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 * Get interrupt from bus id.
62 * \param inode device inode.
63 * \param file_priv DRM file private.
65 * \param arg user argument, pointing to a drm_irq_busid structure.
66 * \return zero on success or a negative number on failure.
68 * Finds the PCI device with the specified bus id and gets its IRQ number.
69 * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
70 * to that of the device that this DRM instance attached to.
72 int drm_irq_by_busid(struct drm_device *dev, void *data,
73 struct drm_file *file_priv)
75 struct drm_irq_busid *p = data;
77 if (!dev->driver->bus->irq_by_busid)
80 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
83 return dev->driver->bus->irq_by_busid(dev, p);
87 * Clear vblank timestamp buffer for a crtc.
89 static void clear_vblank_timestamps(struct drm_device *dev, int crtc)
91 memset(dev->vblank[crtc].time, 0, sizeof(dev->vblank[crtc].time));
95 * Disable vblank irq's on crtc, make sure that last vblank count
96 * of hardware and corresponding consistent software vblank counter
97 * are preserved, even if there are any spurious vblank irq's after
100 static void vblank_disable_and_save(struct drm_device *dev, int crtc)
102 unsigned long irqflags;
106 struct timeval tvblank;
107 int count = DRM_TIMESTAMP_MAXRETRIES;
109 /* Prevent vblank irq processing while disabling vblank irqs,
110 * so no updates of timestamps or count can happen after we've
111 * disabled. Needed to prevent races in case of delayed irq's.
113 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
115 dev->driver->disable_vblank(dev, crtc);
116 dev->vblank[crtc].enabled = false;
118 /* No further vblank irq's will be processed after
119 * this point. Get current hardware vblank count and
120 * vblank timestamp, repeat until they are consistent.
122 * FIXME: There is still a race condition here and in
123 * drm_update_vblank_count() which can cause off-by-one
124 * reinitialization of software vblank counter. If gpu
125 * vblank counter doesn't increment exactly at the leading
126 * edge of a vblank interval, then we can lose 1 count if
127 * we happen to execute between start of vblank and the
128 * delayed gpu counter increment.
131 dev->vblank[crtc].last = dev->driver->get_vblank_counter(dev, crtc);
132 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
133 } while (dev->vblank[crtc].last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
138 /* Compute time difference to stored timestamp of last vblank
139 * as updated by last invocation of drm_handle_vblank() in vblank irq.
141 vblcount = atomic_read(&dev->vblank[crtc].count);
142 diff_ns = timeval_to_ns(&tvblank) -
143 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
145 /* If there is at least 1 msec difference between the last stored
146 * timestamp and tvblank, then we are currently executing our
147 * disable inside a new vblank interval, the tvblank timestamp
148 * corresponds to this new vblank interval and the irq handler
149 * for this vblank didn't run yet and won't run due to our disable.
150 * Therefore we need to do the job of drm_handle_vblank() and
151 * increment the vblank counter by one to account for this vblank.
153 * Skip this step if there isn't any high precision timestamp
154 * available. In that case we can't account for this and just
157 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
158 atomic_inc(&dev->vblank[crtc].count);
159 smp_mb__after_atomic_inc();
162 /* Invalidate all timestamps while vblank irq's are off. */
163 clear_vblank_timestamps(dev, crtc);
165 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
168 static void vblank_disable_fn(unsigned long arg)
170 struct drm_device *dev = (struct drm_device *)arg;
171 unsigned long irqflags;
174 if (!dev->vblank_disable_allowed)
177 for (i = 0; i < dev->num_crtcs; i++) {
178 spin_lock_irqsave(&dev->vbl_lock, irqflags);
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 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
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 spin_lock_init(&dev->vbl_lock);
211 spin_lock_init(&dev->vblank_time_lock);
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);
240 static void drm_irq_vgaarb_nokms(void *cookie, bool state)
242 struct drm_device *dev = cookie;
244 if (dev->driver->vgaarb_irq) {
245 dev->driver->vgaarb_irq(dev, state);
249 if (!dev->irq_enabled)
253 if (dev->driver->irq_uninstall)
254 dev->driver->irq_uninstall(dev);
256 if (dev->driver->irq_preinstall)
257 dev->driver->irq_preinstall(dev);
258 if (dev->driver->irq_postinstall)
259 dev->driver->irq_postinstall(dev);
264 * Install IRQ handler.
266 * \param dev DRM device.
268 * Initializes the IRQ related data. Installs the handler, calling the driver
269 * \c irq_preinstall() and \c irq_postinstall() functions
270 * before and after the installation.
272 int drm_irq_install(struct drm_device *dev)
275 unsigned long sh_flags = 0;
278 irq = drm_dev_to_irq(dev);
280 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
286 mutex_lock(&dev->struct_mutex);
288 /* Driver must have been initialized */
289 if (!dev->dev_private) {
290 mutex_unlock(&dev->struct_mutex);
294 if (dev->irq_enabled) {
295 mutex_unlock(&dev->struct_mutex);
298 dev->irq_enabled = true;
299 mutex_unlock(&dev->struct_mutex);
301 DRM_DEBUG("irq=%d\n", irq);
303 /* Before installing handler */
304 if (dev->driver->irq_preinstall)
305 dev->driver->irq_preinstall(dev);
307 /* Install handler */
308 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
309 sh_flags = IRQF_SHARED;
312 irqname = dev->devname;
314 irqname = dev->driver->name;
316 ret = request_irq(irq, dev->driver->irq_handler,
317 sh_flags, irqname, dev);
320 mutex_lock(&dev->struct_mutex);
321 dev->irq_enabled = false;
322 mutex_unlock(&dev->struct_mutex);
326 if (!drm_core_check_feature(dev, DRIVER_MODESET))
327 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
329 /* After installing handler */
330 if (dev->driver->irq_postinstall)
331 ret = dev->driver->irq_postinstall(dev);
334 mutex_lock(&dev->struct_mutex);
335 dev->irq_enabled = false;
336 mutex_unlock(&dev->struct_mutex);
337 if (!drm_core_check_feature(dev, DRIVER_MODESET))
338 vga_client_register(dev->pdev, NULL, NULL, NULL);
346 EXPORT_SYMBOL(drm_irq_install);
349 * Uninstall the IRQ handler.
351 * \param dev DRM device.
353 * Calls the driver's \c irq_uninstall() function, and stops the irq.
355 int drm_irq_uninstall(struct drm_device *dev)
357 unsigned long irqflags;
361 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
364 mutex_lock(&dev->struct_mutex);
365 irq_enabled = dev->irq_enabled;
366 dev->irq_enabled = false;
367 mutex_unlock(&dev->struct_mutex);
370 * Wake up any waiters so they don't hang.
372 if (dev->num_crtcs) {
373 spin_lock_irqsave(&dev->vbl_lock, irqflags);
374 for (i = 0; i < dev->num_crtcs; i++) {
375 wake_up(&dev->vblank[i].queue);
376 dev->vblank[i].enabled = false;
377 dev->vblank[i].last =
378 dev->driver->get_vblank_counter(dev, i);
380 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
386 DRM_DEBUG("irq=%d\n", dev->irq);
388 if (!drm_core_check_feature(dev, DRIVER_MODESET))
389 vga_client_register(dev->pdev, NULL, NULL, NULL);
391 if (dev->driver->irq_uninstall)
392 dev->driver->irq_uninstall(dev);
394 free_irq(dev->irq, dev);
398 EXPORT_SYMBOL(drm_irq_uninstall);
403 * \param inode device inode.
404 * \param file_priv DRM file private.
405 * \param cmd command.
406 * \param arg user argument, pointing to a drm_control structure.
407 * \return zero on success or a negative number on failure.
409 * Calls irq_install() or irq_uninstall() according to \p arg.
411 int drm_control(struct drm_device *dev, void *data,
412 struct drm_file *file_priv)
414 struct drm_control *ctl = data;
416 /* if we haven't irq we fallback for compatibility reasons -
417 * this used to be a separate function in drm_dma.h
422 case DRM_INST_HANDLER:
423 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
425 if (drm_core_check_feature(dev, DRIVER_MODESET))
427 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
428 ctl->irq != drm_dev_to_irq(dev))
430 return drm_irq_install(dev);
431 case DRM_UNINST_HANDLER:
432 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
434 if (drm_core_check_feature(dev, DRIVER_MODESET))
436 return drm_irq_uninstall(dev);
443 * drm_calc_timestamping_constants - Calculate vblank timestamp constants
445 * @crtc drm_crtc whose timestamp constants should be updated.
446 * @mode display mode containing the scanout timings
448 * Calculate and store various constants which are later
449 * needed by vblank and swap-completion timestamping, e.g,
450 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
451 * derived from crtc's true scanout timing, so they take
452 * things like panel scaling or other adjustments into account.
454 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
455 const struct drm_display_mode *mode)
457 int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
458 int dotclock = mode->crtc_clock;
460 /* Valid dotclock? */
462 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
465 * Convert scanline length in pixels and video
466 * dot clock to line duration, frame duration
467 * and pixel duration in nanoseconds:
469 pixeldur_ns = 1000000 / dotclock;
470 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
471 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
474 * Fields of interlaced scanout modes are only half a frame duration.
476 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
479 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
482 crtc->pixeldur_ns = pixeldur_ns;
483 crtc->linedur_ns = linedur_ns;
484 crtc->framedur_ns = framedur_ns;
486 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
487 crtc->base.id, mode->crtc_htotal,
488 mode->crtc_vtotal, mode->crtc_vdisplay);
489 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
490 crtc->base.id, dotclock, framedur_ns,
491 linedur_ns, pixeldur_ns);
493 EXPORT_SYMBOL(drm_calc_timestamping_constants);
496 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
497 * drivers. Implements calculation of exact vblank timestamps from
498 * given drm_display_mode timings and current video scanout position
499 * of a crtc. This can be called from within get_vblank_timestamp()
500 * implementation of a kms driver to implement the actual timestamping.
502 * Should return timestamps conforming to the OML_sync_control OpenML
503 * extension specification. The timestamp corresponds to the end of
504 * the vblank interval, aka start of scanout of topmost-leftmost display
505 * pixel in the following video frame.
507 * Requires support for optional dev->driver->get_scanout_position()
508 * in kms driver, plus a bit of setup code to provide a drm_display_mode
509 * that corresponds to the true scanout timing.
511 * The current implementation only handles standard video modes. It
512 * returns as no operation if a doublescan or interlaced video mode is
513 * active. Higher level code is expected to handle this.
516 * @crtc: Which crtc's vblank timestamp to retrieve.
517 * @max_error: Desired maximum allowable error in timestamps (nanosecs).
518 * On return contains true maximum error of timestamp.
519 * @vblank_time: Pointer to struct timeval which should receive the timestamp.
520 * @flags: Flags to pass to driver:
522 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
523 * @refcrtc: drm_crtc* of crtc which defines scanout timing.
524 * @mode: mode which defines the scanout timings
526 * Returns negative value on error, failure or if not supported in current
529 * -EINVAL - Invalid crtc.
530 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
531 * -ENOTSUPP - Function not supported in current display mode.
532 * -EIO - Failed, e.g., due to failed scanout position query.
534 * Returns or'ed positive status flags on success:
536 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
537 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
540 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
542 struct timeval *vblank_time,
544 const struct drm_crtc *refcrtc,
545 const struct drm_display_mode *mode)
547 ktime_t stime, etime, mono_time_offset;
548 struct timeval tv_etime;
551 int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
554 if (crtc < 0 || crtc >= dev->num_crtcs) {
555 DRM_ERROR("Invalid crtc %d\n", crtc);
559 /* Scanout position query not supported? Should not happen. */
560 if (!dev->driver->get_scanout_position) {
561 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
565 /* Durations of frames, lines, pixels in nanoseconds. */
566 framedur_ns = refcrtc->framedur_ns;
567 linedur_ns = refcrtc->linedur_ns;
568 pixeldur_ns = refcrtc->pixeldur_ns;
570 /* If mode timing undefined, just return as no-op:
571 * Happens during initial modesetting of a crtc.
573 if (framedur_ns == 0) {
574 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
578 /* Get current scanout position with system timestamp.
579 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
580 * if single query takes longer than max_error nanoseconds.
582 * This guarantees a tight bound on maximum error if
583 * code gets preempted or delayed for some reason.
585 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
587 * Get vertical and horizontal scanout position vpos, hpos,
588 * and bounding timestamps stime, etime, pre/post query.
590 vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
591 &hpos, &stime, &etime);
594 * Get correction for CLOCK_MONOTONIC -> CLOCK_REALTIME if
595 * CLOCK_REALTIME is requested.
597 if (!drm_timestamp_monotonic)
598 mono_time_offset = ktime_get_monotonic_offset();
600 /* Return as no-op if scanout query unsupported or failed. */
601 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
602 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
607 /* Compute uncertainty in timestamp of scanout position query. */
608 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
610 /* Accept result with < max_error nsecs timing uncertainty. */
611 if (duration_ns <= *max_error)
615 /* Noisy system timing? */
616 if (i == DRM_TIMESTAMP_MAXRETRIES) {
617 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
618 crtc, duration_ns/1000, *max_error/1000, i);
621 /* Return upper bound of timestamp precision error. */
622 *max_error = duration_ns;
624 /* Check if in vblank area:
625 * vpos is >=0 in video scanout area, but negative
626 * within vblank area, counting down the number of lines until
629 invbl = vbl_status & DRM_SCANOUTPOS_INVBL;
631 /* Convert scanout position into elapsed time at raw_time query
632 * since start of scanout at first display scanline. delta_ns
633 * can be negative if start of scanout hasn't happened yet.
635 delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
637 if (!drm_timestamp_monotonic)
638 etime = ktime_sub(etime, mono_time_offset);
640 /* save this only for debugging purposes */
641 tv_etime = ktime_to_timeval(etime);
642 /* Subtract time delta from raw timestamp to get final
643 * vblank_time timestamp for end of vblank.
646 etime = ktime_add_ns(etime, -delta_ns);
648 etime = ktime_sub_ns(etime, delta_ns);
649 *vblank_time = ktime_to_timeval(etime);
651 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
652 crtc, (int)vbl_status, hpos, vpos,
653 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
654 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
655 duration_ns/1000, i);
657 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
659 vbl_status |= DRM_VBLANKTIME_INVBL;
663 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
665 static struct timeval get_drm_timestamp(void)
670 if (!drm_timestamp_monotonic)
671 now = ktime_sub(now, ktime_get_monotonic_offset());
673 return ktime_to_timeval(now);
677 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
681 * @crtc: which crtc's vblank timestamp to retrieve
682 * @tvblank: Pointer to target struct timeval which should receive the timestamp
683 * @flags: Flags to pass to driver:
685 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
687 * Fetches the system timestamp corresponding to the time of the most recent
688 * vblank interval on specified crtc. May call into kms-driver to
689 * compute the timestamp with a high-precision GPU specific method.
691 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
692 * call, i.e., it isn't very precisely locked to the true vblank.
694 * Returns non-zero if timestamp is considered to be very precise.
696 u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
697 struct timeval *tvblank, unsigned flags)
701 /* Define requested maximum error on timestamps (nanoseconds). */
702 int max_error = (int) drm_timestamp_precision * 1000;
704 /* Query driver if possible and precision timestamping enabled. */
705 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
706 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
712 /* GPU high precision timestamp query unsupported or failed.
713 * Return current monotonic/gettimeofday timestamp as best estimate.
715 *tvblank = get_drm_timestamp();
719 EXPORT_SYMBOL(drm_get_last_vbltimestamp);
722 * drm_vblank_count - retrieve "cooked" vblank counter value
724 * @crtc: which counter to retrieve
726 * Fetches the "cooked" vblank count value that represents the number of
727 * vblank events since the system was booted, including lost events due to
728 * modesetting activity.
730 u32 drm_vblank_count(struct drm_device *dev, int crtc)
732 return atomic_read(&dev->vblank[crtc].count);
734 EXPORT_SYMBOL(drm_vblank_count);
737 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
738 * and the system timestamp corresponding to that vblank counter value.
741 * @crtc: which counter to retrieve
742 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
744 * Fetches the "cooked" vblank count value that represents the number of
745 * vblank events since the system was booted, including lost events due to
746 * modesetting activity. Returns corresponding system timestamp of the time
747 * of the vblank interval that corresponds to the current value vblank counter
750 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
751 struct timeval *vblanktime)
755 /* Read timestamp from slot of _vblank_time ringbuffer
756 * that corresponds to current vblank count. Retry if
757 * count has incremented during readout. This works like
761 cur_vblank = atomic_read(&dev->vblank[crtc].count);
762 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
764 } while (cur_vblank != atomic_read(&dev->vblank[crtc].count));
768 EXPORT_SYMBOL(drm_vblank_count_and_time);
770 static void send_vblank_event(struct drm_device *dev,
771 struct drm_pending_vblank_event *e,
772 unsigned long seq, struct timeval *now)
774 WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
775 e->event.sequence = seq;
776 e->event.tv_sec = now->tv_sec;
777 e->event.tv_usec = now->tv_usec;
779 list_add_tail(&e->base.link,
780 &e->base.file_priv->event_list);
781 wake_up_interruptible(&e->base.file_priv->event_wait);
782 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
787 * drm_send_vblank_event - helper to send vblank event after pageflip
789 * @crtc: CRTC in question
790 * @e: the event to send
792 * Updates sequence # and timestamp on event, and sends it to userspace.
793 * Caller must hold event lock.
795 void drm_send_vblank_event(struct drm_device *dev, int crtc,
796 struct drm_pending_vblank_event *e)
801 seq = drm_vblank_count_and_time(dev, crtc, &now);
805 now = get_drm_timestamp();
808 send_vblank_event(dev, e, seq, &now);
810 EXPORT_SYMBOL(drm_send_vblank_event);
813 * drm_update_vblank_count - update the master vblank counter
815 * @crtc: counter to update
817 * Call back into the driver to update the appropriate vblank counter
818 * (specified by @crtc). Deal with wraparound, if it occurred, and
819 * update the last read value so we can deal with wraparound on the next
822 * Only necessary when going from off->on, to account for frames we
823 * didn't get an interrupt for.
825 * Note: caller must hold dev->vbl_lock since this reads & writes
826 * device vblank fields.
828 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
830 u32 cur_vblank, diff, tslot, rc;
831 struct timeval t_vblank;
834 * Interrupts were disabled prior to this call, so deal with counter
836 * NOTE! It's possible we lost a full dev->max_vblank_count events
837 * here if the register is small or we had vblank interrupts off for
840 * We repeat the hardware vblank counter & timestamp query until
841 * we get consistent results. This to prevent races between gpu
842 * updating its hardware counter while we are retrieving the
843 * corresponding vblank timestamp.
846 cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
847 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
848 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
850 /* Deal with counter wrap */
851 diff = cur_vblank - dev->vblank[crtc].last;
852 if (cur_vblank < dev->vblank[crtc].last) {
853 diff += dev->max_vblank_count;
855 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
856 crtc, dev->vblank[crtc].last, cur_vblank, diff);
859 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
862 /* Reinitialize corresponding vblank timestamp if high-precision query
863 * available. Skip this step if query unsupported or failed. Will
864 * reinitialize delayed at next vblank interrupt in that case.
867 tslot = atomic_read(&dev->vblank[crtc].count) + diff;
868 vblanktimestamp(dev, crtc, tslot) = t_vblank;
871 smp_mb__before_atomic_inc();
872 atomic_add(diff, &dev->vblank[crtc].count);
873 smp_mb__after_atomic_inc();
877 * drm_vblank_get - get a reference count on vblank events
879 * @crtc: which CRTC to own
881 * Acquire a reference count on vblank events to avoid having them disabled
885 * Zero on success, nonzero on failure.
887 int drm_vblank_get(struct drm_device *dev, int crtc)
889 unsigned long irqflags, irqflags2;
892 spin_lock_irqsave(&dev->vbl_lock, irqflags);
893 /* Going from 0->1 means we have to enable interrupts again */
894 if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) {
895 spin_lock_irqsave(&dev->vblank_time_lock, irqflags2);
896 if (!dev->vblank[crtc].enabled) {
897 /* Enable vblank irqs under vblank_time_lock protection.
898 * All vblank count & timestamp updates are held off
899 * until we are done reinitializing master counter and
900 * timestamps. Filtercode in drm_handle_vblank() will
901 * prevent double-accounting of same vblank interval.
903 ret = dev->driver->enable_vblank(dev, crtc);
904 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n",
907 atomic_dec(&dev->vblank[crtc].refcount);
909 dev->vblank[crtc].enabled = true;
910 drm_update_vblank_count(dev, crtc);
913 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2);
915 if (!dev->vblank[crtc].enabled) {
916 atomic_dec(&dev->vblank[crtc].refcount);
920 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
924 EXPORT_SYMBOL(drm_vblank_get);
927 * drm_vblank_put - give up ownership of vblank events
929 * @crtc: which counter to give up
931 * Release ownership of a given vblank counter, turning off interrupts
932 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
934 void drm_vblank_put(struct drm_device *dev, int crtc)
936 BUG_ON(atomic_read(&dev->vblank[crtc].refcount) == 0);
938 /* Last user schedules interrupt disable */
939 if (atomic_dec_and_test(&dev->vblank[crtc].refcount) &&
940 (drm_vblank_offdelay > 0))
941 mod_timer(&dev->vblank_disable_timer,
942 jiffies + ((drm_vblank_offdelay * HZ)/1000));
944 EXPORT_SYMBOL(drm_vblank_put);
947 * drm_vblank_off - disable vblank events on a CRTC
949 * @crtc: CRTC in question
951 * Caller must hold event lock.
953 void drm_vblank_off(struct drm_device *dev, int crtc)
955 struct drm_pending_vblank_event *e, *t;
957 unsigned long irqflags;
960 spin_lock_irqsave(&dev->vbl_lock, irqflags);
961 vblank_disable_and_save(dev, crtc);
962 wake_up(&dev->vblank[crtc].queue);
964 /* Send any queued vblank events, lest the natives grow disquiet */
965 seq = drm_vblank_count_and_time(dev, crtc, &now);
967 spin_lock(&dev->event_lock);
968 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
971 DRM_DEBUG("Sending premature vblank event on disable: \
972 wanted %d, current %d\n",
973 e->event.sequence, seq);
974 list_del(&e->base.link);
975 drm_vblank_put(dev, e->pipe);
976 send_vblank_event(dev, e, seq, &now);
978 spin_unlock(&dev->event_lock);
980 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
982 EXPORT_SYMBOL(drm_vblank_off);
985 * drm_vblank_pre_modeset - account for vblanks across mode sets
987 * @crtc: CRTC in question
989 * Account for vblank events across mode setting events, which will likely
990 * reset the hardware frame counter.
992 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
994 /* vblank is not initialized (IRQ not installed ?), or has been freed */
998 * To avoid all the problems that might happen if interrupts
999 * were enabled/disabled around or between these calls, we just
1000 * have the kernel take a reference on the CRTC (just once though
1001 * to avoid corrupting the count if multiple, mismatch calls occur),
1002 * so that interrupts remain enabled in the interim.
1004 if (!dev->vblank[crtc].inmodeset) {
1005 dev->vblank[crtc].inmodeset = 0x1;
1006 if (drm_vblank_get(dev, crtc) == 0)
1007 dev->vblank[crtc].inmodeset |= 0x2;
1010 EXPORT_SYMBOL(drm_vblank_pre_modeset);
1012 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
1014 unsigned long irqflags;
1016 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1017 if (!dev->num_crtcs)
1020 if (dev->vblank[crtc].inmodeset) {
1021 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1022 dev->vblank_disable_allowed = true;
1023 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1025 if (dev->vblank[crtc].inmodeset & 0x2)
1026 drm_vblank_put(dev, crtc);
1028 dev->vblank[crtc].inmodeset = 0;
1031 EXPORT_SYMBOL(drm_vblank_post_modeset);
1034 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1035 * @DRM_IOCTL_ARGS: standard ioctl arguments
1037 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1038 * ioctls around modesetting so that any lost vblank events are accounted for.
1040 * Generally the counter will reset across mode sets. If interrupts are
1041 * enabled around this call, we don't have to do anything since the counter
1042 * will have already been incremented.
1044 int drm_modeset_ctl(struct drm_device *dev, void *data,
1045 struct drm_file *file_priv)
1047 struct drm_modeset_ctl *modeset = data;
1050 /* If drm_vblank_init() hasn't been called yet, just no-op */
1051 if (!dev->num_crtcs)
1054 /* KMS drivers handle this internally */
1055 if (drm_core_check_feature(dev, DRIVER_MODESET))
1058 crtc = modeset->crtc;
1059 if (crtc >= dev->num_crtcs)
1062 switch (modeset->cmd) {
1063 case _DRM_PRE_MODESET:
1064 drm_vblank_pre_modeset(dev, crtc);
1066 case _DRM_POST_MODESET:
1067 drm_vblank_post_modeset(dev, crtc);
1076 static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1077 union drm_wait_vblank *vblwait,
1078 struct drm_file *file_priv)
1080 struct drm_pending_vblank_event *e;
1082 unsigned long flags;
1086 e = kzalloc(sizeof *e, GFP_KERNEL);
1093 e->base.pid = current->pid;
1094 e->event.base.type = DRM_EVENT_VBLANK;
1095 e->event.base.length = sizeof e->event;
1096 e->event.user_data = vblwait->request.signal;
1097 e->base.event = &e->event.base;
1098 e->base.file_priv = file_priv;
1099 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
1101 spin_lock_irqsave(&dev->event_lock, flags);
1103 if (file_priv->event_space < sizeof e->event) {
1108 file_priv->event_space -= sizeof e->event;
1109 seq = drm_vblank_count_and_time(dev, pipe, &now);
1111 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1112 (seq - vblwait->request.sequence) <= (1 << 23)) {
1113 vblwait->request.sequence = seq + 1;
1114 vblwait->reply.sequence = vblwait->request.sequence;
1117 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1118 vblwait->request.sequence, seq, pipe);
1120 trace_drm_vblank_event_queued(current->pid, pipe,
1121 vblwait->request.sequence);
1123 e->event.sequence = vblwait->request.sequence;
1124 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1125 drm_vblank_put(dev, pipe);
1126 send_vblank_event(dev, e, seq, &now);
1127 vblwait->reply.sequence = seq;
1129 /* drm_handle_vblank_events will call drm_vblank_put */
1130 list_add_tail(&e->base.link, &dev->vblank_event_list);
1131 vblwait->reply.sequence = vblwait->request.sequence;
1134 spin_unlock_irqrestore(&dev->event_lock, flags);
1139 spin_unlock_irqrestore(&dev->event_lock, flags);
1142 drm_vblank_put(dev, pipe);
1149 * \param inode device inode.
1150 * \param file_priv DRM file private.
1151 * \param cmd command.
1152 * \param data user argument, pointing to a drm_wait_vblank structure.
1153 * \return zero on success or a negative number on failure.
1155 * This function enables the vblank interrupt on the pipe requested, then
1156 * sleeps waiting for the requested sequence number to occur, and drops
1157 * the vblank interrupt refcount afterwards. (vblank irq disable follows that
1158 * after a timeout with no further vblank waits scheduled).
1160 int drm_wait_vblank(struct drm_device *dev, void *data,
1161 struct drm_file *file_priv)
1163 union drm_wait_vblank *vblwait = data;
1165 unsigned int flags, seq, crtc, high_crtc;
1167 if (drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
1168 if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled))
1171 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1174 if (vblwait->request.type &
1175 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1176 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1177 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1178 vblwait->request.type,
1179 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1180 _DRM_VBLANK_HIGH_CRTC_MASK));
1184 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1185 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1187 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1189 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1190 if (crtc >= dev->num_crtcs)
1193 ret = drm_vblank_get(dev, crtc);
1195 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1198 seq = drm_vblank_count(dev, crtc);
1200 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1201 case _DRM_VBLANK_RELATIVE:
1202 vblwait->request.sequence += seq;
1203 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1204 case _DRM_VBLANK_ABSOLUTE:
1211 if (flags & _DRM_VBLANK_EVENT) {
1212 /* must hold on to the vblank ref until the event fires
1213 * drm_vblank_put will be called asynchronously
1215 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1218 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1219 (seq - vblwait->request.sequence) <= (1<<23)) {
1220 vblwait->request.sequence = seq + 1;
1223 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1224 vblwait->request.sequence, crtc);
1225 dev->vblank[crtc].last_wait = vblwait->request.sequence;
1226 DRM_WAIT_ON(ret, dev->vblank[crtc].queue, 3 * HZ,
1227 (((drm_vblank_count(dev, crtc) -
1228 vblwait->request.sequence) <= (1 << 23)) ||
1229 !dev->irq_enabled));
1231 if (ret != -EINTR) {
1234 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1235 vblwait->reply.tval_sec = now.tv_sec;
1236 vblwait->reply.tval_usec = now.tv_usec;
1238 DRM_DEBUG("returning %d to client\n",
1239 vblwait->reply.sequence);
1241 DRM_DEBUG("vblank wait interrupted by signal\n");
1245 drm_vblank_put(dev, crtc);
1249 static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1251 struct drm_pending_vblank_event *e, *t;
1253 unsigned long flags;
1256 seq = drm_vblank_count_and_time(dev, crtc, &now);
1258 spin_lock_irqsave(&dev->event_lock, flags);
1260 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1261 if (e->pipe != crtc)
1263 if ((seq - e->event.sequence) > (1<<23))
1266 DRM_DEBUG("vblank event on %d, current %d\n",
1267 e->event.sequence, seq);
1269 list_del(&e->base.link);
1270 drm_vblank_put(dev, e->pipe);
1271 send_vblank_event(dev, e, seq, &now);
1274 spin_unlock_irqrestore(&dev->event_lock, flags);
1276 trace_drm_vblank_event(crtc, seq);
1280 * drm_handle_vblank - handle a vblank event
1282 * @crtc: where this event occurred
1284 * Drivers should call this routine in their vblank interrupt handlers to
1285 * update the vblank counter and send any signals that may be pending.
1287 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1291 struct timeval tvblank;
1292 unsigned long irqflags;
1294 if (!dev->num_crtcs)
1297 /* Need timestamp lock to prevent concurrent execution with
1298 * vblank enable/disable, as this would cause inconsistent
1299 * or corrupted timestamps and vblank counts.
1301 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
1303 /* Vblank irq handling disabled. Nothing to do. */
1304 if (!dev->vblank[crtc].enabled) {
1305 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1309 /* Fetch corresponding timestamp for this vblank interval from
1310 * driver and store it in proper slot of timestamp ringbuffer.
1313 /* Get current timestamp and count. */
1314 vblcount = atomic_read(&dev->vblank[crtc].count);
1315 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1317 /* Compute time difference to timestamp of last vblank */
1318 diff_ns = timeval_to_ns(&tvblank) -
1319 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1321 /* Update vblank timestamp and count if at least
1322 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1323 * difference between last stored timestamp and current
1324 * timestamp. A smaller difference means basically
1325 * identical timestamps. Happens if this vblank has
1326 * been already processed and this is a redundant call,
1327 * e.g., due to spurious vblank interrupts. We need to
1328 * ignore those for accounting.
1330 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1331 /* Store new timestamp in ringbuffer. */
1332 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1334 /* Increment cooked vblank count. This also atomically commits
1335 * the timestamp computed above.
1337 smp_mb__before_atomic_inc();
1338 atomic_inc(&dev->vblank[crtc].count);
1339 smp_mb__after_atomic_inc();
1341 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1342 crtc, (int) diff_ns);
1345 wake_up(&dev->vblank[crtc].queue);
1346 drm_handle_vblank_events(dev, crtc);
1348 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1351 EXPORT_SYMBOL(drm_handle_vblank);