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