5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
6 * \author Gareth Hughes <gareth@valinux.com>
10 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
12 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14 * All Rights Reserved.
16 * Permission is hereby granted, free of charge, to any person obtaining a
17 * copy of this software and associated documentation files (the "Software"),
18 * to deal in the Software without restriction, including without limitation
19 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
20 * and/or sell copies of the Software, and to permit persons to whom the
21 * Software is furnished to do so, subject to the following conditions:
23 * The above copyright notice and this permission notice (including the next
24 * paragraph) shall be included in all copies or substantial portions of the
27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
28 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
30 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
33 * OTHER DEALINGS IN THE SOFTWARE.
37 #include "drm_trace.h"
39 #include <linux/interrupt.h> /* For task queue support */
40 #include <linux/slab.h>
42 #include <linux/vgaarb.h>
43 #include <linux/export.h>
45 /* Access macro for slots in vblank timestamp ringbuffer. */
46 #define vblanktimestamp(dev, crtc, count) \
47 ((dev)->vblank[crtc].time[(count) % DRM_VBLANKTIME_RBSIZE])
49 /* Retry timestamp calculation up to 3 times to satisfy
50 * drm_timestamp_precision before giving up.
52 #define DRM_TIMESTAMP_MAXRETRIES 3
54 /* Threshold in nanoseconds for detection of redundant
55 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
57 #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
60 * Get interrupt from bus id.
62 * \param inode device inode.
63 * \param file_priv DRM file private.
65 * \param arg user argument, pointing to a drm_irq_busid structure.
66 * \return zero on success or a negative number on failure.
68 * Finds the PCI device with the specified bus id and gets its IRQ number.
69 * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
70 * to that of the device that this DRM instance attached to.
72 int drm_irq_by_busid(struct drm_device *dev, void *data,
73 struct drm_file *file_priv)
75 struct drm_irq_busid *p = data;
77 if (!dev->driver->bus->irq_by_busid)
80 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
83 return dev->driver->bus->irq_by_busid(dev, p);
87 * Clear vblank timestamp buffer for a crtc.
89 static void clear_vblank_timestamps(struct drm_device *dev, int crtc)
91 memset(dev->vblank[crtc].time, 0, sizeof(dev->vblank[crtc].time));
95 * Disable vblank irq's on crtc, make sure that last vblank count
96 * of hardware and corresponding consistent software vblank counter
97 * are preserved, even if there are any spurious vblank irq's after
100 static void vblank_disable_and_save(struct drm_device *dev, int crtc)
102 unsigned long irqflags;
106 struct timeval tvblank;
107 int count = DRM_TIMESTAMP_MAXRETRIES;
109 /* Prevent vblank irq processing while disabling vblank irqs,
110 * so no updates of timestamps or count can happen after we've
111 * disabled. Needed to prevent races in case of delayed irq's.
113 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
115 dev->driver->disable_vblank(dev, crtc);
116 dev->vblank[crtc].enabled = false;
118 /* No further vblank irq's will be processed after
119 * this point. Get current hardware vblank count and
120 * vblank timestamp, repeat until they are consistent.
122 * FIXME: There is still a race condition here and in
123 * drm_update_vblank_count() which can cause off-by-one
124 * reinitialization of software vblank counter. If gpu
125 * vblank counter doesn't increment exactly at the leading
126 * edge of a vblank interval, then we can lose 1 count if
127 * we happen to execute between start of vblank and the
128 * delayed gpu counter increment.
131 dev->vblank[crtc].last = dev->driver->get_vblank_counter(dev, crtc);
132 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
133 } while (dev->vblank[crtc].last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
138 /* Compute time difference to stored timestamp of last vblank
139 * as updated by last invocation of drm_handle_vblank() in vblank irq.
141 vblcount = atomic_read(&dev->vblank[crtc].count);
142 diff_ns = timeval_to_ns(&tvblank) -
143 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
145 /* If there is at least 1 msec difference between the last stored
146 * timestamp and tvblank, then we are currently executing our
147 * disable inside a new vblank interval, the tvblank timestamp
148 * corresponds to this new vblank interval and the irq handler
149 * for this vblank didn't run yet and won't run due to our disable.
150 * Therefore we need to do the job of drm_handle_vblank() and
151 * increment the vblank counter by one to account for this vblank.
153 * Skip this step if there isn't any high precision timestamp
154 * available. In that case we can't account for this and just
157 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
158 atomic_inc(&dev->vblank[crtc].count);
159 smp_mb__after_atomic_inc();
162 /* Invalidate all timestamps while vblank irq's are off. */
163 clear_vblank_timestamps(dev, crtc);
165 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
168 static void vblank_disable_fn(unsigned long arg)
170 struct drm_device *dev = (struct drm_device *)arg;
171 unsigned long irqflags;
174 if (!dev->vblank_disable_allowed)
177 for (i = 0; i < dev->num_crtcs; i++) {
178 spin_lock_irqsave(&dev->vbl_lock, irqflags);
179 if (atomic_read(&dev->vblank[i].refcount) == 0 &&
180 dev->vblank[i].enabled) {
181 DRM_DEBUG("disabling vblank on crtc %d\n", i);
182 vblank_disable_and_save(dev, i);
184 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
188 void drm_vblank_cleanup(struct drm_device *dev)
190 /* Bail if the driver didn't call drm_vblank_init() */
191 if (dev->num_crtcs == 0)
194 del_timer_sync(&dev->vblank_disable_timer);
196 vblank_disable_fn((unsigned long)dev);
202 EXPORT_SYMBOL(drm_vblank_cleanup);
204 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
206 int i, ret = -ENOMEM;
208 setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
210 spin_lock_init(&dev->vbl_lock);
211 spin_lock_init(&dev->vblank_time_lock);
213 dev->num_crtcs = num_crtcs;
215 dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
219 for (i = 0; i < num_crtcs; i++)
220 init_waitqueue_head(&dev->vblank[i].queue);
222 DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
224 /* Driver specific high-precision vblank timestamping supported? */
225 if (dev->driver->get_vblank_timestamp)
226 DRM_INFO("Driver supports precise vblank timestamp query.\n");
228 DRM_INFO("No driver support for vblank timestamp query.\n");
230 dev->vblank_disable_allowed = false;
235 drm_vblank_cleanup(dev);
238 EXPORT_SYMBOL(drm_vblank_init);
240 static void drm_irq_vgaarb_nokms(void *cookie, bool state)
242 struct drm_device *dev = cookie;
244 if (dev->driver->vgaarb_irq) {
245 dev->driver->vgaarb_irq(dev, state);
249 if (!dev->irq_enabled)
253 if (dev->driver->irq_uninstall)
254 dev->driver->irq_uninstall(dev);
256 if (dev->driver->irq_preinstall)
257 dev->driver->irq_preinstall(dev);
258 if (dev->driver->irq_postinstall)
259 dev->driver->irq_postinstall(dev);
264 * Install IRQ handler.
266 * \param dev DRM device.
268 * Initializes the IRQ related data. Installs the handler, calling the driver
269 * \c irq_preinstall() and \c irq_postinstall() functions
270 * before and after the installation.
272 int drm_irq_install(struct drm_device *dev)
275 unsigned long sh_flags = 0;
277 irq = drm_dev_to_irq(dev);
279 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
285 mutex_lock(&dev->struct_mutex);
287 /* Driver must have been initialized */
288 if (!dev->dev_private) {
289 mutex_unlock(&dev->struct_mutex);
293 if (dev->irq_enabled) {
294 mutex_unlock(&dev->struct_mutex);
297 dev->irq_enabled = true;
298 mutex_unlock(&dev->struct_mutex);
300 DRM_DEBUG("irq=%d\n", irq);
302 /* Before installing handler */
303 if (dev->driver->irq_preinstall)
304 dev->driver->irq_preinstall(dev);
306 /* Install handler */
307 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
308 sh_flags = IRQF_SHARED;
310 ret = request_irq(irq, dev->driver->irq_handler,
311 sh_flags, dev->driver->name, dev);
314 mutex_lock(&dev->struct_mutex);
315 dev->irq_enabled = false;
316 mutex_unlock(&dev->struct_mutex);
320 if (!drm_core_check_feature(dev, DRIVER_MODESET))
321 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
323 /* After installing handler */
324 if (dev->driver->irq_postinstall)
325 ret = dev->driver->irq_postinstall(dev);
328 mutex_lock(&dev->struct_mutex);
329 dev->irq_enabled = false;
330 mutex_unlock(&dev->struct_mutex);
331 if (!drm_core_check_feature(dev, DRIVER_MODESET))
332 vga_client_register(dev->pdev, NULL, NULL, NULL);
340 EXPORT_SYMBOL(drm_irq_install);
343 * Uninstall the IRQ handler.
345 * \param dev DRM device.
347 * Calls the driver's \c irq_uninstall() function, and stops the irq.
349 int drm_irq_uninstall(struct drm_device *dev)
351 unsigned long irqflags;
355 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
358 mutex_lock(&dev->struct_mutex);
359 irq_enabled = dev->irq_enabled;
360 dev->irq_enabled = false;
361 mutex_unlock(&dev->struct_mutex);
364 * Wake up any waiters so they don't hang.
366 if (dev->num_crtcs) {
367 spin_lock_irqsave(&dev->vbl_lock, irqflags);
368 for (i = 0; i < dev->num_crtcs; i++) {
369 wake_up(&dev->vblank[i].queue);
370 dev->vblank[i].enabled = false;
371 dev->vblank[i].last =
372 dev->driver->get_vblank_counter(dev, i);
374 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
380 DRM_DEBUG("irq=%d\n", dev->irq);
382 if (!drm_core_check_feature(dev, DRIVER_MODESET))
383 vga_client_register(dev->pdev, NULL, NULL, NULL);
385 if (dev->driver->irq_uninstall)
386 dev->driver->irq_uninstall(dev);
388 free_irq(dev->irq, dev);
392 EXPORT_SYMBOL(drm_irq_uninstall);
397 * \param inode device inode.
398 * \param file_priv DRM file private.
399 * \param cmd command.
400 * \param arg user argument, pointing to a drm_control structure.
401 * \return zero on success or a negative number on failure.
403 * Calls irq_install() or irq_uninstall() according to \p arg.
405 int drm_control(struct drm_device *dev, void *data,
406 struct drm_file *file_priv)
408 struct drm_control *ctl = data;
410 /* if we haven't irq we fallback for compatibility reasons -
411 * this used to be a separate function in drm_dma.h
416 case DRM_INST_HANDLER:
417 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
419 if (drm_core_check_feature(dev, DRIVER_MODESET))
421 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
422 ctl->irq != drm_dev_to_irq(dev))
424 return drm_irq_install(dev);
425 case DRM_UNINST_HANDLER:
426 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
428 if (drm_core_check_feature(dev, DRIVER_MODESET))
430 return drm_irq_uninstall(dev);
437 * drm_calc_timestamping_constants - Calculate vblank timestamp constants
439 * @crtc drm_crtc whose timestamp constants should be updated.
440 * @mode display mode containing the scanout timings
442 * Calculate and store various constants which are later
443 * needed by vblank and swap-completion timestamping, e.g,
444 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
445 * derived from crtc's true scanout timing, so they take
446 * things like panel scaling or other adjustments into account.
448 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
449 const struct drm_display_mode *mode)
451 int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
452 int dotclock = mode->crtc_clock;
454 /* Valid dotclock? */
456 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
459 * Convert scanline length in pixels and video
460 * dot clock to line duration, frame duration
461 * and pixel duration in nanoseconds:
463 pixeldur_ns = 1000000 / dotclock;
464 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
465 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
468 * Fields of interlaced scanout modes are only half a frame duration.
470 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
473 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
476 crtc->pixeldur_ns = pixeldur_ns;
477 crtc->linedur_ns = linedur_ns;
478 crtc->framedur_ns = framedur_ns;
480 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
481 crtc->base.id, mode->crtc_htotal,
482 mode->crtc_vtotal, mode->crtc_vdisplay);
483 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
484 crtc->base.id, dotclock, framedur_ns,
485 linedur_ns, pixeldur_ns);
487 EXPORT_SYMBOL(drm_calc_timestamping_constants);
490 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
491 * drivers. Implements calculation of exact vblank timestamps from
492 * given drm_display_mode timings and current video scanout position
493 * of a crtc. This can be called from within get_vblank_timestamp()
494 * implementation of a kms driver to implement the actual timestamping.
496 * Should return timestamps conforming to the OML_sync_control OpenML
497 * extension specification. The timestamp corresponds to the end of
498 * the vblank interval, aka start of scanout of topmost-leftmost display
499 * pixel in the following video frame.
501 * Requires support for optional dev->driver->get_scanout_position()
502 * in kms driver, plus a bit of setup code to provide a drm_display_mode
503 * that corresponds to the true scanout timing.
505 * The current implementation only handles standard video modes. It
506 * returns as no operation if a doublescan or interlaced video mode is
507 * active. Higher level code is expected to handle this.
510 * @crtc: Which crtc's vblank timestamp to retrieve.
511 * @max_error: Desired maximum allowable error in timestamps (nanosecs).
512 * On return contains true maximum error of timestamp.
513 * @vblank_time: Pointer to struct timeval which should receive the timestamp.
514 * @flags: Flags to pass to driver:
516 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
517 * @refcrtc: drm_crtc* of crtc which defines scanout timing.
518 * @mode: mode which defines the scanout timings
520 * Returns negative value on error, failure or if not supported in current
523 * -EINVAL - Invalid crtc.
524 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
525 * -ENOTSUPP - Function not supported in current display mode.
526 * -EIO - Failed, e.g., due to failed scanout position query.
528 * Returns or'ed positive status flags on success:
530 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
531 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
534 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
536 struct timeval *vblank_time,
538 const struct drm_crtc *refcrtc,
539 const struct drm_display_mode *mode)
541 ktime_t stime, etime, mono_time_offset;
542 struct timeval tv_etime;
545 int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
548 if (crtc < 0 || crtc >= dev->num_crtcs) {
549 DRM_ERROR("Invalid crtc %d\n", crtc);
553 /* Scanout position query not supported? Should not happen. */
554 if (!dev->driver->get_scanout_position) {
555 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
559 /* Durations of frames, lines, pixels in nanoseconds. */
560 framedur_ns = refcrtc->framedur_ns;
561 linedur_ns = refcrtc->linedur_ns;
562 pixeldur_ns = refcrtc->pixeldur_ns;
564 /* If mode timing undefined, just return as no-op:
565 * Happens during initial modesetting of a crtc.
567 if (framedur_ns == 0) {
568 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
572 /* Get current scanout position with system timestamp.
573 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
574 * if single query takes longer than max_error nanoseconds.
576 * This guarantees a tight bound on maximum error if
577 * code gets preempted or delayed for some reason.
579 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
581 * Get vertical and horizontal scanout position vpos, hpos,
582 * and bounding timestamps stime, etime, pre/post query.
584 vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
585 &hpos, &stime, &etime);
588 * Get correction for CLOCK_MONOTONIC -> CLOCK_REALTIME if
589 * CLOCK_REALTIME is requested.
591 if (!drm_timestamp_monotonic)
592 mono_time_offset = ktime_get_monotonic_offset();
594 /* Return as no-op if scanout query unsupported or failed. */
595 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
596 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
601 /* Compute uncertainty in timestamp of scanout position query. */
602 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
604 /* Accept result with < max_error nsecs timing uncertainty. */
605 if (duration_ns <= *max_error)
609 /* Noisy system timing? */
610 if (i == DRM_TIMESTAMP_MAXRETRIES) {
611 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
612 crtc, duration_ns/1000, *max_error/1000, i);
615 /* Return upper bound of timestamp precision error. */
616 *max_error = duration_ns;
618 /* Check if in vblank area:
619 * vpos is >=0 in video scanout area, but negative
620 * within vblank area, counting down the number of lines until
623 invbl = vbl_status & DRM_SCANOUTPOS_INVBL;
625 /* Convert scanout position into elapsed time at raw_time query
626 * since start of scanout at first display scanline. delta_ns
627 * can be negative if start of scanout hasn't happened yet.
629 delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
631 if (!drm_timestamp_monotonic)
632 etime = ktime_sub(etime, mono_time_offset);
634 /* save this only for debugging purposes */
635 tv_etime = ktime_to_timeval(etime);
636 /* Subtract time delta from raw timestamp to get final
637 * vblank_time timestamp for end of vblank.
640 etime = ktime_add_ns(etime, -delta_ns);
642 etime = ktime_sub_ns(etime, delta_ns);
643 *vblank_time = ktime_to_timeval(etime);
645 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
646 crtc, (int)vbl_status, hpos, vpos,
647 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
648 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
649 duration_ns/1000, i);
651 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
653 vbl_status |= DRM_VBLANKTIME_INVBL;
657 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
659 static struct timeval get_drm_timestamp(void)
664 if (!drm_timestamp_monotonic)
665 now = ktime_sub(now, ktime_get_monotonic_offset());
667 return ktime_to_timeval(now);
671 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
675 * @crtc: which crtc's vblank timestamp to retrieve
676 * @tvblank: Pointer to target struct timeval which should receive the timestamp
677 * @flags: Flags to pass to driver:
679 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
681 * Fetches the system timestamp corresponding to the time of the most recent
682 * vblank interval on specified crtc. May call into kms-driver to
683 * compute the timestamp with a high-precision GPU specific method.
685 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
686 * call, i.e., it isn't very precisely locked to the true vblank.
688 * Returns non-zero if timestamp is considered to be very precise.
690 u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
691 struct timeval *tvblank, unsigned flags)
695 /* Define requested maximum error on timestamps (nanoseconds). */
696 int max_error = (int) drm_timestamp_precision * 1000;
698 /* Query driver if possible and precision timestamping enabled. */
699 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
700 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
706 /* GPU high precision timestamp query unsupported or failed.
707 * Return current monotonic/gettimeofday timestamp as best estimate.
709 *tvblank = get_drm_timestamp();
713 EXPORT_SYMBOL(drm_get_last_vbltimestamp);
716 * drm_vblank_count - retrieve "cooked" vblank counter value
718 * @crtc: which counter to retrieve
720 * Fetches the "cooked" vblank count value that represents the number of
721 * vblank events since the system was booted, including lost events due to
722 * modesetting activity.
724 u32 drm_vblank_count(struct drm_device *dev, int crtc)
726 return atomic_read(&dev->vblank[crtc].count);
728 EXPORT_SYMBOL(drm_vblank_count);
731 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
732 * and the system timestamp corresponding to that vblank counter value.
735 * @crtc: which counter to retrieve
736 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
738 * Fetches the "cooked" vblank count value that represents the number of
739 * vblank events since the system was booted, including lost events due to
740 * modesetting activity. Returns corresponding system timestamp of the time
741 * of the vblank interval that corresponds to the current value vblank counter
744 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
745 struct timeval *vblanktime)
749 /* Read timestamp from slot of _vblank_time ringbuffer
750 * that corresponds to current vblank count. Retry if
751 * count has incremented during readout. This works like
755 cur_vblank = atomic_read(&dev->vblank[crtc].count);
756 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
758 } while (cur_vblank != atomic_read(&dev->vblank[crtc].count));
762 EXPORT_SYMBOL(drm_vblank_count_and_time);
764 static void send_vblank_event(struct drm_device *dev,
765 struct drm_pending_vblank_event *e,
766 unsigned long seq, struct timeval *now)
768 WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
769 e->event.sequence = seq;
770 e->event.tv_sec = now->tv_sec;
771 e->event.tv_usec = now->tv_usec;
773 list_add_tail(&e->base.link,
774 &e->base.file_priv->event_list);
775 wake_up_interruptible(&e->base.file_priv->event_wait);
776 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
781 * drm_send_vblank_event - helper to send vblank event after pageflip
783 * @crtc: CRTC in question
784 * @e: the event to send
786 * Updates sequence # and timestamp on event, and sends it to userspace.
787 * Caller must hold event lock.
789 void drm_send_vblank_event(struct drm_device *dev, int crtc,
790 struct drm_pending_vblank_event *e)
795 seq = drm_vblank_count_and_time(dev, crtc, &now);
799 now = get_drm_timestamp();
802 send_vblank_event(dev, e, seq, &now);
804 EXPORT_SYMBOL(drm_send_vblank_event);
807 * drm_update_vblank_count - update the master vblank counter
809 * @crtc: counter to update
811 * Call back into the driver to update the appropriate vblank counter
812 * (specified by @crtc). Deal with wraparound, if it occurred, and
813 * update the last read value so we can deal with wraparound on the next
816 * Only necessary when going from off->on, to account for frames we
817 * didn't get an interrupt for.
819 * Note: caller must hold dev->vbl_lock since this reads & writes
820 * device vblank fields.
822 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
824 u32 cur_vblank, diff, tslot, rc;
825 struct timeval t_vblank;
828 * Interrupts were disabled prior to this call, so deal with counter
830 * NOTE! It's possible we lost a full dev->max_vblank_count events
831 * here if the register is small or we had vblank interrupts off for
834 * We repeat the hardware vblank counter & timestamp query until
835 * we get consistent results. This to prevent races between gpu
836 * updating its hardware counter while we are retrieving the
837 * corresponding vblank timestamp.
840 cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
841 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
842 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
844 /* Deal with counter wrap */
845 diff = cur_vblank - dev->vblank[crtc].last;
846 if (cur_vblank < dev->vblank[crtc].last) {
847 diff += dev->max_vblank_count;
849 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
850 crtc, dev->vblank[crtc].last, cur_vblank, diff);
853 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
856 /* Reinitialize corresponding vblank timestamp if high-precision query
857 * available. Skip this step if query unsupported or failed. Will
858 * reinitialize delayed at next vblank interrupt in that case.
861 tslot = atomic_read(&dev->vblank[crtc].count) + diff;
862 vblanktimestamp(dev, crtc, tslot) = t_vblank;
865 smp_mb__before_atomic_inc();
866 atomic_add(diff, &dev->vblank[crtc].count);
867 smp_mb__after_atomic_inc();
871 * drm_vblank_get - get a reference count on vblank events
873 * @crtc: which CRTC to own
875 * Acquire a reference count on vblank events to avoid having them disabled
879 * Zero on success, nonzero on failure.
881 int drm_vblank_get(struct drm_device *dev, int crtc)
883 unsigned long irqflags, irqflags2;
886 spin_lock_irqsave(&dev->vbl_lock, irqflags);
887 /* Going from 0->1 means we have to enable interrupts again */
888 if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) {
889 spin_lock_irqsave(&dev->vblank_time_lock, irqflags2);
890 if (!dev->vblank[crtc].enabled) {
891 /* Enable vblank irqs under vblank_time_lock protection.
892 * All vblank count & timestamp updates are held off
893 * until we are done reinitializing master counter and
894 * timestamps. Filtercode in drm_handle_vblank() will
895 * prevent double-accounting of same vblank interval.
897 ret = dev->driver->enable_vblank(dev, crtc);
898 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n",
901 atomic_dec(&dev->vblank[crtc].refcount);
903 dev->vblank[crtc].enabled = true;
904 drm_update_vblank_count(dev, crtc);
907 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2);
909 if (!dev->vblank[crtc].enabled) {
910 atomic_dec(&dev->vblank[crtc].refcount);
914 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
918 EXPORT_SYMBOL(drm_vblank_get);
921 * drm_vblank_put - give up ownership of vblank events
923 * @crtc: which counter to give up
925 * Release ownership of a given vblank counter, turning off interrupts
926 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
928 void drm_vblank_put(struct drm_device *dev, int crtc)
930 BUG_ON(atomic_read(&dev->vblank[crtc].refcount) == 0);
932 /* Last user schedules interrupt disable */
933 if (atomic_dec_and_test(&dev->vblank[crtc].refcount) &&
934 (drm_vblank_offdelay > 0))
935 mod_timer(&dev->vblank_disable_timer,
936 jiffies + ((drm_vblank_offdelay * HZ)/1000));
938 EXPORT_SYMBOL(drm_vblank_put);
941 * drm_vblank_off - disable vblank events on a CRTC
943 * @crtc: CRTC in question
945 * Caller must hold event lock.
947 void drm_vblank_off(struct drm_device *dev, int crtc)
949 struct drm_pending_vblank_event *e, *t;
951 unsigned long irqflags;
954 spin_lock_irqsave(&dev->vbl_lock, irqflags);
955 vblank_disable_and_save(dev, crtc);
956 wake_up(&dev->vblank[crtc].queue);
958 /* Send any queued vblank events, lest the natives grow disquiet */
959 seq = drm_vblank_count_and_time(dev, crtc, &now);
961 spin_lock(&dev->event_lock);
962 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
965 DRM_DEBUG("Sending premature vblank event on disable: \
966 wanted %d, current %d\n",
967 e->event.sequence, seq);
968 list_del(&e->base.link);
969 drm_vblank_put(dev, e->pipe);
970 send_vblank_event(dev, e, seq, &now);
972 spin_unlock(&dev->event_lock);
974 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
976 EXPORT_SYMBOL(drm_vblank_off);
979 * drm_vblank_pre_modeset - account for vblanks across mode sets
981 * @crtc: CRTC in question
983 * Account for vblank events across mode setting events, which will likely
984 * reset the hardware frame counter.
986 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
988 /* vblank is not initialized (IRQ not installed ?), or has been freed */
992 * To avoid all the problems that might happen if interrupts
993 * were enabled/disabled around or between these calls, we just
994 * have the kernel take a reference on the CRTC (just once though
995 * to avoid corrupting the count if multiple, mismatch calls occur),
996 * so that interrupts remain enabled in the interim.
998 if (!dev->vblank[crtc].inmodeset) {
999 dev->vblank[crtc].inmodeset = 0x1;
1000 if (drm_vblank_get(dev, crtc) == 0)
1001 dev->vblank[crtc].inmodeset |= 0x2;
1004 EXPORT_SYMBOL(drm_vblank_pre_modeset);
1006 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
1008 unsigned long irqflags;
1010 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1011 if (!dev->num_crtcs)
1014 if (dev->vblank[crtc].inmodeset) {
1015 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1016 dev->vblank_disable_allowed = true;
1017 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1019 if (dev->vblank[crtc].inmodeset & 0x2)
1020 drm_vblank_put(dev, crtc);
1022 dev->vblank[crtc].inmodeset = 0;
1025 EXPORT_SYMBOL(drm_vblank_post_modeset);
1028 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1029 * @DRM_IOCTL_ARGS: standard ioctl arguments
1031 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1032 * ioctls around modesetting so that any lost vblank events are accounted for.
1034 * Generally the counter will reset across mode sets. If interrupts are
1035 * enabled around this call, we don't have to do anything since the counter
1036 * will have already been incremented.
1038 int drm_modeset_ctl(struct drm_device *dev, void *data,
1039 struct drm_file *file_priv)
1041 struct drm_modeset_ctl *modeset = data;
1044 /* If drm_vblank_init() hasn't been called yet, just no-op */
1045 if (!dev->num_crtcs)
1048 /* KMS drivers handle this internally */
1049 if (drm_core_check_feature(dev, DRIVER_MODESET))
1052 crtc = modeset->crtc;
1053 if (crtc >= dev->num_crtcs)
1056 switch (modeset->cmd) {
1057 case _DRM_PRE_MODESET:
1058 drm_vblank_pre_modeset(dev, crtc);
1060 case _DRM_POST_MODESET:
1061 drm_vblank_post_modeset(dev, crtc);
1070 static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1071 union drm_wait_vblank *vblwait,
1072 struct drm_file *file_priv)
1074 struct drm_pending_vblank_event *e;
1076 unsigned long flags;
1080 e = kzalloc(sizeof *e, GFP_KERNEL);
1087 e->base.pid = current->pid;
1088 e->event.base.type = DRM_EVENT_VBLANK;
1089 e->event.base.length = sizeof e->event;
1090 e->event.user_data = vblwait->request.signal;
1091 e->base.event = &e->event.base;
1092 e->base.file_priv = file_priv;
1093 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
1095 spin_lock_irqsave(&dev->event_lock, flags);
1097 if (file_priv->event_space < sizeof e->event) {
1102 file_priv->event_space -= sizeof e->event;
1103 seq = drm_vblank_count_and_time(dev, pipe, &now);
1105 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1106 (seq - vblwait->request.sequence) <= (1 << 23)) {
1107 vblwait->request.sequence = seq + 1;
1108 vblwait->reply.sequence = vblwait->request.sequence;
1111 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1112 vblwait->request.sequence, seq, pipe);
1114 trace_drm_vblank_event_queued(current->pid, pipe,
1115 vblwait->request.sequence);
1117 e->event.sequence = vblwait->request.sequence;
1118 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1119 drm_vblank_put(dev, pipe);
1120 send_vblank_event(dev, e, seq, &now);
1121 vblwait->reply.sequence = seq;
1123 /* drm_handle_vblank_events will call drm_vblank_put */
1124 list_add_tail(&e->base.link, &dev->vblank_event_list);
1125 vblwait->reply.sequence = vblwait->request.sequence;
1128 spin_unlock_irqrestore(&dev->event_lock, flags);
1133 spin_unlock_irqrestore(&dev->event_lock, flags);
1136 drm_vblank_put(dev, pipe);
1143 * \param inode device inode.
1144 * \param file_priv DRM file private.
1145 * \param cmd command.
1146 * \param data user argument, pointing to a drm_wait_vblank structure.
1147 * \return zero on success or a negative number on failure.
1149 * This function enables the vblank interrupt on the pipe requested, then
1150 * sleeps waiting for the requested sequence number to occur, and drops
1151 * the vblank interrupt refcount afterwards. (vblank irq disable follows that
1152 * after a timeout with no further vblank waits scheduled).
1154 int drm_wait_vblank(struct drm_device *dev, void *data,
1155 struct drm_file *file_priv)
1157 union drm_wait_vblank *vblwait = data;
1159 unsigned int flags, seq, crtc, high_crtc;
1161 if (drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
1162 if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled))
1165 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1168 if (vblwait->request.type &
1169 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1170 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1171 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1172 vblwait->request.type,
1173 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1174 _DRM_VBLANK_HIGH_CRTC_MASK));
1178 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1179 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1181 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1183 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1184 if (crtc >= dev->num_crtcs)
1187 ret = drm_vblank_get(dev, crtc);
1189 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1192 seq = drm_vblank_count(dev, crtc);
1194 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1195 case _DRM_VBLANK_RELATIVE:
1196 vblwait->request.sequence += seq;
1197 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1198 case _DRM_VBLANK_ABSOLUTE:
1205 if (flags & _DRM_VBLANK_EVENT) {
1206 /* must hold on to the vblank ref until the event fires
1207 * drm_vblank_put will be called asynchronously
1209 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1212 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1213 (seq - vblwait->request.sequence) <= (1<<23)) {
1214 vblwait->request.sequence = seq + 1;
1217 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1218 vblwait->request.sequence, crtc);
1219 dev->vblank[crtc].last_wait = vblwait->request.sequence;
1220 DRM_WAIT_ON(ret, dev->vblank[crtc].queue, 3 * HZ,
1221 (((drm_vblank_count(dev, crtc) -
1222 vblwait->request.sequence) <= (1 << 23)) ||
1223 !dev->irq_enabled));
1225 if (ret != -EINTR) {
1228 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1229 vblwait->reply.tval_sec = now.tv_sec;
1230 vblwait->reply.tval_usec = now.tv_usec;
1232 DRM_DEBUG("returning %d to client\n",
1233 vblwait->reply.sequence);
1235 DRM_DEBUG("vblank wait interrupted by signal\n");
1239 drm_vblank_put(dev, crtc);
1243 static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1245 struct drm_pending_vblank_event *e, *t;
1247 unsigned long flags;
1250 seq = drm_vblank_count_and_time(dev, crtc, &now);
1252 spin_lock_irqsave(&dev->event_lock, flags);
1254 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1255 if (e->pipe != crtc)
1257 if ((seq - e->event.sequence) > (1<<23))
1260 DRM_DEBUG("vblank event on %d, current %d\n",
1261 e->event.sequence, seq);
1263 list_del(&e->base.link);
1264 drm_vblank_put(dev, e->pipe);
1265 send_vblank_event(dev, e, seq, &now);
1268 spin_unlock_irqrestore(&dev->event_lock, flags);
1270 trace_drm_vblank_event(crtc, seq);
1274 * drm_handle_vblank - handle a vblank event
1276 * @crtc: where this event occurred
1278 * Drivers should call this routine in their vblank interrupt handlers to
1279 * update the vblank counter and send any signals that may be pending.
1281 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1285 struct timeval tvblank;
1286 unsigned long irqflags;
1288 if (!dev->num_crtcs)
1291 /* Need timestamp lock to prevent concurrent execution with
1292 * vblank enable/disable, as this would cause inconsistent
1293 * or corrupted timestamps and vblank counts.
1295 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
1297 /* Vblank irq handling disabled. Nothing to do. */
1298 if (!dev->vblank[crtc].enabled) {
1299 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1303 /* Fetch corresponding timestamp for this vblank interval from
1304 * driver and store it in proper slot of timestamp ringbuffer.
1307 /* Get current timestamp and count. */
1308 vblcount = atomic_read(&dev->vblank[crtc].count);
1309 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1311 /* Compute time difference to timestamp of last vblank */
1312 diff_ns = timeval_to_ns(&tvblank) -
1313 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1315 /* Update vblank timestamp and count if at least
1316 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1317 * difference between last stored timestamp and current
1318 * timestamp. A smaller difference means basically
1319 * identical timestamps. Happens if this vblank has
1320 * been already processed and this is a redundant call,
1321 * e.g., due to spurious vblank interrupts. We need to
1322 * ignore those for accounting.
1324 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1325 /* Store new timestamp in ringbuffer. */
1326 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1328 /* Increment cooked vblank count. This also atomically commits
1329 * the timestamp computed above.
1331 smp_mb__before_atomic_inc();
1332 atomic_inc(&dev->vblank[crtc].count);
1333 smp_mb__after_atomic_inc();
1335 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1336 crtc, (int) diff_ns);
1339 wake_up(&dev->vblank[crtc].queue);
1340 drm_handle_vblank_events(dev, crtc);
1342 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1345 EXPORT_SYMBOL(drm_handle_vblank);