);
  92    assert(sbuf->hwbuf);
  93    if(sbuf->hwbuf) {
  94       sws->buffer_destroy(sws, sbuf->hwbuf);
  95       sbuf->hwbuf = NULL;
  96    }
  97 }
  98
  99
 100
 101 /**
 102  * Allocate DMA'ble storage for the buffer.
 103  *
 104  * Called before mapping a buffer.
 105  */
 106 enum pipe_error
 107 svga_buffer_create_hw_storage(struct svga_screen *ss,
 108                               struct svga_buffer *sbuf)
 109 {
 110    assert(!sbuf->user);
 111
 112    if(!sbuf->hwbuf) {
 113       struct svga_winsys_screen *sws = ss->sws;
 114       unsigned alignment = 16;
 115       unsigned usage = 0;
 116       unsigned size = sbuf->b.b.width0;
 117
 118       sbuf->hwbuf = sws->buffer_create(sws, alignment, usage, size);
 119       if(!sbuf->hwbuf)
 120          return PIPE_ERROR_OUT_OF_MEMORY;
 121
 122       assert(!sbuf->dma.pending);
 123    }
 124
 125    return PIPE_OK;
 126 }
 127
 128
 129
 130 enum pipe_error
 131 svga_buffer_create_host_surface(struct svga_screen *ss,
 132                                 struct svga_buffer *sbuf)
 133 {
 134    assert(!sbuf->user);
 135
 136    if(!sbuf->handle) {
 137       sbuf->key.flags = 0;
 138
 139       sbuf->key.format = SVGA3D_BUFFER;
 140       if(sbuf->b.b.bind & PIPE_BIND_VERTEX_BUFFER)
 141          sbuf->key.flags |= SVGA3D_SURFACE_HINT_VERTEXBUFFER;
 142       if(sbuf->b.b.bind & PIPE_BIND_INDEX_BUFFER)
 143          sbuf->key.flags |= SVGA3D_SURFACE_HINT_INDEXBUFFER;
 144
 145       sbuf->key.size.width = sbuf->b.b.width0;
 146       sbuf->key.size.height = 1;
 147       sbuf->key.size.depth = 1;
 148
 149       sbuf->key.numFaces = 1;
 150       sbuf->key.numMipLevels = 1;
 151       sbuf->key.cachable = 1;
 152
 153       SVGA_DBG(DEBUG_DMA, "surface_create for buffer sz %d\n", sbuf->b.b.width0);
 154
 155       sbuf->handle = svga_screen_surface_create(ss, &sbuf->key);
 156       if(!sbuf->handle)
 157          return PIPE_ERROR_OUT_OF_MEMORY;
 158
 159       /* Always set the discard flag on the first time the buffer is written
 160        * as svga_screen_surface_create might have passed a recycled host
 161        * buffer.
 162        */
 163       sbuf->dma.flags.discard = TRUE;
 164
 165       SVGA_DBG(DEBUG_DMA, "   --> got sid %p sz %d (buffer)\n", sbuf->handle, sbuf->b.b.width0);
 166    }
 167
 168    return PIPE_OK;
 169 }
 170
 171
 172 void
 173 svga_buffer_destroy_host_surface(struct svga_screen *ss,
 174                                  struct svga_buffer *sbuf)
 175 {
 176    if(sbuf->handle) {
 177       SVGA_DBG(DEBUG_DMA, " ungrab sid %p sz %d\n", sbuf->handle, sbuf->b.b.width0);
 178       svga_screen_surface_destroy(ss, &sbuf->key, &sbuf->handle);
 179    }
 180 }
 181
 182
 183 /**
 184  * Variant of SVGA3D_BufferDMA which leaves the copy box temporarily in blank.
 185  */
 186 static enum pipe_error
 187 svga_buffer_upload_command(struct svga_context *svga,
 188                            struct svga_buffer *sbuf)
 189 {
 190    struct svga_winsys_context *swc = svga->swc;
 191    struct svga_winsys_buffer *guest = sbuf->hwbuf;
 192    struct svga_winsys_surface *host = sbuf->handle;
 193    SVGA3dTransferType transfer = SVGA3D_WRITE_HOST_VRAM;
 194    SVGA3dCmdSurfaceDMA *cmd;
 195    uint32 numBoxes = sbuf->map.num_ranges;
 196    SVGA3dCopyBox *boxes;
 197    SVGA3dCmdSurfaceDMASuffix *pSuffix;
 198    unsigned region_flags;
 199    unsigned surface_flags;
 200    struct pipe_resource *dummy;
 201
 202    if(transfer == SVGA3D_WRITE_HOST_VRAM) {
 203       region_flags = SVGA_RELOC_READ;
 204       surface_flags = SVGA_RELOC_WRITE;
 205    }
 206    else if(transfer == SVGA3D_READ_HOST_VRAM) {
 207       region_flags = SVGA_RELOC_WRITE;
 208       surface_flags = SVGA_RELOC_READ;
 209    }
 210    else {
 211       assert(0);
 212       return PIPE_ERROR_BAD_INPUT;
 213    }
 214
 215    assert(numBoxes);
 216
 217    cmd = SVGA3D_FIFOReserve(swc,
 218                             SVGA_3D_CMD_SURFACE_DMA,
 219                             sizeof *cmd + numBoxes * sizeof *boxes + sizeof *pSuffix,
 220                             2);
 221    if(!cmd)
 222       return PIPE_ERROR_OUT_OF_MEMORY;
 223
 224    swc->region_relocation(swc, &cmd->guest.ptr, guest, 0, region_flags);
 225    cmd->guest.pitch = 0;
 226
 227    swc->surface_relocation(swc, &cmd->host.sid, host, surface_flags);
 228    cmd->host.face = 0;
 229    cmd->host.mipmap = 0;
 230
 231    cmd->transfer = transfer;
 232
 233    sbuf->dma.boxes = (SVGA3dCopyBox *)&cmd[1];
 234    sbuf->dma.svga = svga;
 235
 236    /* Increment reference count */
 237    dummy = NULL;
 238    pipe_resource_reference(&dummy, &sbuf->b.b);
 239
 240    pSuffix = (SVGA3dCmdSurfaceDMASuffix *)((uint8_t*)cmd + sizeof *cmd + numBoxes * sizeof *boxes);
 241    pSuffix->suffixSize = sizeof *pSuffix;
 242    pSuffix->maximumOffset = sbuf->b.b.width0;
 243    pSuffix->flags = sbuf->dma.flags;
 244
 245    SVGA_FIFOCommitAll(swc);
 246
 247    sbuf->dma.flags.discard = FALSE;
 248
 249    return PIPE_OK;
 250 }
 251
 252
 253 /**
 254  * Patch up the upload DMA command reserved by svga_buffer_upload_command
 255  * with the final ranges.
 256  */
 257 void
 258 svga_buffer_upload_flush(struct svga_context *svga,
 259                          struct svga_buffer *sbuf)
 260 {
 261    SVGA3dCopyBox *boxes;
 262    unsigned i;
 263    struct pipe_resource *dummy;
 264
 265    if (!sbuf->dma.pending) {
 266       return;
 267    }
 268
 269    assert(sbuf->handle);
 270    assert(sbuf->hwbuf);
 271    assert(sbuf->map.num_ranges);
 272    assert(sbuf->dma.svga == svga);
 273    assert(sbuf->dma.boxes);
 274
 275    /*
 276     * Patch the DMA command with the final copy box.
 277     */
 278
 279    SVGA_DBG(DEBUG_DMA, "dma to sid %p\n", sbuf->handle);
 280
 281    boxes = sbuf->dma.boxes;
 282    for(i = 0; i < sbuf->map.num_ranges; ++i) {
 283       SVGA_DBG(DEBUG_DMA, "  bytes %u - %u\n",
 284                sbuf->map.ranges[i].start, sbuf->map.ranges[i].end);
 285
 286       boxes[i].x = sbuf->map.ranges[i].start;
 287       boxes[i].y = 0;
 288       boxes[i].z = 0;
 289       boxes[i].w = sbuf->map.ranges[i].end - sbuf->map.ranges[i].start;
 290       boxes[i].h = 1;
 291       boxes[i].d = 1;
 292       boxes[i].srcx = sbuf->map.ranges[i].start;
 293       boxes[i].srcy = 0;
 294       boxes[i].srcz = 0;
 295    }
 296
 297    sbuf->map.num_ranges = 0;
 298
 299    assert(sbuf->head.prev && sbuf->head.next);
 300    LIST_DEL(&sbuf->head);
 301 #ifdef DEBUG
 302    sbuf->head.next = sbuf->head.prev = NULL;
 303 #endif
 304    sbuf->dma.pending = FALSE;
 305    sbuf->dma.flags.discard = FALSE;
 306    sbuf->dma.flags.unsynchronized = FALSE;
 307
 308    sbuf->dma.svga = NULL;
 309    sbuf->dma.boxes = NULL;
 310
 311    /* Decrement reference count (and potentially destroy) */
 312    dummy = &sbuf->b.b;
 313    pipe_resource_reference(&dummy, NULL);
 314 }
 315
 316
 317 /**
 318  * Note a dirty range.
 319  *
 320  * This function only notes the range down. It doesn't actually emit a DMA
 321  * upload command. That only happens when a context tries to refer to this
 322  * buffer, and the DMA upload command is added to that context's command buffer.
 323  *
 324  * We try to lump as many contiguous DMA transfers together as possible.
 325  */
 326 void
 327 svga_buffer_add_range(struct svga_buffer *sbuf,
 328                       unsigned start,
 329                       unsigned end)
 330 {
 331    unsigned i;
 332    unsigned nearest_range;
 333    unsigned nearest_dist;
 334
 335    assert(end > start);
 336
 337    if (sbuf->map.num_ranges < SVGA_BUFFER_MAX_RANGES) {
 338       nearest_range = sbuf->map.num_ranges;
 339       nearest_dist = ~0;
 340    } else {
 341       nearest_range = SVGA_BUFFER_MAX_RANGES - 1;
 342       nearest_dist = 0;
 343    }
 344
 345    /*
 346     * Try to grow one of the ranges.
 347     */
 348
 349    for(i = 0; i < sbuf->map.num_ranges; ++i) {
 350       int left_dist;
 351       int right_dist;
 352       int dist;
 353
 354       left_dist = start - sbuf->map.ranges[i].end;
 355       right_dist = sbuf->map.ranges[i].start - end;
 356       dist = MAX2(left_dist, right_dist);
 357
 358       if (dist <= 0) {
 359          /*
 360           * Ranges are contiguous or overlapping -- extend this one and return.
 361           *
 362           * Note that it is not this function's task to prevent overlapping
 363           * ranges, as the GMR was already given so it is too late to do
 364           * anything.  If the ranges overlap here it must surely be because
 365           * PIPE_TRANSFER_UNSYNCHRONIZED was set.
 366           */
 367
 368          sbuf->map.ranges[i].start = MIN2(sbuf->map.ranges[i].start, start);
 369          sbuf->map.ranges[i].end   = MAX2(sbuf->map.ranges[i].end,   end);
 370          return;
 371       }
 372       else {
 373          /*
 374           * Discontiguous ranges -- keep track of the nearest range.
 375           */
 376
 377          if (dist < nearest_dist) {
 378             nearest_range = i;
 379             nearest_dist = dist;
 380          }
 381       }
 382    }
 383
 384    /*
 385     * We cannot add a new range to an existing DMA command, so patch-up the
 386     * pending DMA upload and start clean.
 387     */
 388
 389    svga_buffer_upload_flush(sbuf->dma.svga, sbuf);
 390
 391    assert(!sbuf->dma.pending);
 392    assert(!sbuf->dma.svga);
 393    assert(!sbuf->dma.boxes);
 394
 395    if (sbuf->map.num_ranges < SVGA_BUFFER_MAX_RANGES) {
 396       /*
 397        * Add a new range.
 398        */
 399
 400       sbuf->map.ranges[sbuf->map.num_ranges].start = start;
 401       sbuf->map.ranges[sbuf->map.num_ranges].end = end;
 402       ++sbuf->map.num_ranges;
 403    } else {
 404       /*
 405        * Everything else failed, so just extend the nearest range.
 406        *
 407        * It is OK to do this because we always keep a local copy of the
 408        * host buffer data, for SW TNL, and the host never modifies the buffer.
 409        */
 410
 411       assert(nearest_range < SVGA_BUFFER_MAX_RANGES);
 412       assert(nearest_range < sbuf->map.num_ranges);
 413       sbuf->map.ranges[nearest_range].start = MIN2(sbuf->map.ranges[nearest_range].start, start);
 414       sbuf->map.ranges[nearest_range].end   = MAX2(sbuf->map.ranges[nearest_range].end,   end);
 415    }
 416 }
 417
 418
 419
 420 /**
 421  * Copy the contents of the malloc buffer to a hardware buffer.
 422  */
 423 static INLINE enum pipe_error
 424 svga_buffer_update_hw(struct svga_screen *ss, struct svga_buffer *sbuf)
 425 {
 426    assert(!sbuf->user);
 427    if(!sbuf->hwbuf) {
 428       enum pipe_error ret;
 429       void *map;
 430
 431       assert(sbuf->swbuf);
 432       if(!sbuf->swbuf)
 433          return PIPE_ERROR;
 434
 435       ret = svga_buffer_create_hw_storage(ss, sbuf);
 436       if(ret != PIPE_OK)
 437          return ret;
 438
 439       pipe_mutex_lock(ss->swc_mutex);
 440       map = ss->sws->buffer_map(ss->sws, sbuf->hwbuf, PIPE_TRANSFER_WRITE);
 441       assert(map);
 442       if(!map) {
 443          pipe_mutex_unlock(ss->swc_mutex);
 444          svga_buffer_destroy_hw_storage(ss, sbuf);
 445          return PIPE_ERROR;
 446       }
 447
 448       memcpy(map, sbuf->swbuf, sbuf->b.b.width0);
 449       ss->sws->buffer_unmap(ss->sws, sbuf->hwbuf);
 450
 451       /* This user/malloc buffer is now indistinguishable from a gpu buffer */
 452       assert(!sbuf->map.count);
 453       if(!sbuf->map.count) {
 454          if(sbuf->user)
 455             sbuf->user = FALSE;
 456          else
 457             align_free(sbuf->swbuf);
 458          sbuf->swbuf = NULL;
 459       }
 460
 461       pipe_mutex_unlock(ss->swc_mutex);
 462    }
 463
 464    return PIPE_OK;
 465 }
 466
 467
 468 /**
 469  * Upload the buffer to the host in a piecewise fashion.
 470  *
 471  * Used when the buffer is too big to fit in the GMR aperture.
 472  */
 473 static INLINE enum pipe_error
 474 svga_buffer_upload_piecewise(struct svga_screen *ss,
 475                              struct svga_context *svga,
 476                              struct svga_buffer *sbuf)
 477 {
 478    struct svga_winsys_screen *sws = ss->sws;
 479    const unsigned alignment = sizeof(void *);
 480    const unsigned usage = 0;
 481    unsigned i;
 482
 483    assert(sbuf->map.num_ranges);
 484    assert(!sbuf->dma.pending);
 485
 486    SVGA_DBG(DEBUG_DMA, "dma to sid %p\n", sbuf->handle);
 487
 488    for (i = 0; i < sbuf->map.num_ranges; ++i) {
 489       struct svga_buffer_range *range = &sbuf->map.ranges[i];
 490       unsigned offset = range->start;
 491       unsigned size = range->end - range->start;
 492
 493       while (offset < range->end) {
 494          struct svga_winsys_buffer *hwbuf;
 495          uint8_t *map;
 496          enum pipe_error ret;
 497
 498          if (offset + size > range->end)
 499             size = range->end - offset;
 500
 501          hwbuf = sws->buffer_create(sws, alignment, usage, size);
 502          while (!hwbuf) {
 503             size /= 2;
 504             if (!size)
 505                return PIPE_ERROR_OUT_OF_MEMORY;
 506             hwbuf = sws->buffer_create(sws, alignment, usage, size);
 507          }
 508
 509          SVGA_DBG(DEBUG_DMA, "  bytes %u - %u\n",
 510                   offset, offset + size);
 511
 512          map = sws->buffer_map(sws, hwbuf,
 513                                PIPE_TRANSFER_WRITE |
 514                                PIPE_TRANSFER_DISCARD);
 515          assert(map);
 516          if (map) {
 517             memcpy(map, sbuf->swbuf, size);
 518             sws->buffer_unmap(sws, hwbuf);
 519          }
 520
 521          ret = SVGA3D_BufferDMA(svga->swc,
 522                                 hwbuf, sbuf->handle,
 523                                 SVGA3D_WRITE_HOST_VRAM,
 524                                 size, 0, offset, sbuf->dma.flags);
 525          if(ret != PIPE_OK) {
 526             svga_context_flush(svga, NULL);
 527             ret =  SVGA3D_BufferDMA(svga->swc,
 528                                     hwbuf, sbuf->handle,
 529                                     SVGA3D_WRITE_HOST_VRAM,
 530                                     size, 0, offset, sbuf->dma.flags);
 531             assert(ret == PIPE_OK);
 532          }
 533
 534          sbuf->dma.flags.discard = FALSE;
 535
 536          sws->buffer_destroy(sws, hwbuf);
 537
 538          offset += size;
 539       }
 540    }
 541
 542    sbuf->map.num_ranges = 0;
 543
 544    return PIPE_OK;
 545 }
 546
 547
 548
 549
 550 /* Get (or create/upload) the winsys surface handle so that we can
 551  * refer to this buffer in fifo commands.
 552  */
 553 struct svga_winsys_surface *
 554 svga_buffer_handle(struct svga_context *svga,
 555                    struct pipe_resource *buf)
 556 {
 557    struct pipe_screen *screen = svga->pipe.screen;
 558    struct svga_screen *ss = svga_screen(screen);
 559    struct svga_buffer *sbuf;
 560    enum pipe_error ret;
 561
 562    if(!buf)
 563       return NULL;
 564
 565    sbuf = svga_buffer(buf);
 566
 567    assert(!sbuf->map.count);
 568    assert(!sbuf->user);
 569
 570    if(!sbuf->handle) {
 571       ret = svga_buffer_create_host_surface(ss, sbuf);
 572       if(ret != PIPE_OK)
 573          return NULL;
 574    }
 575
 576    assert(sbuf->handle);
 577
 578    if (sbuf->map.num_ranges) {
 579       if (!sbuf->dma.pending) {
 580          /*
 581           * No pending DMA upload yet, so insert a DMA upload command now.
 582           */
 583
 584          /*
 585           * Migrate the data from swbuf -> hwbuf if necessary.
 586           */
 587          ret = svga_buffer_update_hw(ss, sbuf);
 588          if (ret == PIPE_OK) {
 589             /*
 590              * Queue a dma command.
 591              */
 592
 593             ret = svga_buffer_upload_command(svga, sbuf);
 594             if (ret == PIPE_ERROR_OUT_OF_MEMORY) {
 595                svga_context_flush(svga, NULL);
 596                ret = svga_buffer_upload_command(svga, sbuf);
 597                assert(ret == PIPE_OK);
 598             }
 599             if (ret == PIPE_OK) {
 600                sbuf->dma.pending = TRUE;
 601                assert(!sbuf->head.prev && !sbuf->head.next);
 602                LIST_ADDTAIL(&sbuf->head, &svga->dirty_buffers);
 603             }
 604          }
 605          else if (ret == PIPE_ERROR_OUT_OF_MEMORY) {
 606             /*
 607              * The buffer is too big to fit in the GMR aperture, so break it in
 608              * smaller pieces.
 609              */
 610             ret = svga_buffer_upload_piecewise(ss, svga, sbuf);
 611          }
 612
 613          if (ret != PIPE_OK) {
 614             /*
 615              * Something unexpected happened above. There is very little that
 616              * we can do other than proceeding while ignoring the dirty ranges.
 617              */
 618             assert(0);
 619             sbuf->map.num_ranges = 0;
 620          }
 621       }
 622       else {
 623          /*
 624           * There a pending dma already. Make sure it is from this context.
 625           */
 626          assert(sbuf->dma.svga == svga);
 627       }
 628    }
 629
 630    assert(!sbuf->map.num_ranges || sbuf->dma.pending);
 631
 632    return sbuf->handle;
 633 }
 634
 635
 636
 637 void
 638 svga_context_flush_buffers(struct svga_context *svga)
 639 {
 640    struct list_head *curr, *next;
 641    struct svga_buffer *sbuf;
 642
 643    curr = svga->dirty_buffers.next;
 644    next = curr->next;
 645    while(curr != &svga->dirty_buffers) {
 646       sbuf = LIST_ENTRY(struct svga_buffer, curr, head);
 647
 648       assert(p_atomic_read(&sbuf->b.b.reference.count) != 0);
 649       assert(sbuf->dma.pending);
 650
 651       svga_buffer_upload_flush(svga, sbuf);
 652
 653       curr = next;
 654       next = curr->next;
 655    }
 656 }
 657
 658
 659 void
 660 svga_redefine_user_buffer(struct pipe_context *pipe,
 661                           struct pipe_resource *resource,
 662                           unsigned offset,
 663                           unsigned size)
 664 {
 665    struct svga_screen *ss = svga_screen(pipe->screen);
 666    struct svga_context *svga = svga_context(pipe);
 667    struct svga_buffer *sbuf = svga_buffer(resource);
 668
 669    assert(sbuf->user);
 670    assert(!sbuf->dma.pending);
 671    assert(!sbuf->handle);
 672    assert(!sbuf->hwbuf);
 673
 674    /*
 675     * Release any uploaded user buffer.
 676     *
 677     * TODO: As an optimization, we could try to update the uploaded buffer
 678     * instead.
 679     */
 680
 681    pipe_resource_reference(&sbuf->uploaded.buffer, NULL);
 682
 683    pipe_mutex_lock(ss->swc_mutex);
 684
 685    sbuf->key.size.width = sbuf->b.b.width0 = offset + size;
 686
 687    pipe_mutex_unlock(ss->swc_mutex);
 688
 689    svga->curr.any_user_vertex_buffers = TRUE;
 690    svga->dirty |= SVGA_NEW_VBUFFER | SVGA_NEW_VELEMENT;
 691 }