drivers/gpu/drm/qxl/qxl_cmd.c

   1 /*
   2  * Copyright 2013 Red Hat Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20  * OTHER DEALINGS IN THE SOFTWARE.
  21  *
  22  * Authors: Dave Airlie
  23  *          Alon Levy
  24  */
  25
  26 /* QXL cmd/ring handling */
  27
  28 #include <drm/drm_util.h>
  29
  30 #include "qxl_drv.h"
  31 #include "qxl_object.h"
  32
  33 static int qxl_reap_surface_id(struct qxl_device *qdev, int max_to_reap);
  34
  35 struct ring {
  36         struct qxl_ring_header      header;
  37         uint8_t                     elements[0];
  38 };
  39
  40 struct qxl_ring {
  41         struct ring            *ring;
  42         int                     element_size;
  43         int                     n_elements;
  44         int                     prod_notify;
  45         wait_queue_head_t      *push_event;
  46         spinlock_t             lock;
  47 };
  48
  49 void qxl_ring_free(struct qxl_ring *ring)
  50 {
  51         kfree(ring);
  52 }
  53
  54 void qxl_ring_init_hdr(struct qxl_ring *ring)
  55 {
  56         ring->ring->header.notify_on_prod = ring->n_elements;
  57 }
  58
  59 struct qxl_ring *
  60 qxl_ring_create(struct qxl_ring_header *header,
  61                 int element_size,
  62                 int n_elements,
  63                 int prod_notify,
  64                 bool set_prod_notify,
  65                 wait_queue_head_t *push_event)
  66 {
  67         struct qxl_ring *ring;
  68
  69         ring = kmalloc(sizeof(*ring), GFP_KERNEL);
  70         if (!ring)
  71                 return NULL;
  72
  73         ring->ring = (struct ring *)header;
  74         ring->element_size = element_size;
  75         ring->n_elements = n_elements;
  76         ring->prod_notify = prod_notify;
  77         ring->push_event = push_event;
  78         if (set_prod_notify)
  79                 qxl_ring_init_hdr(ring);
  80         spin_lock_init(&ring->lock);
  81         return ring;
  82 }
  83
  84 static int qxl_check_header(struct qxl_ring *ring)
  85 {
  86         int ret;
  87         struct qxl_ring_header *header = &(ring->ring->header);
  88         unsigned long flags;
  89
  90         spin_lock_irqsave(&ring->lock, flags);
  91         ret = header->prod - header->cons < header->num_items;
  92         if (ret == 0)
  93                 header->notify_on_cons = header->cons + 1;
  94         spin_unlock_irqrestore(&ring->lock, flags);
  95         return ret;
  96 }
  97
  98 int qxl_check_idle(struct qxl_ring *ring)
  99 {
 100         int ret;
 101         struct qxl_ring_header *header = &(ring->ring->header);
 102         unsigned long flags;
 103
 104         spin_lock_irqsave(&ring->lock, flags);
 105         ret = header->prod == header->cons;
 106         spin_unlock_irqrestore(&ring->lock, flags);
 107         return ret;
 108 }
 109
 110 int qxl_ring_push(struct qxl_ring *ring,
 111                   const void *new_elt, bool interruptible)
 112 {
 113         struct qxl_ring_header *header = &(ring->ring->header);
 114         uint8_t *elt;
 115         int idx, ret;
 116         unsigned long flags;
 117
 118         spin_lock_irqsave(&ring->lock, flags);
 119         if (header->prod - header->cons == header->num_items) {
 120                 header->notify_on_cons = header->cons + 1;
 121                 mb();
 122                 spin_unlock_irqrestore(&ring->lock, flags);
 123                 if (!drm_can_sleep()) {
 124                         while (!qxl_check_header(ring))
 125                                 udelay(1);
 126                 } else {
 127                         if (interruptible) {
 128                                 ret = wait_event_interruptible(*ring->push_event,
 129                                                                qxl_check_header(ring));
 130                                 if (ret)
 131                                         return ret;
 132                         } else {
 133                                 wait_event(*ring->push_event,
 134                                            qxl_check_header(ring));
 135                         }
 136
 137                 }
 138                 spin_lock_irqsave(&ring->lock, flags);
 139         }
 140
 141         idx = header->prod & (ring->n_elements - 1);
 142         elt = ring->ring->elements + idx * ring->element_size;
 143
 144         memcpy((void *)elt, new_elt, ring->element_size);
 145
 146         header->prod++;
 147
 148         mb();
 149
 150         if (header->prod == header->notify_on_prod)
 151                 outb(0, ring->prod_notify);
 152
 153         spin_unlock_irqrestore(&ring->lock, flags);
 154         return 0;
 155 }
 156
 157 static bool qxl_ring_pop(struct qxl_ring *ring,
 158                          void *element)
 159 {
 160         volatile struct qxl_ring_header *header = &(ring->ring->header);
 161         volatile uint8_t *ring_elt;
 162         int idx;
 163         unsigned long flags;
 164
 165         spin_lock_irqsave(&ring->lock, flags);
 166         if (header->cons == header->prod) {
 167                 header->notify_on_prod = header->cons + 1;
 168                 spin_unlock_irqrestore(&ring->lock, flags);
 169                 return false;
 170         }
 171
 172         idx = header->cons & (ring->n_elements - 1);
 173         ring_elt = ring->ring->elements + idx * ring->element_size;
 174
 175         memcpy(element, (void *)ring_elt, ring->element_size);
 176
 177         header->cons++;
 178
 179         spin_unlock_irqrestore(&ring->lock, flags);
 180         return true;
 181 }
 182
 183 int
 184 qxl_push_command_ring_release(struct qxl_device *qdev, struct qxl_release *release,
 185                               uint32_t type, bool interruptible)
 186 {
 187         struct qxl_command cmd;
 188
 189         cmd.type = type;
 190         cmd.data = qxl_bo_physical_address(qdev, release->release_bo, release->release_offset);
 191
 192         return qxl_ring_push(qdev->command_ring, &cmd, interruptible);
 193 }
 194
 195 int
 196 qxl_push_cursor_ring_release(struct qxl_device *qdev, struct qxl_release *release,
 197                              uint32_t type, bool interruptible)
 198 {
 199         struct qxl_command cmd;
 200
 201         cmd.type = type;
 202         cmd.data = qxl_bo_physical_address(qdev, release->release_bo, release->release_offset);
 203
 204         return qxl_ring_push(qdev->cursor_ring, &cmd, interruptible);
 205 }
 206
 207 bool qxl_queue_garbage_collect(struct qxl_device *qdev, bool flush)
 208 {
 209         if (!qxl_check_idle(qdev->release_ring)) {
 210                 schedule_work(&qdev->gc_work);
 211                 if (flush)
 212                         flush_work(&qdev->gc_work);
 213                 return true;
 214         }
 215         return false;
 216 }
 217
 218 int qxl_garbage_collect(struct qxl_device *qdev)
 219 {
 220         struct qxl_release *release;
 221         uint64_t id, next_id;
 222         int i = 0;
 223         union qxl_release_info *info;
 224
 225         while (qxl_ring_pop(qdev->release_ring, &id)) {
 226                 DRM_DEBUG_DRIVER("popped %lld\n", id);
 227                 while (id) {
 228                         release = qxl_release_from_id_locked(qdev, id);
 229                         if (release == NULL)
 230                                 break;
 231
 232                         info = qxl_release_map(qdev, release);
 233                         next_id = info->next;
 234                         qxl_release_unmap(qdev, release, info);
 235
 236                         DRM_DEBUG_DRIVER("popped %lld, next %lld\n", id,
 237                                          next_id);
 238
 239                         switch (release->type) {
 240                         case QXL_RELEASE_DRAWABLE:
 241                         case QXL_RELEASE_SURFACE_CMD:
 242                         case QXL_RELEASE_CURSOR_CMD:
 243                                 break;
 244                         default:
 245                                 DRM_ERROR("unexpected release type\n");
 246                                 break;
 247                         }
 248                         id = next_id;
 249
 250                         qxl_release_free(qdev, release);
 251                         ++i;
 252                 }
 253         }
 254
 255         DRM_DEBUG_DRIVER("%d\n", i);
 256
 257         return i;
 258 }
 259
 260 int qxl_alloc_bo_reserved(struct qxl_device *qdev,
 261                           struct qxl_release *release,
 262                           unsigned long size,
 263                           struct qxl_bo **_bo)
 264 {
 265         struct qxl_bo *bo;
 266         int ret;
 267
 268         ret = qxl_bo_create(qdev, size, false /* not kernel - device */,
 269                             false, QXL_GEM_DOMAIN_VRAM, NULL, &bo);
 270         if (ret) {
 271                 DRM_ERROR("failed to allocate VRAM BO\n");
 272                 return ret;
 273         }
 274         ret = qxl_release_list_add(release, bo);
 275         if (ret)
 276                 goto out_unref;
 277
 278         *_bo = bo;
 279         return 0;
 280 out_unref:
 281         qxl_bo_unref(&bo);
 282         return ret;
 283 }
 284
 285 static int wait_for_io_cmd_user(struct qxl_device *qdev, uint8_t val, long port, bool intr)
 286 {
 287         int irq_num;
 288         long addr = qdev->io_base + port;
 289         int ret;
 290
 291         mutex_lock(&qdev->async_io_mutex);
 292         irq_num = atomic_read(&qdev->irq_received_io_cmd);
 293         if (qdev->last_sent_io_cmd > irq_num) {
 294                 if (intr)
 295                         ret = wait_event_interruptible_timeout(qdev->io_cmd_event,
 296                                                                atomic_read(&qdev->irq_received_io_cmd) > irq_num, 5*HZ);
 297                 else
 298                         ret = wait_event_timeout(qdev->io_cmd_event,
 299                                                  atomic_read(&qdev->irq_received_io_cmd) > irq_num, 5*HZ);
 300                 /* 0 is timeout, just bail the "hw" has gone away */
 301                 if (ret <= 0)
 302                         goto out;
 303                 irq_num = atomic_read(&qdev->irq_received_io_cmd);
 304         }
 305         outb(val, addr);
 306         qdev->last_sent_io_cmd = irq_num + 1;
 307         if (intr)
 308                 ret = wait_event_interruptible_timeout(qdev->io_cmd_event,
 309                                                        atomic_read(&qdev->irq_received_io_cmd) > irq_num, 5*HZ);
 310         else
 311                 ret = wait_event_timeout(qdev->io_cmd_event,
 312                                          atomic_read(&qdev->irq_received_io_cmd) > irq_num, 5*HZ);
 313 out:
 314         if (ret > 0)
 315                 ret = 0;
 316         mutex_unlock(&qdev->async_io_mutex);
 317         return ret;
 318 }
 319
 320 static void wait_for_io_cmd(struct qxl_device *qdev, uint8_t val, long port)
 321 {
 322         int ret;
 323
 324 restart:
 325         ret = wait_for_io_cmd_user(qdev, val, port, false);
 326         if (ret == -ERESTARTSYS)
 327                 goto restart;
 328 }
 329
 330 int qxl_io_update_area(struct qxl_device *qdev, struct qxl_bo *surf,
 331                         const struct qxl_rect *area)
 332 {
 333         int surface_id;
 334         uint32_t surface_width, surface_height;
 335         int ret;
 336
 337         if (!surf->hw_surf_alloc)
 338                 DRM_ERROR("got io update area with no hw surface\n");
 339
 340         if (surf->is_primary)
 341                 surface_id = 0;
 342         else
 343                 surface_id = surf->surface_id;
 344         surface_width = surf->surf.width;
 345         surface_height = surf->surf.height;
 346
 347         if (area->left < 0 || area->top < 0 ||
 348             area->right > surface_width || area->bottom > surface_height)
 349                 return -EINVAL;
 350
 351         mutex_lock(&qdev->update_area_mutex);
 352         qdev->ram_header->update_area = *area;
 353         qdev->ram_header->update_surface = surface_id;
 354         ret = wait_for_io_cmd_user(qdev, 0, QXL_IO_UPDATE_AREA_ASYNC, true);
 355         mutex_unlock(&qdev->update_area_mutex);
 356         return ret;
 357 }
 358
 359 void qxl_io_notify_oom(struct qxl_device *qdev)
 360 {
 361         outb(0, qdev->io_base + QXL_IO_NOTIFY_OOM);
 362 }
 363
 364 void qxl_io_flush_release(struct qxl_device *qdev)
 365 {
 366         outb(0, qdev->io_base + QXL_IO_FLUSH_RELEASE);
 367 }
 368
 369 void qxl_io_flush_surfaces(struct qxl_device *qdev)
 370 {
 371         wait_for_io_cmd(qdev, 0, QXL_IO_FLUSH_SURFACES_ASYNC);
 372 }
 373
 374 void qxl_io_destroy_primary(struct qxl_device *qdev)
 375 {
 376         wait_for_io_cmd(qdev, 0, QXL_IO_DESTROY_PRIMARY_ASYNC);
 377         qdev->primary_bo->is_primary = false;
 378         drm_gem_object_put_unlocked(&qdev->primary_bo->gem_base);
 379         qdev->primary_bo = NULL;
 380 }
 381
 382 void qxl_io_create_primary(struct qxl_device *qdev, struct qxl_bo *bo)
 383 {
 384         struct qxl_surface_create *create;
 385
 386         if (WARN_ON(qdev->primary_bo))
 387                 return;
 388
 389         DRM_DEBUG_DRIVER("qdev %p, ram_header %p\n", qdev, qdev->ram_header);
 390         create = &qdev->ram_header->create_surface;
 391         create->format = bo->surf.format;
 392         create->width = bo->surf.width;
 393         create->height = bo->surf.height;
 394         create->stride = bo->surf.stride;
 395         create->mem = qxl_bo_physical_address(qdev, bo, 0);
 396
 397         DRM_DEBUG_DRIVER("mem = %llx, from %p\n", create->mem, bo->kptr);
 398
 399         create->flags = QXL_SURF_FLAG_KEEP_DATA;
 400         create->type = QXL_SURF_TYPE_PRIMARY;
 401
 402         wait_for_io_cmd(qdev, 0, QXL_IO_CREATE_PRIMARY_ASYNC);
 403         qdev->primary_bo = bo;
 404         qdev->primary_bo->is_primary = true;
 405         drm_gem_object_get(&qdev->primary_bo->gem_base);
 406 }
 407
 408 void qxl_io_memslot_add(struct qxl_device *qdev, uint8_t id)
 409 {
 410         DRM_DEBUG_DRIVER("qxl_memslot_add %d\n", id);
 411         wait_for_io_cmd(qdev, id, QXL_IO_MEMSLOT_ADD_ASYNC);
 412 }
 413
 414 void qxl_io_reset(struct qxl_device *qdev)
 415 {
 416         outb(0, qdev->io_base + QXL_IO_RESET);
 417 }
 418
 419 void qxl_io_monitors_config(struct qxl_device *qdev)
 420 {
 421         wait_for_io_cmd(qdev, 0, QXL_IO_MONITORS_CONFIG_ASYNC);
 422 }
 423
 424 int qxl_surface_id_alloc(struct qxl_device *qdev,
 425                       struct qxl_bo *surf)
 426 {
 427         uint32_t handle;
 428         int idr_ret;
 429         int count = 0;
 430 again:
 431         idr_preload(GFP_ATOMIC);
 432         spin_lock(&qdev->surf_id_idr_lock);
 433         idr_ret = idr_alloc(&qdev->surf_id_idr, NULL, 1, 0, GFP_NOWAIT);
 434         spin_unlock(&qdev->surf_id_idr_lock);
 435         idr_preload_end();
 436         if (idr_ret < 0)
 437                 return idr_ret;
 438         handle = idr_ret;
 439
 440         if (handle >= qdev->rom->n_surfaces) {
 441                 count++;
 442                 spin_lock(&qdev->surf_id_idr_lock);
 443                 idr_remove(&qdev->surf_id_idr, handle);
 444                 spin_unlock(&qdev->surf_id_idr_lock);
 445                 qxl_reap_surface_id(qdev, 2);
 446                 goto again;
 447         }
 448         surf->surface_id = handle;
 449
 450         spin_lock(&qdev->surf_id_idr_lock);
 451         qdev->last_alloced_surf_id = handle;
 452         spin_unlock(&qdev->surf_id_idr_lock);
 453         return 0;
 454 }
 455
 456 void qxl_surface_id_dealloc(struct qxl_device *qdev,
 457                             uint32_t surface_id)
 458 {
 459         spin_lock(&qdev->surf_id_idr_lock);
 460         idr_remove(&qdev->surf_id_idr, surface_id);
 461         spin_unlock(&qdev->surf_id_idr_lock);
 462 }
 463
 464 int qxl_hw_surface_alloc(struct qxl_device *qdev,
 465                          struct qxl_bo *surf)
 466 {
 467         struct qxl_surface_cmd *cmd;
 468         struct qxl_release *release;
 469         int ret;
 470
 471         if (surf->hw_surf_alloc)
 472                 return 0;
 473
 474         ret = qxl_alloc_surface_release_reserved(qdev, QXL_SURFACE_CMD_CREATE,
 475                                                  NULL,
 476                                                  &release);
 477         if (ret)
 478                 return ret;
 479
 480         ret = qxl_release_reserve_list(release, true);
 481         if (ret)
 482                 return ret;
 483
 484         cmd = (struct qxl_surface_cmd *)qxl_release_map(qdev, release);
 485         cmd->type = QXL_SURFACE_CMD_CREATE;
 486         cmd->flags = QXL_SURF_FLAG_KEEP_DATA;
 487         cmd->u.surface_create.format = surf->surf.format;
 488         cmd->u.surface_create.width = surf->surf.width;
 489         cmd->u.surface_create.height = surf->surf.height;
 490         cmd->u.surface_create.stride = surf->surf.stride;
 491         cmd->u.surface_create.data = qxl_bo_physical_address(qdev, surf, 0);
 492         cmd->surface_id = surf->surface_id;
 493         qxl_release_unmap(qdev, release, &cmd->release_info);
 494
 495         surf->surf_create = release;
 496
 497         /* no need to add a release to the fence for this surface bo,
 498            since it is only released when we ask to destroy the surface
 499            and it would never signal otherwise */
 500         qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
 501         qxl_release_fence_buffer_objects(release);
 502
 503         surf->hw_surf_alloc = true;
 504         spin_lock(&qdev->surf_id_idr_lock);
 505         idr_replace(&qdev->surf_id_idr, surf, surf->surface_id);
 506         spin_unlock(&qdev->surf_id_idr_lock);
 507         return 0;
 508 }
 509
 510 int qxl_hw_surface_dealloc(struct qxl_device *qdev,
 511                            struct qxl_bo *surf)
 512 {
 513         struct qxl_surface_cmd *cmd;
 514         struct qxl_release *release;
 515         int ret;
 516         int id;
 517
 518         if (!surf->hw_surf_alloc)
 519                 return 0;
 520
 521         ret = qxl_alloc_surface_release_reserved(qdev, QXL_SURFACE_CMD_DESTROY,
 522                                                  surf->surf_create,
 523                                                  &release);
 524         if (ret)
 525                 return ret;
 526
 527         surf->surf_create = NULL;
 528         /* remove the surface from the idr, but not the surface id yet */
 529         spin_lock(&qdev->surf_id_idr_lock);
 530         idr_replace(&qdev->surf_id_idr, NULL, surf->surface_id);
 531         spin_unlock(&qdev->surf_id_idr_lock);
 532         surf->hw_surf_alloc = false;
 533
 534         id = surf->surface_id;
 535         surf->surface_id = 0;
 536
 537         release->surface_release_id = id;
 538         cmd = (struct qxl_surface_cmd *)qxl_release_map(qdev, release);
 539         cmd->type = QXL_SURFACE_CMD_DESTROY;
 540         cmd->surface_id = id;
 541         qxl_release_unmap(qdev, release, &cmd->release_info);
 542
 543         qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
 544
 545         qxl_release_fence_buffer_objects(release);
 546
 547         return 0;
 548 }
 549
 550 static int qxl_update_surface(struct qxl_device *qdev, struct qxl_bo *surf)
 551 {
 552         struct qxl_rect rect;
 553         int ret;
 554
 555         /* if we are evicting, we need to make sure the surface is up
 556            to date */
 557         rect.left = 0;
 558         rect.right = surf->surf.width;
 559         rect.top = 0;
 560         rect.bottom = surf->surf.height;
 561 retry:
 562         ret = qxl_io_update_area(qdev, surf, &rect);
 563         if (ret == -ERESTARTSYS)
 564                 goto retry;
 565         return ret;
 566 }
 567
 568 static void qxl_surface_evict_locked(struct qxl_device *qdev, struct qxl_bo *surf, bool do_update_area)
 569 {
 570         /* no need to update area if we are just freeing the surface normally */
 571         if (do_update_area)
 572                 qxl_update_surface(qdev, surf);
 573
 574         /* nuke the surface id at the hw */
 575         qxl_hw_surface_dealloc(qdev, surf);
 576 }
 577
 578 void qxl_surface_evict(struct qxl_device *qdev, struct qxl_bo *surf, bool do_update_area)
 579 {
 580         mutex_lock(&qdev->surf_evict_mutex);
 581         qxl_surface_evict_locked(qdev, surf, do_update_area);
 582         mutex_unlock(&qdev->surf_evict_mutex);
 583 }
 584
 585 static int qxl_reap_surf(struct qxl_device *qdev, struct qxl_bo *surf, bool stall)
 586 {
 587         int ret;
 588
 589         ret = qxl_bo_reserve(surf, false);
 590         if (ret)
 591                 return ret;
 592
 593         if (stall)
 594                 mutex_unlock(&qdev->surf_evict_mutex);
 595
 596         ret = ttm_bo_wait(&surf->tbo, true, !stall);
 597
 598         if (stall)
 599                 mutex_lock(&qdev->surf_evict_mutex);
 600         if (ret) {
 601                 qxl_bo_unreserve(surf);
 602                 return ret;
 603         }
 604
 605         qxl_surface_evict_locked(qdev, surf, true);
 606         qxl_bo_unreserve(surf);
 607         return 0;
 608 }
 609
 610 static int qxl_reap_surface_id(struct qxl_device *qdev, int max_to_reap)
 611 {
 612         int num_reaped = 0;
 613         int i, ret;
 614         bool stall = false;
 615         int start = 0;
 616
 617         mutex_lock(&qdev->surf_evict_mutex);
 618 again:
 619
 620         spin_lock(&qdev->surf_id_idr_lock);
 621         start = qdev->last_alloced_surf_id + 1;
 622         spin_unlock(&qdev->surf_id_idr_lock);
 623
 624         for (i = start; i < start + qdev->rom->n_surfaces; i++) {
 625                 void *objptr;
 626                 int surfid = i % qdev->rom->n_surfaces;
 627
 628                 /* this avoids the case where the objects is in the
 629                    idr but has been evicted half way - its makes
 630                    the idr lookup atomic with the eviction */
 631                 spin_lock(&qdev->surf_id_idr_lock);
 632                 objptr = idr_find(&qdev->surf_id_idr, surfid);
 633                 spin_unlock(&qdev->surf_id_idr_lock);
 634
 635                 if (!objptr)
 636                         continue;
 637
 638                 ret = qxl_reap_surf(qdev, objptr, stall);
 639                 if (ret == 0)
 640                         num_reaped++;
 641                 if (num_reaped >= max_to_reap)
 642                         break;
 643         }
 644         if (num_reaped == 0 && stall == false) {
 645                 stall = true;
 646                 goto again;
 647         }
 648
 649         mutex_unlock(&qdev->surf_evict_mutex);
 650         if (num_reaped) {
 651                 usleep_range(500, 1000);
 652                 qxl_queue_garbage_collect(qdev, true);
 653         }
 654
 655         return 0;
 656 }