summaryrefslogtreecommitdiffstats
path: root/common
ModeNameSize
-rw-r--r--COPYING35147logstatsplain
-rw-r--r--COPYING.LESSER7643logstatsplain
-rw-r--r--Makefile.am575logstatsplain
-rw-r--r--README230logstatsplain
d---------collection827logstatsplain
-rw-r--r--configure.ac1180logstatsplain
d---------dhash300logstatsplain
d---------elapi1150logstatsplain
d---------ini343logstatsplain
d---------m432logstatsplain
d---------path_utils232logstatsplain
d---------trace74logstatsplain
'#n286'>286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699
/**
 * \file drm_irq.c
 * IRQ support
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
 *
 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#include "drmP.h"

#include <linux/interrupt.h>	/* For task queue support */

/**
 * Get interrupt from bus id.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument, pointing to a drm_irq_busid structure.
 * \return zero on success or a negative number on failure.
 *
 * Finds the PCI device with the specified bus id and gets its IRQ number.
 * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
 * to that of the device that this DRM instance attached to.
 */
int drm_irq_by_busid(struct drm_device *dev, void *data,
		     struct drm_file *file_priv)
{
	struct drm_irq_busid *p = data;

	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return -EINVAL;

	if ((p->busnum >> 8) != drm_get_pci_domain(dev) ||
	    (p->busnum & 0xff) != dev->pdev->bus->number ||
	    p->devnum != PCI_SLOT(dev->pdev->devfn) || p->funcnum != PCI_FUNC(dev->pdev->devfn))
		return -EINVAL;

	p->irq = dev->pdev->irq;

	DRM_DEBUG("%d:%d:%d => IRQ %d\n", p->busnum, p->devnum, p->funcnum,
		  p->irq);

	return 0;
}

static void vblank_disable_fn(unsigned long arg)
{
	struct drm_device *dev = (struct drm_device *)arg;
	unsigned long irqflags;
	int i;

	if (!dev->vblank_disable_allowed)
		return;

	for (i = 0; i < dev->num_crtcs; i++) {
		spin_lock_irqsave(&dev->vbl_lock, irqflags);
		if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
		    dev->vblank_enabled[i]) {
			DRM_DEBUG("disabling vblank on crtc %d\n", i);
			dev->last_vblank[i] =
				dev->driver->get_vblank_counter(dev, i);
			dev->driver->disable_vblank(dev, i);
			dev->vblank_enabled[i] = 0;
		}
		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
	}
}

static void drm_vblank_cleanup(struct drm_device *dev)
{
	/* Bail if the driver didn't call drm_vblank_init() */
	if (dev->num_crtcs == 0)
		return;

	del_timer(&dev->vblank_disable_timer);

	vblank_disable_fn((unsigned long)dev);

	drm_free(dev->vbl_queue, sizeof(*dev->vbl_queue) * dev->num_crtcs,
		 DRM_MEM_DRIVER);
	drm_free(dev->vbl_sigs, sizeof(*dev->vbl_sigs) * dev->num_crtcs,
		 DRM_MEM_DRIVER);
	drm_free(dev->_vblank_count, sizeof(*dev->_vblank_count) *
		 dev->num_crtcs, DRM_MEM_DRIVER);
	drm_free(dev->vblank_refcount, sizeof(*dev->vblank_refcount) *
		 dev->num_crtcs, DRM_MEM_DRIVER);
	drm_free(dev->vblank_enabled, sizeof(*dev->vblank_enabled) *
		 dev->num_crtcs, DRM_MEM_DRIVER);
	drm_free(dev->last_vblank, sizeof(*dev->last_vblank) * dev->num_crtcs,
		 DRM_MEM_DRIVER);
	drm_free(dev->vblank_inmodeset, sizeof(*dev->vblank_inmodeset) *
		 dev->num_crtcs, DRM_MEM_DRIVER);

	dev->num_crtcs = 0;
}

int drm_vblank_init(struct drm_device *dev, int num_crtcs)
{
	int i, ret = -ENOMEM;

	setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
		    (unsigned long)dev);
	spin_lock_init(&dev->vbl_lock);
	atomic_set(&dev->vbl_signal_pending, 0);
	dev->num_crtcs = num_crtcs;

	dev->vbl_queue = drm_alloc(sizeof(wait_queue_head_t) * num_crtcs,
				   DRM_MEM_DRIVER);
	if (!dev->vbl_queue)
		goto err;

	dev->vbl_sigs = drm_alloc(sizeof(struct list_head) * num_crtcs,
				  DRM_MEM_DRIVER);
	if (!dev->vbl_sigs)
		goto err;

	dev->_vblank_count = drm_alloc(sizeof(atomic_t) * num_crtcs,
				      DRM_MEM_DRIVER);
	if (!dev->_vblank_count)
		goto err;

	dev->vblank_refcount = drm_alloc(sizeof(atomic_t) * num_crtcs,
					 DRM_MEM_DRIVER);
	if (!dev->vblank_refcount)
		goto err;

	dev->vblank_enabled = drm_calloc(num_crtcs, sizeof(int),
					 DRM_MEM_DRIVER);
	if (!dev->vblank_enabled)
		goto err;

	dev->last_vblank = drm_calloc(num_crtcs, sizeof(u32), DRM_MEM_DRIVER);
	if (!dev->last_vblank)
		goto err;

	dev->vblank_inmodeset = drm_calloc(num_crtcs, sizeof(int),
					 DRM_MEM_DRIVER);
	if (!dev->vblank_inmodeset)
		goto err;

	/* Zero per-crtc vblank stuff */
	for (i = 0; i < num_crtcs; i++) {
		init_waitqueue_head(&dev->vbl_queue[i]);
		INIT_LIST_HEAD(&dev->vbl_sigs[i]);
		atomic_set(&dev->_vblank_count[i], 0);
		atomic_set(&dev->vblank_refcount[i], 0);
	}

	dev->vblank_disable_allowed = 0;

	return 0;

err:
	drm_vblank_cleanup(dev);
	return ret;
}
EXPORT_SYMBOL(drm_vblank_init);

/**
 * Install IRQ handler.
 *
 * \param dev DRM device.
 *
 * Initializes the IRQ related data. Installs the handler, calling the driver
 * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
 * before and after the installation.
 */
int drm_irq_install(struct drm_device *dev)
{
	int ret = 0;
	unsigned long sh_flags = 0;

	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return -EINVAL;

	if (dev->pdev->irq == 0)
		return -EINVAL;

	mutex_lock(&dev->struct_mutex);

	/* Driver must have been initialized */
	if (!dev->dev_private) {
		mutex_unlock(&dev->struct_mutex);
		return -EINVAL;
	}

	if (dev->irq_enabled) {
		mutex_unlock(&dev->struct_mutex);
		return -EBUSY;
	}
	dev->irq_enabled = 1;
	mutex_unlock(&dev->struct_mutex);

	DRM_DEBUG("irq=%d\n", dev->pdev->irq);

	/* Before installing handler */
	dev->driver->irq_preinstall(dev);

	/* Install handler */
	if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
		sh_flags = IRQF_SHARED;

	ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
			  sh_flags, dev->devname, dev);

	if (ret < 0) {
		mutex_lock(&dev->struct_mutex);
		dev->irq_enabled = 0;
		mutex_unlock(&dev->struct_mutex);
		return ret;
	}

	/* After installing handler */
	ret = dev->driver->irq_postinstall(dev);
	if (ret < 0) {
		mutex_lock(&dev->struct_mutex);
		dev->irq_enabled = 0;
		mutex_unlock(&dev->struct_mutex);
	}

	return ret;
}
EXPORT_SYMBOL(drm_irq_install);

/**
 * Uninstall the IRQ handler.
 *
 * \param dev DRM device.
 *
 * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq.
 */
int drm_irq_uninstall(struct drm_device * dev)
{
	int irq_enabled;

	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return -EINVAL;

	mutex_lock(&dev->struct_mutex);
	irq_enabled = dev->irq_enabled;
	dev->irq_enabled = 0;
	mutex_unlock(&dev->struct_mutex);

	if (!irq_enabled)
		return -EINVAL;

	DRM_DEBUG("irq=%d\n", dev->pdev->irq);

	dev->driver->irq_uninstall(dev);

	free_irq(dev->pdev->irq, dev);

	drm_vblank_cleanup(dev);

	return 0;
}
EXPORT_SYMBOL(drm_irq_uninstall);

/**
 * IRQ control ioctl.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument, pointing to a drm_control structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls irq_install() or irq_uninstall() according to \p arg.
 */
int drm_control(struct drm_device *dev, void *data,
		struct drm_file *file_priv)
{
	struct drm_control *ctl = data;

	/* if we haven't irq we fallback for compatibility reasons - this used to be a separate function in drm_dma.h */


	switch (ctl->func) {
	case DRM_INST_HANDLER:
		if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
			return 0;
		if (dev->if_version < DRM_IF_VERSION(1, 2) &&
		    ctl->irq != dev->pdev->irq)
			return -EINVAL;
		return drm_irq_install(dev);
	case DRM_UNINST_HANDLER:
		if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
			return 0;
		return drm_irq_uninstall(dev);
	default:
		return -EINVAL;
	}
}

/**
 * drm_vblank_count - retrieve "cooked" vblank counter value
 * @dev: DRM device
 * @crtc: which counter to retrieve
 *
 * Fetches the "cooked" vblank count value that represents the number of
 * vblank events since the system was booted, including lost events due to
 * modesetting activity.
 */
u32 drm_vblank_count(struct drm_device *dev, int crtc)
{
	return atomic_read(&dev->_vblank_count[crtc]);
}
EXPORT_SYMBOL(drm_vblank_count);

/**
 * drm_update_vblank_count - update the master vblank counter
 * @dev: DRM device
 * @crtc: counter to update
 *
 * Call back into the driver to update the appropriate vblank counter
 * (specified by @crtc).  Deal with wraparound, if it occurred, and
 * update the last read value so we can deal with wraparound on the next
 * call if necessary.
 *
 * Only necessary when going from off->on, to account for frames we
 * didn't get an interrupt for.
 *
 * Note: caller must hold dev->vbl_lock since this reads & writes
 * device vblank fields.
 */
static void drm_update_vblank_count(struct drm_device *dev, int crtc)
{
	u32 cur_vblank, diff;

	/*
	 * Interrupts were disabled prior to this call, so deal with counter
	 * wrap if needed.
	 * NOTE!  It's possible we lost a full dev->max_vblank_count events
	 * here if the register is small or we had vblank interrupts off for
	 * a long time.
	 */
	cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
	diff = cur_vblank - dev->last_vblank[crtc];
	if (cur_vblank < dev->last_vblank[crtc]) {
		diff += dev->max_vblank_count;

		DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
			  crtc, dev->last_vblank[crtc], cur_vblank, diff);
	}

	DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
		  crtc, diff);

	atomic_add(diff, &dev->_vblank_count[crtc]);
}

/**
 * drm_vblank_get - get a reference count on vblank events
 * @dev: DRM device
 * @crtc: which CRTC to own
 *
 * Acquire a reference count on vblank events to avoid having them disabled
 * while in use.
 *
 * RETURNS
 * Zero on success, nonzero on failure.
 */
int drm_vblank_get(struct drm_device *dev, int crtc)
{
	unsigned long irqflags;
	int ret = 0;

	spin_lock_irqsave(&dev->vbl_lock, irqflags);
	/* Going from 0->1 means we have to enable interrupts again */
	if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1 &&
	    !dev->vblank_enabled[crtc]) {
		ret = dev->driver->enable_vblank(dev, crtc);
		DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
		if (ret)
			atomic_dec(&dev->vblank_refcount[crtc]);
		else {
			dev->vblank_enabled[crtc] = 1;
			drm_update_vblank_count(dev, crtc);
		}
	}
	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

	return ret;
}
EXPORT_SYMBOL(drm_vblank_get);

/**
 * drm_vblank_put - give up ownership of vblank events
 * @dev: DRM device
 * @crtc: which counter to give up
 *
 * Release ownership of a given vblank counter, turning off interrupts
 * if possible.
 */
void drm_vblank_put(struct drm_device *dev, int crtc)
{
	/* Last user schedules interrupt disable */
	if (atomic_dec_and_test(&dev->vblank_refcount[crtc]))
		mod_timer(&dev->vblank_disable_timer, jiffies + 5*DRM_HZ);
}
EXPORT_SYMBOL(drm_vblank_put);

/**
 * drm_modeset_ctl - handle vblank event counter changes across mode switch
 * @DRM_IOCTL_ARGS: standard ioctl arguments
 *
 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
 * ioctls around modesetting so that any lost vblank events are accounted for.
 *
 * Generally the counter will reset across mode sets.  If interrupts are
 * enabled around this call, we don't have to do anything since the counter
 * will have already been incremented.
 */
int drm_modeset_ctl(struct drm_device *dev, void *data,
		    struct drm_file *file_priv)
{
	struct drm_modeset_ctl *modeset = data;
	unsigned long irqflags;
	int crtc, ret = 0;

	/* If drm_vblank_init() hasn't been called yet, just no-op */
	if (!dev->num_crtcs)
		goto out;

	crtc = modeset->crtc;
	if (crtc >= dev->num_crtcs) {
		ret = -EINVAL;
		goto out;
	}

	/*
	 * To avoid all the problems that might happen if interrupts
	 * were enabled/disabled around or between these calls, we just
	 * have the kernel take a reference on the CRTC (just once though
	 * to avoid corrupting the count if multiple, mismatch calls occur),
	 * so that interrupts remain enabled in the interim.
	 */
	switch (modeset->cmd) {
	case _DRM_PRE_MODESET:
		if (!dev->vblank_inmodeset[crtc]) {
			dev->vblank_inmodeset[crtc] = 1;
			drm_vblank_get(dev, crtc);
		}
		break;
	case _DRM_POST_MODESET:
		if (dev->vblank_inmodeset[crtc]) {
			spin_lock_irqsave(&dev->vbl_lock, irqflags);
			dev->vblank_disable_allowed = 1;
			dev->vblank_inmodeset[crtc] = 0;
			spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
			drm_vblank_put(dev, crtc);
		}
		break;
	default:
		ret = -EINVAL;
		break;
	}

out:
	return ret;
}

/**
 * Wait for VBLANK.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param data user argument, pointing to a drm_wait_vblank structure.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the IRQ is installed.
 *
 * If a signal is requested checks if this task has already scheduled the same signal
 * for the same vblank sequence number - nothing to be done in
 * that case. If the number of tasks waiting for the interrupt exceeds 100 the
 * function fails. Otherwise adds a new entry to drm_device::vbl_sigs for this
 * task.
 *
 * If a signal is not requested, then calls vblank_wait().
 */
int drm_wait_vblank(struct drm_device *dev, void *data,
		    struct drm_file *file_priv)
{
	union drm_wait_vblank *vblwait = data;
	int ret = 0;
	unsigned int flags, seq, crtc;

	if ((!dev->pdev->irq) || (!dev->irq_enabled))
		return -EINVAL;

	if (vblwait->request.type &
	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK)) {
		DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
			  vblwait->request.type,
			  (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK));
		return -EINVAL;
	}

	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
	crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;

	if (crtc >= dev->num_crtcs)
		return -EINVAL;

	ret = drm_vblank_get(dev, crtc);
	if (ret) {
		DRM_ERROR("failed to acquire vblank counter, %d\n", ret);
		return ret;
	}
	seq = drm_vblank_count(dev, crtc);

	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
	case _DRM_VBLANK_RELATIVE:
		vblwait->request.sequence += seq;
		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
	case _DRM_VBLANK_ABSOLUTE:
		break;
	default:
		ret = -EINVAL;
		goto done;
	}

	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
	    (seq - vblwait->request.sequence) <= (1<<23)) {
		vblwait->request.sequence = seq + 1;
	}

	if (flags & _DRM_VBLANK_SIGNAL) {
		unsigned long irqflags;
		struct list_head *vbl_sigs = &dev->vbl_sigs[crtc];
		struct drm_vbl_sig *vbl_sig;

		spin_lock_irqsave(&dev->vbl_lock, irqflags);

		/* Check if this task has already scheduled the same signal
		 * for the same vblank sequence number; nothing to be done in
		 * that case
		 */
		list_for_each_entry(vbl_sig, vbl_sigs, head) {
			if (vbl_sig->sequence == vblwait->request.sequence
			    && vbl_sig->info.si_signo ==
			    vblwait->request.signal
			    && vbl_sig->task == current) {
				spin_unlock_irqrestore(&dev->vbl_lock,
						       irqflags);
				vblwait->reply.sequence = seq;
				goto done;
			}
		}

		if (atomic_read(&dev->vbl_signal_pending) >= 100) {
			spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
			ret = -EBUSY;
			goto done;
		}

		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

		vbl_sig = drm_calloc(1, sizeof(struct drm_vbl_sig),
				     DRM_MEM_DRIVER);
		if (!vbl_sig) {
			ret = -ENOMEM;
			goto done;
		}

		/* Get a refcount on the vblank, which will be released by
		 * drm_vbl_send_signals().
		 */
		ret = drm_vblank_get(dev, crtc);
		if (ret) {
			drm_free(vbl_sig, sizeof(struct drm_vbl_sig),
				 DRM_MEM_DRIVER);
			goto done;
		}

		atomic_inc(&dev->vbl_signal_pending);

		vbl_sig->sequence = vblwait->request.sequence;
		vbl_sig->info.si_signo = vblwait->request.signal;
		vbl_sig->task = current;

		spin_lock_irqsave(&dev->vbl_lock, irqflags);

		list_add_tail(&vbl_sig->head, vbl_sigs);

		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

		vblwait->reply.sequence = seq;
	} else {
		DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
			  vblwait->request.sequence, crtc);
		DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
			    ((drm_vblank_count(dev, crtc)
			      - vblwait->request.sequence) <= (1 << 23)));

		if (ret != -EINTR) {
			struct timeval now;

			do_gettimeofday(&now);

			vblwait->reply.tval_sec = now.tv_sec;
			vblwait->reply.tval_usec = now.tv_usec;
			vblwait->reply.sequence = drm_vblank_count(dev, crtc);
			DRM_DEBUG("returning %d to client\n",
				  vblwait->reply.sequence);
		} else {
			DRM_DEBUG("vblank wait interrupted by signal\n");
		}
	}

done:
	drm_vblank_put(dev, crtc);
	return ret;
}

/**
 * Send the VBLANK signals.
 *
 * \param dev DRM device.
 * \param crtc CRTC where the vblank event occurred
 *
 * Sends a signal for each task in drm_device::vbl_sigs and empties the list.
 *
 * If a signal is not requested, then calls vblank_wait().
 */
static void drm_vbl_send_signals(struct drm_device *dev, int crtc)
{
	struct drm_vbl_sig *vbl_sig, *tmp;
	struct list_head *vbl_sigs;
	unsigned int vbl_seq;
	unsigned long flags;

	spin_lock_irqsave(&dev->vbl_lock, flags);

	vbl_sigs = &dev->vbl_sigs[crtc];
	vbl_seq = drm_vblank_count(dev, crtc);

	list_for_each_entry_safe(vbl_sig, tmp, vbl_sigs, head) {
	    if ((vbl_seq - vbl_sig->sequence) <= (1 << 23)) {
		vbl_sig->info.si_code = vbl_seq;
		send_sig_info(vbl_sig->info.si_signo,
			      &vbl_sig->info, vbl_sig->task);

		list_del(&vbl_sig->head);

		drm_free(vbl_sig, sizeof(*vbl_sig),
			 DRM_MEM_DRIVER);
		atomic_dec(&dev->vbl_signal_pending);
		drm_vblank_put(dev, crtc);
	    }
	}

	spin_unlock_irqrestore(&dev->vbl_lock, flags);
}

/**
 * drm_handle_vblank - handle a vblank event
 * @dev: DRM device
 * @crtc: where this event occurred
 *
 * Drivers should call this routine in their vblank interrupt handlers to
 * update the vblank counter and send any signals that may be pending.
 */
void drm_handle_vblank(struct drm_device *dev, int crtc)
{
	atomic_inc(&dev->_vblank_count[crtc]);
	DRM_WAKEUP(&dev->vbl_queue[crtc]);
	drm_vbl_send_signals(dev, crtc);
}
EXPORT_SYMBOL(drm_handle_vblank);