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.
37 #include "drm_trace.h"
39 #include <linux/interrupt.h> /* For task queue support */
40 #include <linux/slab.h>
42 #include <linux/vgaarb.h>
43 #include <linux/export.h>
45 /* Access macro for slots in vblank timestamp ringbuffer. */
46 #define vblanktimestamp(dev, crtc, count) \
47 ((dev)->vblank[crtc].time[(count) % DRM_VBLANKTIME_RBSIZE])
49 /* Retry timestamp calculation up to 3 times to satisfy
50 * drm_timestamp_precision before giving up.
52 #define DRM_TIMESTAMP_MAXRETRIES 3
54 /* Threshold in nanoseconds for detection of redundant
55 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
57 #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
60 * Clear vblank timestamp buffer for a crtc.
62 static void clear_vblank_timestamps(struct drm_device *dev, int crtc)
64 memset(dev->vblank[crtc].time, 0, sizeof(dev->vblank[crtc].time));
68 * Disable vblank irq's on crtc, make sure that last vblank count
69 * of hardware and corresponding consistent software vblank counter
70 * are preserved, even if there are any spurious vblank irq's after
73 static void vblank_disable_and_save(struct drm_device *dev, int crtc)
75 unsigned long irqflags;
79 struct timeval tvblank;
80 int count = DRM_TIMESTAMP_MAXRETRIES;
82 /* Prevent vblank irq processing while disabling vblank irqs,
83 * so no updates of timestamps or count can happen after we've
84 * disabled. Needed to prevent races in case of delayed irq's.
86 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
88 dev->driver->disable_vblank(dev, crtc);
89 dev->vblank[crtc].enabled = false;
91 /* No further vblank irq's will be processed after
92 * this point. Get current hardware vblank count and
93 * vblank timestamp, repeat until they are consistent.
95 * FIXME: There is still a race condition here and in
96 * drm_update_vblank_count() which can cause off-by-one
97 * reinitialization of software vblank counter. If gpu
98 * vblank counter doesn't increment exactly at the leading
99 * edge of a vblank interval, then we can lose 1 count if
100 * we happen to execute between start of vblank and the
101 * delayed gpu counter increment.
104 dev->vblank[crtc].last = dev->driver->get_vblank_counter(dev, crtc);
105 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
106 } while (dev->vblank[crtc].last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
111 /* Compute time difference to stored timestamp of last vblank
112 * as updated by last invocation of drm_handle_vblank() in vblank irq.
114 vblcount = atomic_read(&dev->vblank[crtc].count);
115 diff_ns = timeval_to_ns(&tvblank) -
116 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
118 /* If there is at least 1 msec difference between the last stored
119 * timestamp and tvblank, then we are currently executing our
120 * disable inside a new vblank interval, the tvblank timestamp
121 * corresponds to this new vblank interval and the irq handler
122 * for this vblank didn't run yet and won't run due to our disable.
123 * Therefore we need to do the job of drm_handle_vblank() and
124 * increment the vblank counter by one to account for this vblank.
126 * Skip this step if there isn't any high precision timestamp
127 * available. In that case we can't account for this and just
130 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
131 atomic_inc(&dev->vblank[crtc].count);
132 smp_mb__after_atomic_inc();
135 /* Invalidate all timestamps while vblank irq's are off. */
136 clear_vblank_timestamps(dev, crtc);
138 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
141 static void vblank_disable_fn(unsigned long arg)
143 struct drm_device *dev = (struct drm_device *)arg;
144 unsigned long irqflags;
147 if (!dev->vblank_disable_allowed)
150 for (i = 0; i < dev->num_crtcs; i++) {
151 spin_lock_irqsave(&dev->vbl_lock, irqflags);
152 if (atomic_read(&dev->vblank[i].refcount) == 0 &&
153 dev->vblank[i].enabled) {
154 DRM_DEBUG("disabling vblank on crtc %d\n", i);
155 vblank_disable_and_save(dev, i);
157 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
161 void drm_vblank_cleanup(struct drm_device *dev)
163 /* Bail if the driver didn't call drm_vblank_init() */
164 if (dev->num_crtcs == 0)
167 del_timer_sync(&dev->vblank_disable_timer);
169 vblank_disable_fn((unsigned long)dev);
175 EXPORT_SYMBOL(drm_vblank_cleanup);
177 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
179 int i, ret = -ENOMEM;
181 setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
183 spin_lock_init(&dev->vbl_lock);
184 spin_lock_init(&dev->vblank_time_lock);
186 dev->num_crtcs = num_crtcs;
188 dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
192 for (i = 0; i < num_crtcs; i++)
193 init_waitqueue_head(&dev->vblank[i].queue);
195 DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
197 /* Driver specific high-precision vblank timestamping supported? */
198 if (dev->driver->get_vblank_timestamp)
199 DRM_INFO("Driver supports precise vblank timestamp query.\n");
201 DRM_INFO("No driver support for vblank timestamp query.\n");
203 dev->vblank_disable_allowed = false;
208 drm_vblank_cleanup(dev);
211 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);
237 * Install IRQ handler.
239 * \param dev DRM device.
241 * Initializes the IRQ related data. Installs the handler, calling the driver
242 * \c irq_preinstall() and \c irq_postinstall() functions
243 * before and after the installation.
245 int drm_irq_install(struct drm_device *dev, int irq)
248 unsigned long sh_flags = 0;
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 = true;
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 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
272 sh_flags = IRQF_SHARED;
274 ret = request_irq(irq, dev->driver->irq_handler,
275 sh_flags, dev->driver->name, dev);
278 dev->irq_enabled = false;
282 if (!drm_core_check_feature(dev, DRIVER_MODESET))
283 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
285 /* After installing handler */
286 if (dev->driver->irq_postinstall)
287 ret = dev->driver->irq_postinstall(dev);
290 dev->irq_enabled = false;
291 if (!drm_core_check_feature(dev, DRIVER_MODESET))
292 vga_client_register(dev->pdev, NULL, NULL, NULL);
300 EXPORT_SYMBOL(drm_irq_install);
303 * Uninstall the IRQ handler.
305 * \param dev DRM device.
307 * Calls the driver's \c irq_uninstall() function, and stops the irq.
309 int drm_irq_uninstall(struct drm_device *dev)
311 unsigned long irqflags;
315 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
318 irq_enabled = dev->irq_enabled;
319 dev->irq_enabled = false;
322 * Wake up any waiters so they don't hang.
324 if (dev->num_crtcs) {
325 spin_lock_irqsave(&dev->vbl_lock, irqflags);
326 for (i = 0; i < dev->num_crtcs; i++) {
327 wake_up(&dev->vblank[i].queue);
328 dev->vblank[i].enabled = false;
329 dev->vblank[i].last =
330 dev->driver->get_vblank_counter(dev, i);
332 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
338 DRM_DEBUG("irq=%d\n", dev->irq);
340 if (!drm_core_check_feature(dev, DRIVER_MODESET))
341 vga_client_register(dev->pdev, NULL, NULL, NULL);
343 if (dev->driver->irq_uninstall)
344 dev->driver->irq_uninstall(dev);
346 free_irq(dev->irq, dev);
350 EXPORT_SYMBOL(drm_irq_uninstall);
355 * \param inode device inode.
356 * \param file_priv DRM file private.
357 * \param cmd command.
358 * \param arg user argument, pointing to a drm_control structure.
359 * \return zero on success or a negative number on failure.
361 * Calls irq_install() or irq_uninstall() according to \p arg.
363 int drm_control(struct drm_device *dev, void *data,
364 struct drm_file *file_priv)
366 struct drm_control *ctl = data;
369 /* if we haven't irq we fallback for compatibility reasons -
370 * this used to be a separate function in drm_dma.h
373 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
375 if (drm_core_check_feature(dev, DRIVER_MODESET))
377 /* UMS was only ever support on pci devices. */
378 if (WARN_ON(!dev->pdev))
382 case DRM_INST_HANDLER:
383 irq = dev->pdev->irq;
385 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
388 mutex_lock(&dev->struct_mutex);
389 ret = drm_irq_install(dev, irq);
390 mutex_unlock(&dev->struct_mutex);
393 case DRM_UNINST_HANDLER:
394 mutex_lock(&dev->struct_mutex);
395 ret = drm_irq_uninstall(dev);
396 mutex_unlock(&dev->struct_mutex);
405 * drm_calc_timestamping_constants - Calculate vblank timestamp constants
407 * @crtc drm_crtc whose timestamp constants should be updated.
408 * @mode display mode containing the scanout timings
410 * Calculate and store various constants which are later
411 * needed by vblank and swap-completion timestamping, e.g,
412 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
413 * derived from crtc's true scanout timing, so they take
414 * things like panel scaling or other adjustments into account.
416 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
417 const struct drm_display_mode *mode)
419 int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
420 int dotclock = mode->crtc_clock;
422 /* Valid dotclock? */
424 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
427 * Convert scanline length in pixels and video
428 * dot clock to line duration, frame duration
429 * and pixel duration in nanoseconds:
431 pixeldur_ns = 1000000 / dotclock;
432 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
433 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
436 * Fields of interlaced scanout modes are only half a frame duration.
438 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
441 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
444 crtc->pixeldur_ns = pixeldur_ns;
445 crtc->linedur_ns = linedur_ns;
446 crtc->framedur_ns = framedur_ns;
448 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
449 crtc->base.id, mode->crtc_htotal,
450 mode->crtc_vtotal, mode->crtc_vdisplay);
451 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
452 crtc->base.id, dotclock, framedur_ns,
453 linedur_ns, pixeldur_ns);
455 EXPORT_SYMBOL(drm_calc_timestamping_constants);
458 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
459 * drivers. Implements calculation of exact vblank timestamps from
460 * given drm_display_mode timings and current video scanout position
461 * of a crtc. This can be called from within get_vblank_timestamp()
462 * implementation of a kms driver to implement the actual timestamping.
464 * Should return timestamps conforming to the OML_sync_control OpenML
465 * extension specification. The timestamp corresponds to the end of
466 * the vblank interval, aka start of scanout of topmost-leftmost display
467 * pixel in the following video frame.
469 * Requires support for optional dev->driver->get_scanout_position()
470 * in kms driver, plus a bit of setup code to provide a drm_display_mode
471 * that corresponds to the true scanout timing.
473 * The current implementation only handles standard video modes. It
474 * returns as no operation if a doublescan or interlaced video mode is
475 * active. Higher level code is expected to handle this.
478 * @crtc: Which crtc's vblank timestamp to retrieve.
479 * @max_error: Desired maximum allowable error in timestamps (nanosecs).
480 * On return contains true maximum error of timestamp.
481 * @vblank_time: Pointer to struct timeval which should receive the timestamp.
482 * @flags: Flags to pass to driver:
484 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
485 * @refcrtc: drm_crtc* of crtc which defines scanout timing.
486 * @mode: mode which defines the scanout timings
488 * Returns negative value on error, failure or if not supported in current
491 * -EINVAL - Invalid crtc.
492 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
493 * -ENOTSUPP - Function not supported in current display mode.
494 * -EIO - Failed, e.g., due to failed scanout position query.
496 * Returns or'ed positive status flags on success:
498 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
499 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
502 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
504 struct timeval *vblank_time,
506 const struct drm_crtc *refcrtc,
507 const struct drm_display_mode *mode)
509 ktime_t stime, etime, mono_time_offset;
510 struct timeval tv_etime;
513 int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
516 if (crtc < 0 || crtc >= dev->num_crtcs) {
517 DRM_ERROR("Invalid crtc %d\n", crtc);
521 /* Scanout position query not supported? Should not happen. */
522 if (!dev->driver->get_scanout_position) {
523 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
527 /* Durations of frames, lines, pixels in nanoseconds. */
528 framedur_ns = refcrtc->framedur_ns;
529 linedur_ns = refcrtc->linedur_ns;
530 pixeldur_ns = refcrtc->pixeldur_ns;
532 /* If mode timing undefined, just return as no-op:
533 * Happens during initial modesetting of a crtc.
535 if (framedur_ns == 0) {
536 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
540 /* Get current scanout position with system timestamp.
541 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
542 * if single query takes longer than max_error nanoseconds.
544 * This guarantees a tight bound on maximum error if
545 * code gets preempted or delayed for some reason.
547 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
549 * Get vertical and horizontal scanout position vpos, hpos,
550 * and bounding timestamps stime, etime, pre/post query.
552 vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
553 &hpos, &stime, &etime);
556 * Get correction for CLOCK_MONOTONIC -> CLOCK_REALTIME if
557 * CLOCK_REALTIME is requested.
559 if (!drm_timestamp_monotonic)
560 mono_time_offset = ktime_get_monotonic_offset();
562 /* Return as no-op if scanout query unsupported or failed. */
563 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
564 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
569 /* Compute uncertainty in timestamp of scanout position query. */
570 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
572 /* Accept result with < max_error nsecs timing uncertainty. */
573 if (duration_ns <= *max_error)
577 /* Noisy system timing? */
578 if (i == DRM_TIMESTAMP_MAXRETRIES) {
579 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
580 crtc, duration_ns/1000, *max_error/1000, i);
583 /* Return upper bound of timestamp precision error. */
584 *max_error = duration_ns;
586 /* Check if in vblank area:
587 * vpos is >=0 in video scanout area, but negative
588 * within vblank area, counting down the number of lines until
591 invbl = vbl_status & DRM_SCANOUTPOS_INVBL;
593 /* Convert scanout position into elapsed time at raw_time query
594 * since start of scanout at first display scanline. delta_ns
595 * can be negative if start of scanout hasn't happened yet.
597 delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
599 if (!drm_timestamp_monotonic)
600 etime = ktime_sub(etime, mono_time_offset);
602 /* save this only for debugging purposes */
603 tv_etime = ktime_to_timeval(etime);
604 /* Subtract time delta from raw timestamp to get final
605 * vblank_time timestamp for end of vblank.
608 etime = ktime_add_ns(etime, -delta_ns);
610 etime = ktime_sub_ns(etime, delta_ns);
611 *vblank_time = ktime_to_timeval(etime);
613 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
614 crtc, (int)vbl_status, hpos, vpos,
615 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
616 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
617 duration_ns/1000, i);
619 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
621 vbl_status |= DRM_VBLANKTIME_INVBL;
625 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
627 static struct timeval get_drm_timestamp(void)
632 if (!drm_timestamp_monotonic)
633 now = ktime_sub(now, ktime_get_monotonic_offset());
635 return ktime_to_timeval(now);
639 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
643 * @crtc: which crtc's vblank timestamp to retrieve
644 * @tvblank: Pointer to target struct timeval which should receive the timestamp
645 * @flags: Flags to pass to driver:
647 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
649 * Fetches the system timestamp corresponding to the time of the most recent
650 * vblank interval on specified crtc. May call into kms-driver to
651 * compute the timestamp with a high-precision GPU specific method.
653 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
654 * call, i.e., it isn't very precisely locked to the true vblank.
656 * Returns non-zero if timestamp is considered to be very precise.
658 u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
659 struct timeval *tvblank, unsigned flags)
663 /* Define requested maximum error on timestamps (nanoseconds). */
664 int max_error = (int) drm_timestamp_precision * 1000;
666 /* Query driver if possible and precision timestamping enabled. */
667 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
668 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
674 /* GPU high precision timestamp query unsupported or failed.
675 * Return current monotonic/gettimeofday timestamp as best estimate.
677 *tvblank = get_drm_timestamp();
681 EXPORT_SYMBOL(drm_get_last_vbltimestamp);
684 * drm_vblank_count - retrieve "cooked" vblank counter value
686 * @crtc: which counter to retrieve
688 * Fetches the "cooked" vblank count value that represents the number of
689 * vblank events since the system was booted, including lost events due to
690 * modesetting activity.
692 u32 drm_vblank_count(struct drm_device *dev, int crtc)
694 return atomic_read(&dev->vblank[crtc].count);
696 EXPORT_SYMBOL(drm_vblank_count);
699 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
700 * and the system timestamp corresponding to that vblank counter value.
703 * @crtc: which counter to retrieve
704 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
706 * Fetches the "cooked" vblank count value that represents the number of
707 * vblank events since the system was booted, including lost events due to
708 * modesetting activity. Returns corresponding system timestamp of the time
709 * of the vblank interval that corresponds to the current value vblank counter
712 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
713 struct timeval *vblanktime)
717 /* Read timestamp from slot of _vblank_time ringbuffer
718 * that corresponds to current vblank count. Retry if
719 * count has incremented during readout. This works like
723 cur_vblank = atomic_read(&dev->vblank[crtc].count);
724 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
726 } while (cur_vblank != atomic_read(&dev->vblank[crtc].count));
730 EXPORT_SYMBOL(drm_vblank_count_and_time);
732 static void send_vblank_event(struct drm_device *dev,
733 struct drm_pending_vblank_event *e,
734 unsigned long seq, struct timeval *now)
736 WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
737 e->event.sequence = seq;
738 e->event.tv_sec = now->tv_sec;
739 e->event.tv_usec = now->tv_usec;
741 list_add_tail(&e->base.link,
742 &e->base.file_priv->event_list);
743 wake_up_interruptible(&e->base.file_priv->event_wait);
744 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
749 * drm_send_vblank_event - helper to send vblank event after pageflip
751 * @crtc: CRTC in question
752 * @e: the event to send
754 * Updates sequence # and timestamp on event, and sends it to userspace.
755 * Caller must hold event lock.
757 void drm_send_vblank_event(struct drm_device *dev, int crtc,
758 struct drm_pending_vblank_event *e)
763 seq = drm_vblank_count_and_time(dev, crtc, &now);
767 now = get_drm_timestamp();
770 send_vblank_event(dev, e, seq, &now);
772 EXPORT_SYMBOL(drm_send_vblank_event);
775 * drm_update_vblank_count - update the master vblank counter
777 * @crtc: counter to update
779 * Call back into the driver to update the appropriate vblank counter
780 * (specified by @crtc). Deal with wraparound, if it occurred, and
781 * update the last read value so we can deal with wraparound on the next
784 * Only necessary when going from off->on, to account for frames we
785 * didn't get an interrupt for.
787 * Note: caller must hold dev->vbl_lock since this reads & writes
788 * device vblank fields.
790 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
792 u32 cur_vblank, diff, tslot, rc;
793 struct timeval t_vblank;
796 * Interrupts were disabled prior to this call, so deal with counter
798 * NOTE! It's possible we lost a full dev->max_vblank_count events
799 * here if the register is small or we had vblank interrupts off for
802 * We repeat the hardware vblank counter & timestamp query until
803 * we get consistent results. This to prevent races between gpu
804 * updating its hardware counter while we are retrieving the
805 * corresponding vblank timestamp.
808 cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
809 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
810 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
812 /* Deal with counter wrap */
813 diff = cur_vblank - dev->vblank[crtc].last;
814 if (cur_vblank < dev->vblank[crtc].last) {
815 diff += dev->max_vblank_count;
817 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
818 crtc, dev->vblank[crtc].last, cur_vblank, diff);
821 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
824 /* Reinitialize corresponding vblank timestamp if high-precision query
825 * available. Skip this step if query unsupported or failed. Will
826 * reinitialize delayed at next vblank interrupt in that case.
829 tslot = atomic_read(&dev->vblank[crtc].count) + diff;
830 vblanktimestamp(dev, crtc, tslot) = t_vblank;
833 smp_mb__before_atomic_inc();
834 atomic_add(diff, &dev->vblank[crtc].count);
835 smp_mb__after_atomic_inc();
839 * drm_vblank_get - get a reference count on vblank events
841 * @crtc: which CRTC to own
843 * Acquire a reference count on vblank events to avoid having them disabled
847 * Zero on success, nonzero on failure.
849 int drm_vblank_get(struct drm_device *dev, int crtc)
851 unsigned long irqflags, irqflags2;
854 spin_lock_irqsave(&dev->vbl_lock, irqflags);
855 /* Going from 0->1 means we have to enable interrupts again */
856 if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) {
857 spin_lock_irqsave(&dev->vblank_time_lock, irqflags2);
858 if (!dev->vblank[crtc].enabled) {
859 /* Enable vblank irqs under vblank_time_lock protection.
860 * All vblank count & timestamp updates are held off
861 * until we are done reinitializing master counter and
862 * timestamps. Filtercode in drm_handle_vblank() will
863 * prevent double-accounting of same vblank interval.
865 ret = dev->driver->enable_vblank(dev, crtc);
866 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n",
869 atomic_dec(&dev->vblank[crtc].refcount);
871 dev->vblank[crtc].enabled = true;
872 drm_update_vblank_count(dev, crtc);
875 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2);
877 if (!dev->vblank[crtc].enabled) {
878 atomic_dec(&dev->vblank[crtc].refcount);
882 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
886 EXPORT_SYMBOL(drm_vblank_get);
889 * drm_vblank_put - give up ownership of vblank events
891 * @crtc: which counter to give up
893 * Release ownership of a given vblank counter, turning off interrupts
894 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
896 void drm_vblank_put(struct drm_device *dev, int crtc)
898 BUG_ON(atomic_read(&dev->vblank[crtc].refcount) == 0);
900 /* Last user schedules interrupt disable */
901 if (atomic_dec_and_test(&dev->vblank[crtc].refcount) &&
902 (drm_vblank_offdelay > 0))
903 mod_timer(&dev->vblank_disable_timer,
904 jiffies + ((drm_vblank_offdelay * HZ)/1000));
906 EXPORT_SYMBOL(drm_vblank_put);
909 * drm_vblank_off - disable vblank events on a CRTC
911 * @crtc: CRTC in question
913 * Caller must hold event lock.
915 void drm_vblank_off(struct drm_device *dev, int crtc)
917 struct drm_pending_vblank_event *e, *t;
919 unsigned long irqflags;
922 spin_lock_irqsave(&dev->vbl_lock, irqflags);
923 vblank_disable_and_save(dev, crtc);
924 wake_up(&dev->vblank[crtc].queue);
926 /* Send any queued vblank events, lest the natives grow disquiet */
927 seq = drm_vblank_count_and_time(dev, crtc, &now);
929 spin_lock(&dev->event_lock);
930 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
933 DRM_DEBUG("Sending premature vblank event on disable: \
934 wanted %d, current %d\n",
935 e->event.sequence, seq);
936 list_del(&e->base.link);
937 drm_vblank_put(dev, e->pipe);
938 send_vblank_event(dev, e, seq, &now);
940 spin_unlock(&dev->event_lock);
942 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
944 EXPORT_SYMBOL(drm_vblank_off);
947 * drm_vblank_pre_modeset - account for vblanks across mode sets
949 * @crtc: CRTC in question
951 * Account for vblank events across mode setting events, which will likely
952 * reset the hardware frame counter.
954 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
956 /* vblank is not initialized (IRQ not installed ?), or has been freed */
960 * To avoid all the problems that might happen if interrupts
961 * were enabled/disabled around or between these calls, we just
962 * have the kernel take a reference on the CRTC (just once though
963 * to avoid corrupting the count if multiple, mismatch calls occur),
964 * so that interrupts remain enabled in the interim.
966 if (!dev->vblank[crtc].inmodeset) {
967 dev->vblank[crtc].inmodeset = 0x1;
968 if (drm_vblank_get(dev, crtc) == 0)
969 dev->vblank[crtc].inmodeset |= 0x2;
972 EXPORT_SYMBOL(drm_vblank_pre_modeset);
974 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
976 unsigned long irqflags;
978 /* vblank is not initialized (IRQ not installed ?), or has been freed */
982 if (dev->vblank[crtc].inmodeset) {
983 spin_lock_irqsave(&dev->vbl_lock, irqflags);
984 dev->vblank_disable_allowed = true;
985 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
987 if (dev->vblank[crtc].inmodeset & 0x2)
988 drm_vblank_put(dev, crtc);
990 dev->vblank[crtc].inmodeset = 0;
993 EXPORT_SYMBOL(drm_vblank_post_modeset);
996 * drm_modeset_ctl - handle vblank event counter changes across mode switch
997 * @DRM_IOCTL_ARGS: standard ioctl arguments
999 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1000 * ioctls around modesetting so that any lost vblank events are accounted for.
1002 * Generally the counter will reset across mode sets. If interrupts are
1003 * enabled around this call, we don't have to do anything since the counter
1004 * will have already been incremented.
1006 int drm_modeset_ctl(struct drm_device *dev, void *data,
1007 struct drm_file *file_priv)
1009 struct drm_modeset_ctl *modeset = data;
1012 /* If drm_vblank_init() hasn't been called yet, just no-op */
1013 if (!dev->num_crtcs)
1016 /* KMS drivers handle this internally */
1017 if (drm_core_check_feature(dev, DRIVER_MODESET))
1020 crtc = modeset->crtc;
1021 if (crtc >= dev->num_crtcs)
1024 switch (modeset->cmd) {
1025 case _DRM_PRE_MODESET:
1026 drm_vblank_pre_modeset(dev, crtc);
1028 case _DRM_POST_MODESET:
1029 drm_vblank_post_modeset(dev, crtc);
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;
1044 unsigned long flags;
1048 e = kzalloc(sizeof *e, GFP_KERNEL);
1055 e->base.pid = current->pid;
1056 e->event.base.type = DRM_EVENT_VBLANK;
1057 e->event.base.length = sizeof e->event;
1058 e->event.user_data = vblwait->request.signal;
1059 e->base.event = &e->event.base;
1060 e->base.file_priv = file_priv;
1061 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
1063 spin_lock_irqsave(&dev->event_lock, flags);
1065 if (file_priv->event_space < sizeof e->event) {
1070 file_priv->event_space -= sizeof e->event;
1071 seq = drm_vblank_count_and_time(dev, pipe, &now);
1073 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1074 (seq - vblwait->request.sequence) <= (1 << 23)) {
1075 vblwait->request.sequence = seq + 1;
1076 vblwait->reply.sequence = vblwait->request.sequence;
1079 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1080 vblwait->request.sequence, seq, pipe);
1082 trace_drm_vblank_event_queued(current->pid, pipe,
1083 vblwait->request.sequence);
1085 e->event.sequence = vblwait->request.sequence;
1086 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1087 drm_vblank_put(dev, pipe);
1088 send_vblank_event(dev, e, seq, &now);
1089 vblwait->reply.sequence = seq;
1091 /* drm_handle_vblank_events will call drm_vblank_put */
1092 list_add_tail(&e->base.link, &dev->vblank_event_list);
1093 vblwait->reply.sequence = vblwait->request.sequence;
1096 spin_unlock_irqrestore(&dev->event_lock, flags);
1101 spin_unlock_irqrestore(&dev->event_lock, flags);
1104 drm_vblank_put(dev, pipe);
1111 * \param inode device inode.
1112 * \param file_priv DRM file private.
1113 * \param cmd command.
1114 * \param data user argument, pointing to a drm_wait_vblank structure.
1115 * \return zero on success or a negative number on failure.
1117 * This function enables the vblank interrupt on the pipe requested, then
1118 * sleeps waiting for the requested sequence number to occur, and drops
1119 * the vblank interrupt refcount afterwards. (vblank irq disable follows that
1120 * after a timeout with no further vblank waits scheduled).
1122 int drm_wait_vblank(struct drm_device *dev, void *data,
1123 struct drm_file *file_priv)
1125 union drm_wait_vblank *vblwait = data;
1127 unsigned int flags, seq, crtc, high_crtc;
1129 if (!dev->irq_enabled)
1132 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1135 if (vblwait->request.type &
1136 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1137 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1138 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1139 vblwait->request.type,
1140 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1141 _DRM_VBLANK_HIGH_CRTC_MASK));
1145 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1146 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1148 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1150 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1151 if (crtc >= dev->num_crtcs)
1154 ret = drm_vblank_get(dev, crtc);
1156 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1159 seq = drm_vblank_count(dev, crtc);
1161 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1162 case _DRM_VBLANK_RELATIVE:
1163 vblwait->request.sequence += seq;
1164 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1165 case _DRM_VBLANK_ABSOLUTE:
1172 if (flags & _DRM_VBLANK_EVENT) {
1173 /* must hold on to the vblank ref until the event fires
1174 * drm_vblank_put will be called asynchronously
1176 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1179 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1180 (seq - vblwait->request.sequence) <= (1<<23)) {
1181 vblwait->request.sequence = seq + 1;
1184 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1185 vblwait->request.sequence, crtc);
1186 dev->vblank[crtc].last_wait = vblwait->request.sequence;
1187 DRM_WAIT_ON(ret, dev->vblank[crtc].queue, 3 * HZ,
1188 (((drm_vblank_count(dev, crtc) -
1189 vblwait->request.sequence) <= (1 << 23)) ||
1190 !dev->irq_enabled));
1192 if (ret != -EINTR) {
1195 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1196 vblwait->reply.tval_sec = now.tv_sec;
1197 vblwait->reply.tval_usec = now.tv_usec;
1199 DRM_DEBUG("returning %d to client\n",
1200 vblwait->reply.sequence);
1202 DRM_DEBUG("vblank wait interrupted by signal\n");
1206 drm_vblank_put(dev, crtc);
1210 static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1212 struct drm_pending_vblank_event *e, *t;
1214 unsigned long flags;
1217 seq = drm_vblank_count_and_time(dev, crtc, &now);
1219 spin_lock_irqsave(&dev->event_lock, flags);
1221 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1222 if (e->pipe != crtc)
1224 if ((seq - e->event.sequence) > (1<<23))
1227 DRM_DEBUG("vblank event on %d, current %d\n",
1228 e->event.sequence, seq);
1230 list_del(&e->base.link);
1231 drm_vblank_put(dev, e->pipe);
1232 send_vblank_event(dev, e, seq, &now);
1235 spin_unlock_irqrestore(&dev->event_lock, flags);
1237 trace_drm_vblank_event(crtc, seq);
1241 * drm_handle_vblank - handle a vblank event
1243 * @crtc: where this event occurred
1245 * Drivers should call this routine in their vblank interrupt handlers to
1246 * update the vblank counter and send any signals that may be pending.
1248 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1252 struct timeval tvblank;
1253 unsigned long irqflags;
1255 if (!dev->num_crtcs)
1258 /* Need timestamp lock to prevent concurrent execution with
1259 * vblank enable/disable, as this would cause inconsistent
1260 * or corrupted timestamps and vblank counts.
1262 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
1264 /* Vblank irq handling disabled. Nothing to do. */
1265 if (!dev->vblank[crtc].enabled) {
1266 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1270 /* Fetch corresponding timestamp for this vblank interval from
1271 * driver and store it in proper slot of timestamp ringbuffer.
1274 /* Get current timestamp and count. */
1275 vblcount = atomic_read(&dev->vblank[crtc].count);
1276 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1278 /* Compute time difference to timestamp of last vblank */
1279 diff_ns = timeval_to_ns(&tvblank) -
1280 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1282 /* Update vblank timestamp and count if at least
1283 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1284 * difference between last stored timestamp and current
1285 * timestamp. A smaller difference means basically
1286 * identical timestamps. Happens if this vblank has
1287 * been already processed and this is a redundant call,
1288 * e.g., due to spurious vblank interrupts. We need to
1289 * ignore those for accounting.
1291 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1292 /* Store new timestamp in ringbuffer. */
1293 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1295 /* Increment cooked vblank count. This also atomically commits
1296 * the timestamp computed above.
1298 smp_mb__before_atomic_inc();
1299 atomic_inc(&dev->vblank[crtc].count);
1300 smp_mb__after_atomic_inc();
1302 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1303 crtc, (int) diff_ns);
1306 wake_up(&dev->vblank[crtc].queue);
1307 drm_handle_vblank_events(dev, crtc);
1309 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1312 EXPORT_SYMBOL(drm_handle_vblank);