2 * drm_irq.c IRQ and vblank support
4 * \author Rickard E. (Rik) Faith <faith@valinux.com>
5 * \author Gareth Hughes <gareth@valinux.com>
9 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
11 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
12 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
13 * All Rights Reserved.
15 * Permission is hereby granted, free of charge, to any person obtaining a
16 * copy of this software and associated documentation files (the "Software"),
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19 * and/or sell copies of the Software, and to permit persons to whom the
20 * Software is furnished to do so, subject to the following conditions:
22 * The above copyright notice and this permission notice (including the next
23 * paragraph) shall be included in all copies or substantial portions of the
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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37 #include <linux/slab.h>
39 #include <linux/export.h>
41 /* Access macro for slots in vblank timestamp ringbuffer. */
42 #define vblanktimestamp(dev, crtc, count) \
43 ((dev)->vblank[crtc].time[(count) % DRM_VBLANKTIME_RBSIZE])
45 /* Retry timestamp calculation up to 3 times to satisfy
46 * drm_timestamp_precision before giving up.
48 #define DRM_TIMESTAMP_MAXRETRIES 3
50 /* Threshold in nanoseconds for detection of redundant
51 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
53 #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
56 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
57 struct timeval *tvblank, unsigned flags);
60 * drm_update_vblank_count - update the master vblank counter
62 * @crtc: counter to update
64 * Call back into the driver to update the appropriate vblank counter
65 * (specified by @crtc). Deal with wraparound, if it occurred, and
66 * update the last read value so we can deal with wraparound on the next
69 * Only necessary when going from off->on, to account for frames we
70 * didn't get an interrupt for.
72 * Note: caller must hold dev->vbl_lock since this reads & writes
73 * device vblank fields.
75 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
77 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
78 u32 cur_vblank, diff, tslot;
80 struct timeval t_vblank;
83 * Interrupts were disabled prior to this call, so deal with counter
85 * NOTE! It's possible we lost a full dev->max_vblank_count events
86 * here if the register is small or we had vblank interrupts off for
89 * We repeat the hardware vblank counter & timestamp query until
90 * we get consistent results. This to prevent races between gpu
91 * updating its hardware counter while we are retrieving the
92 * corresponding vblank timestamp.
95 cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
96 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
97 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
99 /* Deal with counter wrap */
100 diff = cur_vblank - vblank->last;
101 if (cur_vblank < vblank->last) {
102 diff += dev->max_vblank_count;
104 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
105 crtc, vblank->last, cur_vblank, diff);
108 DRM_DEBUG("updating vblank count on crtc %d, missed %d\n",
114 /* Reinitialize corresponding vblank timestamp if high-precision query
115 * available. Skip this step if query unsupported or failed. Will
116 * reinitialize delayed at next vblank interrupt in that case.
119 tslot = atomic_read(&vblank->count) + diff;
120 vblanktimestamp(dev, crtc, tslot) = t_vblank;
123 smp_mb__before_atomic();
124 atomic_add(diff, &vblank->count);
125 smp_mb__after_atomic();
129 * Disable vblank irq's on crtc, make sure that last vblank count
130 * of hardware and corresponding consistent software vblank counter
131 * are preserved, even if there are any spurious vblank irq's after
134 static void vblank_disable_and_save(struct drm_device *dev, int crtc)
136 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
140 struct timeval tvblank;
141 int count = DRM_TIMESTAMP_MAXRETRIES;
143 /* Prevent vblank irq processing while disabling vblank irqs,
144 * so no updates of timestamps or count can happen after we've
145 * disabled. Needed to prevent races in case of delayed irq's.
147 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE);
150 * If the vblank interrupt was already disbled update the count
151 * and timestamp to maintain the appearance that the counter
152 * has been ticking all along until this time. This makes the
153 * count account for the entire time between drm_vblank_on() and
156 * But only do this if precise vblank timestamps are available.
157 * Otherwise we might read a totally bogus timestamp since drivers
158 * lacking precise timestamp support rely upon sampling the system clock
159 * at vblank interrupt time. Which obviously won't work out well if the
160 * vblank interrupt is disabled.
162 if (!vblank->enabled &&
163 drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0)) {
164 drm_update_vblank_count(dev, crtc);
165 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
169 dev->driver->disable_vblank(dev, crtc);
170 vblank->enabled = false;
172 /* No further vblank irq's will be processed after
173 * this point. Get current hardware vblank count and
174 * vblank timestamp, repeat until they are consistent.
176 * FIXME: There is still a race condition here and in
177 * drm_update_vblank_count() which can cause off-by-one
178 * reinitialization of software vblank counter. If gpu
179 * vblank counter doesn't increment exactly at the leading
180 * edge of a vblank interval, then we can lose 1 count if
181 * we happen to execute between start of vblank and the
182 * delayed gpu counter increment.
185 vblank->last = dev->driver->get_vblank_counter(dev, crtc);
186 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
187 } while (vblank->last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
192 /* Compute time difference to stored timestamp of last vblank
193 * as updated by last invocation of drm_handle_vblank() in vblank irq.
195 vblcount = atomic_read(&vblank->count);
196 diff_ns = timeval_to_ns(&tvblank) -
197 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
199 /* If there is at least 1 msec difference between the last stored
200 * timestamp and tvblank, then we are currently executing our
201 * disable inside a new vblank interval, the tvblank timestamp
202 * corresponds to this new vblank interval and the irq handler
203 * for this vblank didn't run yet and won't run due to our disable.
204 * Therefore we need to do the job of drm_handle_vblank() and
205 * increment the vblank counter by one to account for this vblank.
207 * Skip this step if there isn't any high precision timestamp
208 * available. In that case we can't account for this and just
211 if (vblrc && (abs64(diff_ns) > 1000000)) {
212 /* Store new timestamp in ringbuffer. */
213 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
215 /* Increment cooked vblank count. This also atomically commits
216 * the timestamp computed above.
218 smp_mb__before_atomic();
219 atomic_inc(&vblank->count);
220 smp_mb__after_atomic();
223 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
226 static void vblank_disable_fn(unsigned long arg)
228 struct drm_vblank_crtc *vblank = (void *)arg;
229 struct drm_device *dev = vblank->dev;
230 int crtc = vblank->crtc;
232 if (!dev->vblank_disable_allowed)
235 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
236 if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
237 DRM_DEBUG("disabling vblank on crtc %d\n", crtc);
238 vblank_disable_and_save(dev, crtc);
240 lockmgr(&dev->vbl_lock, LK_RELEASE);
244 * drm_vblank_cleanup - cleanup vblank support
247 * This function cleans up any resources allocated in drm_vblank_init.
249 void drm_vblank_cleanup(struct drm_device *dev)
253 /* Bail if the driver didn't call drm_vblank_init() */
254 if (dev->num_crtcs == 0)
257 for (crtc = 0; crtc < dev->num_crtcs; crtc++) {
258 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
260 del_timer_sync(&vblank->disable_timer);
262 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
263 vblank_disable_and_save(dev, crtc);
264 lockmgr(&dev->vbl_lock, LK_RELEASE);
271 EXPORT_SYMBOL(drm_vblank_cleanup);
274 * drm_vblank_init - initialize vblank support
276 * @num_crtcs: number of crtcs supported by @dev
278 * This function initializes vblank support for @num_crtcs display pipelines.
281 * Zero on success or a negative error code on failure.
283 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
285 int i, ret = -ENOMEM;
287 lockinit(&dev->vbl_lock, "drmvbl", 0, LK_CANRECURSE);
288 lockinit(&dev->vblank_time_lock, "drmvtl", 0, LK_CANRECURSE);
290 dev->num_crtcs = num_crtcs;
292 dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
296 for (i = 0; i < num_crtcs; i++) {
297 struct drm_vblank_crtc *vblank = &dev->vblank[i];
301 init_waitqueue_head(&vblank->queue);
302 setup_timer(&vblank->disable_timer, vblank_disable_fn,
303 (unsigned long)vblank);
306 DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
308 /* Driver specific high-precision vblank timestamping supported? */
309 if (dev->driver->get_vblank_timestamp)
310 DRM_INFO("Driver supports precise vblank timestamp query.\n");
312 DRM_INFO("No driver support for vblank timestamp query.\n");
314 dev->vblank_disable_allowed = false;
322 EXPORT_SYMBOL(drm_vblank_init);
325 static void drm_irq_vgaarb_nokms(void *cookie, bool state)
327 struct drm_device *dev = cookie;
329 if (dev->driver->vgaarb_irq) {
330 dev->driver->vgaarb_irq(dev, state);
334 if (!dev->irq_enabled)
338 if (dev->driver->irq_uninstall)
339 dev->driver->irq_uninstall(dev);
341 if (dev->driver->irq_preinstall)
342 dev->driver->irq_preinstall(dev);
343 if (dev->driver->irq_postinstall)
344 dev->driver->irq_postinstall(dev);
350 * drm_irq_install - install IRQ handler
352 * @irq: IRQ number to install the handler for
354 * Initializes the IRQ related data. Installs the handler, calling the driver
355 * irq_preinstall() and irq_postinstall() functions before and after the
358 * This is the simplified helper interface provided for drivers with no special
359 * needs. Drivers which need to install interrupt handlers for multiple
360 * interrupts must instead set drm_device->irq_enabled to signal the DRM core
361 * that vblank interrupts are available.
364 * Zero on success or a negative error code on failure.
366 int drm_irq_install(struct drm_device *dev, int irq)
370 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
376 /* Driver must have been initialized */
377 if (!dev->dev_private)
380 if (dev->irq_enabled)
382 dev->irq_enabled = true;
384 DRM_DEBUG("irq=%d\n", irq);
386 /* Before installing handler */
387 if (dev->driver->irq_preinstall)
388 dev->driver->irq_preinstall(dev);
390 /* Install handler */
391 ret = -bus_setup_intr(dev->dev, dev->irqr, INTR_MPSAFE,
392 dev->driver->irq_handler, dev, &dev->irqh, &dev->irq_lock);
395 dev->irq_enabled = false;
399 /* After installing handler */
400 if (dev->driver->irq_postinstall)
401 ret = dev->driver->irq_postinstall(dev);
404 dev->irq_enabled = false;
405 bus_teardown_intr(dev->dev, dev->irqr, dev->irqh);
412 EXPORT_SYMBOL(drm_irq_install);
415 * drm_irq_uninstall - uninstall the IRQ handler
418 * Calls the driver's irq_uninstall() function and unregisters the IRQ handler.
419 * This should only be called by drivers which used drm_irq_install() to set up
420 * their interrupt handler. Other drivers must only reset
421 * drm_device->irq_enabled to false.
423 * Note that for kernel modesetting drivers it is a bug if this function fails.
424 * The sanity checks are only to catch buggy user modesetting drivers which call
425 * the same function through an ioctl.
428 * Zero on success or a negative error code on failure.
430 int drm_irq_uninstall(struct drm_device *dev)
435 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
438 irq_enabled = dev->irq_enabled;
439 dev->irq_enabled = false;
442 * Wake up any waiters so they don't hang.
444 if (dev->num_crtcs) {
445 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
446 for (i = 0; i < dev->num_crtcs; i++) {
447 struct drm_vblank_crtc *vblank = &dev->vblank[i];
449 wake_up(&vblank->queue);
450 vblank->enabled = false;
452 dev->driver->get_vblank_counter(dev, i);
454 lockmgr(&dev->vbl_lock, LK_RELEASE);
460 DRM_DEBUG("irq=%d\n", dev->irq);
462 if (dev->driver->irq_uninstall)
463 dev->driver->irq_uninstall(dev);
465 bus_teardown_intr(dev->dev, dev->irqr, dev->irqh);
469 EXPORT_SYMBOL(drm_irq_uninstall);
474 * \param inode device inode.
475 * \param file_priv DRM file private.
476 * \param cmd command.
477 * \param arg user argument, pointing to a drm_control structure.
478 * \return zero on success or a negative number on failure.
480 * Calls irq_install() or irq_uninstall() according to \p arg.
482 int drm_control(struct drm_device *dev, void *data,
483 struct drm_file *file_priv)
485 struct drm_control *ctl = data;
488 /* if we haven't irq we fallback for compatibility reasons -
489 * this used to be a separate function in drm_dma.h
492 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
494 if (drm_core_check_feature(dev, DRIVER_MODESET))
496 /* UMS was only ever support on pci devices. */
497 if (WARN_ON(!dev->pdev))
501 case DRM_INST_HANDLER:
504 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
507 mutex_lock(&dev->struct_mutex);
508 ret = drm_irq_install(dev, irq);
509 mutex_unlock(&dev->struct_mutex);
512 case DRM_UNINST_HANDLER:
513 mutex_lock(&dev->struct_mutex);
514 ret = drm_irq_uninstall(dev);
515 mutex_unlock(&dev->struct_mutex);
524 * drm_calc_timestamping_constants - calculate vblank timestamp constants
525 * @crtc: drm_crtc whose timestamp constants should be updated.
526 * @mode: display mode containing the scanout timings
528 * Calculate and store various constants which are later
529 * needed by vblank and swap-completion timestamping, e.g,
530 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
531 * derived from CRTC's true scanout timing, so they take
532 * things like panel scaling or other adjustments into account.
534 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
535 const struct drm_display_mode *mode)
537 int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
538 int dotclock = mode->crtc_clock;
540 /* Valid dotclock? */
542 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
545 * Convert scanline length in pixels and video
546 * dot clock to line duration, frame duration
547 * and pixel duration in nanoseconds:
549 pixeldur_ns = 1000000 / dotclock;
550 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
551 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
554 * Fields of interlaced scanout modes are only half a frame duration.
556 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
559 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
562 crtc->pixeldur_ns = pixeldur_ns;
563 crtc->linedur_ns = linedur_ns;
564 crtc->framedur_ns = framedur_ns;
566 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
567 crtc->base.id, mode->crtc_htotal,
568 mode->crtc_vtotal, mode->crtc_vdisplay);
569 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
570 crtc->base.id, dotclock, framedur_ns,
571 linedur_ns, pixeldur_ns);
573 EXPORT_SYMBOL(drm_calc_timestamping_constants);
576 * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
578 * @crtc: Which CRTC's vblank timestamp to retrieve
579 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
580 * On return contains true maximum error of timestamp
581 * @vblank_time: Pointer to struct timeval which should receive the timestamp
582 * @flags: Flags to pass to driver:
584 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
585 * @refcrtc: CRTC which defines scanout timing
586 * @mode: mode which defines the scanout timings
588 * Implements calculation of exact vblank timestamps from given drm_display_mode
589 * timings and current video scanout position of a CRTC. This can be called from
590 * within get_vblank_timestamp() implementation of a kms driver to implement the
591 * actual timestamping.
593 * Should return timestamps conforming to the OML_sync_control OpenML
594 * extension specification. The timestamp corresponds to the end of
595 * the vblank interval, aka start of scanout of topmost-leftmost display
596 * pixel in the following video frame.
598 * Requires support for optional dev->driver->get_scanout_position()
599 * in kms driver, plus a bit of setup code to provide a drm_display_mode
600 * that corresponds to the true scanout timing.
602 * The current implementation only handles standard video modes. It
603 * returns as no operation if a doublescan or interlaced video mode is
604 * active. Higher level code is expected to handle this.
607 * Negative value on error, failure or if not supported in current
610 * -EINVAL - Invalid CRTC.
611 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
612 * -ENOTSUPP - Function not supported in current display mode.
613 * -EIO - Failed, e.g., due to failed scanout position query.
615 * Returns or'ed positive status flags on success:
617 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
618 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
621 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
623 struct timeval *vblank_time,
625 const struct drm_crtc *refcrtc,
626 const struct drm_display_mode *mode)
628 ktime_t stime, etime;
629 struct timeval tv_etime;
632 int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
635 if (crtc < 0 || crtc >= dev->num_crtcs) {
636 DRM_ERROR("Invalid crtc %d\n", crtc);
640 /* Scanout position query not supported? Should not happen. */
641 if (!dev->driver->get_scanout_position) {
642 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
646 /* Durations of frames, lines, pixels in nanoseconds. */
647 framedur_ns = refcrtc->framedur_ns;
648 linedur_ns = refcrtc->linedur_ns;
649 pixeldur_ns = refcrtc->pixeldur_ns;
651 /* If mode timing undefined, just return as no-op:
652 * Happens during initial modesetting of a crtc.
654 if (framedur_ns == 0) {
655 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
659 /* Get current scanout position with system timestamp.
660 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
661 * if single query takes longer than max_error nanoseconds.
663 * This guarantees a tight bound on maximum error if
664 * code gets preempted or delayed for some reason.
666 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
668 * Get vertical and horizontal scanout position vpos, hpos,
669 * and bounding timestamps stime, etime, pre/post query.
671 vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
672 &hpos, &stime, &etime);
675 * Get correction for CLOCK_MONOTONIC -> CLOCK_REALTIME if
676 * CLOCK_REALTIME is requested.
679 if (!drm_timestamp_monotonic)
680 mono_time_offset = ktime_get_monotonic_offset();
683 /* Return as no-op if scanout query unsupported or failed. */
684 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
685 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
690 /* Compute uncertainty in timestamp of scanout position query. */
691 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
693 /* Accept result with < max_error nsecs timing uncertainty. */
694 if (duration_ns <= *max_error)
698 /* Noisy system timing? */
699 if (i == DRM_TIMESTAMP_MAXRETRIES) {
700 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
701 crtc, duration_ns/1000, *max_error/1000, i);
704 /* Return upper bound of timestamp precision error. */
705 *max_error = duration_ns;
707 /* Check if in vblank area:
708 * vpos is >=0 in video scanout area, but negative
709 * within vblank area, counting down the number of lines until
712 invbl = vbl_status & DRM_SCANOUTPOS_IN_VBLANK;
714 /* Convert scanout position into elapsed time at raw_time query
715 * since start of scanout at first display scanline. delta_ns
716 * can be negative if start of scanout hasn't happened yet.
718 delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
721 if (!drm_timestamp_monotonic)
722 etime = ktime_sub(etime, mono_time_offset);
725 /* save this only for debugging purposes */
726 tv_etime = ktime_to_timeval(etime);
727 /* Subtract time delta from raw timestamp to get final
728 * vblank_time timestamp for end of vblank.
731 etime = ktime_add_ns(etime, -delta_ns);
733 etime = ktime_sub_ns(etime, delta_ns);
734 *vblank_time = ktime_to_timeval(etime);
736 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
737 crtc, (int)vbl_status, hpos, vpos,
738 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
739 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
740 duration_ns/1000, i);
742 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
744 vbl_status |= DRM_VBLANKTIME_IN_VBLANK;
748 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
750 static struct timeval get_drm_timestamp(void)
756 if (!drm_timestamp_monotonic)
757 now = ktime_sub(now, ktime_get_monotonic_offset());
760 return ktime_to_timeval(now);
764 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
767 * @crtc: which CRTC's vblank timestamp to retrieve
768 * @tvblank: Pointer to target struct timeval which should receive the timestamp
769 * @flags: Flags to pass to driver:
771 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
773 * Fetches the system timestamp corresponding to the time of the most recent
774 * vblank interval on specified CRTC. May call into kms-driver to
775 * compute the timestamp with a high-precision GPU specific method.
777 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
778 * call, i.e., it isn't very precisely locked to the true vblank.
781 * True if timestamp is considered to be very precise, false otherwise.
784 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
785 struct timeval *tvblank, unsigned flags)
789 /* Define requested maximum error on timestamps (nanoseconds). */
790 int max_error = (int) drm_timestamp_precision * 1000;
792 /* Query driver if possible and precision timestamping enabled. */
793 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
794 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
800 /* GPU high precision timestamp query unsupported or failed.
801 * Return current monotonic/gettimeofday timestamp as best estimate.
803 *tvblank = get_drm_timestamp();
809 * drm_vblank_count - retrieve "cooked" vblank counter value
811 * @crtc: which counter to retrieve
813 * Fetches the "cooked" vblank count value that represents the number of
814 * vblank events since the system was booted, including lost events due to
815 * modesetting activity.
818 * The software vblank counter.
820 u32 drm_vblank_count(struct drm_device *dev, int crtc)
822 if (WARN_ON(crtc >= dev->num_crtcs))
824 return atomic_read(&dev->vblank[crtc].count);
826 EXPORT_SYMBOL(drm_vblank_count);
829 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
830 * and the system timestamp corresponding to that vblank counter value.
833 * @crtc: which counter to retrieve
834 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
836 * Fetches the "cooked" vblank count value that represents the number of
837 * vblank events since the system was booted, including lost events due to
838 * modesetting activity. Returns corresponding system timestamp of the time
839 * of the vblank interval that corresponds to the current vblank counter value.
841 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
842 struct timeval *vblanktime)
844 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
847 if (WARN_ON(crtc >= dev->num_crtcs))
850 /* Read timestamp from slot of _vblank_time ringbuffer
851 * that corresponds to current vblank count. Retry if
852 * count has incremented during readout. This works like
856 cur_vblank = atomic_read(&vblank->count);
857 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
859 } while (cur_vblank != atomic_read(&vblank->count));
863 EXPORT_SYMBOL(drm_vblank_count_and_time);
865 static void send_vblank_event(struct drm_device *dev,
866 struct drm_pending_vblank_event *e,
867 unsigned long seq, struct timeval *now)
870 WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
872 e->event.sequence = seq;
873 e->event.tv_sec = now->tv_sec;
874 e->event.tv_usec = now->tv_usec;
876 list_add_tail(&e->base.link,
877 &e->base.file_priv->event_list);
878 wake_up_interruptible(&e->base.file_priv->event_wait);
880 KNOTE(&e->base.file_priv->dkq.ki_note, 0);
883 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
889 * drm_send_vblank_event - helper to send vblank event after pageflip
891 * @crtc: CRTC in question
892 * @e: the event to send
894 * Updates sequence # and timestamp on event, and sends it to userspace.
895 * Caller must hold event lock.
897 void drm_send_vblank_event(struct drm_device *dev, int crtc,
898 struct drm_pending_vblank_event *e)
903 seq = drm_vblank_count_and_time(dev, crtc, &now);
907 now = get_drm_timestamp();
910 send_vblank_event(dev, e, seq, &now);
912 EXPORT_SYMBOL(drm_send_vblank_event);
915 * drm_vblank_enable - enable the vblank interrupt on a CRTC
917 * @crtc: CRTC in question
919 static int drm_vblank_enable(struct drm_device *dev, int crtc)
921 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
924 assert_spin_locked(&dev->vbl_lock);
926 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE);
928 if (!vblank->enabled) {
930 * Enable vblank irqs under vblank_time_lock protection.
931 * All vblank count & timestamp updates are held off
932 * until we are done reinitializing master counter and
933 * timestamps. Filtercode in drm_handle_vblank() will
934 * prevent double-accounting of same vblank interval.
936 ret = dev->driver->enable_vblank(dev, crtc);
937 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
939 atomic_dec(&vblank->refcount);
941 vblank->enabled = true;
942 drm_update_vblank_count(dev, crtc);
946 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
952 * drm_vblank_get - get a reference count on vblank events
954 * @crtc: which CRTC to own
956 * Acquire a reference count on vblank events to avoid having them disabled
959 * This is the legacy version of drm_crtc_vblank_get().
962 * Zero on success, nonzero on failure.
964 int drm_vblank_get(struct drm_device *dev, int crtc)
966 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
969 if (WARN_ON(crtc >= dev->num_crtcs))
972 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
973 /* Going from 0->1 means we have to enable interrupts again */
974 if (atomic_add_return(1, &vblank->refcount) == 1) {
975 ret = drm_vblank_enable(dev, crtc);
977 if (!vblank->enabled) {
978 atomic_dec(&vblank->refcount);
982 lockmgr(&dev->vbl_lock, LK_RELEASE);
986 EXPORT_SYMBOL(drm_vblank_get);
989 * drm_crtc_vblank_get - get a reference count on vblank events
990 * @crtc: which CRTC to own
992 * Acquire a reference count on vblank events to avoid having them disabled
995 * This is the native kms version of drm_vblank_off().
998 * Zero on success, nonzero on failure.
1000 int drm_crtc_vblank_get(struct drm_crtc *crtc)
1002 return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
1004 EXPORT_SYMBOL(drm_crtc_vblank_get);
1007 * drm_vblank_put - give up ownership of vblank events
1009 * @crtc: which counter to give up
1011 * Release ownership of a given vblank counter, turning off interrupts
1012 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1014 * This is the legacy version of drm_crtc_vblank_put().
1016 void drm_vblank_put(struct drm_device *dev, int crtc)
1018 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1020 BUG_ON(atomic_read(&vblank->refcount) == 0);
1022 if (WARN_ON(crtc >= dev->num_crtcs))
1025 /* Last user schedules interrupt disable */
1026 if (atomic_dec_and_test(&vblank->refcount)) {
1027 if (drm_vblank_offdelay == 0)
1029 else if (dev->vblank_disable_immediate || drm_vblank_offdelay < 0)
1030 vblank_disable_fn((unsigned long)vblank);
1032 mod_timer(&vblank->disable_timer,
1033 jiffies + ((drm_vblank_offdelay * HZ)/1000));
1036 EXPORT_SYMBOL(drm_vblank_put);
1039 * drm_crtc_vblank_put - give up ownership of vblank events
1040 * @crtc: which counter to give up
1042 * Release ownership of a given vblank counter, turning off interrupts
1043 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1045 * This is the native kms version of drm_vblank_put().
1047 void drm_crtc_vblank_put(struct drm_crtc *crtc)
1049 drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
1051 EXPORT_SYMBOL(drm_crtc_vblank_put);
1054 * drm_wait_one_vblank - wait for one vblank
1058 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
1059 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
1060 * due to lack of driver support or because the crtc is off.
1062 void drm_wait_one_vblank(struct drm_device *dev, int crtc)
1067 ret = drm_vblank_get(dev, crtc);
1068 if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", crtc, ret))
1071 last = drm_vblank_count(dev, crtc);
1073 ret = wait_event_timeout(dev->vblank[crtc].queue,
1074 last != drm_vblank_count(dev, crtc),
1075 msecs_to_jiffies(100));
1077 WARN(ret == 0, "vblank wait timed out on crtc %i\n", crtc);
1079 drm_vblank_put(dev, crtc);
1081 EXPORT_SYMBOL(drm_wait_one_vblank);
1084 * drm_crtc_wait_one_vblank - wait for one vblank
1087 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
1088 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
1089 * due to lack of driver support or because the crtc is off.
1091 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
1093 drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
1095 EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
1098 * drm_vblank_off - disable vblank events on a CRTC
1100 * @crtc: CRTC in question
1102 * Drivers can use this function to shut down the vblank interrupt handling when
1103 * disabling a crtc. This function ensures that the latest vblank frame count is
1104 * stored so that drm_vblank_on() can restore it again.
1106 * Drivers must use this function when the hardware vblank counter can get
1107 * reset, e.g. when suspending.
1109 * This is the legacy version of drm_crtc_vblank_off().
1111 void drm_vblank_off(struct drm_device *dev, int crtc)
1113 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1114 struct drm_pending_vblank_event *e, *t;
1118 lockmgr(&dev->event_lock, LK_EXCLUSIVE);
1120 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
1121 vblank_disable_and_save(dev, crtc);
1122 wake_up(&vblank->queue);
1125 * Prevent subsequent drm_vblank_get() from re-enabling
1126 * the vblank interrupt by bumping the refcount.
1128 if (!vblank->inmodeset) {
1129 atomic_inc(&vblank->refcount);
1130 vblank->inmodeset = 1;
1132 lockmgr(&dev->vbl_lock, LK_RELEASE);
1134 /* Send any queued vblank events, lest the natives grow disquiet */
1135 seq = drm_vblank_count_and_time(dev, crtc, &now);
1137 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1138 if (e->pipe != crtc)
1140 DRM_DEBUG("Sending premature vblank event on disable: \
1141 wanted %d, current %d\n",
1142 e->event.sequence, seq);
1143 list_del(&e->base.link);
1144 drm_vblank_put(dev, e->pipe);
1145 send_vblank_event(dev, e, seq, &now);
1147 lockmgr(&dev->event_lock, LK_RELEASE);
1149 EXPORT_SYMBOL(drm_vblank_off);
1152 * drm_crtc_vblank_off - disable vblank events on a CRTC
1153 * @crtc: CRTC in question
1155 * Drivers can use this function to shut down the vblank interrupt handling when
1156 * disabling a crtc. This function ensures that the latest vblank frame count is
1157 * stored so that drm_vblank_on can restore it again.
1159 * Drivers must use this function when the hardware vblank counter can get
1160 * reset, e.g. when suspending.
1162 * This is the native kms version of drm_vblank_off().
1164 void drm_crtc_vblank_off(struct drm_crtc *crtc)
1166 drm_vblank_off(crtc->dev, drm_crtc_index(crtc));
1168 EXPORT_SYMBOL(drm_crtc_vblank_off);
1171 * drm_vblank_on - enable vblank events on a CRTC
1173 * @crtc: CRTC in question
1175 * This functions restores the vblank interrupt state captured with
1176 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1177 * drm_vblank_off() can be unbalanced and so can also be unconditionaly called
1178 * in driver load code to reflect the current hardware state of the crtc.
1180 * This is the legacy version of drm_crtc_vblank_on().
1182 void drm_vblank_on(struct drm_device *dev, int crtc)
1184 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1186 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
1187 /* Drop our private "prevent drm_vblank_get" refcount */
1188 if (vblank->inmodeset) {
1189 atomic_dec(&vblank->refcount);
1190 vblank->inmodeset = 0;
1194 * sample the current counter to avoid random jumps
1195 * when drm_vblank_enable() applies the diff
1197 * -1 to make sure user will never see the same
1198 * vblank counter value before and after a modeset
1201 (dev->driver->get_vblank_counter(dev, crtc) - 1) &
1202 dev->max_vblank_count;
1204 * re-enable interrupts if there are users left, or the
1205 * user wishes vblank interrupts to be enabled all the time.
1207 if (atomic_read(&vblank->refcount) != 0 ||
1208 (!dev->vblank_disable_immediate && drm_vblank_offdelay == 0))
1209 WARN_ON(drm_vblank_enable(dev, crtc));
1210 lockmgr(&dev->vbl_lock, LK_RELEASE);
1212 EXPORT_SYMBOL(drm_vblank_on);
1215 * drm_crtc_vblank_on - enable vblank events on a CRTC
1216 * @crtc: CRTC in question
1218 * This functions restores the vblank interrupt state captured with
1219 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1220 * drm_vblank_off() can be unbalanced and so can also be unconditionaly called
1221 * in driver load code to reflect the current hardware state of the crtc.
1223 * This is the native kms version of drm_vblank_on().
1225 void drm_crtc_vblank_on(struct drm_crtc *crtc)
1227 drm_vblank_on(crtc->dev, drm_crtc_index(crtc));
1229 EXPORT_SYMBOL(drm_crtc_vblank_on);
1232 * drm_vblank_pre_modeset - account for vblanks across mode sets
1234 * @crtc: CRTC in question
1236 * Account for vblank events across mode setting events, which will likely
1237 * reset the hardware frame counter.
1239 * This is done by grabbing a temporary vblank reference to ensure that the
1240 * vblank interrupt keeps running across the modeset sequence. With this the
1241 * software-side vblank frame counting will ensure that there are no jumps or
1244 * Unfortunately this approach is racy and also doesn't work when the vblank
1245 * interrupt stops running, e.g. across system suspend resume. It is therefore
1246 * highly recommended that drivers use the newer drm_vblank_off() and
1247 * drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when
1248 * using "cooked" software vblank frame counters and not relying on any hardware
1251 * Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc
1254 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
1256 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1258 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1259 if (!dev->num_crtcs)
1262 if (WARN_ON(crtc >= dev->num_crtcs))
1266 * To avoid all the problems that might happen if interrupts
1267 * were enabled/disabled around or between these calls, we just
1268 * have the kernel take a reference on the CRTC (just once though
1269 * to avoid corrupting the count if multiple, mismatch calls occur),
1270 * so that interrupts remain enabled in the interim.
1272 if (!vblank->inmodeset) {
1273 vblank->inmodeset = 0x1;
1274 if (drm_vblank_get(dev, crtc) == 0)
1275 vblank->inmodeset |= 0x2;
1278 EXPORT_SYMBOL(drm_vblank_pre_modeset);
1281 * drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes
1283 * @crtc: CRTC in question
1285 * This function again drops the temporary vblank reference acquired in
1286 * drm_vblank_pre_modeset.
1288 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
1290 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1292 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1293 if (!dev->num_crtcs)
1296 if (vblank->inmodeset) {
1297 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
1298 dev->vblank_disable_allowed = true;
1299 lockmgr(&dev->vbl_lock, LK_RELEASE);
1301 if (vblank->inmodeset & 0x2)
1302 drm_vblank_put(dev, crtc);
1304 vblank->inmodeset = 0;
1307 EXPORT_SYMBOL(drm_vblank_post_modeset);
1310 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1311 * @DRM_IOCTL_ARGS: standard ioctl arguments
1313 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1314 * ioctls around modesetting so that any lost vblank events are accounted for.
1316 * Generally the counter will reset across mode sets. If interrupts are
1317 * enabled around this call, we don't have to do anything since the counter
1318 * will have already been incremented.
1320 int drm_modeset_ctl(struct drm_device *dev, void *data,
1321 struct drm_file *file_priv)
1323 struct drm_modeset_ctl *modeset = data;
1326 /* If drm_vblank_init() hasn't been called yet, just no-op */
1327 if (!dev->num_crtcs)
1330 /* KMS drivers handle this internally */
1331 if (drm_core_check_feature(dev, DRIVER_MODESET))
1334 crtc = modeset->crtc;
1335 if (crtc >= dev->num_crtcs)
1338 switch (modeset->cmd) {
1339 case _DRM_PRE_MODESET:
1340 drm_vblank_pre_modeset(dev, crtc);
1342 case _DRM_POST_MODESET:
1343 drm_vblank_post_modeset(dev, crtc);
1352 #ifdef __DragonFly__
1354 drm_vblank_event_destroy(struct drm_pending_event *e)
1360 static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1361 union drm_wait_vblank *vblwait,
1362 struct drm_file *file_priv)
1364 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1365 struct drm_pending_vblank_event *e;
1370 e = kzalloc(sizeof *e, GFP_KERNEL);
1377 e->base.pid = curproc->p_pid;
1378 e->event.base.type = DRM_EVENT_VBLANK;
1379 e->event.base.length = sizeof e->event;
1380 e->event.user_data = vblwait->request.signal;
1381 e->base.event = &e->event.base;
1382 e->base.file_priv = file_priv;
1383 e->base.destroy = drm_vblank_event_destroy;
1385 lockmgr(&dev->event_lock, LK_EXCLUSIVE);
1388 * drm_vblank_off() might have been called after we called
1389 * drm_vblank_get(). drm_vblank_off() holds event_lock
1390 * around the vblank disable, so no need for further locking.
1391 * The reference from drm_vblank_get() protects against
1392 * vblank disable from another source.
1394 if (!vblank->enabled) {
1399 if (file_priv->event_space < sizeof e->event) {
1404 file_priv->event_space -= sizeof e->event;
1405 seq = drm_vblank_count_and_time(dev, pipe, &now);
1407 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1408 (seq - vblwait->request.sequence) <= (1 << 23)) {
1409 vblwait->request.sequence = seq + 1;
1410 vblwait->reply.sequence = vblwait->request.sequence;
1413 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1414 vblwait->request.sequence, seq, pipe);
1417 trace_drm_vblank_event_queued(current->pid, pipe,
1418 vblwait->request.sequence);
1421 e->event.sequence = vblwait->request.sequence;
1422 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1423 drm_vblank_put(dev, pipe);
1424 send_vblank_event(dev, e, seq, &now);
1425 vblwait->reply.sequence = seq;
1427 /* drm_handle_vblank_events will call drm_vblank_put */
1428 list_add_tail(&e->base.link, &dev->vblank_event_list);
1429 vblwait->reply.sequence = vblwait->request.sequence;
1432 lockmgr(&dev->event_lock, LK_RELEASE);
1437 lockmgr(&dev->event_lock, LK_RELEASE);
1440 drm_vblank_put(dev, pipe);
1447 * \param inode device inode.
1448 * \param file_priv DRM file private.
1449 * \param cmd command.
1450 * \param data user argument, pointing to a drm_wait_vblank structure.
1451 * \return zero on success or a negative number on failure.
1453 * This function enables the vblank interrupt on the pipe requested, then
1454 * sleeps waiting for the requested sequence number to occur, and drops
1455 * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
1456 * after a timeout with no further vblank waits scheduled).
1458 int drm_wait_vblank(struct drm_device *dev, void *data,
1459 struct drm_file *file_priv)
1461 struct drm_vblank_crtc *vblank;
1462 union drm_wait_vblank *vblwait = data;
1464 unsigned int flags, seq, crtc, high_crtc;
1466 if (!dev->irq_enabled)
1469 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1472 if (vblwait->request.type &
1473 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1474 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1475 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1476 vblwait->request.type,
1477 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1478 _DRM_VBLANK_HIGH_CRTC_MASK));
1482 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1483 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1485 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1487 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1488 if (crtc >= dev->num_crtcs)
1491 vblank = &dev->vblank[crtc];
1493 ret = drm_vblank_get(dev, crtc);
1495 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1498 seq = drm_vblank_count(dev, crtc);
1500 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1501 case _DRM_VBLANK_RELATIVE:
1502 vblwait->request.sequence += seq;
1503 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1504 case _DRM_VBLANK_ABSOLUTE:
1511 if (flags & _DRM_VBLANK_EVENT) {
1512 /* must hold on to the vblank ref until the event fires
1513 * drm_vblank_put will be called asynchronously
1515 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1518 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1519 (seq - vblwait->request.sequence) <= (1<<23)) {
1520 vblwait->request.sequence = seq + 1;
1523 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1524 vblwait->request.sequence, crtc);
1525 vblank->last_wait = vblwait->request.sequence;
1526 DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
1527 (((drm_vblank_count(dev, crtc) -
1528 vblwait->request.sequence) <= (1 << 23)) ||
1530 !dev->irq_enabled));
1532 if (ret != -EINTR) {
1535 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1536 vblwait->reply.tval_sec = now.tv_sec;
1537 vblwait->reply.tval_usec = now.tv_usec;
1539 DRM_DEBUG("returning %d to client\n",
1540 vblwait->reply.sequence);
1542 DRM_DEBUG("vblank wait interrupted by signal\n");
1546 drm_vblank_put(dev, crtc);
1550 static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1552 struct drm_pending_vblank_event *e, *t;
1557 seq = drm_vblank_count_and_time(dev, crtc, &now);
1559 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1560 if (e->pipe != crtc)
1562 if ((seq - e->event.sequence) > (1<<23))
1565 DRM_DEBUG("vblank event on %d, current %d\n",
1566 e->event.sequence, seq);
1568 list_del(&e->base.link);
1569 drm_vblank_put(dev, e->pipe);
1570 send_vblank_event(dev, e, seq, &now);
1574 trace_drm_vblank_event(crtc, seq);
1579 * drm_handle_vblank - handle a vblank event
1581 * @crtc: where this event occurred
1583 * Drivers should call this routine in their vblank interrupt handlers to
1584 * update the vblank counter and send any signals that may be pending.
1586 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1588 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1591 struct timeval tvblank;
1593 if (!dev->num_crtcs)
1596 lockmgr(&dev->event_lock, LK_EXCLUSIVE);
1598 if (WARN_ON(crtc >= dev->num_crtcs))
1601 /* Need timestamp lock to prevent concurrent execution with
1602 * vblank enable/disable, as this would cause inconsistent
1603 * or corrupted timestamps and vblank counts.
1605 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE);
1607 /* Vblank irq handling disabled. Nothing to do. */
1608 if (!vblank->enabled) {
1609 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
1610 lockmgr(&dev->event_lock, LK_RELEASE);
1614 /* Fetch corresponding timestamp for this vblank interval from
1615 * driver and store it in proper slot of timestamp ringbuffer.
1618 /* Get current timestamp and count. */
1619 vblcount = atomic_read(&vblank->count);
1620 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1622 /* Compute time difference to timestamp of last vblank */
1623 diff_ns = timeval_to_ns(&tvblank) -
1624 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1626 /* Update vblank timestamp and count if at least
1627 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1628 * difference between last stored timestamp and current
1629 * timestamp. A smaller difference means basically
1630 * identical timestamps. Happens if this vblank has
1631 * been already processed and this is a redundant call,
1632 * e.g., due to spurious vblank interrupts. We need to
1633 * ignore those for accounting.
1635 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1636 /* Store new timestamp in ringbuffer. */
1637 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1639 /* Increment cooked vblank count. This also atomically commits
1640 * the timestamp computed above.
1642 smp_mb__before_atomic();
1643 atomic_inc(&vblank->count);
1644 smp_mb__after_atomic();
1646 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1647 crtc, (int) diff_ns);
1650 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
1652 wake_up(&vblank->queue);
1653 drm_handle_vblank_events(dev, crtc);
1655 lockmgr(&dev->event_lock, LK_RELEASE);
1659 EXPORT_SYMBOL(drm_handle_vblank);