shared-core/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(drm_device_t *dev)
  46 {
  47         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
  48         unsigned int irqflags;
  49         struct list_head *list, *tmp;
  50
  51         DRM_DEBUG("\n");
  52
  53         spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
  54
  55         list_for_each_safe(list, tmp, &dev_priv->vbl_swaps.head) {
  56                 drm_i915_vbl_swap_t *vbl_swap =
  57                         list_entry(list, drm_i915_vbl_swap_t, head);
  58                 atomic_t *counter = vbl_swap->pipe ? &dev->vbl_received2 :
  59                         &dev->vbl_received;
  60
  61                 if ((atomic_read(counter) - vbl_swap->sequence) <= (1<<23)) {
  62                         drm_drawable_info_t *drw;
  63
  64                         spin_unlock(&dev_priv->swaps_lock);
  65
  66                         spin_lock(&dev->drw_lock);
  67
  68                         drw = drm_get_drawable_info(dev, vbl_swap->drw_id);
  69
  70                         if (drw) {
  71                                 int i, num_rects = drw->num_rects;
  72                                 drm_clip_rect_t *rect = drw->rects;
  73                                 drm_i915_sarea_t *sarea_priv =
  74                                     dev_priv->sarea_priv;
  75                                 u32 cpp = dev_priv->cpp;
  76                                 u32 cmd = (cpp == 4) ? (XY_SRC_COPY_BLT_CMD |
  77                                                         XY_SRC_COPY_BLT_WRITE_ALPHA |
  78                                                         XY_SRC_COPY_BLT_WRITE_RGB)
  79                                                      : XY_SRC_COPY_BLT_CMD;
  80                                 u32 pitchropcpp = (sarea_priv->pitch * cpp) |
  81                                                   (0xcc << 16) | (cpp << 23) |
  82                                                   (1 << 24);
  83                                 RING_LOCALS;
  84
  85                                 i915_kernel_lost_context(dev);
  86
  87                                 BEGIN_LP_RING(6);
  88
  89                                 OUT_RING(GFX_OP_DRAWRECT_INFO);
  90                                 OUT_RING(0);
  91                                 OUT_RING(0);
  92                                 OUT_RING(sarea_priv->width |
  93                                          sarea_priv->height << 16);
  94                                 OUT_RING(sarea_priv->width |
  95                                          sarea_priv->height << 16);
  96                                 OUT_RING(0);
  97
  98                                 ADVANCE_LP_RING();
  99
 100                                 sarea_priv->ctxOwner = DRM_KERNEL_CONTEXT;
 101
 102                                 for (i = 0; i < num_rects; i++, rect++) {
 103                                         BEGIN_LP_RING(8);
 104
 105                                         OUT_RING(cmd);
 106                                         OUT_RING(pitchropcpp);
 107                                         OUT_RING((rect->y1 << 16) | rect->x1);
 108                                         OUT_RING((rect->y2 << 16) | rect->x2);
 109                                         OUT_RING(sarea_priv->front_offset);
 110                                         OUT_RING((rect->y1 << 16) | rect->x1);
 111                                         OUT_RING(pitchropcpp & 0xffff);
 112                                         OUT_RING(sarea_priv->back_offset);
 113
 114                                         ADVANCE_LP_RING();
 115                                 }
 116                         }
 117
 118                         spin_unlock(&dev->drw_lock);
 119
 120                         spin_lock(&dev_priv->swaps_lock);
 121
 122                         list_del(list);
 123
 124                         drm_free(vbl_swap, sizeof(*vbl_swap), DRM_MEM_DRIVER);
 125
 126                         dev_priv->swaps_pending--;
 127                 }
 128         }
 129
 130         spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
 131 }
 132
 133 irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
 134 {
 135         drm_device_t *dev = (drm_device_t *) arg;
 136         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 137         u16 temp;
 138
 139         temp = I915_READ16(I915REG_INT_IDENTITY_R);
 140
 141         temp &= (dev_priv->irq_enable_reg | USER_INT_FLAG);
 142
 143 #if 0
 144         DRM_DEBUG("%s flag=%08x\n", __FUNCTION__, temp);
 145 #endif
 146         if (temp == 0)
 147                 return IRQ_NONE;
 148
 149         I915_WRITE16(I915REG_INT_IDENTITY_R, temp);
 150
 151         dev_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
 152
 153         if (temp & USER_INT_FLAG) {
 154                 DRM_WAKEUP(&dev_priv->irq_queue);
 155 #ifdef I915_HAVE_FENCE
 156                 i915_fence_handler(dev);
 157 #endif
 158         }
 159
 160         if (temp & (VSYNC_PIPEA_FLAG | VSYNC_PIPEB_FLAG)) {
 161                 int vblank_pipe = dev_priv->vblank_pipe;
 162
 163                 if ((vblank_pipe &
 164                      (DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B))
 165                     == (DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B)) {
 166                         if (temp & VSYNC_PIPEA_FLAG)
 167                                 atomic_inc(&dev->vbl_received);
 168                         if (temp & VSYNC_PIPEB_FLAG)
 169                                 atomic_inc(&dev->vbl_received2);
 170                 } else if (((temp & VSYNC_PIPEA_FLAG) &&
 171                             (vblank_pipe & DRM_I915_VBLANK_PIPE_A)) ||
 172                            ((temp & VSYNC_PIPEB_FLAG) &&
 173                             (vblank_pipe & DRM_I915_VBLANK_PIPE_B)))
 174                         atomic_inc(&dev->vbl_received);
 175
 176                 DRM_WAKEUP(&dev->vbl_queue);
 177                 drm_vbl_send_signals(dev);
 178
 179                 if (dev_priv->swaps_pending > 0)
 180                         drm_locked_tasklet(dev, i915_vblank_tasklet);
 181         }
 182
 183         return IRQ_HANDLED;
 184 }
 185
 186 int i915_emit_irq(drm_device_t * dev)
 187 {
 188
 189         drm_i915_private_t *dev_priv = dev->dev_private;
 190         RING_LOCALS;
 191
 192         i915_kernel_lost_context(dev);
 193
 194         DRM_DEBUG("%s\n", __FUNCTION__);
 195
 196         dev_priv->sarea_priv->last_enqueue = ++dev_priv->counter;
 197
 198         if (dev_priv->counter > 0x7FFFFFFFUL)
 199                  dev_priv->sarea_priv->last_enqueue = dev_priv->counter = 1;
 200
 201         BEGIN_LP_RING(6);
 202         OUT_RING(CMD_STORE_DWORD_IDX);
 203         OUT_RING(20);
 204         OUT_RING(dev_priv->counter);
 205
 206         OUT_RING(0);
 207         OUT_RING(0);
 208         OUT_RING(GFX_OP_USER_INTERRUPT);
 209         ADVANCE_LP_RING();
 210
 211         return dev_priv->counter;
 212
 213
 214 }
 215
 216 void i915_user_irq_on(drm_i915_private_t *dev_priv)
 217 {
 218         spin_lock(&dev_priv->user_irq_lock);
 219         if (dev_priv->irq_enabled && (++dev_priv->user_irq_refcount == 1)){
 220                 dev_priv->irq_enable_reg |= USER_INT_FLAG;
 221                 I915_WRITE16(I915REG_INT_ENABLE_R, dev_priv->irq_enable_reg);
 222         }
 223         spin_unlock(&dev_priv->user_irq_lock);
 224
 225 }
 226
 227 void i915_user_irq_off(drm_i915_private_t *dev_priv)
 228 {
 229         spin_lock(&dev_priv->user_irq_lock);
 230         if (dev_priv->irq_enabled && (--dev_priv->user_irq_refcount == 0)) {
 231                 //              dev_priv->irq_enable_reg &= ~USER_INT_FLAG;
 232                 //              I915_WRITE16(I915REG_INT_ENABLE_R, dev_priv->irq_enable_reg);
 233         }
 234         spin_unlock(&dev_priv->user_irq_lock);
 235 }
 236
 237
 238 static int i915_wait_irq(drm_device_t * dev, int irq_nr)
 239 {
 240         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 241         int ret = 0;
 242
 243         DRM_DEBUG("%s irq_nr=%d breadcrumb=%d\n", __FUNCTION__, irq_nr,
 244                   READ_BREADCRUMB(dev_priv));
 245
 246         if (READ_BREADCRUMB(dev_priv) >= irq_nr)
 247                 return 0;
 248
 249         dev_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;
 250
 251         i915_user_irq_on(dev_priv);
 252         DRM_WAIT_ON(ret, dev_priv->irq_queue, 3 * DRM_HZ,
 253                     READ_BREADCRUMB(dev_priv) >= irq_nr);
 254         i915_user_irq_off(dev_priv);
 255
 256         if (ret == DRM_ERR(EBUSY)) {
 257                 DRM_ERROR("%s: EBUSY -- rec: %d emitted: %d\n",
 258                           __FUNCTION__,
 259                           READ_BREADCRUMB(dev_priv), (int)dev_priv->counter);
 260         }
 261
 262         dev_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
 263         return ret;
 264 }
 265
 266 static int i915_driver_vblank_do_wait(drm_device_t *dev, unsigned int *sequence,
 267                                       atomic_t *counter)
 268 {
 269         drm_i915_private_t *dev_priv = dev->dev_private;
 270         unsigned int cur_vblank;
 271         int ret = 0;
 272
 273         if (!dev_priv) {
 274                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 275                 return DRM_ERR(EINVAL);
 276         }
 277
 278         DRM_WAIT_ON(ret, dev->vbl_queue, 3 * DRM_HZ,
 279                     (((cur_vblank = atomic_read(counter))
 280                         - *sequence) <= (1<<23)));
 281
 282         *sequence = cur_vblank;
 283
 284         return ret;
 285 }
 286
 287 int i915_driver_vblank_wait(drm_device_t *dev, unsigned int *sequence)
 288 {
 289         return i915_driver_vblank_do_wait(dev, sequence, &dev->vbl_received);
 290 }
 291
 292 int i915_driver_vblank_wait2(drm_device_t *dev, unsigned int *sequence)
 293 {
 294         return i915_driver_vblank_do_wait(dev, sequence, &dev->vbl_received2);
 295 }
 296
 297 /* Needs the lock as it touches the ring.
 298  */
 299 int i915_irq_emit(DRM_IOCTL_ARGS)
 300 {
 301         DRM_DEVICE;
 302         drm_i915_private_t *dev_priv = dev->dev_private;
 303         drm_i915_irq_emit_t emit;
 304         int result;
 305
 306         LOCK_TEST_WITH_RETURN(dev, filp);
 307
 308         if (!dev_priv) {
 309                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 310                 return DRM_ERR(EINVAL);
 311         }
 312
 313         DRM_COPY_FROM_USER_IOCTL(emit, (drm_i915_irq_emit_t __user *) data,
 314                                  sizeof(emit));
 315
 316         result = i915_emit_irq(dev);
 317
 318         if (DRM_COPY_TO_USER(emit.irq_seq, &result, sizeof(int))) {
 319                 DRM_ERROR("copy_to_user\n");
 320                 return DRM_ERR(EFAULT);
 321         }
 322
 323         return 0;
 324 }
 325
 326 /* Doesn't need the hardware lock.
 327  */
 328 int i915_irq_wait(DRM_IOCTL_ARGS)
 329 {
 330         DRM_DEVICE;
 331         drm_i915_private_t *dev_priv = dev->dev_private;
 332         drm_i915_irq_wait_t irqwait;
 333
 334         if (!dev_priv) {
 335                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 336                 return DRM_ERR(EINVAL);
 337         }
 338
 339         DRM_COPY_FROM_USER_IOCTL(irqwait, (drm_i915_irq_wait_t __user *) data,
 340                                  sizeof(irqwait));
 341
 342         return i915_wait_irq(dev, irqwait.irq_seq);
 343 }
 344
 345 static void i915_enable_interrupt (drm_device_t *dev)
 346 {
 347         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 348
 349         dev_priv->irq_enable_reg = USER_INT_FLAG; //&= ~(VSYNC_PIPEA_FLAG | VSYNC_PIPEB_FLAG);
 350         if (dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_A)
 351                 dev_priv->irq_enable_reg |= VSYNC_PIPEA_FLAG;
 352         if (dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_B)
 353                 dev_priv->irq_enable_reg |= VSYNC_PIPEB_FLAG;
 354
 355         I915_WRITE16(I915REG_INT_ENABLE_R, dev_priv->irq_enable_reg);
 356         dev_priv->irq_enabled = 1;
 357 }
 358
 359 /* Set the vblank monitor pipe
 360  */
 361 int i915_vblank_pipe_set(DRM_IOCTL_ARGS)
 362 {
 363         DRM_DEVICE;
 364         drm_i915_private_t *dev_priv = dev->dev_private;
 365         drm_i915_vblank_pipe_t pipe;
 366
 367         if (!dev_priv) {
 368                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 369                 return DRM_ERR(EINVAL);
 370         }
 371
 372         DRM_COPY_FROM_USER_IOCTL(pipe, (drm_i915_vblank_pipe_t __user *) data,
 373                                  sizeof(pipe));
 374
 375         if (pipe.pipe & ~(DRM_I915_VBLANK_PIPE_A|DRM_I915_VBLANK_PIPE_B)) {
 376                 DRM_ERROR("%s called with invalid pipe 0x%x\n",
 377                           __FUNCTION__, pipe.pipe);
 378                 return DRM_ERR(EINVAL);
 379         }
 380
 381         dev_priv->vblank_pipe = pipe.pipe;
 382
 383         i915_enable_interrupt (dev);
 384
 385         return 0;
 386 }
 387
 388 int i915_vblank_pipe_get(DRM_IOCTL_ARGS)
 389 {
 390         DRM_DEVICE;
 391         drm_i915_private_t *dev_priv = dev->dev_private;
 392         drm_i915_vblank_pipe_t pipe;
 393         u16 flag;
 394
 395         if (!dev_priv) {
 396                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 397                 return DRM_ERR(EINVAL);
 398         }
 399
 400         flag = I915_READ(I915REG_INT_ENABLE_R);
 401         pipe.pipe = 0;
 402         if (flag & VSYNC_PIPEA_FLAG)
 403                 pipe.pipe |= DRM_I915_VBLANK_PIPE_A;
 404         if (flag & VSYNC_PIPEB_FLAG)
 405                 pipe.pipe |= DRM_I915_VBLANK_PIPE_B;
 406         DRM_COPY_TO_USER_IOCTL((drm_i915_vblank_pipe_t __user *) data, pipe,
 407                                  sizeof(pipe));
 408         return 0;
 409 }
 410
 411 /**
 412  * Schedule buffer swap at given vertical blank.
 413  */
 414 int i915_vblank_swap(DRM_IOCTL_ARGS)
 415 {
 416         DRM_DEVICE;
 417         drm_i915_private_t *dev_priv = dev->dev_private;
 418         drm_i915_vblank_swap_t swap;
 419         drm_i915_vbl_swap_t *vbl_swap;
 420         unsigned int pipe, seqtype, irqflags, curseq;
 421         struct list_head *list;
 422
 423         if (!dev_priv) {
 424                 DRM_ERROR("%s called with no initialization\n", __func__);
 425                 return DRM_ERR(EINVAL);
 426         }
 427
 428         if (dev_priv->sarea_priv->rotation) {
 429                 DRM_DEBUG("Rotation not supported\n");
 430                 return DRM_ERR(EINVAL);
 431         }
 432
 433         DRM_COPY_FROM_USER_IOCTL(swap, (drm_i915_vblank_swap_t __user *) data,
 434                                  sizeof(swap));
 435
 436         if (swap.seqtype & ~(_DRM_VBLANK_RELATIVE | _DRM_VBLANK_ABSOLUTE |
 437                              _DRM_VBLANK_SECONDARY | _DRM_VBLANK_NEXTONMISS)) {
 438                 DRM_ERROR("Invalid sequence type 0x%x\n", swap.seqtype);
 439                 return DRM_ERR(EINVAL);
 440         }
 441
 442         pipe = (swap.seqtype & _DRM_VBLANK_SECONDARY) ? 1 : 0;
 443
 444         seqtype = swap.seqtype & (_DRM_VBLANK_RELATIVE | _DRM_VBLANK_ABSOLUTE);
 445
 446         if (!(dev_priv->vblank_pipe & (1 << pipe))) {
 447                 DRM_ERROR("Invalid pipe %d\n", pipe);
 448                 return DRM_ERR(EINVAL);
 449         }
 450
 451         spin_lock_irqsave(&dev->drw_lock, irqflags);
 452
 453         if (!drm_get_drawable_info(dev, swap.drawable)) {
 454                 spin_unlock_irqrestore(&dev->drw_lock, irqflags);
 455                 DRM_ERROR("Invalid drawable ID %d\n", swap.drawable);
 456                 return DRM_ERR(EINVAL);
 457         }
 458
 459         spin_unlock_irqrestore(&dev->drw_lock, irqflags);
 460
 461         curseq = atomic_read(pipe ? &dev->vbl_received2 : &dev->vbl_received);
 462
 463         if (seqtype == _DRM_VBLANK_RELATIVE)
 464                 swap.sequence += curseq;
 465
 466         if ((curseq - swap.sequence) <= (1<<23)) {
 467                 if (swap.seqtype & _DRM_VBLANK_NEXTONMISS) {
 468                         swap.sequence = curseq + 1;
 469                 } else {
 470                         DRM_DEBUG("Missed target sequence\n");
 471                         return DRM_ERR(EINVAL);
 472                 }
 473         }
 474
 475         spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
 476
 477         list_for_each(list, &dev_priv->vbl_swaps.head) {
 478                 vbl_swap = list_entry(list, drm_i915_vbl_swap_t, head);
 479
 480                 if (vbl_swap->drw_id == swap.drawable &&
 481                     vbl_swap->pipe == pipe &&
 482                     vbl_swap->sequence == swap.sequence) {
 483                         spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
 484                         DRM_DEBUG("Already scheduled\n");
 485                         return 0;
 486                 }
 487         }
 488
 489         spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
 490
 491         if (dev_priv->swaps_pending >= 100) {
 492                 DRM_DEBUG("Too many swaps queued\n");
 493                 return DRM_ERR(EBUSY);
 494         }
 495
 496         vbl_swap = drm_calloc(1, sizeof(vbl_swap), DRM_MEM_DRIVER);
 497
 498         if (!vbl_swap) {
 499                 DRM_ERROR("Failed to allocate memory to queue swap\n");
 500                 return DRM_ERR(ENOMEM);
 501         }
 502
 503         DRM_DEBUG("\n");
 504
 505         vbl_swap->drw_id = swap.drawable;
 506         vbl_swap->pipe = pipe;
 507         vbl_swap->sequence = swap.sequence;
 508
 509         spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
 510
 511         list_add_tail((struct list_head *)vbl_swap, &dev_priv->vbl_swaps.head);
 512         dev_priv->swaps_pending++;
 513
 514         spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
 515
 516         DRM_COPY_TO_USER_IOCTL((drm_i915_vblank_swap_t __user *) data, swap,
 517                                sizeof(swap));
 518
 519         return 0;
 520 }
 521
 522 /* drm_dma.h hooks
 523 */
 524 void i915_driver_irq_preinstall(drm_device_t * dev)
 525 {
 526         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 527
 528         I915_WRITE16(I915REG_HWSTAM, 0xeffe);
 529         I915_WRITE16(I915REG_INT_MASK_R, 0x0);
 530         I915_WRITE16(I915REG_INT_ENABLE_R, 0x0);
 531 }
 532
 533 void i915_driver_irq_postinstall(drm_device_t * dev)
 534 {
 535         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 536
 537         dev_priv->swaps_lock = SPIN_LOCK_UNLOCKED;
 538         INIT_LIST_HEAD(&dev_priv->vbl_swaps.head);
 539         dev_priv->swaps_pending = 0;
 540
 541         dev_priv->user_irq_lock = SPIN_LOCK_UNLOCKED;
 542         dev_priv->user_irq_refcount = 0;
 543
 544         if (!dev_priv->vblank_pipe)
 545                 dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A;
 546         i915_enable_interrupt(dev);
 547         DRM_INIT_WAITQUEUE(&dev_priv->irq_queue);
 548
 549         /*
 550          * Initialize the hardware status page IRQ location.
 551          */
 552
 553         I915_WRITE(I915REG_INSTPM, ( 1 << 5) | ( 1 << 21));
 554 }
 555
 556 void i915_driver_irq_uninstall(drm_device_t * dev)
 557 {
 558         drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 559         u16 temp;
 560         if (!dev_priv)
 561                 return;
 562
 563         dev_priv->irq_enabled = 0;
 564         I915_WRITE16(I915REG_HWSTAM, 0xffff);
 565         I915_WRITE16(I915REG_INT_MASK_R, 0xffff);
 566         I915_WRITE16(I915REG_INT_ENABLE_R, 0x0);
 567
 568         temp = I915_READ16(I915REG_INT_IDENTITY_R);
 569         I915_WRITE16(I915REG_INT_IDENTITY_R, temp);
 570 }