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);
77 static void store_vblank(struct drm_device *dev, int crtc,
78 unsigned vblank_count_inc,
79 struct timeval *t_vblank)
81 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
84 assert_spin_locked(&dev->vblank_time_lock);
87 /* All writers hold the spinlock, but readers are serialized by
88 * the latching of vblank->count below.
90 tslot = vblank->count + vblank_count_inc;
91 vblanktimestamp(dev, crtc, tslot) = *t_vblank;
95 * vblank timestamp updates are protected on the write side with
96 * vblank_time_lock, but on the read side done locklessly using a
97 * sequence-lock on the vblank counter. Ensure correct ordering using
98 * memory barrriers. We need the barrier both before and also after the
99 * counter update to synchronize with the next timestamp write.
100 * The read-side barriers for this are in drm_vblank_count_and_time.
103 vblank->count += vblank_count_inc;
108 * drm_update_vblank_count - update the master vblank counter
110 * @crtc: counter to update
112 * Call back into the driver to update the appropriate vblank counter
113 * (specified by @crtc). Deal with wraparound, if it occurred, and
114 * update the last read value so we can deal with wraparound on the next
117 * Only necessary when going from off->on, to account for frames we
118 * didn't get an interrupt for.
120 * Note: caller must hold dev->vbl_lock since this reads & writes
121 * device vblank fields.
123 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
125 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
126 u32 cur_vblank, diff;
128 struct timeval t_vblank;
131 * Interrupts were disabled prior to this call, so deal with counter
133 * NOTE! It's possible we lost a full dev->max_vblank_count + 1 events
134 * here if the register is small or we had vblank interrupts off for
137 * We repeat the hardware vblank counter & timestamp query until
138 * we get consistent results. This to prevent races between gpu
139 * updating its hardware counter while we are retrieving the
140 * corresponding vblank timestamp.
143 cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
144 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
145 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
147 /* Deal with counter wrap */
148 diff = cur_vblank - vblank->last;
149 if (cur_vblank < vblank->last) {
150 diff += dev->max_vblank_count + 1;
152 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
153 crtc, vblank->last, cur_vblank, diff);
156 DRM_DEBUG("updating vblank count on crtc %d, missed %d\n",
163 * Only reinitialize corresponding vblank timestamp if high-precision query
164 * available and didn't fail. Otherwise reinitialize delayed at next vblank
165 * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid.
168 t_vblank = (struct timeval) {0, 0};
170 store_vblank(dev, crtc, diff, &t_vblank);
174 * Disable vblank irq's on crtc, make sure that last vblank count
175 * of hardware and corresponding consistent software vblank counter
176 * are preserved, even if there are any spurious vblank irq's after
179 static void vblank_disable_and_save(struct drm_device *dev, int crtc)
181 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
182 unsigned long irqflags;
186 struct timeval tvblank;
187 int count = DRM_TIMESTAMP_MAXRETRIES;
189 /* Prevent vblank irq processing while disabling vblank irqs,
190 * so no updates of timestamps or count can happen after we've
191 * disabled. Needed to prevent races in case of delayed irq's.
193 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
196 * If the vblank interrupt was already disabled update the count
197 * and timestamp to maintain the appearance that the counter
198 * has been ticking all along until this time. This makes the
199 * count account for the entire time between drm_vblank_on() and
202 * But only do this if precise vblank timestamps are available.
203 * Otherwise we might read a totally bogus timestamp since drivers
204 * lacking precise timestamp support rely upon sampling the system clock
205 * at vblank interrupt time. Which obviously won't work out well if the
206 * vblank interrupt is disabled.
208 if (!vblank->enabled &&
209 drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0)) {
210 drm_update_vblank_count(dev, crtc);
211 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
216 * Only disable vblank interrupts if they're enabled. This avoids
217 * calling the ->disable_vblank() operation in atomic context with the
218 * hardware potentially runtime suspended.
220 if (vblank->enabled) {
221 dev->driver->disable_vblank(dev, crtc);
222 vblank->enabled = false;
225 /* No further vblank irq's will be processed after
226 * this point. Get current hardware vblank count and
227 * vblank timestamp, repeat until they are consistent.
229 * FIXME: There is still a race condition here and in
230 * drm_update_vblank_count() which can cause off-by-one
231 * reinitialization of software vblank counter. If gpu
232 * vblank counter doesn't increment exactly at the leading
233 * edge of a vblank interval, then we can lose 1 count if
234 * we happen to execute between start of vblank and the
235 * delayed gpu counter increment.
238 vblank->last = dev->driver->get_vblank_counter(dev, crtc);
239 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
240 } while (vblank->last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
245 /* Compute time difference to stored timestamp of last vblank
246 * as updated by last invocation of drm_handle_vblank() in vblank irq.
248 vblcount = vblank->count;
249 diff_ns = timeval_to_ns(&tvblank) -
250 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
252 /* If there is at least 1 msec difference between the last stored
253 * timestamp and tvblank, then we are currently executing our
254 * disable inside a new vblank interval, the tvblank timestamp
255 * corresponds to this new vblank interval and the irq handler
256 * for this vblank didn't run yet and won't run due to our disable.
257 * Therefore we need to do the job of drm_handle_vblank() and
258 * increment the vblank counter by one to account for this vblank.
260 * Skip this step if there isn't any high precision timestamp
261 * available. In that case we can't account for this and just
264 if (vblrc && (abs64(diff_ns) > 1000000))
265 store_vblank(dev, crtc, 1, &tvblank);
267 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
270 static void vblank_disable_fn(unsigned long arg)
272 struct drm_vblank_crtc *vblank = (void *)arg;
273 struct drm_device *dev = vblank->dev;
274 unsigned long irqflags;
275 int crtc = vblank->crtc;
277 if (!dev->vblank_disable_allowed)
280 spin_lock_irqsave(&dev->vbl_lock, irqflags);
281 if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
282 DRM_DEBUG("disabling vblank on crtc %d\n", crtc);
283 vblank_disable_and_save(dev, crtc);
285 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
289 * drm_vblank_cleanup - cleanup vblank support
292 * This function cleans up any resources allocated in drm_vblank_init.
294 void drm_vblank_cleanup(struct drm_device *dev)
298 /* Bail if the driver didn't call drm_vblank_init() */
299 if (dev->num_crtcs == 0)
302 for (crtc = 0; crtc < dev->num_crtcs; crtc++) {
303 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
305 WARN_ON(vblank->enabled &&
306 drm_core_check_feature(dev, DRIVER_MODESET));
308 del_timer_sync(&vblank->disable_timer);
315 EXPORT_SYMBOL(drm_vblank_cleanup);
318 * drm_vblank_init - initialize vblank support
320 * @num_crtcs: number of crtcs supported by @dev
322 * This function initializes vblank support for @num_crtcs display pipelines.
325 * Zero on success or a negative error code on failure.
327 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
329 int i, ret = -ENOMEM;
331 spin_lock_init(&dev->vbl_lock);
332 spin_lock_init(&dev->vblank_time_lock);
334 dev->num_crtcs = num_crtcs;
336 dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
340 for (i = 0; i < num_crtcs; i++) {
341 struct drm_vblank_crtc *vblank = &dev->vblank[i];
345 init_waitqueue_head(&vblank->queue);
346 setup_timer(&vblank->disable_timer, vblank_disable_fn,
347 (unsigned long)vblank);
350 DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
352 /* Driver specific high-precision vblank timestamping supported? */
353 if (dev->driver->get_vblank_timestamp)
354 DRM_INFO("Driver supports precise vblank timestamp query.\n");
356 DRM_INFO("No driver support for vblank timestamp query.\n");
358 /* Must have precise timestamping for reliable vblank instant disable */
359 if (dev->vblank_disable_immediate && !dev->driver->get_vblank_timestamp) {
360 dev->vblank_disable_immediate = false;
361 DRM_INFO("Setting vblank_disable_immediate to false because "
362 "get_vblank_timestamp == NULL\n");
365 dev->vblank_disable_allowed = false;
373 EXPORT_SYMBOL(drm_vblank_init);
375 static void drm_irq_vgaarb_nokms(void *cookie, bool state)
377 struct drm_device *dev = cookie;
379 if (dev->driver->vgaarb_irq) {
380 dev->driver->vgaarb_irq(dev, state);
384 if (!dev->irq_enabled)
388 if (dev->driver->irq_uninstall)
389 dev->driver->irq_uninstall(dev);
391 if (dev->driver->irq_preinstall)
392 dev->driver->irq_preinstall(dev);
393 if (dev->driver->irq_postinstall)
394 dev->driver->irq_postinstall(dev);
399 * drm_irq_install - install IRQ handler
401 * @irq: IRQ number to install the handler for
403 * Initializes the IRQ related data. Installs the handler, calling the driver
404 * irq_preinstall() and irq_postinstall() functions before and after the
407 * This is the simplified helper interface provided for drivers with no special
408 * needs. Drivers which need to install interrupt handlers for multiple
409 * interrupts must instead set drm_device->irq_enabled to signal the DRM core
410 * that vblank interrupts are available.
413 * Zero on success or a negative error code on failure.
415 int drm_irq_install(struct drm_device *dev, int irq)
418 unsigned long sh_flags = 0;
420 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
426 /* Driver must have been initialized */
427 if (!dev->dev_private)
430 if (dev->irq_enabled)
432 dev->irq_enabled = true;
434 DRM_DEBUG("irq=%d\n", irq);
436 /* Before installing handler */
437 if (dev->driver->irq_preinstall)
438 dev->driver->irq_preinstall(dev);
440 /* Install handler */
441 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
442 sh_flags = IRQF_SHARED;
444 ret = request_irq(irq, dev->driver->irq_handler,
445 sh_flags, dev->driver->name, dev);
448 dev->irq_enabled = false;
452 if (!drm_core_check_feature(dev, DRIVER_MODESET))
453 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
455 /* After installing handler */
456 if (dev->driver->irq_postinstall)
457 ret = dev->driver->irq_postinstall(dev);
460 dev->irq_enabled = false;
461 if (!drm_core_check_feature(dev, DRIVER_MODESET))
462 vga_client_register(dev->pdev, NULL, NULL, NULL);
470 EXPORT_SYMBOL(drm_irq_install);
473 * drm_irq_uninstall - uninstall the IRQ handler
476 * Calls the driver's irq_uninstall() function and unregisters the IRQ handler.
477 * This should only be called by drivers which used drm_irq_install() to set up
478 * their interrupt handler. Other drivers must only reset
479 * drm_device->irq_enabled to false.
481 * Note that for kernel modesetting drivers it is a bug if this function fails.
482 * The sanity checks are only to catch buggy user modesetting drivers which call
483 * the same function through an ioctl.
486 * Zero on success or a negative error code on failure.
488 int drm_irq_uninstall(struct drm_device *dev)
490 unsigned long irqflags;
494 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
497 irq_enabled = dev->irq_enabled;
498 dev->irq_enabled = false;
501 * Wake up any waiters so they don't hang. This is just to paper over
502 * isssues for UMS drivers which aren't in full control of their
503 * vblank/irq handling. KMS drivers must ensure that vblanks are all
504 * disabled when uninstalling the irq handler.
506 if (dev->num_crtcs) {
507 spin_lock_irqsave(&dev->vbl_lock, irqflags);
508 for (i = 0; i < dev->num_crtcs; i++) {
509 struct drm_vblank_crtc *vblank = &dev->vblank[i];
511 if (!vblank->enabled)
514 WARN_ON(drm_core_check_feature(dev, DRIVER_MODESET));
516 vblank_disable_and_save(dev, i);
517 wake_up(&vblank->queue);
519 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
525 DRM_DEBUG("irq=%d\n", dev->irq);
527 if (!drm_core_check_feature(dev, DRIVER_MODESET))
528 vga_client_register(dev->pdev, NULL, NULL, NULL);
530 if (dev->driver->irq_uninstall)
531 dev->driver->irq_uninstall(dev);
533 free_irq(dev->irq, dev);
537 EXPORT_SYMBOL(drm_irq_uninstall);
542 * \param inode device inode.
543 * \param file_priv DRM file private.
544 * \param cmd command.
545 * \param arg user argument, pointing to a drm_control structure.
546 * \return zero on success or a negative number on failure.
548 * Calls irq_install() or irq_uninstall() according to \p arg.
550 int drm_control(struct drm_device *dev, void *data,
551 struct drm_file *file_priv)
553 struct drm_control *ctl = data;
556 /* if we haven't irq we fallback for compatibility reasons -
557 * this used to be a separate function in drm_dma.h
560 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
562 if (drm_core_check_feature(dev, DRIVER_MODESET))
564 /* UMS was only ever support on pci devices. */
565 if (WARN_ON(!dev->pdev))
569 case DRM_INST_HANDLER:
570 irq = dev->pdev->irq;
572 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
575 mutex_lock(&dev->struct_mutex);
576 ret = drm_irq_install(dev, irq);
577 mutex_unlock(&dev->struct_mutex);
580 case DRM_UNINST_HANDLER:
581 mutex_lock(&dev->struct_mutex);
582 ret = drm_irq_uninstall(dev);
583 mutex_unlock(&dev->struct_mutex);
592 * drm_calc_timestamping_constants - calculate vblank timestamp constants
593 * @crtc: drm_crtc whose timestamp constants should be updated.
594 * @mode: display mode containing the scanout timings
596 * Calculate and store various constants which are later
597 * needed by vblank and swap-completion timestamping, e.g,
598 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
599 * derived from CRTC's true scanout timing, so they take
600 * things like panel scaling or other adjustments into account.
602 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
603 const struct drm_display_mode *mode)
605 int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
606 int dotclock = mode->crtc_clock;
608 /* Valid dotclock? */
610 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
613 * Convert scanline length in pixels and video
614 * dot clock to line duration, frame duration
615 * and pixel duration in nanoseconds:
617 pixeldur_ns = 1000000 / dotclock;
618 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
619 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
622 * Fields of interlaced scanout modes are only half a frame duration.
624 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
627 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
630 crtc->pixeldur_ns = pixeldur_ns;
631 crtc->linedur_ns = linedur_ns;
632 crtc->framedur_ns = framedur_ns;
634 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
635 crtc->base.id, mode->crtc_htotal,
636 mode->crtc_vtotal, mode->crtc_vdisplay);
637 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
638 crtc->base.id, dotclock, framedur_ns,
639 linedur_ns, pixeldur_ns);
641 EXPORT_SYMBOL(drm_calc_timestamping_constants);
644 * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
646 * @crtc: Which CRTC's vblank timestamp to retrieve
647 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
648 * On return contains true maximum error of timestamp
649 * @vblank_time: Pointer to struct timeval which should receive the timestamp
650 * @flags: Flags to pass to driver:
652 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
653 * @refcrtc: CRTC which defines scanout timing
654 * @mode: mode which defines the scanout timings
656 * Implements calculation of exact vblank timestamps from given drm_display_mode
657 * timings and current video scanout position of a CRTC. This can be called from
658 * within get_vblank_timestamp() implementation of a kms driver to implement the
659 * actual timestamping.
661 * Should return timestamps conforming to the OML_sync_control OpenML
662 * extension specification. The timestamp corresponds to the end of
663 * the vblank interval, aka start of scanout of topmost-leftmost display
664 * pixel in the following video frame.
666 * Requires support for optional dev->driver->get_scanout_position()
667 * in kms driver, plus a bit of setup code to provide a drm_display_mode
668 * that corresponds to the true scanout timing.
670 * The current implementation only handles standard video modes. It
671 * returns as no operation if a doublescan or interlaced video mode is
672 * active. Higher level code is expected to handle this.
675 * Negative value on error, failure or if not supported in current
678 * -EINVAL - Invalid CRTC.
679 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
680 * -ENOTSUPP - Function not supported in current display mode.
681 * -EIO - Failed, e.g., due to failed scanout position query.
683 * Returns or'ed positive status flags on success:
685 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
686 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
689 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
691 struct timeval *vblank_time,
693 const struct drm_crtc *refcrtc,
694 const struct drm_display_mode *mode)
696 struct timeval tv_etime;
697 ktime_t stime, etime;
700 int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
703 if (crtc < 0 || crtc >= dev->num_crtcs) {
704 DRM_ERROR("Invalid crtc %d\n", crtc);
708 /* Scanout position query not supported? Should not happen. */
709 if (!dev->driver->get_scanout_position) {
710 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
714 /* Durations of frames, lines, pixels in nanoseconds. */
715 framedur_ns = refcrtc->framedur_ns;
716 linedur_ns = refcrtc->linedur_ns;
717 pixeldur_ns = refcrtc->pixeldur_ns;
719 /* If mode timing undefined, just return as no-op:
720 * Happens during initial modesetting of a crtc.
722 if (framedur_ns == 0) {
723 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
727 /* Get current scanout position with system timestamp.
728 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
729 * if single query takes longer than max_error nanoseconds.
731 * This guarantees a tight bound on maximum error if
732 * code gets preempted or delayed for some reason.
734 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
736 * Get vertical and horizontal scanout position vpos, hpos,
737 * and bounding timestamps stime, etime, pre/post query.
739 vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
740 &hpos, &stime, &etime);
742 /* Return as no-op if scanout query unsupported or failed. */
743 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
744 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
749 /* Compute uncertainty in timestamp of scanout position query. */
750 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
752 /* Accept result with < max_error nsecs timing uncertainty. */
753 if (duration_ns <= *max_error)
757 /* Noisy system timing? */
758 if (i == DRM_TIMESTAMP_MAXRETRIES) {
759 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
760 crtc, duration_ns/1000, *max_error/1000, i);
763 /* Return upper bound of timestamp precision error. */
764 *max_error = duration_ns;
766 /* Check if in vblank area:
767 * vpos is >=0 in video scanout area, but negative
768 * within vblank area, counting down the number of lines until
771 invbl = vbl_status & DRM_SCANOUTPOS_IN_VBLANK;
773 /* Convert scanout position into elapsed time at raw_time query
774 * since start of scanout at first display scanline. delta_ns
775 * can be negative if start of scanout hasn't happened yet.
777 delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
779 if (!drm_timestamp_monotonic)
780 etime = ktime_mono_to_real(etime);
782 /* save this only for debugging purposes */
783 tv_etime = ktime_to_timeval(etime);
784 /* Subtract time delta from raw timestamp to get final
785 * vblank_time timestamp for end of vblank.
788 etime = ktime_add_ns(etime, -delta_ns);
790 etime = ktime_sub_ns(etime, delta_ns);
791 *vblank_time = ktime_to_timeval(etime);
793 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
794 crtc, (int)vbl_status, hpos, vpos,
795 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
796 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
797 duration_ns/1000, i);
799 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
801 vbl_status |= DRM_VBLANKTIME_IN_VBLANK;
805 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
807 static struct timeval get_drm_timestamp(void)
811 now = drm_timestamp_monotonic ? ktime_get() : ktime_get_real();
812 return ktime_to_timeval(now);
816 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
819 * @crtc: which CRTC's vblank timestamp to retrieve
820 * @tvblank: Pointer to target struct timeval which should receive the timestamp
821 * @flags: Flags to pass to driver:
823 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
825 * Fetches the system timestamp corresponding to the time of the most recent
826 * vblank interval on specified CRTC. May call into kms-driver to
827 * compute the timestamp with a high-precision GPU specific method.
829 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
830 * call, i.e., it isn't very precisely locked to the true vblank.
833 * True if timestamp is considered to be very precise, false otherwise.
836 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
837 struct timeval *tvblank, unsigned flags)
841 /* Define requested maximum error on timestamps (nanoseconds). */
842 int max_error = (int) drm_timestamp_precision * 1000;
844 /* Query driver if possible and precision timestamping enabled. */
845 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
846 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
852 /* GPU high precision timestamp query unsupported or failed.
853 * Return current monotonic/gettimeofday timestamp as best estimate.
855 *tvblank = get_drm_timestamp();
861 * drm_vblank_count - retrieve "cooked" vblank counter value
863 * @crtc: which counter to retrieve
865 * Fetches the "cooked" vblank count value that represents the number of
866 * vblank events since the system was booted, including lost events due to
867 * modesetting activity.
869 * This is the legacy version of drm_crtc_vblank_count().
872 * The software vblank counter.
874 u32 drm_vblank_count(struct drm_device *dev, int crtc)
876 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
878 if (WARN_ON(crtc >= dev->num_crtcs))
881 return vblank->count;
883 EXPORT_SYMBOL(drm_vblank_count);
886 * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
887 * @crtc: which counter to retrieve
889 * Fetches the "cooked" vblank count value that represents the number of
890 * vblank events since the system was booted, including lost events due to
891 * modesetting activity.
893 * This is the native KMS version of drm_vblank_count().
896 * The software vblank counter.
898 u32 drm_crtc_vblank_count(struct drm_crtc *crtc)
900 return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
902 EXPORT_SYMBOL(drm_crtc_vblank_count);
905 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
906 * and the system timestamp corresponding to that vblank counter value.
909 * @crtc: which counter to retrieve
910 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
912 * Fetches the "cooked" vblank count value that represents the number of
913 * vblank events since the system was booted, including lost events due to
914 * modesetting activity. Returns corresponding system timestamp of the time
915 * of the vblank interval that corresponds to the current vblank counter value.
917 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
918 struct timeval *vblanktime)
920 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
923 if (WARN_ON(crtc >= dev->num_crtcs))
927 * Vblank timestamps are read lockless. To ensure consistency the vblank
928 * counter is rechecked and ordering is ensured using memory barriers.
929 * This works like a seqlock. The write-side barriers are in store_vblank.
932 cur_vblank = vblank->count;
934 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
936 } while (cur_vblank != vblank->count);
940 EXPORT_SYMBOL(drm_vblank_count_and_time);
942 static void send_vblank_event(struct drm_device *dev,
943 struct drm_pending_vblank_event *e,
944 unsigned long seq, struct timeval *now)
946 WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
947 e->event.sequence = seq;
948 e->event.tv_sec = now->tv_sec;
949 e->event.tv_usec = now->tv_usec;
951 list_add_tail(&e->base.link,
952 &e->base.file_priv->event_list);
953 wake_up_interruptible(&e->base.file_priv->event_wait);
954 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
959 * drm_send_vblank_event - helper to send vblank event after pageflip
961 * @crtc: CRTC in question
962 * @e: the event to send
964 * Updates sequence # and timestamp on event, and sends it to userspace.
965 * Caller must hold event lock.
967 * This is the legacy version of drm_crtc_send_vblank_event().
969 void drm_send_vblank_event(struct drm_device *dev, int crtc,
970 struct drm_pending_vblank_event *e)
975 if (dev->num_crtcs > 0) {
976 seq = drm_vblank_count_and_time(dev, crtc, &now);
980 now = get_drm_timestamp();
983 send_vblank_event(dev, e, seq, &now);
985 EXPORT_SYMBOL(drm_send_vblank_event);
988 * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
989 * @crtc: the source CRTC of the vblank event
990 * @e: the event to send
992 * Updates sequence # and timestamp on event, and sends it to userspace.
993 * Caller must hold event lock.
995 * This is the native KMS version of drm_send_vblank_event().
997 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
998 struct drm_pending_vblank_event *e)
1000 drm_send_vblank_event(crtc->dev, drm_crtc_index(crtc), e);
1002 EXPORT_SYMBOL(drm_crtc_send_vblank_event);
1005 * drm_vblank_enable - enable the vblank interrupt on a CRTC
1007 * @crtc: CRTC in question
1009 static int drm_vblank_enable(struct drm_device *dev, int crtc)
1011 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1014 assert_spin_locked(&dev->vbl_lock);
1016 spin_lock(&dev->vblank_time_lock);
1018 if (!vblank->enabled) {
1020 * Enable vblank irqs under vblank_time_lock protection.
1021 * All vblank count & timestamp updates are held off
1022 * until we are done reinitializing master counter and
1023 * timestamps. Filtercode in drm_handle_vblank() will
1024 * prevent double-accounting of same vblank interval.
1026 ret = dev->driver->enable_vblank(dev, crtc);
1027 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
1029 atomic_dec(&vblank->refcount);
1031 vblank->enabled = true;
1032 drm_update_vblank_count(dev, crtc);
1036 spin_unlock(&dev->vblank_time_lock);
1042 * drm_vblank_get - get a reference count on vblank events
1044 * @crtc: which CRTC to own
1046 * Acquire a reference count on vblank events to avoid having them disabled
1049 * This is the legacy version of drm_crtc_vblank_get().
1052 * Zero on success, nonzero on failure.
1054 int drm_vblank_get(struct drm_device *dev, int crtc)
1056 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1057 unsigned long irqflags;
1060 if (!dev->num_crtcs)
1063 if (WARN_ON(crtc >= dev->num_crtcs))
1066 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1067 /* Going from 0->1 means we have to enable interrupts again */
1068 if (atomic_add_return(1, &vblank->refcount) == 1) {
1069 ret = drm_vblank_enable(dev, crtc);
1071 if (!vblank->enabled) {
1072 atomic_dec(&vblank->refcount);
1076 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1080 EXPORT_SYMBOL(drm_vblank_get);
1083 * drm_crtc_vblank_get - get a reference count on vblank events
1084 * @crtc: which CRTC to own
1086 * Acquire a reference count on vblank events to avoid having them disabled
1089 * This is the native kms version of drm_vblank_get().
1092 * Zero on success, nonzero on failure.
1094 int drm_crtc_vblank_get(struct drm_crtc *crtc)
1096 return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
1098 EXPORT_SYMBOL(drm_crtc_vblank_get);
1101 * drm_vblank_put - give up ownership of vblank events
1103 * @crtc: which counter to give up
1105 * Release ownership of a given vblank counter, turning off interrupts
1106 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1108 * This is the legacy version of drm_crtc_vblank_put().
1110 void drm_vblank_put(struct drm_device *dev, int crtc)
1112 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1114 if (WARN_ON(crtc >= dev->num_crtcs))
1117 if (WARN_ON(atomic_read(&vblank->refcount) == 0))
1120 /* Last user schedules interrupt disable */
1121 if (atomic_dec_and_test(&vblank->refcount)) {
1122 if (drm_vblank_offdelay == 0)
1124 else if (dev->vblank_disable_immediate || drm_vblank_offdelay < 0)
1125 vblank_disable_fn((unsigned long)vblank);
1127 mod_timer(&vblank->disable_timer,
1128 jiffies + ((drm_vblank_offdelay * HZ)/1000));
1131 EXPORT_SYMBOL(drm_vblank_put);
1134 * drm_crtc_vblank_put - give up ownership of vblank events
1135 * @crtc: which counter to give up
1137 * Release ownership of a given vblank counter, turning off interrupts
1138 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1140 * This is the native kms version of drm_vblank_put().
1142 void drm_crtc_vblank_put(struct drm_crtc *crtc)
1144 drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
1146 EXPORT_SYMBOL(drm_crtc_vblank_put);
1149 * drm_wait_one_vblank - wait for one vblank
1153 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
1154 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
1155 * due to lack of driver support or because the crtc is off.
1157 void drm_wait_one_vblank(struct drm_device *dev, int crtc)
1162 if (WARN_ON(crtc >= dev->num_crtcs))
1165 ret = drm_vblank_get(dev, crtc);
1166 if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", crtc, ret))
1169 last = drm_vblank_count(dev, crtc);
1171 ret = wait_event_timeout(dev->vblank[crtc].queue,
1172 last != drm_vblank_count(dev, crtc),
1173 msecs_to_jiffies(100));
1175 WARN(ret == 0, "vblank wait timed out on crtc %i\n", crtc);
1177 drm_vblank_put(dev, crtc);
1179 EXPORT_SYMBOL(drm_wait_one_vblank);
1182 * drm_crtc_wait_one_vblank - wait for one vblank
1185 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
1186 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
1187 * due to lack of driver support or because the crtc is off.
1189 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
1191 drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
1193 EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
1196 * drm_vblank_off - disable vblank events on a CRTC
1198 * @crtc: CRTC in question
1200 * Drivers can use this function to shut down the vblank interrupt handling when
1201 * disabling a crtc. This function ensures that the latest vblank frame count is
1202 * stored so that drm_vblank_on() can restore it again.
1204 * Drivers must use this function when the hardware vblank counter can get
1205 * reset, e.g. when suspending.
1207 * This is the legacy version of drm_crtc_vblank_off().
1209 void drm_vblank_off(struct drm_device *dev, int crtc)
1211 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1212 struct drm_pending_vblank_event *e, *t;
1214 unsigned long irqflags;
1217 if (WARN_ON(crtc >= dev->num_crtcs))
1220 spin_lock_irqsave(&dev->event_lock, irqflags);
1222 spin_lock(&dev->vbl_lock);
1223 vblank_disable_and_save(dev, crtc);
1224 wake_up(&vblank->queue);
1227 * Prevent subsequent drm_vblank_get() from re-enabling
1228 * the vblank interrupt by bumping the refcount.
1230 if (!vblank->inmodeset) {
1231 atomic_inc(&vblank->refcount);
1232 vblank->inmodeset = 1;
1234 spin_unlock(&dev->vbl_lock);
1236 /* Send any queued vblank events, lest the natives grow disquiet */
1237 seq = drm_vblank_count_and_time(dev, crtc, &now);
1239 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1240 if (e->pipe != crtc)
1242 DRM_DEBUG("Sending premature vblank event on disable: \
1243 wanted %d, current %d\n",
1244 e->event.sequence, seq);
1245 list_del(&e->base.link);
1246 drm_vblank_put(dev, e->pipe);
1247 send_vblank_event(dev, e, seq, &now);
1249 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1251 EXPORT_SYMBOL(drm_vblank_off);
1254 * drm_crtc_vblank_off - disable vblank events on a CRTC
1255 * @crtc: CRTC in question
1257 * Drivers can use this function to shut down the vblank interrupt handling when
1258 * disabling a crtc. This function ensures that the latest vblank frame count is
1259 * stored so that drm_vblank_on can restore it again.
1261 * Drivers must use this function when the hardware vblank counter can get
1262 * reset, e.g. when suspending.
1264 * This is the native kms version of drm_vblank_off().
1266 void drm_crtc_vblank_off(struct drm_crtc *crtc)
1268 drm_vblank_off(crtc->dev, drm_crtc_index(crtc));
1270 EXPORT_SYMBOL(drm_crtc_vblank_off);
1273 * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
1274 * @drm_crtc: CRTC in question
1276 * Drivers can use this function to reset the vblank state to off at load time.
1277 * Drivers should use this together with the drm_crtc_vblank_off() and
1278 * drm_crtc_vblank_on() functions. The difference compared to
1279 * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
1280 * and hence doesn't need to call any driver hooks.
1282 void drm_crtc_vblank_reset(struct drm_crtc *drm_crtc)
1284 struct drm_device *dev = drm_crtc->dev;
1285 unsigned long irqflags;
1286 int crtc = drm_crtc_index(drm_crtc);
1287 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1289 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1291 * Prevent subsequent drm_vblank_get() from enabling the vblank
1292 * interrupt by bumping the refcount.
1294 if (!vblank->inmodeset) {
1295 atomic_inc(&vblank->refcount);
1296 vblank->inmodeset = 1;
1298 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1300 WARN_ON(!list_empty(&dev->vblank_event_list));
1302 EXPORT_SYMBOL(drm_crtc_vblank_reset);
1305 * drm_vblank_on - enable vblank events on a CRTC
1307 * @crtc: CRTC in question
1309 * This functions restores the vblank interrupt state captured with
1310 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1311 * drm_vblank_off() can be unbalanced and so can also be unconditionally called
1312 * in driver load code to reflect the current hardware state of the crtc.
1314 * This is the legacy version of drm_crtc_vblank_on().
1316 void drm_vblank_on(struct drm_device *dev, int crtc)
1318 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1319 unsigned long irqflags;
1321 if (WARN_ON(crtc >= dev->num_crtcs))
1324 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1325 /* Drop our private "prevent drm_vblank_get" refcount */
1326 if (vblank->inmodeset) {
1327 atomic_dec(&vblank->refcount);
1328 vblank->inmodeset = 0;
1332 * sample the current counter to avoid random jumps
1333 * when drm_vblank_enable() applies the diff
1335 * -1 to make sure user will never see the same
1336 * vblank counter value before and after a modeset
1339 (dev->driver->get_vblank_counter(dev, crtc) - 1) &
1340 dev->max_vblank_count;
1342 * re-enable interrupts if there are users left, or the
1343 * user wishes vblank interrupts to be enabled all the time.
1345 if (atomic_read(&vblank->refcount) != 0 ||
1346 (!dev->vblank_disable_immediate && drm_vblank_offdelay == 0))
1347 WARN_ON(drm_vblank_enable(dev, crtc));
1348 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1350 EXPORT_SYMBOL(drm_vblank_on);
1353 * drm_crtc_vblank_on - enable vblank events on a CRTC
1354 * @crtc: CRTC in question
1356 * This functions restores the vblank interrupt state captured with
1357 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1358 * drm_vblank_off() can be unbalanced and so can also be unconditionally called
1359 * in driver load code to reflect the current hardware state of the crtc.
1361 * This is the native kms version of drm_vblank_on().
1363 void drm_crtc_vblank_on(struct drm_crtc *crtc)
1365 drm_vblank_on(crtc->dev, drm_crtc_index(crtc));
1367 EXPORT_SYMBOL(drm_crtc_vblank_on);
1370 * drm_vblank_pre_modeset - account for vblanks across mode sets
1372 * @crtc: CRTC in question
1374 * Account for vblank events across mode setting events, which will likely
1375 * reset the hardware frame counter.
1377 * This is done by grabbing a temporary vblank reference to ensure that the
1378 * vblank interrupt keeps running across the modeset sequence. With this the
1379 * software-side vblank frame counting will ensure that there are no jumps or
1382 * Unfortunately this approach is racy and also doesn't work when the vblank
1383 * interrupt stops running, e.g. across system suspend resume. It is therefore
1384 * highly recommended that drivers use the newer drm_vblank_off() and
1385 * drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when
1386 * using "cooked" software vblank frame counters and not relying on any hardware
1389 * Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc
1392 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
1394 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1396 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1397 if (!dev->num_crtcs)
1400 if (WARN_ON(crtc >= dev->num_crtcs))
1404 * To avoid all the problems that might happen if interrupts
1405 * were enabled/disabled around or between these calls, we just
1406 * have the kernel take a reference on the CRTC (just once though
1407 * to avoid corrupting the count if multiple, mismatch calls occur),
1408 * so that interrupts remain enabled in the interim.
1410 if (!vblank->inmodeset) {
1411 vblank->inmodeset = 0x1;
1412 if (drm_vblank_get(dev, crtc) == 0)
1413 vblank->inmodeset |= 0x2;
1416 EXPORT_SYMBOL(drm_vblank_pre_modeset);
1419 * drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes
1421 * @crtc: CRTC in question
1423 * This function again drops the temporary vblank reference acquired in
1424 * drm_vblank_pre_modeset.
1426 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
1428 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1429 unsigned long irqflags;
1431 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1432 if (!dev->num_crtcs)
1435 if (WARN_ON(crtc >= dev->num_crtcs))
1438 if (vblank->inmodeset) {
1439 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1440 dev->vblank_disable_allowed = true;
1441 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1443 if (vblank->inmodeset & 0x2)
1444 drm_vblank_put(dev, crtc);
1446 vblank->inmodeset = 0;
1449 EXPORT_SYMBOL(drm_vblank_post_modeset);
1452 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1453 * @DRM_IOCTL_ARGS: standard ioctl arguments
1455 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1456 * ioctls around modesetting so that any lost vblank events are accounted for.
1458 * Generally the counter will reset across mode sets. If interrupts are
1459 * enabled around this call, we don't have to do anything since the counter
1460 * will have already been incremented.
1462 int drm_modeset_ctl(struct drm_device *dev, void *data,
1463 struct drm_file *file_priv)
1465 struct drm_modeset_ctl *modeset = data;
1468 /* If drm_vblank_init() hasn't been called yet, just no-op */
1469 if (!dev->num_crtcs)
1472 /* KMS drivers handle this internally */
1473 if (drm_core_check_feature(dev, DRIVER_MODESET))
1476 crtc = modeset->crtc;
1477 if (crtc >= dev->num_crtcs)
1480 switch (modeset->cmd) {
1481 case _DRM_PRE_MODESET:
1482 drm_vblank_pre_modeset(dev, crtc);
1484 case _DRM_POST_MODESET:
1485 drm_vblank_post_modeset(dev, crtc);
1494 static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1495 union drm_wait_vblank *vblwait,
1496 struct drm_file *file_priv)
1498 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1499 struct drm_pending_vblank_event *e;
1501 unsigned long flags;
1505 e = kzalloc(sizeof(*e), GFP_KERNEL);
1512 e->base.pid = current->pid;
1513 e->event.base.type = DRM_EVENT_VBLANK;
1514 e->event.base.length = sizeof(e->event);
1515 e->event.user_data = vblwait->request.signal;
1516 e->base.event = &e->event.base;
1517 e->base.file_priv = file_priv;
1518 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
1520 spin_lock_irqsave(&dev->event_lock, flags);
1523 * drm_vblank_off() might have been called after we called
1524 * drm_vblank_get(). drm_vblank_off() holds event_lock
1525 * around the vblank disable, so no need for further locking.
1526 * The reference from drm_vblank_get() protects against
1527 * vblank disable from another source.
1529 if (!vblank->enabled) {
1534 if (file_priv->event_space < sizeof(e->event)) {
1539 file_priv->event_space -= sizeof(e->event);
1540 seq = drm_vblank_count_and_time(dev, pipe, &now);
1542 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1543 (seq - vblwait->request.sequence) <= (1 << 23)) {
1544 vblwait->request.sequence = seq + 1;
1545 vblwait->reply.sequence = vblwait->request.sequence;
1548 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1549 vblwait->request.sequence, seq, pipe);
1551 trace_drm_vblank_event_queued(current->pid, pipe,
1552 vblwait->request.sequence);
1554 e->event.sequence = vblwait->request.sequence;
1555 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1556 drm_vblank_put(dev, pipe);
1557 send_vblank_event(dev, e, seq, &now);
1558 vblwait->reply.sequence = seq;
1560 /* drm_handle_vblank_events will call drm_vblank_put */
1561 list_add_tail(&e->base.link, &dev->vblank_event_list);
1562 vblwait->reply.sequence = vblwait->request.sequence;
1565 spin_unlock_irqrestore(&dev->event_lock, flags);
1570 spin_unlock_irqrestore(&dev->event_lock, flags);
1573 drm_vblank_put(dev, pipe);
1580 * \param inode device inode.
1581 * \param file_priv DRM file private.
1582 * \param cmd command.
1583 * \param data user argument, pointing to a drm_wait_vblank structure.
1584 * \return zero on success or a negative number on failure.
1586 * This function enables the vblank interrupt on the pipe requested, then
1587 * sleeps waiting for the requested sequence number to occur, and drops
1588 * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
1589 * after a timeout with no further vblank waits scheduled).
1591 int drm_wait_vblank(struct drm_device *dev, void *data,
1592 struct drm_file *file_priv)
1594 struct drm_vblank_crtc *vblank;
1595 union drm_wait_vblank *vblwait = data;
1597 unsigned int flags, seq, crtc, high_crtc;
1599 if (!dev->irq_enabled)
1602 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1605 if (vblwait->request.type &
1606 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1607 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1608 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1609 vblwait->request.type,
1610 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1611 _DRM_VBLANK_HIGH_CRTC_MASK));
1615 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1616 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1618 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1620 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1621 if (crtc >= dev->num_crtcs)
1624 vblank = &dev->vblank[crtc];
1626 ret = drm_vblank_get(dev, crtc);
1628 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1631 seq = drm_vblank_count(dev, crtc);
1633 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1634 case _DRM_VBLANK_RELATIVE:
1635 vblwait->request.sequence += seq;
1636 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1637 case _DRM_VBLANK_ABSOLUTE:
1644 if (flags & _DRM_VBLANK_EVENT) {
1645 /* must hold on to the vblank ref until the event fires
1646 * drm_vblank_put will be called asynchronously
1648 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1651 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1652 (seq - vblwait->request.sequence) <= (1<<23)) {
1653 vblwait->request.sequence = seq + 1;
1656 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1657 vblwait->request.sequence, crtc);
1658 vblank->last_wait = vblwait->request.sequence;
1659 DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
1660 (((drm_vblank_count(dev, crtc) -
1661 vblwait->request.sequence) <= (1 << 23)) ||
1663 !dev->irq_enabled));
1665 if (ret != -EINTR) {
1668 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1669 vblwait->reply.tval_sec = now.tv_sec;
1670 vblwait->reply.tval_usec = now.tv_usec;
1672 DRM_DEBUG("returning %d to client\n",
1673 vblwait->reply.sequence);
1675 DRM_DEBUG("vblank wait interrupted by signal\n");
1679 drm_vblank_put(dev, crtc);
1683 static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1685 struct drm_pending_vblank_event *e, *t;
1689 assert_spin_locked(&dev->event_lock);
1691 seq = drm_vblank_count_and_time(dev, crtc, &now);
1693 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1694 if (e->pipe != crtc)
1696 if ((seq - e->event.sequence) > (1<<23))
1699 DRM_DEBUG("vblank event on %d, current %d\n",
1700 e->event.sequence, seq);
1702 list_del(&e->base.link);
1703 drm_vblank_put(dev, e->pipe);
1704 send_vblank_event(dev, e, seq, &now);
1707 trace_drm_vblank_event(crtc, seq);
1711 * drm_handle_vblank - handle a vblank event
1713 * @crtc: where this event occurred
1715 * Drivers should call this routine in their vblank interrupt handlers to
1716 * update the vblank counter and send any signals that may be pending.
1718 * This is the legacy version of drm_crtc_handle_vblank().
1720 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1722 struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
1725 struct timeval tvblank;
1726 unsigned long irqflags;
1728 if (WARN_ON_ONCE(!dev->num_crtcs))
1731 if (WARN_ON(crtc >= dev->num_crtcs))
1734 spin_lock_irqsave(&dev->event_lock, irqflags);
1736 /* Need timestamp lock to prevent concurrent execution with
1737 * vblank enable/disable, as this would cause inconsistent
1738 * or corrupted timestamps and vblank counts.
1740 spin_lock(&dev->vblank_time_lock);
1742 /* Vblank irq handling disabled. Nothing to do. */
1743 if (!vblank->enabled) {
1744 spin_unlock(&dev->vblank_time_lock);
1745 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1749 /* Fetch corresponding timestamp for this vblank interval from
1750 * driver and store it in proper slot of timestamp ringbuffer.
1753 /* Get current timestamp and count. */
1754 vblcount = vblank->count;
1755 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1757 /* Compute time difference to timestamp of last vblank */
1758 diff_ns = timeval_to_ns(&tvblank) -
1759 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1761 /* Update vblank timestamp and count if at least
1762 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1763 * difference between last stored timestamp and current
1764 * timestamp. A smaller difference means basically
1765 * identical timestamps. Happens if this vblank has
1766 * been already processed and this is a redundant call,
1767 * e.g., due to spurious vblank interrupts. We need to
1768 * ignore those for accounting.
1770 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS)
1771 store_vblank(dev, crtc, 1, &tvblank);
1773 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1774 crtc, (int) diff_ns);
1776 spin_unlock(&dev->vblank_time_lock);
1778 wake_up(&vblank->queue);
1779 drm_handle_vblank_events(dev, crtc);
1781 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1785 EXPORT_SYMBOL(drm_handle_vblank);
1788 * drm_crtc_handle_vblank - handle a vblank event
1789 * @crtc: where this event occurred
1791 * Drivers should call this routine in their vblank interrupt handlers to
1792 * update the vblank counter and send any signals that may be pending.
1794 * This is the native KMS version of drm_handle_vblank().
1797 * True if the event was successfully handled, false on failure.
1799 bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
1801 return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
1803 EXPORT_SYMBOL(drm_crtc_handle_vblank);