drivers/char/drm/i915_irq.c

   1 /* i915_irq.c -- IRQ support for the I915 -*- linux-c -*-
   2  */
   3 /*
   4  * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  21  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  22  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  23  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  24  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  25  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  */
  28
  29 #include "drmP.h"
  30 #include "drm.h"
  31 #include "i915_drm.h"
  32 #include "i915_drv.h"
  33
  34 #define USER_INT_FLAG (1<<1)
  35 #define VSYNC_PIPEB_FLAG (1<<5)
  36 #define VSYNC_PIPEA_FLAG (1<<7)
  37
  38 #define MAX_NOPID ((u32)~0)
  39
  40 /**
  41  * Emit blits for scheduled buffer swaps.
  42  *
  43  * This function will be called with the HW lock held.
  44  */
  45 static void i915_vblank_tasklet(struct drm_device *dev)
  46 {
  47         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
  48         unsigned long irqflags;
  49         struct list_head *list, *tmp, hits, *hit;
  50         int nhits, nrects, slice[2], upper[2], lower[2], i;
  51         unsigned counter[2] = { atomic_read(&dev->vbl_received),
  52                                 atomic_read(&dev->vbl_received2) };
  53         struct drm_drawable_info *drw;
  54         drm_i915_sarea_t *sarea_priv = dev_priv->sarea_priv;
  55         u32 cpp = dev_priv->cpp;
  56         u32 cmd = (cpp == 4) ? (XY_SRC_COPY_BLT_CMD |
  57                                 XY_SRC_COPY_BLT_WRITE_ALPHA |
  58                                 XY_SRC_COPY_BLT_WRITE_RGB)
  59                              : XY_SRC_COPY_BLT_CMD;
  60         u32 pitchropcpp = (sarea_priv->pitch * cpp) | (0xcc << 16) |
  61                           (cpp << 23) | (1 << 24);
  62         RING_LOCALS;
  63
  64         DRM_DEBUG("\n");
  65
  66         INIT_LIST_HEAD(&hits);
  67
  68         nhits = nrects = 0;
  69
  70         spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
  71
  72         /* Find buffer swaps scheduled for this vertical blank */
  73         list_for_each_safe(list, tmp, &dev_priv->vbl_swaps.head) {
  74                 drm_i915_vbl_swap_t *vbl_swap =
  75                         list_entry(list, drm_i915_vbl_swap_t, head);
  76
  77                 if ((counter[vbl_swap->pipe] - vbl_swap->sequence) > (1<<23))
  78                         continue;
  79
  80                 list_del(list);
  81                 dev_priv->swaps_pending--;
  82
  83                 spin_unlock(&dev_priv->swaps_lock);
  84                 spin_lock(&dev->drw_lock);
  85
  86                 drw = drm_get_drawable_info(dev, vbl_swap->drw_id);
  87
  88                 if (!drw) {
  89                         spin_unlock(&dev->drw_lock);
  90                         drm_free(vbl_swap, sizeof(*vbl_swap), DRM_MEM_DRIVER);
  91                         spin_lock(&dev_priv->swaps_lock);
  92                         continue;
  93                 }
  94
  95                 list_for_each(hit, &hits) {
  96                         drm_i915_vbl_swap_t *swap_cmp =
  97                                 list_entry(hit, drm_i915_vbl_swap_t, head);
  98                         struct drm_drawable_info *drw_cmp =
  99                                 drm_get_drawable_info(dev, swap_cmp->drw_id);
 100
 101                         if (drw_cmp &&
 102                             drw_cmp->rects[0].y1 > drw->rects[0].y1) {
 103                                 list_add_tail(list, hit);
 104                                 break;
 105                         }
 106                 }
 107
 108                 spin_unlock(&dev->drw_lock);
 109
 110                 /* List of hits was empty, or we reached the end of it */
 111                 if (hit == &hits)
 112                         list_add_tail(list, hits.prev);
 113
 114                 nhits++;
 115
 116                 spin_lock(&dev_priv->swaps_lock);
 117         }
 118
 119         if (nhits == 0) {
 120                 spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
 121                 return;
 122         }
 123
 124         spin_unlock(&dev_priv->swaps_lock);
 125
 126         i915_kernel_lost_context(dev);
 127
 128         BEGIN_LP_RING(6);
 129
 130         OUT_RING(GFX_OP_DRAWRECT_INFO);
 131         OUT_RING(0);
 132         OUT_RING(0);
 133         OUT_RING(sarea_priv->width | sarea_priv->height << 16);
 134         OUT_RING(sarea_priv->width | sarea_priv->height << 16);
 135         OUT_RING(0);
 136
 137         ADVANCE_LP_RING();
 138
 139         sarea_priv->ctxOwner = DRM_KERNEL_CONTEXT;
 140
 141         upper[0] = upper[1] = 0;
 142         slice[0] = max(sarea_priv->pipeA_h / nhits, 1);
 143         slice[1] = max(sarea_priv->pipeB_h / nhits, 1);
 144         lower[0] = sarea_priv->pipeA_y + slice[0];
 145         lower[1] = sarea_priv->pipeB_y + slice[0];
 146
 147         spin_lock(&dev->drw_lock);
 148
 149         /* Emit blits for buffer swaps, partitioning both outputs into as many
 150          * slices as there are buffer swaps scheduled in order to avoid tearing
 151          * (based on the assumption that a single buffer swap would always
 152          * complete before scanout starts).
 153          */
 154         for (i = 0; i++ < nhits;
 155              upper[0] = lower[0], lower[0] += slice[0],
 156              upper[1] = lower[1], lower[1] += slice[1]) {
 157                 if (i == nhits)
 158                         lower[0] = lower[1] = sarea_priv->height;
 159
 160                 list_for_each(hit, &hits) {
 161                         drm_i915_vbl_swap_t *swap_hit =
 162                                 list_entry(hit, drm_i915_vbl_swap_t, head);
 163                         struct drm_clip_rect *rect;
 164                         int num_rects, pipe;
 165                         unsigned short top, bottom;
 166
 167                         drw = drm_get_drawable_info(dev, swap_hit->drw_id);
 168
 169                         if (!drw)
 170                                 continue;
 171
 172                         rect = drw->rects;
 173                         pipe = swap_hit->pipe;
 174                         top = upper[pipe];
 175                         bottom = lower[pipe];
 176
 177                         for (num_rects = drw->num_rects; num_rects--; rect++) {
 178                                 int y1 = max(rect->y1, top);
 179                                 int y2 = min(rect->y2, bottom);
 180
 181                                 if (y1 >= y2)
 182                                         continue;
 183
 184                                 BEGIN_LP_RING(8);
 185
 186                                 OUT_RING(cmd);
 187                                 OUT_RING(pitchropcpp);
 188                                 OUT_RING((y1 << 16) | rect->x1);
 189                                 OUT_RING((y2 << 16) | rect->x2);
 190                                 OUT_RING(sarea_priv->front_offset);
 191                                 OUT_RING((y1 << 16) | rect->x1);
 192                                 OUT_RING(pitchropcpp & 0xffff);
 193                                 OUT_RING(sarea_priv->back_offset);
 194
 195                                 ADVANCE_LP_RING();
 196                         }
 197                 }
 198         }
 199
 200         spin_unlock_irqrestore(&dev->drw_lock, irqflags);
 201
 202         list_for_each_safe(hit, tmp, &hits) {
 203                 drm_i915_vbl_swap_t *swap_hit =
 204                         list_entry(hit, drm_i915_vbl_swap_t, head);
 205
 206                 list_del(hit);
 207
 208                 drm_free(swap_hit, sizeof(*swap_hit), DRM_MEM_DRIVER);
 209         }
 210 }
 211
 212 irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
 213 {
 214         struct drm_device *dev = (struct drm_device *) arg;
 215         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 216         u16 temp;
 217         u32 pipea_stats, pipeb_stats;
 218
 219         pipea_stats = I915_READ(I915REG_PIPEASTAT);
 220         pipeb_stats = I915_READ(I915REG_PIPEBSTAT);
 221
 222         temp = I915_READ16(I915REG_INT_IDENTITY_R);
 223
 224         temp &= (USER_INT_FLAG | VSYNC_PIPEA_FLAG | VSYNC_PIPEB_FLAG);
 225
 226         DRM_DEBUG("%s flag=%08x\n", __FUNCTION__, temp);
 227
 228         if (temp == 0)
 229                 return IRQ_NONE;
 230
 231         I915_WRITE16(I915REG_INT_IDENTITY_R, temp);
 232         (void) I915_READ16(I915REG_INT_IDENTITY_R);
 233         DRM_READMEMORYBARRIER();
 234
 235         dev_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
 236
 237         if (temp & USER_INT_FLAG)
 238                 DRM_WAKEUP(&dev_priv->irq_queue);
 239
 240         if (temp & (VSYNC_PIPEA_FLAG | VSYNC_PIPEB_FLAG)) {
 241                 int vblank_pipe = dev_priv->vblank_pipe;
 242
 243                 if ((vblank_pipe &
 244                      (DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B))
 245                     == (DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B)) {
 246                         if (temp & VSYNC_PIPEA_FLAG)
 247                                 atomic_inc(&dev->vbl_received);
 248                         if (temp & VSYNC_PIPEB_FLAG)
 249                                 atomic_inc(&dev->vbl_received2);
 250                 } else if (((temp & VSYNC_PIPEA_FLAG) &&
 251                             (vblank_pipe & DRM_I915_VBLANK_PIPE_A)) ||
 252                            ((temp & VSYNC_PIPEB_FLAG) &&
 253                             (vblank_pipe & DRM_I915_VBLANK_PIPE_B)))
 254                         atomic_inc(&dev->vbl_received);
 255
 256                 DRM_WAKEUP(&dev->vbl_queue);
 257                 drm_vbl_send_signals(dev);
 258
 259                 if (dev_priv->swaps_pending > 0)
 260                         drm_locked_tasklet(dev, i915_vblank_tasklet);
 261                 I915_WRITE(I915REG_PIPEASTAT,
 262                         pipea_stats|I915_VBLANK_INTERRUPT_ENABLE|
 263                         I915_VBLANK_CLEAR);
 264                 I915_WRITE(I915REG_PIPEBSTAT,
 265                         pipeb_stats|I915_VBLANK_INTERRUPT_ENABLE|
 266                         I915_VBLANK_CLEAR);
 267         }
 268
 269         return IRQ_HANDLED;
 270 }
 271
 272 static int i915_emit_irq(struct drm_device * dev)
 273 {
 274         drm_i915_private_t *dev_priv = dev->dev_private;
 275         RING_LOCALS;
 276
 277         i915_kernel_lost_context(dev);
 278
 279         DRM_DEBUG("\n");
 280
 281         dev_priv->sarea_priv->last_enqueue = ++dev_priv->counter;
 282
 283         if (dev_priv->counter > 0x7FFFFFFFUL)
 284                 dev_priv->sarea_priv->last_enqueue = dev_priv->counter = 1;
 285
 286         BEGIN_LP_RING(6);
 287         OUT_RING(CMD_STORE_DWORD_IDX);
 288         OUT_RING(20);
 289         OUT_RING(dev_priv->counter);
 290         OUT_RING(0);
 291         OUT_RING(0);
 292         OUT_RING(GFX_OP_USER_INTERRUPT);
 293         ADVANCE_LP_RING();
 294
 295         return dev_priv->counter;
 296 }
 297
 298 static int i915_wait_irq(struct drm_device * dev, int irq_nr)
 299 {
 300         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 301         int ret = 0;
 302
 303         DRM_DEBUG("irq_nr=%d breadcrumb=%d\n", irq_nr,
 304                   READ_BREADCRUMB(dev_priv));
 305
 306         if (READ_BREADCRUMB(dev_priv) >= irq_nr)
 307                 return 0;
 308
 309         dev_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;
 310
 311         DRM_WAIT_ON(ret, dev_priv->irq_queue, 3 * DRM_HZ,
 312                     READ_BREADCRUMB(dev_priv) >= irq_nr);
 313
 314         if (ret == -EBUSY) {
 315                 DRM_ERROR("EBUSY -- rec: %d emitted: %d\n",
 316                           READ_BREADCRUMB(dev_priv), (int)dev_priv->counter);
 317         }
 318
 319         dev_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
 320         return ret;
 321 }
 322
 323 static int i915_driver_vblank_do_wait(struct drm_device *dev, unsigned int *sequence,
 324                                       atomic_t *counter)
 325 {
 326         drm_i915_private_t *dev_priv = dev->dev_private;
 327         unsigned int cur_vblank;
 328         int ret = 0;
 329
 330         if (!dev_priv) {
 331                 DRM_ERROR("called with no initialization\n");
 332                 return -EINVAL;
 333         }
 334
 335         DRM_WAIT_ON(ret, dev->vbl_queue, 3 * DRM_HZ,
 336                     (((cur_vblank = atomic_read(counter))
 337                         - *sequence) <= (1<<23)));
 338
 339         *sequence = cur_vblank;
 340
 341         return ret;
 342 }
 343
 344
 345 int i915_driver_vblank_wait(struct drm_device *dev, unsigned int *sequence)
 346 {
 347         return i915_driver_vblank_do_wait(dev, sequence, &dev->vbl_received);
 348 }
 349
 350 int i915_driver_vblank_wait2(struct drm_device *dev, unsigned int *sequence)
 351 {
 352         return i915_driver_vblank_do_wait(dev, sequence, &dev->vbl_received2);
 353 }
 354
 355 /* Needs the lock as it touches the ring.
 356  */
 357 int i915_irq_emit(struct drm_device *dev, void *data,
 358                          struct drm_file *file_priv)
 359 {
 360         drm_i915_private_t *dev_priv = dev->dev_private;
 361         drm_i915_irq_emit_t *emit = data;
 362         int result;
 363
 364         LOCK_TEST_WITH_RETURN(dev, file_priv);
 365
 366         if (!dev_priv) {
 367                 DRM_ERROR("called with no initialization\n");
 368                 return -EINVAL;
 369         }
 370
 371         result = i915_emit_irq(dev);
 372
 373         if (DRM_COPY_TO_USER(emit->irq_seq, &result, sizeof(int))) {
 374                 DRM_ERROR("copy_to_user\n");
 375                 return -EFAULT;
 376         }
 377
 378         return 0;
 379 }
 380
 381 /* Doesn't need the hardware lock.
 382  */
 383 int i915_irq_wait(struct drm_device *dev, void *data,
 384                          struct drm_file *file_priv)
 385 {
 386         drm_i915_private_t *dev_priv = dev->dev_private;
 387         drm_i915_irq_wait_t *irqwait = data;
 388
 389         if (!dev_priv) {
 390                 DRM_ERROR("called with no initialization\n");
 391                 return -EINVAL;
 392         }
 393
 394         return i915_wait_irq(dev, irqwait->irq_seq);
 395 }
 396
 397 static void i915_enable_interrupt (struct drm_device *dev)
 398 {
 399         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 400         u16 flag;
 401
 402         flag = 0;
 403         if (dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_A)
 404                 flag |= VSYNC_PIPEA_FLAG;
 405         if (dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_B)
 406                 flag |= VSYNC_PIPEB_FLAG;
 407
 408         I915_WRITE16(I915REG_INT_ENABLE_R, USER_INT_FLAG | flag);
 409 }
 410
 411 /* Set the vblank monitor pipe
 412  */
 413 int i915_vblank_pipe_set(struct drm_device *dev, void *data,
 414                          struct drm_file *file_priv)
 415 {
 416         drm_i915_private_t *dev_priv = dev->dev_private;
 417         drm_i915_vblank_pipe_t *pipe = data;
 418
 419         if (!dev_priv) {
 420                 DRM_ERROR("called with no initialization\n");
 421                 return -EINVAL;
 422         }
 423
 424         if (pipe->pipe & ~(DRM_I915_VBLANK_PIPE_A|DRM_I915_VBLANK_PIPE_B)) {
 425                 DRM_ERROR("called with invalid pipe 0x%x\n", pipe->pipe);
 426                 return -EINVAL;
 427         }
 428
 429         dev_priv->vblank_pipe = pipe->pipe;
 430
 431         i915_enable_interrupt (dev);
 432
 433         return 0;
 434 }
 435
 436 int i915_vblank_pipe_get(struct drm_device *dev, void *data,
 437                          struct drm_file *file_priv)
 438 {
 439         drm_i915_private_t *dev_priv = dev->dev_private;
 440         drm_i915_vblank_pipe_t *pipe = data;
 441         u16 flag;
 442
 443         if (!dev_priv) {
 444                 DRM_ERROR("called with no initialization\n");
 445                 return -EINVAL;
 446         }
 447
 448         flag = I915_READ(I915REG_INT_ENABLE_R);
 449         pipe->pipe = 0;
 450         if (flag & VSYNC_PIPEA_FLAG)
 451                 pipe->pipe |= DRM_I915_VBLANK_PIPE_A;
 452         if (flag & VSYNC_PIPEB_FLAG)
 453                 pipe->pipe |= DRM_I915_VBLANK_PIPE_B;
 454
 455         return 0;
 456 }
 457
 458 /**
 459  * Schedule buffer swap at given vertical blank.
 460  */
 461 int i915_vblank_swap(struct drm_device *dev, void *data,
 462                      struct drm_file *file_priv)
 463 {
 464         drm_i915_private_t *dev_priv = dev->dev_private;
 465         drm_i915_vblank_swap_t *swap = data;
 466         drm_i915_vbl_swap_t *vbl_swap;
 467         unsigned int pipe, seqtype, curseq;
 468         unsigned long irqflags;
 469         struct list_head *list;
 470
 471         if (!dev_priv) {
 472                 DRM_ERROR("%s called with no initialization\n", __func__);
 473                 return -EINVAL;
 474         }
 475
 476         if (dev_priv->sarea_priv->rotation) {
 477                 DRM_DEBUG("Rotation not supported\n");
 478                 return -EINVAL;
 479         }
 480
 481         if (swap->seqtype & ~(_DRM_VBLANK_RELATIVE | _DRM_VBLANK_ABSOLUTE |
 482                              _DRM_VBLANK_SECONDARY | _DRM_VBLANK_NEXTONMISS)) {
 483                 DRM_ERROR("Invalid sequence type 0x%x\n", swap->seqtype);
 484                 return -EINVAL;
 485         }
 486
 487         pipe = (swap->seqtype & _DRM_VBLANK_SECONDARY) ? 1 : 0;
 488
 489         seqtype = swap->seqtype & (_DRM_VBLANK_RELATIVE | _DRM_VBLANK_ABSOLUTE);
 490
 491         if (!(dev_priv->vblank_pipe & (1 << pipe))) {
 492                 DRM_ERROR("Invalid pipe %d\n", pipe);
 493                 return -EINVAL;
 494         }
 495
 496         spin_lock_irqsave(&dev->drw_lock, irqflags);
 497
 498         if (!drm_get_drawable_info(dev, swap->drawable)) {
 499                 spin_unlock_irqrestore(&dev->drw_lock, irqflags);
 500                 DRM_DEBUG("Invalid drawable ID %d\n", swap->drawable);
 501                 return -EINVAL;
 502         }
 503
 504         spin_unlock_irqrestore(&dev->drw_lock, irqflags);
 505
 506         curseq = atomic_read(pipe ? &dev->vbl_received2 : &dev->vbl_received);
 507
 508         if (seqtype == _DRM_VBLANK_RELATIVE)
 509                 swap->sequence += curseq;
 510
 511         if ((curseq - swap->sequence) <= (1<<23)) {
 512                 if (swap->seqtype & _DRM_VBLANK_NEXTONMISS) {
 513                         swap->sequence = curseq + 1;
 514                 } else {
 515                         DRM_DEBUG("Missed target sequence\n");
 516                         return -EINVAL;
 517                 }
 518         }
 519
 520         spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
 521
 522         list_for_each(list, &dev_priv->vbl_swaps.head) {
 523                 vbl_swap = list_entry(list, drm_i915_vbl_swap_t, head);
 524
 525                 if (vbl_swap->drw_id == swap->drawable &&
 526                     vbl_swap->pipe == pipe &&
 527                     vbl_swap->sequence == swap->sequence) {
 528                         spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
 529                         DRM_DEBUG("Already scheduled\n");
 530                         return 0;
 531                 }
 532         }
 533
 534         spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
 535
 536         if (dev_priv->swaps_pending >= 100) {
 537                 DRM_DEBUG("Too many swaps queued\n");
 538                 return -EBUSY;
 539         }
 540
 541         vbl_swap = drm_calloc(1, sizeof(*vbl_swap), DRM_MEM_DRIVER);
 542
 543         if (!vbl_swap) {
 544                 DRM_ERROR("Failed to allocate memory to queue swap\n");
 545                 return -ENOMEM;
 546         }
 547
 548         DRM_DEBUG("\n");
 549
 550         vbl_swap->drw_id = swap->drawable;
 551         vbl_swap->pipe = pipe;
 552         vbl_swap->sequence = swap->sequence;
 553
 554         spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
 555
 556         list_add_tail(&vbl_swap->head, &dev_priv->vbl_swaps.head);
 557         dev_priv->swaps_pending++;
 558
 559         spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
 560
 561         return 0;
 562 }
 563
 564 /* drm_dma.h hooks
 565 */
 566 void i915_driver_irq_preinstall(struct drm_device * dev)
 567 {
 568         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 569
 570         I915_WRITE16(I915REG_HWSTAM, 0xfffe);
 571         I915_WRITE16(I915REG_INT_MASK_R, 0x0);
 572         I915_WRITE16(I915REG_INT_ENABLE_R, 0x0);
 573 }
 574
 575 void i915_driver_irq_postinstall(struct drm_device * dev)
 576 {
 577         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 578
 579         spin_lock_init(&dev_priv->swaps_lock);
 580         INIT_LIST_HEAD(&dev_priv->vbl_swaps.head);
 581         dev_priv->swaps_pending = 0;
 582
 583         if (!dev_priv->vblank_pipe)
 584                 dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A;
 585         i915_enable_interrupt(dev);
 586         DRM_INIT_WAITQUEUE(&dev_priv->irq_queue);
 587 }
 588
 589 void i915_driver_irq_uninstall(struct drm_device * dev)
 590 {
 591         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 592         u16 temp;
 593
 594         if (!dev_priv)
 595                 return;
 596
 597         I915_WRITE16(I915REG_HWSTAM, 0xffff);
 598         I915_WRITE16(I915REG_INT_MASK_R, 0xffff);
 599         I915_WRITE16(I915REG_INT_ENABLE_R, 0x0);
 600
 601         temp = I915_READ16(I915REG_INT_IDENTITY_R);
 602         I915_WRITE16(I915REG_INT_IDENTITY_R, temp);
 603 }