drivers/gpu/drm/drm_irq.c

   1 /**
   2  * \file drm_irq.c
   3  * IRQ support
   4  *
   5  * \author Rickard E. (Rik) Faith <faith@valinux.com>
   6  * \author Gareth Hughes <gareth@valinux.com>
   7  */
   8
   9 /*
  10  * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
  11  *
  12  * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
  13  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
  14  * All Rights Reserved.
  15  *
  16  * Permission is hereby granted, free of charge, to any person obtaining a
  17  * copy of this software and associated documentation files (the "Software"),
  18  * to deal in the Software without restriction, including without limitation
  19  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  20  * and/or sell copies of the Software, and to permit persons to whom the
  21  * Software is furnished to do so, subject to the following conditions:
  22  *
  23  * The above copyright notice and this permission notice (including the next
  24  * paragraph) shall be included in all copies or substantial portions of the
  25  * Software.
  26  *
  27  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  28  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  29  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  30  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  31  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  32  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  33  * OTHER DEALINGS IN THE SOFTWARE.
  34  */
  35
  36 #include "drmP.h"
  37
  38 #include <linux/interrupt.h>    /* For task queue support */
  39
  40 /**
  41  * Get interrupt from bus id.
  42  *
  43  * \param inode device inode.
  44  * \param file_priv DRM file private.
  45  * \param cmd command.
  46  * \param arg user argument, pointing to a drm_irq_busid structure.
  47  * \return zero on success or a negative number on failure.
  48  *
  49  * Finds the PCI device with the specified bus id and gets its IRQ number.
  50  * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
  51  * to that of the device that this DRM instance attached to.
  52  */
  53 int drm_irq_by_busid(struct drm_device *dev, void *data,
  54                      struct drm_file *file_priv)
  55 {
  56         struct drm_irq_busid *p = data;
  57
  58         if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
  59                 return -EINVAL;
  60
  61         if ((p->busnum >> 8) != drm_get_pci_domain(dev) ||
  62             (p->busnum & 0xff) != dev->pdev->bus->number ||
  63             p->devnum != PCI_SLOT(dev->pdev->devfn) || p->funcnum != PCI_FUNC(dev->pdev->devfn))
  64                 return -EINVAL;
  65
  66         p->irq = dev->pdev->irq;
  67
  68         DRM_DEBUG("%d:%d:%d => IRQ %d\n", p->busnum, p->devnum, p->funcnum,
  69                   p->irq);
  70
  71         return 0;
  72 }
  73
  74 static void vblank_disable_fn(unsigned long arg)
  75 {
  76         struct drm_device *dev = (struct drm_device *)arg;
  77         unsigned long irqflags;
  78         int i;
  79
  80         if (!dev->vblank_disable_allowed)
  81                 return;
  82
  83         for (i = 0; i < dev->num_crtcs; i++) {
  84                 spin_lock_irqsave(&dev->vbl_lock, irqflags);
  85                 if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
  86                     dev->vblank_enabled[i]) {
  87                         DRM_DEBUG("disabling vblank on crtc %d\n", i);
  88                         dev->last_vblank[i] =
  89                                 dev->driver->get_vblank_counter(dev, i);
  90                         dev->driver->disable_vblank(dev, i);
  91                         dev->vblank_enabled[i] = 0;
  92                 }
  93                 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
  94         }
  95 }
  96
  97 void drm_vblank_cleanup(struct drm_device *dev)
  98 {
  99         /* Bail if the driver didn't call drm_vblank_init() */
 100         if (dev->num_crtcs == 0)
 101                 return;
 102
 103         del_timer(&dev->vblank_disable_timer);
 104
 105         vblank_disable_fn((unsigned long)dev);
 106
 107         drm_free(dev->vbl_queue, sizeof(*dev->vbl_queue) * dev->num_crtcs,
 108                  DRM_MEM_DRIVER);
 109         drm_free(dev->_vblank_count, sizeof(*dev->_vblank_count) *
 110                  dev->num_crtcs, DRM_MEM_DRIVER);
 111         drm_free(dev->vblank_refcount, sizeof(*dev->vblank_refcount) *
 112                  dev->num_crtcs, DRM_MEM_DRIVER);
 113         drm_free(dev->vblank_enabled, sizeof(*dev->vblank_enabled) *
 114                  dev->num_crtcs, DRM_MEM_DRIVER);
 115         drm_free(dev->last_vblank, sizeof(*dev->last_vblank) * dev->num_crtcs,
 116                  DRM_MEM_DRIVER);
 117         drm_free(dev->last_vblank_wait,
 118                  sizeof(*dev->last_vblank_wait) * dev->num_crtcs,
 119                  DRM_MEM_DRIVER);
 120         drm_free(dev->vblank_inmodeset, sizeof(*dev->vblank_inmodeset) *
 121                  dev->num_crtcs, DRM_MEM_DRIVER);
 122
 123         dev->num_crtcs = 0;
 124 }
 125
 126 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
 127 {
 128         int i, ret = -ENOMEM;
 129
 130         setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
 131                     (unsigned long)dev);
 132         spin_lock_init(&dev->vbl_lock);
 133         dev->num_crtcs = num_crtcs;
 134
 135         dev->vbl_queue = drm_alloc(sizeof(wait_queue_head_t) * num_crtcs,
 136                                    DRM_MEM_DRIVER);
 137         if (!dev->vbl_queue)
 138                 goto err;
 139
 140         dev->_vblank_count = drm_alloc(sizeof(atomic_t) * num_crtcs,
 141                                       DRM_MEM_DRIVER);
 142         if (!dev->_vblank_count)
 143                 goto err;
 144
 145         dev->vblank_refcount = drm_alloc(sizeof(atomic_t) * num_crtcs,
 146                                          DRM_MEM_DRIVER);
 147         if (!dev->vblank_refcount)
 148                 goto err;
 149
 150         dev->vblank_enabled = drm_calloc(num_crtcs, sizeof(int),
 151                                          DRM_MEM_DRIVER);
 152         if (!dev->vblank_enabled)
 153                 goto err;
 154
 155         dev->last_vblank = drm_calloc(num_crtcs, sizeof(u32), DRM_MEM_DRIVER);
 156         if (!dev->last_vblank)
 157                 goto err;
 158
 159         dev->last_vblank_wait = drm_calloc(num_crtcs, sizeof(u32),
 160                                            DRM_MEM_DRIVER);
 161         if (!dev->last_vblank_wait)
 162                 goto err;
 163
 164         dev->vblank_inmodeset = drm_calloc(num_crtcs, sizeof(int),
 165                                          DRM_MEM_DRIVER);
 166         if (!dev->vblank_inmodeset)
 167                 goto err;
 168
 169         /* Zero per-crtc vblank stuff */
 170         for (i = 0; i < num_crtcs; i++) {
 171                 init_waitqueue_head(&dev->vbl_queue[i]);
 172                 atomic_set(&dev->_vblank_count[i], 0);
 173                 atomic_set(&dev->vblank_refcount[i], 0);
 174         }
 175
 176         dev->vblank_disable_allowed = 0;
 177
 178         return 0;
 179
 180 err:
 181         drm_vblank_cleanup(dev);
 182         return ret;
 183 }
 184 EXPORT_SYMBOL(drm_vblank_init);
 185
 186 /**
 187  * Install IRQ handler.
 188  *
 189  * \param dev DRM device.
 190  *
 191  * Initializes the IRQ related data. Installs the handler, calling the driver
 192  * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
 193  * before and after the installation.
 194  */
 195 int drm_irq_install(struct drm_device *dev)
 196 {
 197         int ret = 0;
 198         unsigned long sh_flags = 0;
 199
 200         if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 201                 return -EINVAL;
 202
 203         if (dev->pdev->irq == 0)
 204                 return -EINVAL;
 205
 206         mutex_lock(&dev->struct_mutex);
 207
 208         /* Driver must have been initialized */
 209         if (!dev->dev_private) {
 210                 mutex_unlock(&dev->struct_mutex);
 211                 return -EINVAL;
 212         }
 213
 214         if (dev->irq_enabled) {
 215                 mutex_unlock(&dev->struct_mutex);
 216                 return -EBUSY;
 217         }
 218         dev->irq_enabled = 1;
 219         mutex_unlock(&dev->struct_mutex);
 220
 221         DRM_DEBUG("irq=%d\n", dev->pdev->irq);
 222
 223         /* Before installing handler */
 224         dev->driver->irq_preinstall(dev);
 225
 226         /* Install handler */
 227         if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
 228                 sh_flags = IRQF_SHARED;
 229
 230         ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
 231                           sh_flags, dev->devname, dev);
 232
 233         if (ret < 0) {
 234                 mutex_lock(&dev->struct_mutex);
 235                 dev->irq_enabled = 0;
 236                 mutex_unlock(&dev->struct_mutex);
 237                 return ret;
 238         }
 239
 240         /* After installing handler */
 241         ret = dev->driver->irq_postinstall(dev);
 242         if (ret < 0) {
 243                 mutex_lock(&dev->struct_mutex);
 244                 dev->irq_enabled = 0;
 245                 mutex_unlock(&dev->struct_mutex);
 246         }
 247
 248         return ret;
 249 }
 250 EXPORT_SYMBOL(drm_irq_install);
 251
 252 /**
 253  * Uninstall the IRQ handler.
 254  *
 255  * \param dev DRM device.
 256  *
 257  * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq.
 258  */
 259 int drm_irq_uninstall(struct drm_device * dev)
 260 {
 261         unsigned long irqflags;
 262         int irq_enabled, i;
 263
 264         if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 265                 return -EINVAL;
 266
 267         mutex_lock(&dev->struct_mutex);
 268         irq_enabled = dev->irq_enabled;
 269         dev->irq_enabled = 0;
 270         mutex_unlock(&dev->struct_mutex);
 271
 272         /*
 273          * Wake up any waiters so they don't hang.
 274          */
 275         spin_lock_irqsave(&dev->vbl_lock, irqflags);
 276         for (i = 0; i < dev->num_crtcs; i++) {
 277                 DRM_WAKEUP(&dev->vbl_queue[i]);
 278                 dev->vblank_enabled[i] = 0;
 279                 dev->last_vblank[i] = dev->driver->get_vblank_counter(dev, i);
 280         }
 281         spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 282
 283         if (!irq_enabled)
 284                 return -EINVAL;
 285
 286         DRM_DEBUG("irq=%d\n", dev->pdev->irq);
 287
 288         dev->driver->irq_uninstall(dev);
 289
 290         free_irq(dev->pdev->irq, dev);
 291
 292         return 0;
 293 }
 294 EXPORT_SYMBOL(drm_irq_uninstall);
 295
 296 /**
 297  * IRQ control ioctl.
 298  *
 299  * \param inode device inode.
 300  * \param file_priv DRM file private.
 301  * \param cmd command.
 302  * \param arg user argument, pointing to a drm_control structure.
 303  * \return zero on success or a negative number on failure.
 304  *
 305  * Calls irq_install() or irq_uninstall() according to \p arg.
 306  */
 307 int drm_control(struct drm_device *dev, void *data,
 308                 struct drm_file *file_priv)
 309 {
 310         struct drm_control *ctl = data;
 311
 312         /* if we haven't irq we fallback for compatibility reasons - this used to be a separate function in drm_dma.h */
 313
 314
 315         switch (ctl->func) {
 316         case DRM_INST_HANDLER:
 317                 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 318                         return 0;
 319                 if (drm_core_check_feature(dev, DRIVER_MODESET))
 320                         return 0;
 321                 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
 322                     ctl->irq != dev->pdev->irq)
 323                         return -EINVAL;
 324                 return drm_irq_install(dev);
 325         case DRM_UNINST_HANDLER:
 326                 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 327                         return 0;
 328                 if (drm_core_check_feature(dev, DRIVER_MODESET))
 329                         return 0;
 330                 return drm_irq_uninstall(dev);
 331         default:
 332                 return -EINVAL;
 333         }
 334 }
 335
 336 /**
 337  * drm_vblank_count - retrieve "cooked" vblank counter value
 338  * @dev: DRM device
 339  * @crtc: which counter to retrieve
 340  *
 341  * Fetches the "cooked" vblank count value that represents the number of
 342  * vblank events since the system was booted, including lost events due to
 343  * modesetting activity.
 344  */
 345 u32 drm_vblank_count(struct drm_device *dev, int crtc)
 346 {
 347         return atomic_read(&dev->_vblank_count[crtc]);
 348 }
 349 EXPORT_SYMBOL(drm_vblank_count);
 350
 351 /**
 352  * drm_update_vblank_count - update the master vblank counter
 353  * @dev: DRM device
 354  * @crtc: counter to update
 355  *
 356  * Call back into the driver to update the appropriate vblank counter
 357  * (specified by @crtc).  Deal with wraparound, if it occurred, and
 358  * update the last read value so we can deal with wraparound on the next
 359  * call if necessary.
 360  *
 361  * Only necessary when going from off->on, to account for frames we
 362  * didn't get an interrupt for.
 363  *
 364  * Note: caller must hold dev->vbl_lock since this reads & writes
 365  * device vblank fields.
 366  */
 367 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
 368 {
 369         u32 cur_vblank, diff;
 370
 371         /*
 372          * Interrupts were disabled prior to this call, so deal with counter
 373          * wrap if needed.
 374          * NOTE!  It's possible we lost a full dev->max_vblank_count events
 375          * here if the register is small or we had vblank interrupts off for
 376          * a long time.
 377          */
 378         cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
 379         diff = cur_vblank - dev->last_vblank[crtc];
 380         if (cur_vblank < dev->last_vblank[crtc]) {
 381                 diff += dev->max_vblank_count;
 382
 383                 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
 384                           crtc, dev->last_vblank[crtc], cur_vblank, diff);
 385         }
 386
 387         DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
 388                   crtc, diff);
 389
 390         atomic_add(diff, &dev->_vblank_count[crtc]);
 391 }
 392
 393 /**
 394  * drm_vblank_get - get a reference count on vblank events
 395  * @dev: DRM device
 396  * @crtc: which CRTC to own
 397  *
 398  * Acquire a reference count on vblank events to avoid having them disabled
 399  * while in use.
 400  *
 401  * RETURNS
 402  * Zero on success, nonzero on failure.
 403  */
 404 int drm_vblank_get(struct drm_device *dev, int crtc)
 405 {
 406         unsigned long irqflags;
 407         int ret = 0;
 408
 409         spin_lock_irqsave(&dev->vbl_lock, irqflags);
 410         /* Going from 0->1 means we have to enable interrupts again */
 411         if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1 &&
 412             !dev->vblank_enabled[crtc]) {
 413                 ret = dev->driver->enable_vblank(dev, crtc);
 414                 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
 415                 if (ret)
 416                         atomic_dec(&dev->vblank_refcount[crtc]);
 417                 else {
 418                         dev->vblank_enabled[crtc] = 1;
 419                         drm_update_vblank_count(dev, crtc);
 420                 }
 421         }
 422         spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 423
 424         return ret;
 425 }
 426 EXPORT_SYMBOL(drm_vblank_get);
 427
 428 /**
 429  * drm_vblank_put - give up ownership of vblank events
 430  * @dev: DRM device
 431  * @crtc: which counter to give up
 432  *
 433  * Release ownership of a given vblank counter, turning off interrupts
 434  * if possible.
 435  */
 436 void drm_vblank_put(struct drm_device *dev, int crtc)
 437 {
 438         /* Last user schedules interrupt disable */
 439         if (atomic_dec_and_test(&dev->vblank_refcount[crtc]))
 440                 mod_timer(&dev->vblank_disable_timer, jiffies + 5*DRM_HZ);
 441 }
 442 EXPORT_SYMBOL(drm_vblank_put);
 443
 444 /**
 445  * drm_vblank_pre_modeset - account for vblanks across mode sets
 446  * @dev: DRM device
 447  * @crtc: CRTC in question
 448  * @post: post or pre mode set?
 449  *
 450  * Account for vblank events across mode setting events, which will likely
 451  * reset the hardware frame counter.
 452  */
 453 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
 454 {
 455         /*
 456          * To avoid all the problems that might happen if interrupts
 457          * were enabled/disabled around or between these calls, we just
 458          * have the kernel take a reference on the CRTC (just once though
 459          * to avoid corrupting the count if multiple, mismatch calls occur),
 460          * so that interrupts remain enabled in the interim.
 461          */
 462         if (!dev->vblank_inmodeset[crtc]) {
 463                 dev->vblank_inmodeset[crtc] = 1;
 464                 drm_vblank_get(dev, crtc);
 465         }
 466 }
 467 EXPORT_SYMBOL(drm_vblank_pre_modeset);
 468
 469 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
 470 {
 471         unsigned long irqflags;
 472
 473         if (dev->vblank_inmodeset[crtc]) {
 474                 spin_lock_irqsave(&dev->vbl_lock, irqflags);
 475                 dev->vblank_disable_allowed = 1;
 476                 dev->vblank_inmodeset[crtc] = 0;
 477                 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 478                 drm_vblank_put(dev, crtc);
 479         }
 480 }
 481 EXPORT_SYMBOL(drm_vblank_post_modeset);
 482
 483 /**
 484  * drm_modeset_ctl - handle vblank event counter changes across mode switch
 485  * @DRM_IOCTL_ARGS: standard ioctl arguments
 486  *
 487  * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
 488  * ioctls around modesetting so that any lost vblank events are accounted for.
 489  *
 490  * Generally the counter will reset across mode sets.  If interrupts are
 491  * enabled around this call, we don't have to do anything since the counter
 492  * will have already been incremented.
 493  */
 494 int drm_modeset_ctl(struct drm_device *dev, void *data,
 495                     struct drm_file *file_priv)
 496 {
 497         struct drm_modeset_ctl *modeset = data;
 498         int crtc, ret = 0;
 499
 500         /* If drm_vblank_init() hasn't been called yet, just no-op */
 501         if (!dev->num_crtcs)
 502                 goto out;
 503
 504         crtc = modeset->crtc;
 505         if (crtc >= dev->num_crtcs) {
 506                 ret = -EINVAL;
 507                 goto out;
 508         }
 509
 510         switch (modeset->cmd) {
 511         case _DRM_PRE_MODESET:
 512                 drm_vblank_pre_modeset(dev, crtc);
 513                 break;
 514         case _DRM_POST_MODESET:
 515                 drm_vblank_post_modeset(dev, crtc);
 516                 break;
 517         default:
 518                 ret = -EINVAL;
 519                 break;
 520         }
 521
 522 out:
 523         return ret;
 524 }
 525
 526 /**
 527  * Wait for VBLANK.
 528  *
 529  * \param inode device inode.
 530  * \param file_priv DRM file private.
 531  * \param cmd command.
 532  * \param data user argument, pointing to a drm_wait_vblank structure.
 533  * \return zero on success or a negative number on failure.
 534  *
 535  * This function enables the vblank interrupt on the pipe requested, then
 536  * sleeps waiting for the requested sequence number to occur, and drops
 537  * the vblank interrupt refcount afterwards. (vblank irq disable follows that
 538  * after a timeout with no further vblank waits scheduled).
 539  */
 540 int drm_wait_vblank(struct drm_device *dev, void *data,
 541                     struct drm_file *file_priv)
 542 {
 543         union drm_wait_vblank *vblwait = data;
 544         int ret = 0;
 545         unsigned int flags, seq, crtc;
 546
 547         if ((!dev->pdev->irq) || (!dev->irq_enabled))
 548                 return -EINVAL;
 549
 550         if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
 551                 return -EINVAL;
 552
 553         if (vblwait->request.type &
 554             ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK)) {
 555                 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
 556                           vblwait->request.type,
 557                           (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK));
 558                 return -EINVAL;
 559         }
 560
 561         flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
 562         crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
 563
 564         if (crtc >= dev->num_crtcs)
 565                 return -EINVAL;
 566
 567         ret = drm_vblank_get(dev, crtc);
 568         if (ret) {
 569                 DRM_ERROR("failed to acquire vblank counter, %d\n", ret);
 570                 return ret;
 571         }
 572         seq = drm_vblank_count(dev, crtc);
 573
 574         switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
 575         case _DRM_VBLANK_RELATIVE:
 576                 vblwait->request.sequence += seq;
 577                 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
 578         case _DRM_VBLANK_ABSOLUTE:
 579                 break;
 580         default:
 581                 ret = -EINVAL;
 582                 goto done;
 583         }
 584
 585         if ((flags & _DRM_VBLANK_NEXTONMISS) &&
 586             (seq - vblwait->request.sequence) <= (1<<23)) {
 587                 vblwait->request.sequence = seq + 1;
 588         }
 589
 590         DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
 591                   vblwait->request.sequence, crtc);
 592         dev->last_vblank_wait[crtc] = vblwait->request.sequence;
 593         DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
 594                     (((drm_vblank_count(dev, crtc) -
 595                        vblwait->request.sequence) <= (1 << 23)) ||
 596                      !dev->irq_enabled));
 597
 598         if (ret != -EINTR) {
 599                 struct timeval now;
 600
 601                 do_gettimeofday(&now);
 602
 603                 vblwait->reply.tval_sec = now.tv_sec;
 604                 vblwait->reply.tval_usec = now.tv_usec;
 605                 vblwait->reply.sequence = drm_vblank_count(dev, crtc);
 606                 DRM_DEBUG("returning %d to client\n",
 607                           vblwait->reply.sequence);
 608         } else {
 609                 DRM_DEBUG("vblank wait interrupted by signal\n");
 610         }
 611
 612 done:
 613         drm_vblank_put(dev, crtc);
 614         return ret;
 615 }
 616
 617 /**
 618  * drm_handle_vblank - handle a vblank event
 619  * @dev: DRM device
 620  * @crtc: where this event occurred
 621  *
 622  * Drivers should call this routine in their vblank interrupt handlers to
 623  * update the vblank counter and send any signals that may be pending.
 624  */
 625 void drm_handle_vblank(struct drm_device *dev, int crtc)
 626 {
 627         atomic_inc(&dev->_vblank_count[crtc]);
 628         DRM_WAKEUP(&dev->vbl_queue[crtc]);
 629 }
 630 EXPORT_SYMBOL(drm_handle_vblank);