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.
36 #include <linux/export.h>
37 #include <linux/mutex.h>
38 #include <linux/time.h>
39 #include <linux/timer.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 * Get interrupt from bus id.
59 * \param inode device inode.
60 * \param file_priv DRM file private.
62 * \param arg user argument, pointing to a drm_irq_busid structure.
63 * \return zero on success or a negative number on failure.
65 * Finds the PCI device with the specified bus id and gets its IRQ number.
66 * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
67 * to that of the device that this DRM instance attached to.
69 int drm_irq_by_busid(struct drm_device *dev, void *data,
70 struct drm_file *file_priv)
72 struct drm_irq_busid *irq = data;
74 if ((irq->busnum >> 8) != dev->pci_domain ||
75 (irq->busnum & 0xff) != dev->pci_bus ||
76 irq->devnum != dev->pci_slot ||
77 irq->funcnum != dev->pci_func)
82 DRM_DEBUG("%d:%d:%d => IRQ %d\n",
83 irq->busnum, irq->devnum, irq->funcnum, irq->irq);
89 * Clear vblank timestamp buffer for a crtc.
91 static void clear_vblank_timestamps(struct drm_device *dev, int crtc)
93 memset(dev->vblank[crtc].time, 0, sizeof(dev->vblank[crtc].time));
97 * Disable vblank irq's on crtc, make sure that last vblank count
98 * of hardware and corresponding consistent software vblank counter
99 * are preserved, even if there are any spurious vblank irq's after
102 static void vblank_disable_and_save(struct drm_device *dev, int crtc)
107 struct timeval tvblank;
108 int count = DRM_TIMESTAMP_MAXRETRIES;
110 /* Prevent vblank irq processing while disabling vblank irqs,
111 * so no updates of timestamps or count can happen after we've
112 * disabled. Needed to prevent races in case of delayed irq's.
114 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE);
116 dev->driver->disable_vblank(dev, crtc);
117 dev->vblank[crtc].enabled = false;
119 /* No further vblank irq's will be processed after
120 * this point. Get current hardware vblank count and
121 * vblank timestamp, repeat until they are consistent.
123 * FIXME: There is still a race condition here and in
124 * drm_update_vblank_count() which can cause off-by-one
125 * reinitialization of software vblank counter. If gpu
126 * vblank counter doesn't increment exactly at the leading
127 * edge of a vblank interval, then we can lose 1 count if
128 * we happen to execute between start of vblank and the
129 * delayed gpu counter increment.
132 dev->vblank[crtc].last = dev->driver->get_vblank_counter(dev, crtc);
133 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
134 } while (dev->vblank[crtc].last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
139 /* Compute time difference to stored timestamp of last vblank
140 * as updated by last invocation of drm_handle_vblank() in vblank irq.
142 vblcount = atomic_read(&dev->vblank[crtc].count);
143 diff_ns = timeval_to_ns(&tvblank) -
144 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
146 /* If there is at least 1 msec difference between the last stored
147 * timestamp and tvblank, then we are currently executing our
148 * disable inside a new vblank interval, the tvblank timestamp
149 * corresponds to this new vblank interval and the irq handler
150 * for this vblank didn't run yet and won't run due to our disable.
151 * Therefore we need to do the job of drm_handle_vblank() and
152 * increment the vblank counter by one to account for this vblank.
154 * Skip this step if there isn't any high precision timestamp
155 * available. In that case we can't account for this and just
158 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
159 atomic_inc(&dev->vblank[crtc].count);
160 smp_mb__after_atomic_inc();
163 /* Invalidate all timestamps while vblank irq's are off. */
164 clear_vblank_timestamps(dev, crtc);
166 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
169 static void vblank_disable_fn(unsigned long arg)
171 struct drm_device *dev = (struct drm_device *)arg;
174 if (!dev->vblank_disable_allowed)
177 for (i = 0; i < dev->num_crtcs; i++) {
178 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
179 if (atomic_read(&dev->vblank[i].refcount) == 0 &&
180 dev->vblank[i].enabled) {
181 DRM_DEBUG("disabling vblank on crtc %d\n", i);
182 vblank_disable_and_save(dev, i);
184 lockmgr(&dev->vbl_lock, LK_RELEASE);
188 void drm_vblank_cleanup(struct drm_device *dev)
190 /* Bail if the driver didn't call drm_vblank_init() */
191 if (dev->num_crtcs == 0)
194 del_timer_sync(&dev->vblank_disable_timer);
196 vblank_disable_fn((unsigned long)dev);
202 EXPORT_SYMBOL(drm_vblank_cleanup);
204 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
206 int i, ret = -ENOMEM;
208 setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
210 lockinit(&dev->vbl_lock, "drmvbl", 0, LK_CANRECURSE);
211 lockinit(&dev->vblank_time_lock, "drmvtl", 0, LK_CANRECURSE);
213 dev->num_crtcs = num_crtcs;
215 dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
219 for (i = 0; i < num_crtcs; i++)
220 init_waitqueue_head(&dev->vblank[i].queue);
222 DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
224 /* Driver specific high-precision vblank timestamping supported? */
225 if (dev->driver->get_vblank_timestamp)
226 DRM_INFO("Driver supports precise vblank timestamp query.\n");
228 DRM_INFO("No driver support for vblank timestamp query.\n");
230 dev->vblank_disable_allowed = false;
235 drm_vblank_cleanup(dev);
238 EXPORT_SYMBOL(drm_vblank_init);
241 * Install IRQ handler.
243 * \param dev DRM device.
245 * Initializes the IRQ related data. Installs the handler, calling the driver
246 * \c irq_preinstall() and \c irq_postinstall() functions
247 * before and after the installation.
249 int drm_irq_install(struct drm_device *dev)
253 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
261 /* Driver must have been initialized */
262 if (!dev->dev_private) {
267 if (dev->irq_enabled) {
271 dev->irq_enabled = 1;
274 DRM_DEBUG("irq=%d\n", dev->irq);
276 /* Before installing handler */
277 if (dev->driver->irq_preinstall)
278 dev->driver->irq_preinstall(dev);
280 /* Install handler */
281 ret = bus_setup_intr(dev->dev, dev->irqr, INTR_MPSAFE,
282 dev->driver->irq_handler, dev, &dev->irqh, &dev->irq_lock);
286 dev->irq_enabled = 0;
291 /* After installing handler */
292 if (dev->driver->irq_postinstall)
293 ret = dev->driver->irq_postinstall(dev);
297 dev->irq_enabled = 0;
299 bus_teardown_intr(dev->dev, dev->irqr, dev->irqh);
304 EXPORT_SYMBOL(drm_irq_install);
307 * Uninstall the IRQ handler.
309 * \param dev DRM device.
311 * Calls the driver's \c irq_uninstall() function, and stops the irq.
313 int drm_irq_uninstall(struct drm_device *dev)
318 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
321 mutex_lock(&dev->struct_mutex);
322 irq_enabled = dev->irq_enabled;
323 dev->irq_enabled = false;
324 mutex_unlock(&dev->struct_mutex);
327 * Wake up any waiters so they don't hang.
329 if (dev->num_crtcs) {
330 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
331 for (i = 0; i < dev->num_crtcs; i++) {
332 wake_up(&dev->vblank[i].queue);
333 dev->vblank[i].enabled = false;
334 dev->vblank[i].last =
335 dev->driver->get_vblank_counter(dev, i);
337 lockmgr(&dev->vbl_lock, LK_RELEASE);
343 DRM_DEBUG("irq=%d\n", dev->irq);
345 if (dev->driver->irq_uninstall)
346 dev->driver->irq_uninstall(dev);
348 bus_teardown_intr(dev->dev, dev->irqr, dev->irqh);
352 EXPORT_SYMBOL(drm_irq_uninstall);
357 * \param inode device inode.
358 * \param file_priv DRM file private.
359 * \param cmd command.
360 * \param arg user argument, pointing to a drm_control structure.
361 * \return zero on success or a negative number on failure.
363 * Calls irq_install() or irq_uninstall() according to \p arg.
365 int drm_control(struct drm_device *dev, void *data,
366 struct drm_file *file_priv)
368 struct drm_control *ctl = data;
370 /* if we haven't irq we fallback for compatibility reasons -
371 * this used to be a separate function in drm_dma.h
376 case DRM_INST_HANDLER:
377 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
379 if (drm_core_check_feature(dev, DRIVER_MODESET))
381 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
382 ctl->irq != dev->irq)
384 return drm_irq_install(dev);
385 case DRM_UNINST_HANDLER:
386 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
388 if (drm_core_check_feature(dev, DRIVER_MODESET))
390 return drm_irq_uninstall(dev);
397 * drm_calc_timestamping_constants - Calculate vblank timestamp constants
399 * @crtc drm_crtc whose timestamp constants should be updated.
400 * @mode display mode containing the scanout timings
402 * Calculate and store various constants which are later
403 * needed by vblank and swap-completion timestamping, e.g,
404 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
405 * derived from crtc's true scanout timing, so they take
406 * things like panel scaling or other adjustments into account.
408 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
409 const struct drm_display_mode *mode)
411 int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
412 int dotclock = mode->crtc_clock;
414 /* Valid dotclock? */
416 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
419 * Convert scanline length in pixels and video
420 * dot clock to line duration, frame duration
421 * and pixel duration in nanoseconds:
423 pixeldur_ns = 1000000 / dotclock;
424 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
425 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
428 * Fields of interlaced scanout modes are only half a frame duration.
430 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
433 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
436 crtc->pixeldur_ns = pixeldur_ns;
437 crtc->linedur_ns = linedur_ns;
438 crtc->framedur_ns = framedur_ns;
440 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
441 crtc->base.id, mode->crtc_htotal,
442 mode->crtc_vtotal, mode->crtc_vdisplay);
443 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
444 crtc->base.id, dotclock, framedur_ns,
445 linedur_ns, pixeldur_ns);
447 EXPORT_SYMBOL(drm_calc_timestamping_constants);
450 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
451 * drivers. Implements calculation of exact vblank timestamps from
452 * given drm_display_mode timings and current video scanout position
453 * of a crtc. This can be called from within get_vblank_timestamp()
454 * implementation of a kms driver to implement the actual timestamping.
456 * Should return timestamps conforming to the OML_sync_control OpenML
457 * extension specification. The timestamp corresponds to the end of
458 * the vblank interval, aka start of scanout of topmost-leftmost display
459 * pixel in the following video frame.
461 * Requires support for optional dev->driver->get_scanout_position()
462 * in kms driver, plus a bit of setup code to provide a drm_display_mode
463 * that corresponds to the true scanout timing.
465 * The current implementation only handles standard video modes. It
466 * returns as no operation if a doublescan or interlaced video mode is
467 * active. Higher level code is expected to handle this.
470 * @crtc: Which crtc's vblank timestamp to retrieve.
471 * @max_error: Desired maximum allowable error in timestamps (nanosecs).
472 * On return contains true maximum error of timestamp.
473 * @vblank_time: Pointer to struct timeval which should receive the timestamp.
474 * @flags: Flags to pass to driver:
476 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
477 * @refcrtc: drm_crtc* of crtc which defines scanout timing.
478 * @mode: mode which defines the scanout timings
480 * Returns negative value on error, failure or if not supported in current
483 * -EINVAL - Invalid crtc.
484 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
485 * -ENOTSUPP - Function not supported in current display mode.
486 * -EIO - Failed, e.g., due to failed scanout position query.
488 * Returns or'ed positive status flags on success:
490 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
491 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
494 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
496 struct timeval *vblank_time,
498 const struct drm_crtc *refcrtc,
499 const struct drm_display_mode *mode)
501 ktime_t stime, etime;
502 struct timeval tv_etime;
505 int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
508 if (crtc < 0 || crtc >= dev->num_crtcs) {
509 DRM_ERROR("Invalid crtc %d\n", crtc);
513 /* Scanout position query not supported? Should not happen. */
514 if (!dev->driver->get_scanout_position) {
515 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
519 /* Durations of frames, lines, pixels in nanoseconds. */
520 framedur_ns = refcrtc->framedur_ns;
521 linedur_ns = refcrtc->linedur_ns;
522 pixeldur_ns = refcrtc->pixeldur_ns;
524 /* If mode timing undefined, just return as no-op:
525 * Happens during initial modesetting of a crtc.
527 if (framedur_ns == 0) {
528 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
532 /* Get current scanout position with system timestamp.
533 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
534 * if single query takes longer than max_error nanoseconds.
536 * This guarantees a tight bound on maximum error if
537 * code gets preempted or delayed for some reason.
539 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
541 * Get vertical and horizontal scanout position vpos, hpos,
542 * and bounding timestamps stime, etime, pre/post query.
544 vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
545 &hpos, &stime, &etime);
548 * Get correction for CLOCK_MONOTONIC -> CLOCK_REALTIME if
549 * CLOCK_REALTIME is requested.
552 if (!drm_timestamp_monotonic)
553 mono_time_offset = 0;
556 /* Return as no-op if scanout query unsupported or failed. */
557 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
558 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
563 /* Compute uncertainty in timestamp of scanout position query. */
564 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
566 /* Accept result with < max_error nsecs timing uncertainty. */
567 if (duration_ns <= *max_error)
571 /* Noisy system timing? */
572 if (i == DRM_TIMESTAMP_MAXRETRIES) {
573 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
574 crtc, duration_ns/1000, *max_error/1000, i);
577 /* Return upper bound of timestamp precision error. */
578 *max_error = duration_ns;
580 /* Check if in vblank area:
581 * vpos is >=0 in video scanout area, but negative
582 * within vblank area, counting down the number of lines until
585 invbl = vbl_status & DRM_SCANOUTPOS_INVBL;
587 /* Convert scanout position into elapsed time at raw_time query
588 * since start of scanout at first display scanline. delta_ns
589 * can be negative if start of scanout hasn't happened yet.
591 delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
594 if (!drm_timestamp_monotonic)
595 etime = ktime_sub(etime, mono_time_offset);
598 /* save this only for debugging purposes */
599 tv_etime = ktime_to_timeval(etime);
600 /* Subtract time delta from raw timestamp to get final
601 * vblank_time timestamp for end of vblank.
604 etime = ktime_add_ns(etime, -delta_ns);
606 etime = ktime_sub_ns(etime, delta_ns);
607 *vblank_time = ktime_to_timeval(etime);
609 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
610 crtc, (int)vbl_status, hpos, vpos,
611 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
612 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
613 duration_ns/1000, i);
615 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
617 vbl_status |= DRM_VBLANKTIME_INVBL;
621 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
623 static struct timeval get_drm_timestamp(void)
627 getmicrouptime(&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 KKASSERT(mutex_is_locked(&dev->event_lock));
731 e->event.sequence = seq;
732 e->event.tv_sec = now->tv_sec;
733 e->event.tv_usec = now->tv_usec;
735 list_add_tail(&e->base.link,
736 &e->base.file_priv->event_list);
737 drm_event_wakeup(&e->base);
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_inc();
830 atomic_add(diff, &dev->vblank[crtc].count);
831 smp_mb__after_atomic_inc();
835 * drm_vblank_get - get a reference count on vblank events
837 * @crtc: which CRTC to own
839 * Acquire a reference count on vblank events to avoid having them disabled
843 * Zero on success, nonzero on failure.
845 int drm_vblank_get(struct drm_device *dev, int crtc)
849 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
850 /* Going from 0->1 means we have to enable interrupts again */
851 if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) {
852 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE);
853 if (!dev->vblank[crtc].enabled) {
854 /* Enable vblank irqs under vblank_time_lock protection.
855 * All vblank count & timestamp updates are held off
856 * until we are done reinitializing master counter and
857 * timestamps. Filtercode in drm_handle_vblank() will
858 * prevent double-accounting of same vblank interval.
860 ret = dev->driver->enable_vblank(dev, crtc);
861 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n",
864 atomic_dec(&dev->vblank[crtc].refcount);
866 dev->vblank[crtc].enabled = true;
867 drm_update_vblank_count(dev, crtc);
870 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
872 if (!dev->vblank[crtc].enabled) {
873 atomic_dec(&dev->vblank[crtc].refcount);
877 lockmgr(&dev->vbl_lock, LK_RELEASE);
881 EXPORT_SYMBOL(drm_vblank_get);
884 * drm_vblank_put - give up ownership of vblank events
886 * @crtc: which counter to give up
888 * Release ownership of a given vblank counter, turning off interrupts
889 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
891 void drm_vblank_put(struct drm_device *dev, int crtc)
893 BUG_ON(atomic_read(&dev->vblank[crtc].refcount) == 0);
895 /* Last user schedules interrupt disable */
896 if (atomic_dec_and_test(&dev->vblank[crtc].refcount) &&
897 (drm_vblank_offdelay > 0))
898 mod_timer(&dev->vblank_disable_timer,
899 jiffies + ((drm_vblank_offdelay * HZ)/1000));
901 EXPORT_SYMBOL(drm_vblank_put);
904 * drm_vblank_off - disable vblank events on a CRTC
906 * @crtc: CRTC in question
908 * Caller must hold event lock.
910 void drm_vblank_off(struct drm_device *dev, int crtc)
912 struct drm_pending_vblank_event *e, *t;
916 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
917 vblank_disable_and_save(dev, crtc);
918 wake_up(&dev->vblank[crtc].queue);
920 /* Send any queued vblank events, lest the natives grow disquiet */
921 seq = drm_vblank_count_and_time(dev, crtc, &now);
923 lockmgr(&dev->event_lock, LK_EXCLUSIVE);
924 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
927 DRM_DEBUG("Sending premature vblank event on disable: \
928 wanted %d, current %d\n",
929 e->event.sequence, seq);
930 list_del(&e->base.link);
931 drm_vblank_put(dev, e->pipe);
932 send_vblank_event(dev, e, seq, &now);
934 lockmgr(&dev->event_lock, LK_RELEASE);
936 lockmgr(&dev->vbl_lock, LK_RELEASE);
938 EXPORT_SYMBOL(drm_vblank_off);
941 * drm_vblank_pre_modeset - account for vblanks across mode sets
943 * @crtc: CRTC in question
945 * Account for vblank events across mode setting events, which will likely
946 * reset the hardware frame counter.
948 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
950 /* vblank is not initialized (IRQ not installed ?), or has been freed */
954 * To avoid all the problems that might happen if interrupts
955 * were enabled/disabled around or between these calls, we just
956 * have the kernel take a reference on the CRTC (just once though
957 * to avoid corrupting the count if multiple, mismatch calls occur),
958 * so that interrupts remain enabled in the interim.
960 if (!dev->vblank[crtc].inmodeset) {
961 dev->vblank[crtc].inmodeset = 0x1;
962 if (drm_vblank_get(dev, crtc) == 0)
963 dev->vblank[crtc].inmodeset |= 0x2;
966 EXPORT_SYMBOL(drm_vblank_pre_modeset);
968 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
971 /* vblank is not initialized (IRQ not installed ?), or has been freed */
975 if (dev->vblank[crtc].inmodeset) {
976 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE);
977 dev->vblank_disable_allowed = true;
978 lockmgr(&dev->vbl_lock, LK_RELEASE);
980 if (dev->vblank[crtc].inmodeset & 0x2)
981 drm_vblank_put(dev, crtc);
983 dev->vblank[crtc].inmodeset = 0;
986 EXPORT_SYMBOL(drm_vblank_post_modeset);
989 * drm_modeset_ctl - handle vblank event counter changes across mode switch
990 * @DRM_IOCTL_ARGS: standard ioctl arguments
992 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
993 * ioctls around modesetting so that any lost vblank events are accounted for.
995 * Generally the counter will reset across mode sets. If interrupts are
996 * enabled around this call, we don't have to do anything since the counter
997 * will have already been incremented.
999 int drm_modeset_ctl(struct drm_device *dev, void *data,
1000 struct drm_file *file_priv)
1002 struct drm_modeset_ctl *modeset = data;
1005 /* If drm_vblank_init() hasn't been called yet, just no-op */
1006 if (!dev->num_crtcs)
1009 /* KMS drivers handle this internally */
1010 if (drm_core_check_feature(dev, DRIVER_MODESET))
1013 crtc = modeset->crtc;
1014 if (crtc >= dev->num_crtcs)
1017 switch (modeset->cmd) {
1018 case _DRM_PRE_MODESET:
1019 drm_vblank_pre_modeset(dev, crtc);
1021 case _DRM_POST_MODESET:
1022 drm_vblank_post_modeset(dev, crtc);
1032 drm_vblank_event_destroy(struct drm_pending_event *e)
1038 static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1039 union drm_wait_vblank *vblwait,
1040 struct drm_file *file_priv)
1042 struct drm_pending_vblank_event *e;
1047 e = kzalloc(sizeof *e, GFP_KERNEL);
1054 e->base.pid = curproc->p_pid;
1055 e->event.base.type = DRM_EVENT_VBLANK;
1056 e->event.base.length = sizeof e->event;
1057 e->event.user_data = vblwait->request.signal;
1058 e->base.event = &e->event.base;
1059 e->base.file_priv = file_priv;
1060 e->base.destroy = drm_vblank_event_destroy;
1062 lockmgr(&dev->event_lock, LK_EXCLUSIVE);
1064 if (file_priv->event_space < sizeof e->event) {
1069 file_priv->event_space -= sizeof e->event;
1070 seq = drm_vblank_count_and_time(dev, pipe, &now);
1072 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1073 (seq - vblwait->request.sequence) <= (1 << 23)) {
1074 vblwait->request.sequence = seq + 1;
1075 vblwait->reply.sequence = vblwait->request.sequence;
1078 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1079 vblwait->request.sequence, seq, pipe);
1081 e->event.sequence = vblwait->request.sequence;
1082 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1083 drm_vblank_put(dev, pipe);
1084 send_vblank_event(dev, e, seq, &now);
1085 vblwait->reply.sequence = seq;
1087 /* drm_handle_vblank_events will call drm_vblank_put */
1088 list_add_tail(&e->base.link, &dev->vblank_event_list);
1089 vblwait->reply.sequence = vblwait->request.sequence;
1092 lockmgr(&dev->event_lock, LK_RELEASE);
1097 lockmgr(&dev->event_lock, LK_RELEASE);
1100 drm_vblank_put(dev, pipe);
1107 * \param inode device inode.
1108 * \param file_priv DRM file private.
1109 * \param cmd command.
1110 * \param data user argument, pointing to a drm_wait_vblank structure.
1111 * \return zero on success or a negative number on failure.
1113 * This function enables the vblank interrupt on the pipe requested, then
1114 * sleeps waiting for the requested sequence number to occur, and drops
1115 * the vblank interrupt refcount afterwards. (vblank irq disable follows that
1116 * after a timeout with no further vblank waits scheduled).
1118 int drm_wait_vblank(struct drm_device *dev, void *data,
1119 struct drm_file *file_priv)
1121 union drm_wait_vblank *vblwait = data;
1123 unsigned int flags, seq, crtc, high_crtc;
1125 if (drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
1126 if ((!dev->irq_enabled))
1129 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1132 if (vblwait->request.type &
1133 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1134 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1135 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1136 vblwait->request.type,
1137 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1138 _DRM_VBLANK_HIGH_CRTC_MASK));
1142 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1143 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1145 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1147 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1148 if (crtc >= dev->num_crtcs)
1151 ret = drm_vblank_get(dev, crtc);
1153 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1156 seq = drm_vblank_count(dev, crtc);
1158 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1159 case _DRM_VBLANK_RELATIVE:
1160 vblwait->request.sequence += seq;
1161 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1162 case _DRM_VBLANK_ABSOLUTE:
1169 if (flags & _DRM_VBLANK_EVENT) {
1170 /* must hold on to the vblank ref until the event fires
1171 * drm_vblank_put will be called asynchronously
1173 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1176 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1177 (seq - vblwait->request.sequence) <= (1<<23)) {
1178 vblwait->request.sequence = seq + 1;
1181 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1182 vblwait->request.sequence, crtc);
1183 dev->vblank[crtc].last_wait = vblwait->request.sequence;
1184 DRM_WAIT_ON(ret, dev->vblank[crtc].queue, 3 * HZ,
1185 (((drm_vblank_count(dev, crtc) -
1186 vblwait->request.sequence) <= (1 << 23)) ||
1187 !dev->irq_enabled));
1189 if (ret != -EINTR) {
1192 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1193 vblwait->reply.tval_sec = now.tv_sec;
1194 vblwait->reply.tval_usec = now.tv_usec;
1196 DRM_DEBUG("returning %d to client\n",
1197 vblwait->reply.sequence);
1199 DRM_DEBUG("vblank wait interrupted by signal\n");
1203 drm_vblank_put(dev, crtc);
1207 static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1209 struct drm_pending_vblank_event *e, *t;
1213 seq = drm_vblank_count_and_time(dev, crtc, &now);
1215 lockmgr(&dev->event_lock, LK_EXCLUSIVE);
1217 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1218 if (e->pipe != crtc)
1220 if ((seq - e->event.sequence) > (1<<23))
1223 DRM_DEBUG("vblank event on %d, current %d\n",
1224 e->event.sequence, seq);
1226 list_del(&e->base.link);
1227 drm_vblank_put(dev, e->pipe);
1228 send_vblank_event(dev, e, seq, &now);
1231 lockmgr(&dev->event_lock, LK_RELEASE);
1235 * drm_handle_vblank - handle a vblank event
1237 * @crtc: where this event occurred
1239 * Drivers should call this routine in their vblank interrupt handlers to
1240 * update the vblank counter and send any signals that may be pending.
1242 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1246 struct timeval tvblank;
1248 if (!dev->num_crtcs)
1251 /* Need timestamp lock to prevent concurrent execution with
1252 * vblank enable/disable, as this would cause inconsistent
1253 * or corrupted timestamps and vblank counts.
1255 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE);
1257 /* Vblank irq handling disabled. Nothing to do. */
1258 if (!dev->vblank[crtc].enabled) {
1259 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
1263 /* Fetch corresponding timestamp for this vblank interval from
1264 * driver and store it in proper slot of timestamp ringbuffer.
1267 /* Get current timestamp and count. */
1268 vblcount = atomic_read(&dev->vblank[crtc].count);
1269 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1271 /* Compute time difference to timestamp of last vblank */
1272 diff_ns = timeval_to_ns(&tvblank) -
1273 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1275 /* Update vblank timestamp and count if at least
1276 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1277 * difference between last stored timestamp and current
1278 * timestamp. A smaller difference means basically
1279 * identical timestamps. Happens if this vblank has
1280 * been already processed and this is a redundant call,
1281 * e.g., due to spurious vblank interrupts. We need to
1282 * ignore those for accounting.
1284 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1285 /* Store new timestamp in ringbuffer. */
1286 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1288 /* Increment cooked vblank count. This also atomically commits
1289 * the timestamp computed above.
1291 smp_mb__before_atomic_inc();
1292 atomic_inc(&dev->vblank[crtc].count);
1293 smp_mb__after_atomic_inc();
1295 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1296 crtc, (int) diff_ns);
1299 wake_up(&dev->vblank[crtc].queue);
1300 drm_handle_vblank_events(dev, crtc);
1302 lockmgr(&dev->vblank_time_lock, LK_RELEASE);
1305 EXPORT_SYMBOL(drm_handle_vblank);