git.oblomov.eu Git - linux-2.6/blob - 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->vbl_sigs, sizeof(*dev->vbl_sigs) * dev->num_crtcs,
 110                  DRM_MEM_DRIVER);
 111         drm_free(dev->_vblank_count, sizeof(*dev->_vblank_count) *
 112                  dev->num_crtcs, DRM_MEM_DRIVER);
 113         drm_free(dev->vblank_refcount, sizeof(*dev->vblank_refcount) *
 114                  dev->num_crtcs, DRM_MEM_DRIVER);
 115         drm_free(dev->vblank_enabled, sizeof(*dev->vblank_enabled) *
 116                  dev->num_crtcs, DRM_MEM_DRIVER);
 117         drm_free(dev->last_vblank, sizeof(*dev->last_vblank) * dev->num_crtcs,
 118                  DRM_MEM_DRIVER);
 119         drm_free(dev->last_vblank_wait,
 120                  sizeof(*dev->last_vblank_wait) * dev->num_crtcs,
 121                  DRM_MEM_DRIVER);
 122         drm_free(dev->vblank_inmodeset, sizeof(*dev->vblank_inmodeset) *
 123                  dev->num_crtcs, DRM_MEM_DRIVER);
 124
 125         dev->num_crtcs = 0;
 126 }
 127
 128 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
 129 {
 130         int i, ret = -ENOMEM;
 131
 132         setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
 133                     (unsigned long)dev);
 134         spin_lock_init(&dev->vbl_lock);
 135         atomic_set(&dev->vbl_signal_pending, 0);
 136         dev->num_crtcs = num_crtcs;
 137
 138         dev->vbl_queue = drm_alloc(sizeof(wait_queue_head_t) * num_crtcs,
 139                                    DRM_MEM_DRIVER);
 140         if (!dev->vbl_queue)
 141                 goto err;
 142
 143         dev->vbl_sigs = drm_alloc(sizeof(struct list_head) * num_crtcs,
 144                                   DRM_MEM_DRIVER);
 145         if (!dev->vbl_sigs)
 146                 goto err;
 147
 148         dev->_vblank_count = drm_alloc(sizeof(atomic_t) * num_crtcs,
 149                                       DRM_MEM_DRIVER);
 150         if (!dev->_vblank_count)
 151                 goto err;
 152
 153         dev->vblank_refcount = drm_alloc(sizeof(atomic_t) * num_crtcs,
 154                                          DRM_MEM_DRIVER);
 155         if (!dev->vblank_refcount)
 156                 goto err;
 157
 158         dev->vblank_enabled = drm_calloc(num_crtcs, sizeof(int),
 159                                          DRM_MEM_DRIVER);
 160         if (!dev->vblank_enabled)
 161                 goto err;
 162
 163         dev->last_vblank = drm_calloc(num_crtcs, sizeof(u32), DRM_MEM_DRIVER);
 164         if (!dev->last_vblank)
 165                 goto err;
 166
 167         dev->last_vblank_wait = drm_calloc(num_crtcs, sizeof(u32),
 168                                            DRM_MEM_DRIVER);
 169         if (!dev->last_vblank_wait)
 170                 goto err;
 171
 172         dev->vblank_inmodeset = drm_calloc(num_crtcs, sizeof(int),
 173                                          DRM_MEM_DRIVER);
 174         if (!dev->vblank_inmodeset)
 175                 goto err;
 176
 177         /* Zero per-crtc vblank stuff */
 178         for (i = 0; i < num_crtcs; i++) {
 179                 init_waitqueue_head(&dev->vbl_queue[i]);
 180                 INIT_LIST_HEAD(&dev->vbl_sigs[i]);
 181                 atomic_set(&dev->_vblank_count[i], 0);
 182                 atomic_set(&dev->vblank_refcount[i], 0);
 183         }
 184
 185         dev->vblank_disable_allowed = 0;
 186
 187         return 0;
 188
 189 err:
 190         drm_vblank_cleanup(dev);
 191         return ret;
 192 }
 193 EXPORT_SYMBOL(drm_vblank_init);
 194
 195 /**
 196  * Install IRQ handler.
 197  *
 198  * \param dev DRM device.
 199  *
 200  * Initializes the IRQ related data. Installs the handler, calling the driver
 201  * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
 202  * before and after the installation.
 203  */
 204 int drm_irq_install(struct drm_device *dev)
 205 {
 206         int ret = 0;
 207         unsigned long sh_flags = 0;
 208
 209         if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 210                 return -EINVAL;
 211
 212         if (dev->pdev->irq == 0)
 213                 return -EINVAL;
 214
 215         mutex_lock(&dev->struct_mutex);
 216
 217         /* Driver must have been initialized */
 218         if (!dev->dev_private) {
 219                 mutex_unlock(&dev->struct_mutex);
 220                 return -EINVAL;
 221         }
 222
 223         if (dev->irq_enabled) {
 224                 mutex_unlock(&dev->struct_mutex);
 225                 return -EBUSY;
 226         }
 227         dev->irq_enabled = 1;
 228         mutex_unlock(&dev->struct_mutex);
 229
 230         DRM_DEBUG("irq=%d\n", dev->pdev->irq);
 231
 232         /* Before installing handler */
 233         dev->driver->irq_preinstall(dev);
 234
 235         /* Install handler */
 236         if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
 237                 sh_flags = IRQF_SHARED;
 238
 239         ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
 240                           sh_flags, dev->devname, dev);
 241
 242         if (ret < 0) {
 243                 mutex_lock(&dev->struct_mutex);
 244                 dev->irq_enabled = 0;
 245                 mutex_unlock(&dev->struct_mutex);
 246                 return ret;
 247         }
 248
 249         /* After installing handler */
 250         ret = dev->driver->irq_postinstall(dev);
 251         if (ret < 0) {
 252                 mutex_lock(&dev->struct_mutex);
 253                 dev->irq_enabled = 0;
 254                 mutex_unlock(&dev->struct_mutex);
 255         }
 256
 257         return ret;
 258 }
 259 EXPORT_SYMBOL(drm_irq_install);
 260
 261 /**
 262  * Uninstall the IRQ handler.
 263  *
 264  * \param dev DRM device.
 265  *
 266  * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq.
 267  */
 268 int drm_irq_uninstall(struct drm_device * dev)
 269 {
 270         int irq_enabled;
 271
 272         if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 273                 return -EINVAL;
 274
 275         mutex_lock(&dev->struct_mutex);
 276         irq_enabled = dev->irq_enabled;
 277         dev->irq_enabled = 0;
 278         mutex_unlock(&dev->struct_mutex);
 279
 280         if (!irq_enabled)
 281                 return -EINVAL;
 282
 283         DRM_DEBUG("irq=%d\n", dev->pdev->irq);
 284
 285         dev->driver->irq_uninstall(dev);
 286
 287         free_irq(dev->pdev->irq, dev);
 288
 289         return 0;
 290 }
 291 EXPORT_SYMBOL(drm_irq_uninstall);
 292
 293 /**
 294  * IRQ control ioctl.
 295  *
 296  * \param inode device inode.
 297  * \param file_priv DRM file private.
 298  * \param cmd command.
 299  * \param arg user argument, pointing to a drm_control structure.
 300  * \return zero on success or a negative number on failure.
 301  *
 302  * Calls irq_install() or irq_uninstall() according to \p arg.
 303  */
 304 int drm_control(struct drm_device *dev, void *data,
 305                 struct drm_file *file_priv)
 306 {
 307         struct drm_control *ctl = data;
 308
 309         /* if we haven't irq we fallback for compatibility reasons - this used to be a separate function in drm_dma.h */
 310
 311
 312         switch (ctl->func) {
 313         case DRM_INST_HANDLER:
 314                 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 315                         return 0;
 316                 if (drm_core_check_feature(dev, DRIVER_MODESET))
 317                         return 0;
 318                 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
 319                     ctl->irq != dev->pdev->irq)
 320                         return -EINVAL;
 321                 return drm_irq_install(dev);
 322         case DRM_UNINST_HANDLER:
 323                 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 324                         return 0;
 325                 if (drm_core_check_feature(dev, DRIVER_MODESET))
 326                         return 0;
 327                 return drm_irq_uninstall(dev);
 328         default:
 329                 return -EINVAL;
 330         }
 331 }
 332
 333 /**
 334  * drm_vblank_count - retrieve "cooked" vblank counter value
 335  * @dev: DRM device
 336  * @crtc: which counter to retrieve
 337  *
 338  * Fetches the "cooked" vblank count value that represents the number of
 339  * vblank events since the system was booted, including lost events due to
 340  * modesetting activity.
 341  */
 342 u32 drm_vblank_count(struct drm_device *dev, int crtc)
 343 {
 344         return atomic_read(&dev->_vblank_count[crtc]);
 345 }
 346 EXPORT_SYMBOL(drm_vblank_count);
 347
 348 /**
 349  * drm_update_vblank_count - update the master vblank counter
 350  * @dev: DRM device
 351  * @crtc: counter to update
 352  *
 353  * Call back into the driver to update the appropriate vblank counter
 354  * (specified by @crtc).  Deal with wraparound, if it occurred, and
 355  * update the last read value so we can deal with wraparound on the next
 356  * call if necessary.
 357  *
 358  * Only necessary when going from off->on, to account for frames we
 359  * didn't get an interrupt for.
 360  *
 361  * Note: caller must hold dev->vbl_lock since this reads & writes
 362  * device vblank fields.
 363  */
 364 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
 365 {
 366         u32 cur_vblank, diff;
 367
 368         /*
 369          * Interrupts were disabled prior to this call, so deal with counter
 370          * wrap if needed.
 371          * NOTE!  It's possible we lost a full dev->max_vblank_count events
 372          * here if the register is small or we had vblank interrupts off for
 373          * a long time.
 374          */
 375         cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
 376         diff = cur_vblank - dev->last_vblank[crtc];
 377         if (cur_vblank < dev->last_vblank[crtc]) {
 378                 diff += dev->max_vblank_count;
 379
 380                 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
 381                           crtc, dev->last_vblank[crtc], cur_vblank, diff);
 382         }
 383
 384         DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
 385                   crtc, diff);
 386
 387         atomic_add(diff, &dev->_vblank_count[crtc]);
 388 }
 389
 390 /**
 391  * drm_vblank_get - get a reference count on vblank events
 392  * @dev: DRM device
 393  * @crtc: which CRTC to own
 394  *
 395  * Acquire a reference count on vblank events to avoid having them disabled
 396  * while in use.
 397  *
 398  * RETURNS
 399  * Zero on success, nonzero on failure.
 400  */
 401 int drm_vblank_get(struct drm_device *dev, int crtc)
 402 {
 403         unsigned long irqflags;
 404         int ret = 0;
 405
 406         spin_lock_irqsave(&dev->vbl_lock, irqflags);
 407         /* Going from 0->1 means we have to enable interrupts again */
 408         if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1 &&
 409             !dev->vblank_enabled[crtc]) {
 410                 ret = dev->driver->enable_vblank(dev, crtc);
 411                 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
 412                 if (ret)
 413                         atomic_dec(&dev->vblank_refcount[crtc]);
 414                 else {
 415                         dev->vblank_enabled[crtc] = 1;
 416                         drm_update_vblank_count(dev, crtc);
 417                 }
 418         }
 419         spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 420
 421         return ret;
 422 }
 423 EXPORT_SYMBOL(drm_vblank_get);
 424
 425 /**
 426  * drm_vblank_put - give up ownership of vblank events
 427  * @dev: DRM device
 428  * @crtc: which counter to give up
 429  *
 430  * Release ownership of a given vblank counter, turning off interrupts
 431  * if possible.
 432  */
 433 void drm_vblank_put(struct drm_device *dev, int crtc)
 434 {
 435         /* Last user schedules interrupt disable */
 436         if (atomic_dec_and_test(&dev->vblank_refcount[crtc]))
 437                 mod_timer(&dev->vblank_disable_timer, jiffies + 5*DRM_HZ);
 438 }
 439 EXPORT_SYMBOL(drm_vblank_put);
 440
 441 /**
 442  * drm_vblank_pre_modeset - account for vblanks across mode sets
 443  * @dev: DRM device
 444  * @crtc: CRTC in question
 445  * @post: post or pre mode set?
 446  *
 447  * Account for vblank events across mode setting events, which will likely
 448  * reset the hardware frame counter.
 449  */
 450 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
 451 {
 452         /*
 453          * To avoid all the problems that might happen if interrupts
 454          * were enabled/disabled around or between these calls, we just
 455          * have the kernel take a reference on the CRTC (just once though
 456          * to avoid corrupting the count if multiple, mismatch calls occur),
 457          * so that interrupts remain enabled in the interim.
 458          */
 459         if (!dev->vblank_inmodeset[crtc]) {
 460                 dev->vblank_inmodeset[crtc] = 1;
 461                 drm_vblank_get(dev, crtc);
 462         }
 463 }
 464 EXPORT_SYMBOL(drm_vblank_pre_modeset);
 465
 466 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
 467 {
 468         unsigned long irqflags;
 469
 470         if (dev->vblank_inmodeset[crtc]) {
 471                 spin_lock_irqsave(&dev->vbl_lock, irqflags);
 472                 dev->vblank_disable_allowed = 1;
 473                 dev->vblank_inmodeset[crtc] = 0;
 474                 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 475                 drm_vblank_put(dev, crtc);
 476         }
 477 }
 478 EXPORT_SYMBOL(drm_vblank_post_modeset);
 479
 480 /**
 481  * drm_modeset_ctl - handle vblank event counter changes across mode switch
 482  * @DRM_IOCTL_ARGS: standard ioctl arguments
 483  *
 484  * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
 485  * ioctls around modesetting so that any lost vblank events are accounted for.
 486  *
 487  * Generally the counter will reset across mode sets.  If interrupts are
 488  * enabled around this call, we don't have to do anything since the counter
 489  * will have already been incremented.
 490  */
 491 int drm_modeset_ctl(struct drm_device *dev, void *data,
 492                     struct drm_file *file_priv)
 493 {
 494         struct drm_modeset_ctl *modeset = data;
 495         int crtc, ret = 0;
 496
 497         /* If drm_vblank_init() hasn't been called yet, just no-op */
 498         if (!dev->num_crtcs)
 499                 goto out;
 500
 501         crtc = modeset->crtc;
 502         if (crtc >= dev->num_crtcs) {
 503                 ret = -EINVAL;
 504                 goto out;
 505         }
 506
 507         switch (modeset->cmd) {
 508         case _DRM_PRE_MODESET:
 509                 drm_vblank_pre_modeset(dev, crtc);
 510                 break;
 511         case _DRM_POST_MODESET:
 512                 drm_vblank_post_modeset(dev, crtc);
 513                 break;
 514         default:
 515                 ret = -EINVAL;
 516                 break;
 517         }
 518
 519 out:
 520         return ret;
 521 }
 522
 523 /**
 524  * Wait for VBLANK.
 525  *
 526  * \param inode device inode.
 527  * \param file_priv DRM file private.
 528  * \param cmd command.
 529  * \param data user argument, pointing to a drm_wait_vblank structure.
 530  * \return zero on success or a negative number on failure.
 531  *
 532  * Verifies the IRQ is installed.
 533  *
 534  * If a signal is requested checks if this task has already scheduled the same signal
 535  * for the same vblank sequence number - nothing to be done in
 536  * that case. If the number of tasks waiting for the interrupt exceeds 100 the
 537  * function fails. Otherwise adds a new entry to drm_device::vbl_sigs for this
 538  * task.
 539  *
 540  * If a signal is not requested, then calls vblank_wait().
 541  */
 542 int drm_wait_vblank(struct drm_device *dev, void *data,
 543                     struct drm_file *file_priv)
 544 {
 545         union drm_wait_vblank *vblwait = data;
 546         int ret = 0;
 547         unsigned int flags, seq, crtc;
 548
 549         if ((!dev->pdev->irq) || (!dev->irq_enabled))
 550                 return -EINVAL;
 551
 552         if (vblwait->request.type &
 553             ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK)) {
 554                 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
 555                           vblwait->request.type,
 556                           (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK));
 557                 return -EINVAL;
 558         }
 559
 560         flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
 561         crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
 562
 563         if (crtc >= dev->num_crtcs)
 564                 return -EINVAL;
 565
 566         ret = drm_vblank_get(dev, crtc);
 567         if (ret) {
 568                 DRM_ERROR("failed to acquire vblank counter, %d\n", ret);
 569                 return ret;
 570         }
 571         seq = drm_vblank_count(dev, crtc);
 572
 573         switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
 574         case _DRM_VBLANK_RELATIVE:
 575                 vblwait->request.sequence += seq;
 576                 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
 577         case _DRM_VBLANK_ABSOLUTE:
 578                 break;
 579         default:
 580                 ret = -EINVAL;
 581                 goto done;
 582         }
 583
 584         if ((flags & _DRM_VBLANK_NEXTONMISS) &&
 585             (seq - vblwait->request.sequence) <= (1<<23)) {
 586                 vblwait->request.sequence = seq + 1;
 587         }
 588
 589         if (flags & _DRM_VBLANK_SIGNAL) {
 590                 unsigned long irqflags;
 591                 struct list_head *vbl_sigs = &dev->vbl_sigs[crtc];
 592                 struct drm_vbl_sig *vbl_sig;
 593
 594                 spin_lock_irqsave(&dev->vbl_lock, irqflags);
 595
 596                 /* Check if this task has already scheduled the same signal
 597                  * for the same vblank sequence number; nothing to be done in
 598                  * that case
 599                  */
 600                 list_for_each_entry(vbl_sig, vbl_sigs, head) {
 601                         if (vbl_sig->sequence == vblwait->request.sequence
 602                             && vbl_sig->info.si_signo ==
 603                             vblwait->request.signal
 604                             && vbl_sig->task == current) {
 605                                 spin_unlock_irqrestore(&dev->vbl_lock,
 606                                                        irqflags);
 607                                 vblwait->reply.sequence = seq;
 608                                 goto done;
 609                         }
 610                 }
 611
 612                 if (atomic_read(&dev->vbl_signal_pending) >= 100) {
 613                         spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 614                         ret = -EBUSY;
 615                         goto done;
 616                 }
 617
 618                 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 619
 620                 vbl_sig = drm_calloc(1, sizeof(struct drm_vbl_sig),
 621                                      DRM_MEM_DRIVER);
 622                 if (!vbl_sig) {
 623                         ret = -ENOMEM;
 624                         goto done;
 625                 }
 626
 627                 /* Get a refcount on the vblank, which will be released by
 628                  * drm_vbl_send_signals().
 629                  */
 630                 ret = drm_vblank_get(dev, crtc);
 631                 if (ret) {
 632                         drm_free(vbl_sig, sizeof(struct drm_vbl_sig),
 633                                  DRM_MEM_DRIVER);
 634                         goto done;
 635                 }
 636
 637                 atomic_inc(&dev->vbl_signal_pending);
 638
 639                 vbl_sig->sequence = vblwait->request.sequence;
 640                 vbl_sig->info.si_signo = vblwait->request.signal;
 641                 vbl_sig->task = current;
 642
 643                 spin_lock_irqsave(&dev->vbl_lock, irqflags);
 644
 645                 list_add_tail(&vbl_sig->head, vbl_sigs);
 646
 647                 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 648
 649                 vblwait->reply.sequence = seq;
 650         } else {
 651                 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
 652                           vblwait->request.sequence, crtc);
 653                 dev->last_vblank_wait[crtc] = vblwait->request.sequence;
 654                 DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
 655                             ((drm_vblank_count(dev, crtc)
 656                               - vblwait->request.sequence) <= (1 << 23)));
 657
 658                 if (ret != -EINTR) {
 659                         struct timeval now;
 660
 661                         do_gettimeofday(&now);
 662
 663                         vblwait->reply.tval_sec = now.tv_sec;
 664                         vblwait->reply.tval_usec = now.tv_usec;
 665                         vblwait->reply.sequence = drm_vblank_count(dev, crtc);
 666                         DRM_DEBUG("returning %d to client\n",
 667                                   vblwait->reply.sequence);
 668                 } else {
 669                         DRM_DEBUG("vblank wait interrupted by signal\n");
 670                 }
 671         }
 672
 673 done:
 674         drm_vblank_put(dev, crtc);
 675         return ret;
 676 }
 677
 678 /**
 679  * Send the VBLANK signals.
 680  *
 681  * \param dev DRM device.
 682  * \param crtc CRTC where the vblank event occurred
 683  *
 684  * Sends a signal for each task in drm_device::vbl_sigs and empties the list.
 685  *
 686  * If a signal is not requested, then calls vblank_wait().
 687  */
 688 static void drm_vbl_send_signals(struct drm_device *dev, int crtc)
 689 {
 690         struct drm_vbl_sig *vbl_sig, *tmp;
 691         struct list_head *vbl_sigs;
 692         unsigned int vbl_seq;
 693         unsigned long flags;
 694
 695         spin_lock_irqsave(&dev->vbl_lock, flags);
 696
 697         vbl_sigs = &dev->vbl_sigs[crtc];
 698         vbl_seq = drm_vblank_count(dev, crtc);
 699
 700         list_for_each_entry_safe(vbl_sig, tmp, vbl_sigs, head) {
 701             if ((vbl_seq - vbl_sig->sequence) <= (1 << 23)) {
 702                 vbl_sig->info.si_code = vbl_seq;
 703                 send_sig_info(vbl_sig->info.si_signo,
 704                               &vbl_sig->info, vbl_sig->task);
 705
 706                 list_del(&vbl_sig->head);
 707
 708                 drm_free(vbl_sig, sizeof(*vbl_sig),
 709                          DRM_MEM_DRIVER);
 710                 atomic_dec(&dev->vbl_signal_pending);
 711                 drm_vblank_put(dev, crtc);
 712             }
 713         }
 714
 715         spin_unlock_irqrestore(&dev->vbl_lock, flags);
 716 }
 717
 718 /**
 719  * drm_handle_vblank - handle a vblank event
 720  * @dev: DRM device
 721  * @crtc: where this event occurred
 722  *
 723  * Drivers should call this routine in their vblank interrupt handlers to
 724  * update the vblank counter and send any signals that may be pending.
 725  */
 726 void drm_handle_vblank(struct drm_device *dev, int crtc)
 727 {
 728         atomic_inc(&dev->_vblank_count[crtc]);
 729         DRM_WAKEUP(&dev->vbl_queue[crtc]);
 730         drm_vbl_send_signals(dev, crtc);
 731 }
 732 EXPORT_SYMBOL(drm_handle_vblank);