5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
6 * \author Gareth Hughes <gareth@valinux.com>
10 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
12 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14 * All Rights Reserved.
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:
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
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.
38 #include <linux/slab.h>
40 #include <linux/export.h>
42 /* Access macro for slots in vblank timestamp ringbuffer. */
43 #define vblanktimestamp(dev, crtc, count) \
44 ((dev)->vblank[crtc].time[(count) % DRM_VBLANKTIME_RBSIZE])
46 /* Retry timestamp calculation up to 3 times to satisfy
47 * drm_timestamp_precision before giving up.
49 #define DRM_TIMESTAMP_MAXRETRIES 3
51 /* Threshold in nanoseconds for detection of redundant
52 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
54 #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
57 * Clear vblank timestamp buffer for a crtc.
59 static void clear_vblank_timestamps(struct drm_device *dev, int crtc)
61 memset(dev->vblank[crtc].time, 0, sizeof(dev->vblank[crtc].time));
65 * Disable vblank irq's on crtc, make sure that last vblank count
66 * of hardware and corresponding consistent software vblank counter
67 * are preserved, even if there are any spurious vblank irq's after
70 static void vblank_disable_and_save(struct drm_device *dev, int crtc)
75 struct timeval tvblank;
76 int count = DRM_TIMESTAMP_MAXRETRIES;
78 /* Prevent vblank irq processing while disabling vblank irqs,
79 * so no updates of timestamps or count can happen after we've
80 * disabled. Needed to prevent races in case of delayed irq's.
82 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE);
84 dev->driver->disable_vblank(dev, crtc);
85 dev->vblank[crtc].enabled = false;
87 /* No further vblank irq's will be processed after
88 * this point. Get current hardware vblank count and
89 * vblank timestamp, repeat until they are consistent.
91 * FIXME: There is still a race condition here and in
92 * drm_update_vblank_count() which can cause off-by-one
93 * reinitialization of software vblank counter. If gpu
94 * vblank counter doesn't increment exactly at the leading
95 * edge of a vblank interval, then we can lose 1 count if
96 * we happen to execute between start of vblank and the
97 * delayed gpu counter increment.
100 dev->vblank[crtc].last = dev->driver->get_vblank_counter(dev, crtc);
101 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
102 } while (dev->vblank[crtc].last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
107 /* Compute time difference to stored timestamp of last vblank
108 * as updated by last invocation of drm_handle_vblank() in vblank irq.
110 vblcount = atomic_read(&dev->vblank[crtc].count);
111 diff_ns = timeval_to_ns(&tvblank) -
112 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
114 /* If there is at least 1 msec difference between the last stored
115 * timestamp and tvblank, then we are currently executing our
116 * disable inside a new vblank interval, the tvblank timestamp
117 * corresponds to this new vblank interval and the irq handler
118 * for this vblank didn't run yet and won't run due to our disable.
119 * Therefore we need to do the job of drm_handle_vblank() and
120 * increment the vblank counter by one to account for this vblank.
122 * Skip this step if there isn't any high precision timestamp
123 * available. In that case we can't account for this and just
126 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
127 atomic_inc(&dev->vblank[crtc].count);
128 smp_mb__after_atomic();
131 /* Invalidate all timestamps while vblank irq's are off. */
132 clear_vblank_timestamps(dev, crtc);
134 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
137 static void vblank_disable_fn(unsigned long arg)
139 struct drm_vblank_crtc *vblank = (void *)arg;
140 struct drm_device *dev = vblank->dev;
141 int crtc = vblank->crtc;
143 if (!dev->vblank_disable_allowed)
146 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
147 if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
148 DRM_DEBUG("disabling vblank on crtc %d\n", crtc);
149 vblank_disable_and_save(dev, crtc);
151 lockmgr(&dev->vbl_lock, LK_RELEASE);
154 void drm_vblank_cleanup(struct drm_device *dev)
158 /* Bail if the driver didn't call drm_vblank_init() */
159 if (dev->num_crtcs == 0)
162 for (crtc = 0; crtc < dev->num_crtcs; crtc++) {
163 del_timer_sync(&dev->vblank[crtc].disable_timer);
164 vblank_disable_fn((unsigned long)&dev->vblank[crtc]);
171 EXPORT_SYMBOL(drm_vblank_cleanup);
173 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
175 int i, ret = -ENOMEM;
177 lockinit(&dev->vbl_lock, "drmvbl", 0, LK_CANRECURSE);
178 lockinit(&dev->vblank_time_lock, "drmvtl", 0, LK_CANRECURSE);
180 dev->num_crtcs = num_crtcs;
182 dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
186 for (i = 0; i < num_crtcs; i++) {
187 dev->vblank[i].dev = dev;
188 dev->vblank[i].crtc = i;
189 init_waitqueue_head(&dev->vblank[i].queue);
190 setup_timer(&dev->vblank[i].disable_timer, vblank_disable_fn,
191 (unsigned long)&dev->vblank[i]);
194 DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
196 /* Driver specific high-precision vblank timestamping supported? */
197 if (dev->driver->get_vblank_timestamp)
198 DRM_INFO("Driver supports precise vblank timestamp query.\n");
200 DRM_INFO("No driver support for vblank timestamp query.\n");
202 dev->vblank_disable_allowed = false;
207 drm_vblank_cleanup(dev);
210 EXPORT_SYMBOL(drm_vblank_init);
213 static void drm_irq_vgaarb_nokms(void *cookie, bool state)
215 struct drm_device *dev = cookie;
217 if (dev->driver->vgaarb_irq) {
218 dev->driver->vgaarb_irq(dev, state);
222 if (!dev->irq_enabled)
226 if (dev->driver->irq_uninstall)
227 dev->driver->irq_uninstall(dev);
229 if (dev->driver->irq_preinstall)
230 dev->driver->irq_preinstall(dev);
231 if (dev->driver->irq_postinstall)
232 dev->driver->irq_postinstall(dev);
238 * Install IRQ handler.
240 * \param dev DRM device.
242 * Initializes the IRQ related data. Installs the handler, calling the driver
243 * \c irq_preinstall() and \c irq_postinstall() functions
244 * before and after the installation.
246 int drm_irq_install(struct drm_device *dev, int irq)
250 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
256 /* Driver must have been initialized */
257 if (!dev->dev_private)
260 if (dev->irq_enabled)
262 dev->irq_enabled = 1;
264 DRM_DEBUG("irq=%d\n", irq);
266 /* Before installing handler */
267 if (dev->driver->irq_preinstall)
268 dev->driver->irq_preinstall(dev);
270 /* Install handler */
271 ret = bus_setup_intr(dev->dev, dev->irqr, INTR_MPSAFE,
272 dev->driver->irq_handler, dev, &dev->irqh, &dev->irq_lock);
275 dev->irq_enabled = 0;
279 /* After installing handler */
280 if (dev->driver->irq_postinstall)
281 ret = dev->driver->irq_postinstall(dev);
284 dev->irq_enabled = 0;
285 bus_teardown_intr(dev->dev, dev->irqr, dev->irqh);
292 EXPORT_SYMBOL(drm_irq_install);
295 * Uninstall the IRQ handler.
297 * \param dev DRM device.
299 * Calls the driver's \c irq_uninstall() function, and stops the irq.
301 int drm_irq_uninstall(struct drm_device *dev)
306 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
309 irq_enabled = dev->irq_enabled;
310 dev->irq_enabled = false;
313 * Wake up any waiters so they don't hang.
315 if (dev->num_crtcs) {
316 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
317 for (i = 0; i < dev->num_crtcs; i++) {
318 wake_up(&dev->vblank[i].queue);
319 dev->vblank[i].enabled = false;
320 dev->vblank[i].last =
321 dev->driver->get_vblank_counter(dev, i);
323 lockmgr(&dev->vbl_lock, LK_RELEASE);
329 DRM_DEBUG("irq=%d\n", dev->irq);
331 if (dev->driver->irq_uninstall)
332 dev->driver->irq_uninstall(dev);
334 bus_teardown_intr(dev->dev, dev->irqr, dev->irqh);
338 EXPORT_SYMBOL(drm_irq_uninstall);
343 * \param inode device inode.
344 * \param file_priv DRM file private.
345 * \param cmd command.
346 * \param arg user argument, pointing to a drm_control structure.
347 * \return zero on success or a negative number on failure.
349 * Calls irq_install() or irq_uninstall() according to \p arg.
351 int drm_control(struct drm_device *dev, void *data,
352 struct drm_file *file_priv)
354 struct drm_control *ctl = data;
357 /* if we haven't irq we fallback for compatibility reasons -
358 * this used to be a separate function in drm_dma.h
361 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
363 if (drm_core_check_feature(dev, DRIVER_MODESET))
365 /* UMS was only ever support on pci devices. */
366 if (WARN_ON(!dev->pdev))
370 case DRM_INST_HANDLER:
373 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
376 mutex_lock(&dev->struct_mutex);
377 ret = drm_irq_install(dev, irq);
378 mutex_unlock(&dev->struct_mutex);
381 case DRM_UNINST_HANDLER:
382 mutex_lock(&dev->struct_mutex);
383 ret = drm_irq_uninstall(dev);
384 mutex_unlock(&dev->struct_mutex);
393 * drm_calc_timestamping_constants - Calculate vblank timestamp constants
395 * @crtc drm_crtc whose timestamp constants should be updated.
396 * @mode display mode containing the scanout timings
398 * Calculate and store various constants which are later
399 * needed by vblank and swap-completion timestamping, e.g,
400 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
401 * derived from crtc's true scanout timing, so they take
402 * things like panel scaling or other adjustments into account.
404 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
405 const struct drm_display_mode *mode)
407 int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
408 int dotclock = mode->crtc_clock;
410 /* Valid dotclock? */
412 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
415 * Convert scanline length in pixels and video
416 * dot clock to line duration, frame duration
417 * and pixel duration in nanoseconds:
419 pixeldur_ns = 1000000 / dotclock;
420 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
421 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
424 * Fields of interlaced scanout modes are only half a frame duration.
426 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
429 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
432 crtc->pixeldur_ns = pixeldur_ns;
433 crtc->linedur_ns = linedur_ns;
434 crtc->framedur_ns = framedur_ns;
436 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
437 crtc->base.id, mode->crtc_htotal,
438 mode->crtc_vtotal, mode->crtc_vdisplay);
439 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
440 crtc->base.id, dotclock, framedur_ns,
441 linedur_ns, pixeldur_ns);
443 EXPORT_SYMBOL(drm_calc_timestamping_constants);
446 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
447 * drivers. Implements calculation of exact vblank timestamps from
448 * given drm_display_mode timings and current video scanout position
449 * of a crtc. This can be called from within get_vblank_timestamp()
450 * implementation of a kms driver to implement the actual timestamping.
452 * Should return timestamps conforming to the OML_sync_control OpenML
453 * extension specification. The timestamp corresponds to the end of
454 * the vblank interval, aka start of scanout of topmost-leftmost display
455 * pixel in the following video frame.
457 * Requires support for optional dev->driver->get_scanout_position()
458 * in kms driver, plus a bit of setup code to provide a drm_display_mode
459 * that corresponds to the true scanout timing.
461 * The current implementation only handles standard video modes. It
462 * returns as no operation if a doublescan or interlaced video mode is
463 * active. Higher level code is expected to handle this.
466 * @crtc: Which crtc's vblank timestamp to retrieve.
467 * @max_error: Desired maximum allowable error in timestamps (nanosecs).
468 * On return contains true maximum error of timestamp.
469 * @vblank_time: Pointer to struct timeval which should receive the timestamp.
470 * @flags: Flags to pass to driver:
472 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
473 * @refcrtc: drm_crtc* of crtc which defines scanout timing.
474 * @mode: mode which defines the scanout timings
476 * Returns negative value on error, failure or if not supported in current
479 * -EINVAL - Invalid crtc.
480 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
481 * -ENOTSUPP - Function not supported in current display mode.
482 * -EIO - Failed, e.g., due to failed scanout position query.
484 * Returns or'ed positive status flags on success:
486 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
487 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
490 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
492 struct timeval *vblank_time,
494 const struct drm_crtc *refcrtc,
495 const struct drm_display_mode *mode)
497 ktime_t stime, etime;
498 struct timeval tv_etime;
501 int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
504 if (crtc < 0 || crtc >= dev->num_crtcs) {
505 DRM_ERROR("Invalid crtc %d\n", crtc);
509 /* Scanout position query not supported? Should not happen. */
510 if (!dev->driver->get_scanout_position) {
511 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
515 /* Durations of frames, lines, pixels in nanoseconds. */
516 framedur_ns = refcrtc->framedur_ns;
517 linedur_ns = refcrtc->linedur_ns;
518 pixeldur_ns = refcrtc->pixeldur_ns;
520 /* If mode timing undefined, just return as no-op:
521 * Happens during initial modesetting of a crtc.
523 if (framedur_ns == 0) {
524 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
528 /* Get current scanout position with system timestamp.
529 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
530 * if single query takes longer than max_error nanoseconds.
532 * This guarantees a tight bound on maximum error if
533 * code gets preempted or delayed for some reason.
535 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
537 * Get vertical and horizontal scanout position vpos, hpos,
538 * and bounding timestamps stime, etime, pre/post query.
540 vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
541 &hpos, &stime, &etime);
544 * Get correction for CLOCK_MONOTONIC -> CLOCK_REALTIME if
545 * CLOCK_REALTIME is requested.
548 if (!drm_timestamp_monotonic)
549 mono_time_offset = ktime_get_monotonic_offset();
552 /* Return as no-op if scanout query unsupported or failed. */
553 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
554 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
559 /* Compute uncertainty in timestamp of scanout position query. */
560 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
562 /* Accept result with < max_error nsecs timing uncertainty. */
563 if (duration_ns <= *max_error)
567 /* Noisy system timing? */
568 if (i == DRM_TIMESTAMP_MAXRETRIES) {
569 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
570 crtc, duration_ns/1000, *max_error/1000, i);
573 /* Return upper bound of timestamp precision error. */
574 *max_error = duration_ns;
576 /* Check if in vblank area:
577 * vpos is >=0 in video scanout area, but negative
578 * within vblank area, counting down the number of lines until
581 invbl = vbl_status & DRM_SCANOUTPOS_INVBL;
583 /* Convert scanout position into elapsed time at raw_time query
584 * since start of scanout at first display scanline. delta_ns
585 * can be negative if start of scanout hasn't happened yet.
587 delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
590 if (!drm_timestamp_monotonic)
591 etime = ktime_sub(etime, mono_time_offset);
594 /* save this only for debugging purposes */
595 tv_etime = ktime_to_timeval(etime);
596 /* Subtract time delta from raw timestamp to get final
597 * vblank_time timestamp for end of vblank.
600 etime = ktime_add_ns(etime, -delta_ns);
602 etime = ktime_sub_ns(etime, delta_ns);
603 *vblank_time = ktime_to_timeval(etime);
605 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
606 crtc, (int)vbl_status, hpos, vpos,
607 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
608 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
609 duration_ns/1000, i);
611 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
613 vbl_status |= DRM_VBLANKTIME_INVBL;
617 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
619 static struct timeval get_drm_timestamp(void)
625 if (!drm_timestamp_monotonic)
626 now = ktime_sub(now, ktime_get_monotonic_offset());
629 return ktime_to_timeval(now);
633 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
637 * @crtc: which crtc's vblank timestamp to retrieve
638 * @tvblank: Pointer to target struct timeval which should receive the timestamp
639 * @flags: Flags to pass to driver:
641 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
643 * Fetches the system timestamp corresponding to the time of the most recent
644 * vblank interval on specified crtc. May call into kms-driver to
645 * compute the timestamp with a high-precision GPU specific method.
647 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
648 * call, i.e., it isn't very precisely locked to the true vblank.
650 * Returns non-zero if timestamp is considered to be very precise.
652 u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
653 struct timeval *tvblank, unsigned flags)
657 /* Define requested maximum error on timestamps (nanoseconds). */
658 int max_error = (int) drm_timestamp_precision * 1000;
660 /* Query driver if possible and precision timestamping enabled. */
661 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
662 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
668 /* GPU high precision timestamp query unsupported or failed.
669 * Return current monotonic/gettimeofday timestamp as best estimate.
671 *tvblank = get_drm_timestamp();
675 EXPORT_SYMBOL(drm_get_last_vbltimestamp);
678 * drm_vblank_count - retrieve "cooked" vblank counter value
680 * @crtc: which counter to retrieve
682 * Fetches the "cooked" vblank count value that represents the number of
683 * vblank events since the system was booted, including lost events due to
684 * modesetting activity.
686 u32 drm_vblank_count(struct drm_device *dev, int crtc)
688 return atomic_read(&dev->vblank[crtc].count);
690 EXPORT_SYMBOL(drm_vblank_count);
693 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
694 * and the system timestamp corresponding to that vblank counter value.
697 * @crtc: which counter to retrieve
698 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
700 * Fetches the "cooked" vblank count value that represents the number of
701 * vblank events since the system was booted, including lost events due to
702 * modesetting activity. Returns corresponding system timestamp of the time
703 * of the vblank interval that corresponds to the current value vblank counter
706 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
707 struct timeval *vblanktime)
711 /* Read timestamp from slot of _vblank_time ringbuffer
712 * that corresponds to current vblank count. Retry if
713 * count has incremented during readout. This works like
717 cur_vblank = atomic_read(&dev->vblank[crtc].count);
718 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
720 } while (cur_vblank != atomic_read(&dev->vblank[crtc].count));
724 EXPORT_SYMBOL(drm_vblank_count_and_time);
726 static void send_vblank_event(struct drm_device *dev,
727 struct drm_pending_vblank_event *e,
728 unsigned long seq, struct timeval *now)
730 e->event.sequence = seq;
731 e->event.tv_sec = now->tv_sec;
732 e->event.tv_usec = now->tv_usec;
734 list_add_tail(&e->base.link,
735 &e->base.file_priv->event_list);
736 drm_event_wakeup(&e->base);
738 wake_up_interruptible(&e->base.file_priv->event_wait);
739 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
745 * drm_send_vblank_event - helper to send vblank event after pageflip
747 * @crtc: CRTC in question
748 * @e: the event to send
750 * Updates sequence # and timestamp on event, and sends it to userspace.
751 * Caller must hold event lock.
753 void drm_send_vblank_event(struct drm_device *dev, int crtc,
754 struct drm_pending_vblank_event *e)
759 seq = drm_vblank_count_and_time(dev, crtc, &now);
763 now = get_drm_timestamp();
766 send_vblank_event(dev, e, seq, &now);
768 EXPORT_SYMBOL(drm_send_vblank_event);
771 * drm_update_vblank_count - update the master vblank counter
773 * @crtc: counter to update
775 * Call back into the driver to update the appropriate vblank counter
776 * (specified by @crtc). Deal with wraparound, if it occurred, and
777 * update the last read value so we can deal with wraparound on the next
780 * Only necessary when going from off->on, to account for frames we
781 * didn't get an interrupt for.
783 * Note: caller must hold dev->vbl_lock since this reads & writes
784 * device vblank fields.
786 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
788 u32 cur_vblank, diff, tslot, rc;
789 struct timeval t_vblank;
792 * Interrupts were disabled prior to this call, so deal with counter
794 * NOTE! It's possible we lost a full dev->max_vblank_count events
795 * here if the register is small or we had vblank interrupts off for
798 * We repeat the hardware vblank counter & timestamp query until
799 * we get consistent results. This to prevent races between gpu
800 * updating its hardware counter while we are retrieving the
801 * corresponding vblank timestamp.
804 cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
805 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
806 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
808 /* Deal with counter wrap */
809 diff = cur_vblank - dev->vblank[crtc].last;
810 if (cur_vblank < dev->vblank[crtc].last) {
811 diff += dev->max_vblank_count;
813 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
814 crtc, dev->vblank[crtc].last, cur_vblank, diff);
817 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
820 /* Reinitialize corresponding vblank timestamp if high-precision query
821 * available. Skip this step if query unsupported or failed. Will
822 * reinitialize delayed at next vblank interrupt in that case.
825 tslot = atomic_read(&dev->vblank[crtc].count) + diff;
826 vblanktimestamp(dev, crtc, tslot) = t_vblank;
829 smp_mb__before_atomic();
830 atomic_add(diff, &dev->vblank[crtc].count);
831 smp_mb__after_atomic();
835 * drm_vblank_enable - enable the vblank interrupt on a CRTC
837 * @crtc: CRTC in question
839 static int drm_vblank_enable(struct drm_device *dev, int crtc)
843 assert_spin_locked(&dev->vbl_lock);
845 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE);
847 if (!dev->vblank[crtc].enabled) {
848 /* Enable vblank irqs under vblank_time_lock protection.
849 * All vblank count & timestamp updates are held off
850 * until we are done reinitializing master counter and
851 * timestamps. Filtercode in drm_handle_vblank() will
852 * prevent double-accounting of same vblank interval.
854 ret = dev->driver->enable_vblank(dev, crtc);
855 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
857 atomic_dec(&dev->vblank[crtc].refcount);
859 dev->vblank[crtc].enabled = true;
860 drm_update_vblank_count(dev, crtc);
864 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
870 * drm_vblank_get - get a reference count on vblank events
872 * @crtc: which CRTC to own
874 * Acquire a reference count on vblank events to avoid having them disabled
878 * Zero on success, nonzero on failure.
880 int drm_vblank_get(struct drm_device *dev, int crtc)
884 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
885 /* Going from 0->1 means we have to enable interrupts again */
886 if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) {
887 ret = drm_vblank_enable(dev, crtc);
889 if (!dev->vblank[crtc].enabled) {
890 atomic_dec(&dev->vblank[crtc].refcount);
894 lockmgr(&dev->vbl_lock, LK_RELEASE);
898 EXPORT_SYMBOL(drm_vblank_get);
901 * drm_crtc_vblank_get - get a reference count on vblank events
902 * @crtc: which CRTC to own
904 * Acquire a reference count on vblank events to avoid having them disabled
907 * This is the native kms version of drm_vblank_off().
910 * Zero on success, nonzero on failure.
912 int drm_crtc_vblank_get(struct drm_crtc *crtc)
914 return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
916 EXPORT_SYMBOL(drm_crtc_vblank_get);
919 * drm_vblank_put - give up ownership of vblank events
921 * @crtc: which counter to give up
923 * Release ownership of a given vblank counter, turning off interrupts
924 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
926 void drm_vblank_put(struct drm_device *dev, int crtc)
928 BUG_ON(atomic_read(&dev->vblank[crtc].refcount) == 0);
930 /* Last user schedules interrupt disable */
931 if (atomic_dec_and_test(&dev->vblank[crtc].refcount) &&
932 (drm_vblank_offdelay > 0))
933 mod_timer(&dev->vblank[crtc].disable_timer,
934 jiffies + ((drm_vblank_offdelay * HZ)/1000));
936 EXPORT_SYMBOL(drm_vblank_put);
939 * drm_crtc_vblank_put - give up ownership of vblank events
940 * @crtc: which counter to give up
942 * Release ownership of a given vblank counter, turning off interrupts
943 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
945 * This is the native kms version of drm_vblank_put().
947 void drm_crtc_vblank_put(struct drm_crtc *crtc)
949 drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
951 EXPORT_SYMBOL(drm_crtc_vblank_put);
954 * drm_vblank_off - disable vblank events on a CRTC
956 * @crtc: CRTC in question
958 * Drivers can use this function to shut down the vblank interrupt handling when
959 * disabling a crtc. This function ensures that the latest vblank frame count is
960 * stored so that drm_vblank_on() can restore it again.
962 * Drivers must use this function when the hardware vblank counter can get
963 * reset, e.g. when suspending.
965 * This is the legacy version of drm_crtc_vblank_off().
967 void drm_vblank_off(struct drm_device *dev, int crtc)
969 struct drm_pending_vblank_event *e, *t;
973 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
974 vblank_disable_and_save(dev, crtc);
975 wake_up(&dev->vblank[crtc].queue);
977 /* Send any queued vblank events, lest the natives grow disquiet */
978 seq = drm_vblank_count_and_time(dev, crtc, &now);
980 lockmgr(&dev->event_lock, LK_EXCLUSIVE);
981 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
984 DRM_DEBUG("Sending premature vblank event on disable: \
985 wanted %d, current %d\n",
986 e->event.sequence, seq);
987 list_del(&e->base.link);
988 drm_vblank_put(dev, e->pipe);
989 send_vblank_event(dev, e, seq, &now);
991 lockmgr(&dev->event_lock, LK_RELEASE);
993 lockmgr(&dev->vbl_lock, LK_RELEASE);
995 EXPORT_SYMBOL(drm_vblank_off);
998 * drm_crtc_vblank_off - disable vblank events on a CRTC
999 * @crtc: CRTC in question
1001 * Drivers can use this function to shut down the vblank interrupt handling when
1002 * disabling a crtc. This function ensures that the latest vblank frame count is
1003 * stored so that drm_vblank_on can restore it again.
1005 * Drivers must use this function when the hardware vblank counter can get
1006 * reset, e.g. when suspending.
1008 * This is the native kms version of drm_vblank_off().
1010 void drm_crtc_vblank_off(struct drm_crtc *crtc)
1012 drm_vblank_off(crtc->dev, drm_crtc_index(crtc));
1014 EXPORT_SYMBOL(drm_crtc_vblank_off);
1017 * drm_vblank_on - enable vblank events on a CRTC
1019 * @crtc: CRTC in question
1021 * This functions restores the vblank interrupt state captured with
1022 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1023 * drm_vblank_off() can be unbalanced and so can also be unconditionaly called
1024 * in driver load code to reflect the current hardware state of the crtc.
1026 * This is the legacy version of drm_crtc_vblank_on().
1028 void drm_vblank_on(struct drm_device *dev, int crtc)
1031 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
1032 /* re-enable interrupts if there's are users left */
1033 if (atomic_read(&dev->vblank[crtc].refcount) != 0)
1034 WARN_ON(drm_vblank_enable(dev, crtc));
1035 lockmgr(&dev->vbl_lock, LK_RELEASE);
1037 EXPORT_SYMBOL(drm_vblank_on);
1040 * drm_crtc_vblank_on - enable vblank events on a CRTC
1041 * @crtc: CRTC in question
1043 * This functions restores the vblank interrupt state captured with
1044 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1045 * drm_vblank_off() can be unbalanced and so can also be unconditionaly called
1046 * in driver load code to reflect the current hardware state of the crtc.
1048 * This is the native kms version of drm_vblank_on().
1050 void drm_crtc_vblank_on(struct drm_crtc *crtc)
1052 drm_vblank_on(crtc->dev, drm_crtc_index(crtc));
1054 EXPORT_SYMBOL(drm_crtc_vblank_on);
1057 * drm_vblank_pre_modeset - account for vblanks across mode sets
1059 * @crtc: CRTC in question
1061 * Account for vblank events across mode setting events, which will likely
1062 * reset the hardware frame counter.
1064 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
1066 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1067 if (!dev->num_crtcs)
1070 * To avoid all the problems that might happen if interrupts
1071 * were enabled/disabled around or between these calls, we just
1072 * have the kernel take a reference on the CRTC (just once though
1073 * to avoid corrupting the count if multiple, mismatch calls occur),
1074 * so that interrupts remain enabled in the interim.
1076 if (!dev->vblank[crtc].inmodeset) {
1077 dev->vblank[crtc].inmodeset = 0x1;
1078 if (drm_vblank_get(dev, crtc) == 0)
1079 dev->vblank[crtc].inmodeset |= 0x2;
1082 EXPORT_SYMBOL(drm_vblank_pre_modeset);
1084 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
1087 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1088 if (!dev->num_crtcs)
1091 if (dev->vblank[crtc].inmodeset) {
1092 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
1093 dev->vblank_disable_allowed = true;
1094 lockmgr(&dev->vbl_lock, LK_RELEASE);
1096 if (dev->vblank[crtc].inmodeset & 0x2)
1097 drm_vblank_put(dev, crtc);
1099 dev->vblank[crtc].inmodeset = 0;
1102 EXPORT_SYMBOL(drm_vblank_post_modeset);
1105 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1106 * @DRM_IOCTL_ARGS: standard ioctl arguments
1108 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1109 * ioctls around modesetting so that any lost vblank events are accounted for.
1111 * Generally the counter will reset across mode sets. If interrupts are
1112 * enabled around this call, we don't have to do anything since the counter
1113 * will have already been incremented.
1115 int drm_modeset_ctl(struct drm_device *dev, void *data,
1116 struct drm_file *file_priv)
1118 struct drm_modeset_ctl *modeset = data;
1121 /* If drm_vblank_init() hasn't been called yet, just no-op */
1122 if (!dev->num_crtcs)
1125 /* KMS drivers handle this internally */
1126 if (drm_core_check_feature(dev, DRIVER_MODESET))
1129 crtc = modeset->crtc;
1130 if (crtc >= dev->num_crtcs)
1133 switch (modeset->cmd) {
1134 case _DRM_PRE_MODESET:
1135 drm_vblank_pre_modeset(dev, crtc);
1137 case _DRM_POST_MODESET:
1138 drm_vblank_post_modeset(dev, crtc);
1148 drm_vblank_event_destroy(struct drm_pending_event *e)
1153 static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1154 union drm_wait_vblank *vblwait,
1155 struct drm_file *file_priv)
1157 struct drm_pending_vblank_event *e;
1162 e = kzalloc(sizeof *e, GFP_KERNEL);
1169 e->base.pid = curproc->p_pid;
1170 e->event.base.type = DRM_EVENT_VBLANK;
1171 e->event.base.length = sizeof e->event;
1172 e->event.user_data = vblwait->request.signal;
1173 e->base.event = &e->event.base;
1174 e->base.file_priv = file_priv;
1175 e->base.destroy = drm_vblank_event_destroy;
1177 lockmgr(&dev->event_lock, LK_EXCLUSIVE);
1179 if (file_priv->event_space < sizeof e->event) {
1184 file_priv->event_space -= sizeof e->event;
1185 seq = drm_vblank_count_and_time(dev, pipe, &now);
1187 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1188 (seq - vblwait->request.sequence) <= (1 << 23)) {
1189 vblwait->request.sequence = seq + 1;
1190 vblwait->reply.sequence = vblwait->request.sequence;
1193 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1194 vblwait->request.sequence, seq, pipe);
1196 e->event.sequence = vblwait->request.sequence;
1197 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1198 drm_vblank_put(dev, pipe);
1199 send_vblank_event(dev, e, seq, &now);
1200 vblwait->reply.sequence = seq;
1202 /* drm_handle_vblank_events will call drm_vblank_put */
1203 list_add_tail(&e->base.link, &dev->vblank_event_list);
1204 vblwait->reply.sequence = vblwait->request.sequence;
1207 lockmgr(&dev->event_lock, LK_RELEASE);
1212 lockmgr(&dev->event_lock, LK_RELEASE);
1215 drm_vblank_put(dev, pipe);
1222 * \param inode device inode.
1223 * \param file_priv DRM file private.
1224 * \param cmd command.
1225 * \param data user argument, pointing to a drm_wait_vblank structure.
1226 * \return zero on success or a negative number on failure.
1228 * This function enables the vblank interrupt on the pipe requested, then
1229 * sleeps waiting for the requested sequence number to occur, and drops
1230 * the vblank interrupt refcount afterwards. (vblank irq disable follows that
1231 * after a timeout with no further vblank waits scheduled).
1233 int drm_wait_vblank(struct drm_device *dev, void *data,
1234 struct drm_file *file_priv)
1236 union drm_wait_vblank *vblwait = data;
1238 unsigned int flags, seq, crtc, high_crtc;
1240 if (!dev->irq_enabled)
1243 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1246 if (vblwait->request.type &
1247 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1248 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1249 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1250 vblwait->request.type,
1251 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1252 _DRM_VBLANK_HIGH_CRTC_MASK));
1256 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1257 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1259 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1261 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1262 if (crtc >= dev->num_crtcs)
1265 ret = drm_vblank_get(dev, crtc);
1267 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1270 seq = drm_vblank_count(dev, crtc);
1272 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1273 case _DRM_VBLANK_RELATIVE:
1274 vblwait->request.sequence += seq;
1275 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1276 case _DRM_VBLANK_ABSOLUTE:
1283 if (flags & _DRM_VBLANK_EVENT) {
1284 /* must hold on to the vblank ref until the event fires
1285 * drm_vblank_put will be called asynchronously
1287 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1290 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1291 (seq - vblwait->request.sequence) <= (1<<23)) {
1292 vblwait->request.sequence = seq + 1;
1295 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1296 vblwait->request.sequence, crtc);
1297 dev->vblank[crtc].last_wait = vblwait->request.sequence;
1298 DRM_WAIT_ON(ret, dev->vblank[crtc].queue, 3 * HZ,
1299 (((drm_vblank_count(dev, crtc) -
1300 vblwait->request.sequence) <= (1 << 23)) ||
1301 !dev->vblank[crtc].enabled ||
1302 !dev->irq_enabled));
1304 if (ret != -EINTR) {
1307 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1308 vblwait->reply.tval_sec = now.tv_sec;
1309 vblwait->reply.tval_usec = now.tv_usec;
1311 DRM_DEBUG("returning %d to client\n",
1312 vblwait->reply.sequence);
1314 DRM_DEBUG("vblank wait interrupted by signal\n");
1318 drm_vblank_put(dev, crtc);
1322 static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1324 struct drm_pending_vblank_event *e, *t;
1328 seq = drm_vblank_count_and_time(dev, crtc, &now);
1330 lockmgr(&dev->event_lock, LK_EXCLUSIVE);
1332 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1333 if (e->pipe != crtc)
1335 if ((seq - e->event.sequence) > (1<<23))
1338 DRM_DEBUG("vblank event on %d, current %d\n",
1339 e->event.sequence, seq);
1341 list_del(&e->base.link);
1342 drm_vblank_put(dev, e->pipe);
1343 send_vblank_event(dev, e, seq, &now);
1346 lockmgr(&dev->event_lock, LK_RELEASE);
1350 * drm_handle_vblank - handle a vblank event
1352 * @crtc: where this event occurred
1354 * Drivers should call this routine in their vblank interrupt handlers to
1355 * update the vblank counter and send any signals that may be pending.
1357 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1361 struct timeval tvblank;
1363 if (!dev->num_crtcs)
1366 /* Need timestamp lock to prevent concurrent execution with
1367 * vblank enable/disable, as this would cause inconsistent
1368 * or corrupted timestamps and vblank counts.
1370 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE);
1372 /* Vblank irq handling disabled. Nothing to do. */
1373 if (!dev->vblank[crtc].enabled) {
1374 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
1378 /* Fetch corresponding timestamp for this vblank interval from
1379 * driver and store it in proper slot of timestamp ringbuffer.
1382 /* Get current timestamp and count. */
1383 vblcount = atomic_read(&dev->vblank[crtc].count);
1384 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1386 /* Compute time difference to timestamp of last vblank */
1387 diff_ns = timeval_to_ns(&tvblank) -
1388 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1390 /* Update vblank timestamp and count if at least
1391 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1392 * difference between last stored timestamp and current
1393 * timestamp. A smaller difference means basically
1394 * identical timestamps. Happens if this vblank has
1395 * been already processed and this is a redundant call,
1396 * e.g., due to spurious vblank interrupts. We need to
1397 * ignore those for accounting.
1399 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1400 /* Store new timestamp in ringbuffer. */
1401 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1403 /* Increment cooked vblank count. This also atomically commits
1404 * the timestamp computed above.
1406 smp_mb__before_atomic();
1407 atomic_inc(&dev->vblank[crtc].count);
1408 smp_mb__after_atomic();
1410 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1411 crtc, (int) diff_ns);
1414 wake_up(&dev->vblank[crtc].queue);
1415 drm_handle_vblank_events(dev, crtc);
1417 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
1420 EXPORT_SYMBOL(drm_handle_vblank);