2 * drm_irq.c IRQ and vblank support
4 * \author Rickard E. (Rik) Faith <faith@valinux.com>
5 * \author Gareth Hughes <gareth@valinux.com>
9 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
11 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
12 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
13 * All Rights Reserved.
15 * Permission is hereby granted, free of charge, to any person obtaining a
16 * copy of this software and associated documentation files (the "Software"),
17 * to deal in the Software without restriction, including without limitation
18 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
19 * and/or sell copies of the Software, and to permit persons to whom the
20 * Software is furnished to do so, subject to the following conditions:
22 * The above copyright notice and this permission notice (including the next
23 * paragraph) shall be included in all copies or substantial portions of the
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
29 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
30 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
31 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
32 * OTHER DEALINGS IN THE SOFTWARE.
36 #include "drm_trace.h"
37 #include "drm_internal.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 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
61 struct timeval *tvblank, unsigned flags);
63 static unsigned int drm_timestamp_precision = 20; /* Default to 20 usecs. */
66 * Default to use monotonic timestamps for wait-for-vblank and page-flip
69 unsigned int drm_timestamp_monotonic = 1;
71 static int drm_vblank_offdelay = 5000; /* Default to 5000 msecs. */
73 module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
74 module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
75 module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);
78 * drm_update_vblank_count - update the master vblank counter
80 * @crtc: counter to update
82 * Call back into the driver to update the appropriate vblank counter
83 * (specified by @crtc). Deal with wraparound, if it occurred, and
84 * update the last read value so we can deal with wraparound on the next
87 * Only necessary when going from off->on, to account for frames we
88 * didn't get an interrupt for.
90 * Note: caller must hold dev->vbl_lock since this reads & writes
91 * device vblank fields.
93 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
95 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
96 u32 cur_vblank, diff, tslot;
98 struct timeval t_vblank;
101 * Interrupts were disabled prior to this call, so deal with counter
103 * NOTE! It's possible we lost a full dev->max_vblank_count events
104 * here if the register is small or we had vblank interrupts off for
107 * We repeat the hardware vblank counter & timestamp query until
108 * we get consistent results. This to prevent races between gpu
109 * updating its hardware counter while we are retrieving the
110 * corresponding vblank timestamp.
113 cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
114 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
115 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
117 /* Deal with counter wrap */
118 diff = cur_vblank - vblank->last;
119 if (cur_vblank < vblank->last) {
120 diff += dev->max_vblank_count;
122 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
123 crtc, vblank->last, cur_vblank, diff);
126 DRM_DEBUG("updating vblank count on crtc %d, missed %d\n",
132 /* Reinitialize corresponding vblank timestamp if high-precision query
133 * available. Skip this step if query unsupported or failed. Will
134 * reinitialize delayed at next vblank interrupt in that case.
137 tslot = atomic_read(&vblank->count) + diff;
138 vblanktimestamp(dev, crtc, tslot) = t_vblank;
141 smp_mb__before_atomic();
142 atomic_add(diff, &vblank->count);
143 smp_mb__after_atomic();
147 * Disable vblank irq's on crtc, make sure that last vblank count
148 * of hardware and corresponding consistent software vblank counter
149 * are preserved, even if there are any spurious vblank irq's after
152 static void vblank_disable_and_save(struct drm_device *dev, int crtc)
154 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
155 unsigned long irqflags;
159 struct timeval tvblank;
160 int count = DRM_TIMESTAMP_MAXRETRIES;
162 /* Prevent vblank irq processing while disabling vblank irqs,
163 * so no updates of timestamps or count can happen after we've
164 * disabled. Needed to prevent races in case of delayed irq's.
166 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
169 * If the vblank interrupt was already disabled update the count
170 * and timestamp to maintain the appearance that the counter
171 * has been ticking all along until this time. This makes the
172 * count account for the entire time between drm_vblank_on() and
175 * But only do this if precise vblank timestamps are available.
176 * Otherwise we might read a totally bogus timestamp since drivers
177 * lacking precise timestamp support rely upon sampling the system clock
178 * at vblank interrupt time. Which obviously won't work out well if the
179 * vblank interrupt is disabled.
181 if (!vblank->enabled &&
182 drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0)) {
183 drm_update_vblank_count(dev, crtc);
184 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
188 dev->driver->disable_vblank(dev, crtc);
189 vblank->enabled = false;
191 /* No further vblank irq's will be processed after
192 * this point. Get current hardware vblank count and
193 * vblank timestamp, repeat until they are consistent.
195 * FIXME: There is still a race condition here and in
196 * drm_update_vblank_count() which can cause off-by-one
197 * reinitialization of software vblank counter. If gpu
198 * vblank counter doesn't increment exactly at the leading
199 * edge of a vblank interval, then we can lose 1 count if
200 * we happen to execute between start of vblank and the
201 * delayed gpu counter increment.
204 vblank->last = dev->driver->get_vblank_counter(dev, crtc);
205 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
206 } while (vblank->last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
211 /* Compute time difference to stored timestamp of last vblank
212 * as updated by last invocation of drm_handle_vblank() in vblank irq.
214 vblcount = atomic_read(&vblank->count);
215 diff_ns = timeval_to_ns(&tvblank) -
216 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
218 /* If there is at least 1 msec difference between the last stored
219 * timestamp and tvblank, then we are currently executing our
220 * disable inside a new vblank interval, the tvblank timestamp
221 * corresponds to this new vblank interval and the irq handler
222 * for this vblank didn't run yet and won't run due to our disable.
223 * Therefore we need to do the job of drm_handle_vblank() and
224 * increment the vblank counter by one to account for this vblank.
226 * Skip this step if there isn't any high precision timestamp
227 * available. In that case we can't account for this and just
230 if (vblrc && (abs64(diff_ns) > 1000000)) {
231 /* Store new timestamp in ringbuffer. */
232 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
234 /* Increment cooked vblank count. This also atomically commits
235 * the timestamp computed above.
237 smp_mb__before_atomic();
238 atomic_inc(&vblank->count);
239 smp_mb__after_atomic();
242 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
245 static void vblank_disable_fn(unsigned long arg)
247 struct drm_vblank_crtc *vblank = (void *)arg;
248 struct drm_device *dev = vblank->dev;
249 unsigned long irqflags;
250 int crtc = vblank->crtc;
252 if (!dev->vblank_disable_allowed)
255 spin_lock_irqsave(&dev->vbl_lock, irqflags);
256 if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
257 DRM_DEBUG("disabling vblank on crtc %d\n", crtc);
258 vblank_disable_and_save(dev, crtc);
260 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
264 * drm_vblank_cleanup - cleanup vblank support
267 * This function cleans up any resources allocated in drm_vblank_init.
269 void drm_vblank_cleanup(struct drm_device *dev)
272 unsigned long irqflags;
274 /* Bail if the driver didn't call drm_vblank_init() */
275 if (dev->num_crtcs == 0)
278 for (crtc = 0; crtc < dev->num_crtcs; crtc++) {
279 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
281 del_timer_sync(&vblank->disable_timer);
283 spin_lock_irqsave(&dev->vbl_lock, irqflags);
284 vblank_disable_and_save(dev, crtc);
285 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
292 EXPORT_SYMBOL(drm_vblank_cleanup);
295 * drm_vblank_init - initialize vblank support
297 * @num_crtcs: number of crtcs supported by @dev
299 * This function initializes vblank support for @num_crtcs display pipelines.
302 * Zero on success or a negative error code on failure.
304 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
306 int i, ret = -ENOMEM;
308 spin_lock_init(&dev->vbl_lock);
309 spin_lock_init(&dev->vblank_time_lock);
311 dev->num_crtcs = num_crtcs;
313 dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
317 for (i = 0; i < num_crtcs; i++) {
318 struct drm_vblank_crtc *vblank = &dev->vblank[i];
322 init_waitqueue_head(&vblank->queue);
323 setup_timer(&vblank->disable_timer, vblank_disable_fn,
324 (unsigned long)vblank);
327 DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
329 /* Driver specific high-precision vblank timestamping supported? */
330 if (dev->driver->get_vblank_timestamp)
331 DRM_INFO("Driver supports precise vblank timestamp query.\n");
333 DRM_INFO("No driver support for vblank timestamp query.\n");
335 dev->vblank_disable_allowed = false;
343 EXPORT_SYMBOL(drm_vblank_init);
345 static void drm_irq_vgaarb_nokms(void *cookie, bool state)
347 struct drm_device *dev = cookie;
349 if (dev->driver->vgaarb_irq) {
350 dev->driver->vgaarb_irq(dev, state);
354 if (!dev->irq_enabled)
358 if (dev->driver->irq_uninstall)
359 dev->driver->irq_uninstall(dev);
361 if (dev->driver->irq_preinstall)
362 dev->driver->irq_preinstall(dev);
363 if (dev->driver->irq_postinstall)
364 dev->driver->irq_postinstall(dev);
369 * drm_irq_install - install IRQ handler
371 * @irq: IRQ number to install the handler for
373 * Initializes the IRQ related data. Installs the handler, calling the driver
374 * irq_preinstall() and irq_postinstall() functions before and after the
377 * This is the simplified helper interface provided for drivers with no special
378 * needs. Drivers which need to install interrupt handlers for multiple
379 * interrupts must instead set drm_device->irq_enabled to signal the DRM core
380 * that vblank interrupts are available.
383 * Zero on success or a negative error code on failure.
385 int drm_irq_install(struct drm_device *dev, int irq)
388 unsigned long sh_flags = 0;
390 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
396 /* Driver must have been initialized */
397 if (!dev->dev_private)
400 if (dev->irq_enabled)
402 dev->irq_enabled = true;
404 DRM_DEBUG("irq=%d\n", irq);
406 /* Before installing handler */
407 if (dev->driver->irq_preinstall)
408 dev->driver->irq_preinstall(dev);
410 /* Install handler */
411 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
412 sh_flags = IRQF_SHARED;
414 ret = request_irq(irq, dev->driver->irq_handler,
415 sh_flags, dev->driver->name, dev);
418 dev->irq_enabled = false;
422 if (!drm_core_check_feature(dev, DRIVER_MODESET))
423 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
425 /* After installing handler */
426 if (dev->driver->irq_postinstall)
427 ret = dev->driver->irq_postinstall(dev);
430 dev->irq_enabled = false;
431 if (!drm_core_check_feature(dev, DRIVER_MODESET))
432 vga_client_register(dev->pdev, NULL, NULL, NULL);
440 EXPORT_SYMBOL(drm_irq_install);
443 * drm_irq_uninstall - uninstall the IRQ handler
446 * Calls the driver's irq_uninstall() function and unregisters the IRQ handler.
447 * This should only be called by drivers which used drm_irq_install() to set up
448 * their interrupt handler. Other drivers must only reset
449 * drm_device->irq_enabled to false.
451 * Note that for kernel modesetting drivers it is a bug if this function fails.
452 * The sanity checks are only to catch buggy user modesetting drivers which call
453 * the same function through an ioctl.
456 * Zero on success or a negative error code on failure.
458 int drm_irq_uninstall(struct drm_device *dev)
460 unsigned long irqflags;
464 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
467 irq_enabled = dev->irq_enabled;
468 dev->irq_enabled = false;
471 * Wake up any waiters so they don't hang.
473 if (dev->num_crtcs) {
474 spin_lock_irqsave(&dev->vbl_lock, irqflags);
475 for (i = 0; i < dev->num_crtcs; i++) {
476 struct drm_vblank_crtc *vblank = &dev->vblank[i];
478 wake_up(&vblank->queue);
479 vblank->enabled = false;
481 dev->driver->get_vblank_counter(dev, i);
483 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
489 DRM_DEBUG("irq=%d\n", dev->irq);
491 if (!drm_core_check_feature(dev, DRIVER_MODESET))
492 vga_client_register(dev->pdev, NULL, NULL, NULL);
494 if (dev->driver->irq_uninstall)
495 dev->driver->irq_uninstall(dev);
497 free_irq(dev->irq, dev);
501 EXPORT_SYMBOL(drm_irq_uninstall);
506 * \param inode device inode.
507 * \param file_priv DRM file private.
508 * \param cmd command.
509 * \param arg user argument, pointing to a drm_control structure.
510 * \return zero on success or a negative number on failure.
512 * Calls irq_install() or irq_uninstall() according to \p arg.
514 int drm_control(struct drm_device *dev, void *data,
515 struct drm_file *file_priv)
517 struct drm_control *ctl = data;
520 /* if we haven't irq we fallback for compatibility reasons -
521 * this used to be a separate function in drm_dma.h
524 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
526 if (drm_core_check_feature(dev, DRIVER_MODESET))
528 /* UMS was only ever support on pci devices. */
529 if (WARN_ON(!dev->pdev))
533 case DRM_INST_HANDLER:
534 irq = dev->pdev->irq;
536 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
539 mutex_lock(&dev->struct_mutex);
540 ret = drm_irq_install(dev, irq);
541 mutex_unlock(&dev->struct_mutex);
544 case DRM_UNINST_HANDLER:
545 mutex_lock(&dev->struct_mutex);
546 ret = drm_irq_uninstall(dev);
547 mutex_unlock(&dev->struct_mutex);
556 * drm_calc_timestamping_constants - calculate vblank timestamp constants
557 * @crtc: drm_crtc whose timestamp constants should be updated.
558 * @mode: display mode containing the scanout timings
560 * Calculate and store various constants which are later
561 * needed by vblank and swap-completion timestamping, e.g,
562 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
563 * derived from CRTC's true scanout timing, so they take
564 * things like panel scaling or other adjustments into account.
566 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
567 const struct drm_display_mode *mode)
569 int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
570 int dotclock = mode->crtc_clock;
572 /* Valid dotclock? */
574 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
577 * Convert scanline length in pixels and video
578 * dot clock to line duration, frame duration
579 * and pixel duration in nanoseconds:
581 pixeldur_ns = 1000000 / dotclock;
582 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
583 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
586 * Fields of interlaced scanout modes are only half a frame duration.
588 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
591 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
594 crtc->pixeldur_ns = pixeldur_ns;
595 crtc->linedur_ns = linedur_ns;
596 crtc->framedur_ns = framedur_ns;
598 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
599 crtc->base.id, mode->crtc_htotal,
600 mode->crtc_vtotal, mode->crtc_vdisplay);
601 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
602 crtc->base.id, dotclock, framedur_ns,
603 linedur_ns, pixeldur_ns);
605 EXPORT_SYMBOL(drm_calc_timestamping_constants);
608 * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
610 * @crtc: Which CRTC's vblank timestamp to retrieve
611 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
612 * On return contains true maximum error of timestamp
613 * @vblank_time: Pointer to struct timeval which should receive the timestamp
614 * @flags: Flags to pass to driver:
616 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
617 * @refcrtc: CRTC which defines scanout timing
618 * @mode: mode which defines the scanout timings
620 * Implements calculation of exact vblank timestamps from given drm_display_mode
621 * timings and current video scanout position of a CRTC. This can be called from
622 * within get_vblank_timestamp() implementation of a kms driver to implement the
623 * actual timestamping.
625 * Should return timestamps conforming to the OML_sync_control OpenML
626 * extension specification. The timestamp corresponds to the end of
627 * the vblank interval, aka start of scanout of topmost-leftmost display
628 * pixel in the following video frame.
630 * Requires support for optional dev->driver->get_scanout_position()
631 * in kms driver, plus a bit of setup code to provide a drm_display_mode
632 * that corresponds to the true scanout timing.
634 * The current implementation only handles standard video modes. It
635 * returns as no operation if a doublescan or interlaced video mode is
636 * active. Higher level code is expected to handle this.
639 * Negative value on error, failure or if not supported in current
642 * -EINVAL - Invalid CRTC.
643 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
644 * -ENOTSUPP - Function not supported in current display mode.
645 * -EIO - Failed, e.g., due to failed scanout position query.
647 * Returns or'ed positive status flags on success:
649 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
650 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
653 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
655 struct timeval *vblank_time,
657 const struct drm_crtc *refcrtc,
658 const struct drm_display_mode *mode)
660 struct timeval tv_etime;
661 ktime_t stime, etime;
664 int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
667 if (crtc < 0 || crtc >= dev->num_crtcs) {
668 DRM_ERROR("Invalid crtc %d\n", crtc);
672 /* Scanout position query not supported? Should not happen. */
673 if (!dev->driver->get_scanout_position) {
674 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
678 /* Durations of frames, lines, pixels in nanoseconds. */
679 framedur_ns = refcrtc->framedur_ns;
680 linedur_ns = refcrtc->linedur_ns;
681 pixeldur_ns = refcrtc->pixeldur_ns;
683 /* If mode timing undefined, just return as no-op:
684 * Happens during initial modesetting of a crtc.
686 if (framedur_ns == 0) {
687 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
691 /* Get current scanout position with system timestamp.
692 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
693 * if single query takes longer than max_error nanoseconds.
695 * This guarantees a tight bound on maximum error if
696 * code gets preempted or delayed for some reason.
698 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
700 * Get vertical and horizontal scanout position vpos, hpos,
701 * and bounding timestamps stime, etime, pre/post query.
703 vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
704 &hpos, &stime, &etime);
706 /* Return as no-op if scanout query unsupported or failed. */
707 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
708 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
713 /* Compute uncertainty in timestamp of scanout position query. */
714 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
716 /* Accept result with < max_error nsecs timing uncertainty. */
717 if (duration_ns <= *max_error)
721 /* Noisy system timing? */
722 if (i == DRM_TIMESTAMP_MAXRETRIES) {
723 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
724 crtc, duration_ns/1000, *max_error/1000, i);
727 /* Return upper bound of timestamp precision error. */
728 *max_error = duration_ns;
730 /* Check if in vblank area:
731 * vpos is >=0 in video scanout area, but negative
732 * within vblank area, counting down the number of lines until
735 invbl = vbl_status & DRM_SCANOUTPOS_IN_VBLANK;
737 /* Convert scanout position into elapsed time at raw_time query
738 * since start of scanout at first display scanline. delta_ns
739 * can be negative if start of scanout hasn't happened yet.
741 delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
743 if (!drm_timestamp_monotonic)
744 etime = ktime_mono_to_real(etime);
746 /* save this only for debugging purposes */
747 tv_etime = ktime_to_timeval(etime);
748 /* Subtract time delta from raw timestamp to get final
749 * vblank_time timestamp for end of vblank.
752 etime = ktime_add_ns(etime, -delta_ns);
754 etime = ktime_sub_ns(etime, delta_ns);
755 *vblank_time = ktime_to_timeval(etime);
757 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
758 crtc, (int)vbl_status, hpos, vpos,
759 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
760 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
761 duration_ns/1000, i);
763 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
765 vbl_status |= DRM_VBLANKTIME_IN_VBLANK;
769 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
771 static struct timeval get_drm_timestamp(void)
775 now = drm_timestamp_monotonic ? ktime_get() : ktime_get_real();
776 return ktime_to_timeval(now);
780 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
783 * @crtc: which CRTC's vblank timestamp to retrieve
784 * @tvblank: Pointer to target struct timeval which should receive the timestamp
785 * @flags: Flags to pass to driver:
787 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
789 * Fetches the system timestamp corresponding to the time of the most recent
790 * vblank interval on specified CRTC. May call into kms-driver to
791 * compute the timestamp with a high-precision GPU specific method.
793 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
794 * call, i.e., it isn't very precisely locked to the true vblank.
797 * True if timestamp is considered to be very precise, false otherwise.
800 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
801 struct timeval *tvblank, unsigned flags)
805 /* Define requested maximum error on timestamps (nanoseconds). */
806 int max_error = (int) drm_timestamp_precision * 1000;
808 /* Query driver if possible and precision timestamping enabled. */
809 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
810 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
816 /* GPU high precision timestamp query unsupported or failed.
817 * Return current monotonic/gettimeofday timestamp as best estimate.
819 *tvblank = get_drm_timestamp();
825 * drm_vblank_count - retrieve "cooked" vblank counter value
827 * @crtc: which counter to retrieve
829 * Fetches the "cooked" vblank count value that represents the number of
830 * vblank events since the system was booted, including lost events due to
831 * modesetting activity.
834 * The software vblank counter.
836 u32 drm_vblank_count(struct drm_device *dev, int crtc)
838 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
840 if (WARN_ON(crtc >= dev->num_crtcs))
842 return atomic_read(&vblank->count);
844 EXPORT_SYMBOL(drm_vblank_count);
847 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
848 * and the system timestamp corresponding to that vblank counter value.
851 * @crtc: which counter to retrieve
852 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
854 * Fetches the "cooked" vblank count value that represents the number of
855 * vblank events since the system was booted, including lost events due to
856 * modesetting activity. Returns corresponding system timestamp of the time
857 * of the vblank interval that corresponds to the current vblank counter value.
859 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
860 struct timeval *vblanktime)
862 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
865 if (WARN_ON(crtc >= dev->num_crtcs))
868 /* Read timestamp from slot of _vblank_time ringbuffer
869 * that corresponds to current vblank count. Retry if
870 * count has incremented during readout. This works like
874 cur_vblank = atomic_read(&vblank->count);
875 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
877 } while (cur_vblank != atomic_read(&vblank->count));
881 EXPORT_SYMBOL(drm_vblank_count_and_time);
883 static void send_vblank_event(struct drm_device *dev,
884 struct drm_pending_vblank_event *e,
885 unsigned long seq, struct timeval *now)
887 WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
888 e->event.sequence = seq;
889 e->event.tv_sec = now->tv_sec;
890 e->event.tv_usec = now->tv_usec;
892 list_add_tail(&e->base.link,
893 &e->base.file_priv->event_list);
894 wake_up_interruptible(&e->base.file_priv->event_wait);
895 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
900 * drm_send_vblank_event - helper to send vblank event after pageflip
902 * @crtc: CRTC in question
903 * @e: the event to send
905 * Updates sequence # and timestamp on event, and sends it to userspace.
906 * Caller must hold event lock.
908 void drm_send_vblank_event(struct drm_device *dev, int crtc,
909 struct drm_pending_vblank_event *e)
915 seq = drm_vblank_count_and_time(dev, crtc, &now);
919 now = get_drm_timestamp();
922 send_vblank_event(dev, e, seq, &now);
924 EXPORT_SYMBOL(drm_send_vblank_event);
927 * drm_vblank_enable - enable the vblank interrupt on a CRTC
929 * @crtc: CRTC in question
931 static int drm_vblank_enable(struct drm_device *dev, int crtc)
933 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
936 assert_spin_locked(&dev->vbl_lock);
938 spin_lock(&dev->vblank_time_lock);
940 if (!vblank->enabled) {
942 * Enable vblank irqs under vblank_time_lock protection.
943 * All vblank count & timestamp updates are held off
944 * until we are done reinitializing master counter and
945 * timestamps. Filtercode in drm_handle_vblank() will
946 * prevent double-accounting of same vblank interval.
948 ret = dev->driver->enable_vblank(dev, crtc);
949 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
951 atomic_dec(&vblank->refcount);
953 vblank->enabled = true;
954 drm_update_vblank_count(dev, crtc);
958 spin_unlock(&dev->vblank_time_lock);
964 * drm_vblank_get - get a reference count on vblank events
966 * @crtc: which CRTC to own
968 * Acquire a reference count on vblank events to avoid having them disabled
971 * This is the legacy version of drm_crtc_vblank_get().
974 * Zero on success, nonzero on failure.
976 int drm_vblank_get(struct drm_device *dev, int crtc)
978 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
979 unsigned long irqflags;
982 if (WARN_ON(crtc >= dev->num_crtcs))
985 spin_lock_irqsave(&dev->vbl_lock, irqflags);
986 /* Going from 0->1 means we have to enable interrupts again */
987 if (atomic_add_return(1, &vblank->refcount) == 1) {
988 ret = drm_vblank_enable(dev, crtc);
990 if (!vblank->enabled) {
991 atomic_dec(&vblank->refcount);
995 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
999 EXPORT_SYMBOL(drm_vblank_get);
1002 * drm_crtc_vblank_get - get a reference count on vblank events
1003 * @crtc: which CRTC to own
1005 * Acquire a reference count on vblank events to avoid having them disabled
1008 * This is the native kms version of drm_vblank_off().
1011 * Zero on success, nonzero on failure.
1013 int drm_crtc_vblank_get(struct drm_crtc *crtc)
1015 return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
1017 EXPORT_SYMBOL(drm_crtc_vblank_get);
1020 * drm_vblank_put - give up ownership of vblank events
1022 * @crtc: which counter to give up
1024 * Release ownership of a given vblank counter, turning off interrupts
1025 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1027 * This is the legacy version of drm_crtc_vblank_put().
1029 void drm_vblank_put(struct drm_device *dev, int crtc)
1031 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1033 if (WARN_ON(atomic_read(&vblank->refcount) == 0))
1036 if (WARN_ON(crtc >= dev->num_crtcs))
1039 /* Last user schedules interrupt disable */
1040 if (atomic_dec_and_test(&vblank->refcount)) {
1041 if (drm_vblank_offdelay == 0)
1043 else if (dev->vblank_disable_immediate || drm_vblank_offdelay < 0)
1044 vblank_disable_fn((unsigned long)vblank);
1046 mod_timer(&vblank->disable_timer,
1047 jiffies + ((drm_vblank_offdelay * HZ)/1000));
1050 EXPORT_SYMBOL(drm_vblank_put);
1053 * drm_crtc_vblank_put - give up ownership of vblank events
1054 * @crtc: which counter to give up
1056 * Release ownership of a given vblank counter, turning off interrupts
1057 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1059 * This is the native kms version of drm_vblank_put().
1061 void drm_crtc_vblank_put(struct drm_crtc *crtc)
1063 drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
1065 EXPORT_SYMBOL(drm_crtc_vblank_put);
1068 * drm_wait_one_vblank - wait for one vblank
1072 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
1073 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
1074 * due to lack of driver support or because the crtc is off.
1076 void drm_wait_one_vblank(struct drm_device *dev, int crtc)
1081 ret = drm_vblank_get(dev, crtc);
1082 if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", crtc, ret))
1085 last = drm_vblank_count(dev, crtc);
1087 ret = wait_event_timeout(dev->vblank[crtc].queue,
1088 last != drm_vblank_count(dev, crtc),
1089 msecs_to_jiffies(100));
1091 WARN(ret == 0, "vblank wait timed out on crtc %i\n", crtc);
1093 drm_vblank_put(dev, crtc);
1095 EXPORT_SYMBOL(drm_wait_one_vblank);
1098 * drm_crtc_wait_one_vblank - wait for one vblank
1101 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
1102 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
1103 * due to lack of driver support or because the crtc is off.
1105 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
1107 drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
1109 EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
1112 * drm_vblank_off - disable vblank events on a CRTC
1114 * @crtc: CRTC in question
1116 * Drivers can use this function to shut down the vblank interrupt handling when
1117 * disabling a crtc. This function ensures that the latest vblank frame count is
1118 * stored so that drm_vblank_on() can restore it again.
1120 * Drivers must use this function when the hardware vblank counter can get
1121 * reset, e.g. when suspending.
1123 * This is the legacy version of drm_crtc_vblank_off().
1125 void drm_vblank_off(struct drm_device *dev, int crtc)
1127 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1128 struct drm_pending_vblank_event *e, *t;
1130 unsigned long irqflags;
1133 if (WARN_ON(crtc >= dev->num_crtcs))
1136 spin_lock_irqsave(&dev->event_lock, irqflags);
1138 spin_lock(&dev->vbl_lock);
1139 vblank_disable_and_save(dev, crtc);
1140 wake_up(&vblank->queue);
1143 * Prevent subsequent drm_vblank_get() from re-enabling
1144 * the vblank interrupt by bumping the refcount.
1146 if (!vblank->inmodeset) {
1147 atomic_inc(&vblank->refcount);
1148 vblank->inmodeset = 1;
1150 spin_unlock(&dev->vbl_lock);
1152 /* Send any queued vblank events, lest the natives grow disquiet */
1153 seq = drm_vblank_count_and_time(dev, crtc, &now);
1155 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1156 if (e->pipe != crtc)
1158 DRM_DEBUG("Sending premature vblank event on disable: \
1159 wanted %d, current %d\n",
1160 e->event.sequence, seq);
1161 list_del(&e->base.link);
1162 drm_vblank_put(dev, e->pipe);
1163 send_vblank_event(dev, e, seq, &now);
1165 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1167 EXPORT_SYMBOL(drm_vblank_off);
1170 * drm_crtc_vblank_off - disable vblank events on a CRTC
1171 * @crtc: CRTC in question
1173 * Drivers can use this function to shut down the vblank interrupt handling when
1174 * disabling a crtc. This function ensures that the latest vblank frame count is
1175 * stored so that drm_vblank_on can restore it again.
1177 * Drivers must use this function when the hardware vblank counter can get
1178 * reset, e.g. when suspending.
1180 * This is the native kms version of drm_vblank_off().
1182 void drm_crtc_vblank_off(struct drm_crtc *crtc)
1184 drm_vblank_off(crtc->dev, drm_crtc_index(crtc));
1186 EXPORT_SYMBOL(drm_crtc_vblank_off);
1189 * drm_vblank_on - enable vblank events on a CRTC
1191 * @crtc: CRTC in question
1193 * This functions restores the vblank interrupt state captured with
1194 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1195 * drm_vblank_off() can be unbalanced and so can also be unconditionally called
1196 * in driver load code to reflect the current hardware state of the crtc.
1198 * This is the legacy version of drm_crtc_vblank_on().
1200 void drm_vblank_on(struct drm_device *dev, int crtc)
1202 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1203 unsigned long irqflags;
1205 if (WARN_ON(crtc >= dev->num_crtcs))
1208 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1209 /* Drop our private "prevent drm_vblank_get" refcount */
1210 if (vblank->inmodeset) {
1211 atomic_dec(&vblank->refcount);
1212 vblank->inmodeset = 0;
1216 * sample the current counter to avoid random jumps
1217 * when drm_vblank_enable() applies the diff
1219 * -1 to make sure user will never see the same
1220 * vblank counter value before and after a modeset
1223 (dev->driver->get_vblank_counter(dev, crtc) - 1) &
1224 dev->max_vblank_count;
1226 * re-enable interrupts if there are users left, or the
1227 * user wishes vblank interrupts to be enabled all the time.
1229 if (atomic_read(&vblank->refcount) != 0 ||
1230 (!dev->vblank_disable_immediate && drm_vblank_offdelay == 0))
1231 WARN_ON(drm_vblank_enable(dev, crtc));
1232 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1234 EXPORT_SYMBOL(drm_vblank_on);
1237 * drm_crtc_vblank_on - enable vblank events on a CRTC
1238 * @crtc: CRTC in question
1240 * This functions restores the vblank interrupt state captured with
1241 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1242 * drm_vblank_off() can be unbalanced and so can also be unconditionally called
1243 * in driver load code to reflect the current hardware state of the crtc.
1245 * This is the native kms version of drm_vblank_on().
1247 void drm_crtc_vblank_on(struct drm_crtc *crtc)
1249 drm_vblank_on(crtc->dev, drm_crtc_index(crtc));
1251 EXPORT_SYMBOL(drm_crtc_vblank_on);
1254 * drm_vblank_pre_modeset - account for vblanks across mode sets
1256 * @crtc: CRTC in question
1258 * Account for vblank events across mode setting events, which will likely
1259 * reset the hardware frame counter.
1261 * This is done by grabbing a temporary vblank reference to ensure that the
1262 * vblank interrupt keeps running across the modeset sequence. With this the
1263 * software-side vblank frame counting will ensure that there are no jumps or
1266 * Unfortunately this approach is racy and also doesn't work when the vblank
1267 * interrupt stops running, e.g. across system suspend resume. It is therefore
1268 * highly recommended that drivers use the newer drm_vblank_off() and
1269 * drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when
1270 * using "cooked" software vblank frame counters and not relying on any hardware
1273 * Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc
1276 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
1278 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1280 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1281 if (!dev->num_crtcs)
1284 if (WARN_ON(crtc >= dev->num_crtcs))
1288 * To avoid all the problems that might happen if interrupts
1289 * were enabled/disabled around or between these calls, we just
1290 * have the kernel take a reference on the CRTC (just once though
1291 * to avoid corrupting the count if multiple, mismatch calls occur),
1292 * so that interrupts remain enabled in the interim.
1294 if (!vblank->inmodeset) {
1295 vblank->inmodeset = 0x1;
1296 if (drm_vblank_get(dev, crtc) == 0)
1297 vblank->inmodeset |= 0x2;
1300 EXPORT_SYMBOL(drm_vblank_pre_modeset);
1303 * drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes
1305 * @crtc: CRTC in question
1307 * This function again drops the temporary vblank reference acquired in
1308 * drm_vblank_pre_modeset.
1310 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
1312 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1313 unsigned long irqflags;
1315 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1316 if (!dev->num_crtcs)
1319 if (vblank->inmodeset) {
1320 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1321 dev->vblank_disable_allowed = true;
1322 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1324 if (vblank->inmodeset & 0x2)
1325 drm_vblank_put(dev, crtc);
1327 vblank->inmodeset = 0;
1330 EXPORT_SYMBOL(drm_vblank_post_modeset);
1333 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1334 * @DRM_IOCTL_ARGS: standard ioctl arguments
1336 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1337 * ioctls around modesetting so that any lost vblank events are accounted for.
1339 * Generally the counter will reset across mode sets. If interrupts are
1340 * enabled around this call, we don't have to do anything since the counter
1341 * will have already been incremented.
1343 int drm_modeset_ctl(struct drm_device *dev, void *data,
1344 struct drm_file *file_priv)
1346 struct drm_modeset_ctl *modeset = data;
1349 /* If drm_vblank_init() hasn't been called yet, just no-op */
1350 if (!dev->num_crtcs)
1353 /* KMS drivers handle this internally */
1354 if (drm_core_check_feature(dev, DRIVER_MODESET))
1357 crtc = modeset->crtc;
1358 if (crtc >= dev->num_crtcs)
1361 switch (modeset->cmd) {
1362 case _DRM_PRE_MODESET:
1363 drm_vblank_pre_modeset(dev, crtc);
1365 case _DRM_POST_MODESET:
1366 drm_vblank_post_modeset(dev, crtc);
1375 static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1376 union drm_wait_vblank *vblwait,
1377 struct drm_file *file_priv)
1379 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1380 struct drm_pending_vblank_event *e;
1382 unsigned long flags;
1386 e = kzalloc(sizeof *e, GFP_KERNEL);
1393 e->base.pid = current->pid;
1394 e->event.base.type = DRM_EVENT_VBLANK;
1395 e->event.base.length = sizeof e->event;
1396 e->event.user_data = vblwait->request.signal;
1397 e->base.event = &e->event.base;
1398 e->base.file_priv = file_priv;
1399 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
1401 spin_lock_irqsave(&dev->event_lock, flags);
1404 * drm_vblank_off() might have been called after we called
1405 * drm_vblank_get(). drm_vblank_off() holds event_lock
1406 * around the vblank disable, so no need for further locking.
1407 * The reference from drm_vblank_get() protects against
1408 * vblank disable from another source.
1410 if (!vblank->enabled) {
1415 if (file_priv->event_space < sizeof e->event) {
1420 file_priv->event_space -= sizeof e->event;
1421 seq = drm_vblank_count_and_time(dev, pipe, &now);
1423 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1424 (seq - vblwait->request.sequence) <= (1 << 23)) {
1425 vblwait->request.sequence = seq + 1;
1426 vblwait->reply.sequence = vblwait->request.sequence;
1429 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1430 vblwait->request.sequence, seq, pipe);
1432 trace_drm_vblank_event_queued(current->pid, pipe,
1433 vblwait->request.sequence);
1435 e->event.sequence = vblwait->request.sequence;
1436 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1437 drm_vblank_put(dev, pipe);
1438 send_vblank_event(dev, e, seq, &now);
1439 vblwait->reply.sequence = seq;
1441 /* drm_handle_vblank_events will call drm_vblank_put */
1442 list_add_tail(&e->base.link, &dev->vblank_event_list);
1443 vblwait->reply.sequence = vblwait->request.sequence;
1446 spin_unlock_irqrestore(&dev->event_lock, flags);
1451 spin_unlock_irqrestore(&dev->event_lock, flags);
1454 drm_vblank_put(dev, pipe);
1461 * \param inode device inode.
1462 * \param file_priv DRM file private.
1463 * \param cmd command.
1464 * \param data user argument, pointing to a drm_wait_vblank structure.
1465 * \return zero on success or a negative number on failure.
1467 * This function enables the vblank interrupt on the pipe requested, then
1468 * sleeps waiting for the requested sequence number to occur, and drops
1469 * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
1470 * after a timeout with no further vblank waits scheduled).
1472 int drm_wait_vblank(struct drm_device *dev, void *data,
1473 struct drm_file *file_priv)
1475 struct drm_vblank_crtc *vblank;
1476 union drm_wait_vblank *vblwait = data;
1478 unsigned int flags, seq, crtc, high_crtc;
1480 if (!dev->irq_enabled)
1483 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1486 if (vblwait->request.type &
1487 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1488 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1489 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1490 vblwait->request.type,
1491 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1492 _DRM_VBLANK_HIGH_CRTC_MASK));
1496 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1497 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1499 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1501 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1502 if (crtc >= dev->num_crtcs)
1505 vblank = &dev->vblank[crtc];
1507 ret = drm_vblank_get(dev, crtc);
1509 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1512 seq = drm_vblank_count(dev, crtc);
1514 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1515 case _DRM_VBLANK_RELATIVE:
1516 vblwait->request.sequence += seq;
1517 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1518 case _DRM_VBLANK_ABSOLUTE:
1525 if (flags & _DRM_VBLANK_EVENT) {
1526 /* must hold on to the vblank ref until the event fires
1527 * drm_vblank_put will be called asynchronously
1529 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1532 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1533 (seq - vblwait->request.sequence) <= (1<<23)) {
1534 vblwait->request.sequence = seq + 1;
1537 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1538 vblwait->request.sequence, crtc);
1539 vblank->last_wait = vblwait->request.sequence;
1540 DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
1541 (((drm_vblank_count(dev, crtc) -
1542 vblwait->request.sequence) <= (1 << 23)) ||
1544 !dev->irq_enabled));
1546 if (ret != -EINTR) {
1549 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1550 vblwait->reply.tval_sec = now.tv_sec;
1551 vblwait->reply.tval_usec = now.tv_usec;
1553 DRM_DEBUG("returning %d to client\n",
1554 vblwait->reply.sequence);
1556 DRM_DEBUG("vblank wait interrupted by signal\n");
1560 drm_vblank_put(dev, crtc);
1564 static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1566 struct drm_pending_vblank_event *e, *t;
1570 assert_spin_locked(&dev->event_lock);
1572 seq = drm_vblank_count_and_time(dev, crtc, &now);
1574 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1575 if (e->pipe != crtc)
1577 if ((seq - e->event.sequence) > (1<<23))
1580 DRM_DEBUG("vblank event on %d, current %d\n",
1581 e->event.sequence, seq);
1583 list_del(&e->base.link);
1584 drm_vblank_put(dev, e->pipe);
1585 send_vblank_event(dev, e, seq, &now);
1588 trace_drm_vblank_event(crtc, seq);
1592 * drm_handle_vblank - handle a vblank event
1594 * @crtc: where this event occurred
1596 * Drivers should call this routine in their vblank interrupt handlers to
1597 * update the vblank counter and send any signals that may be pending.
1599 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1601 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1604 struct timeval tvblank;
1605 unsigned long irqflags;
1607 if (!dev->num_crtcs)
1610 if (WARN_ON(crtc >= dev->num_crtcs))
1613 spin_lock_irqsave(&dev->event_lock, irqflags);
1615 /* Need timestamp lock to prevent concurrent execution with
1616 * vblank enable/disable, as this would cause inconsistent
1617 * or corrupted timestamps and vblank counts.
1619 spin_lock(&dev->vblank_time_lock);
1621 /* Vblank irq handling disabled. Nothing to do. */
1622 if (!vblank->enabled) {
1623 spin_unlock(&dev->vblank_time_lock);
1624 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1628 /* Fetch corresponding timestamp for this vblank interval from
1629 * driver and store it in proper slot of timestamp ringbuffer.
1632 /* Get current timestamp and count. */
1633 vblcount = atomic_read(&vblank->count);
1634 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1636 /* Compute time difference to timestamp of last vblank */
1637 diff_ns = timeval_to_ns(&tvblank) -
1638 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1640 /* Update vblank timestamp and count if at least
1641 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1642 * difference between last stored timestamp and current
1643 * timestamp. A smaller difference means basically
1644 * identical timestamps. Happens if this vblank has
1645 * been already processed and this is a redundant call,
1646 * e.g., due to spurious vblank interrupts. We need to
1647 * ignore those for accounting.
1649 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1650 /* Store new timestamp in ringbuffer. */
1651 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1653 /* Increment cooked vblank count. This also atomically commits
1654 * the timestamp computed above.
1656 smp_mb__before_atomic();
1657 atomic_inc(&vblank->count);
1658 smp_mb__after_atomic();
1660 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1661 crtc, (int) diff_ns);
1664 spin_unlock(&dev->vblank_time_lock);
1666 wake_up(&vblank->queue);
1667 drm_handle_vblank_events(dev, crtc);
1669 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1673 EXPORT_SYMBOL(drm_handle_vblank);