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_time[(crtc) * DRM_VBLANKTIME_RBSIZE + \
48 ((count) % DRM_VBLANKTIME_RBSIZE)])
50 /* Retry timestamp calculation up to 3 times to satisfy
51 * drm_timestamp_precision before giving up.
53 #define DRM_TIMESTAMP_MAXRETRIES 3
55 /* Threshold in nanoseconds for detection of redundant
56 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
58 #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
61 * Get interrupt from bus id.
63 * \param inode device inode.
64 * \param file_priv DRM file private.
66 * \param arg user argument, pointing to a drm_irq_busid structure.
67 * \return zero on success or a negative number on failure.
69 * Finds the PCI device with the specified bus id and gets its IRQ number.
70 * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
71 * to that of the device that this DRM instance attached to.
73 int drm_irq_by_busid(struct drm_device *dev, void *data,
74 struct drm_file *file_priv)
76 struct drm_irq_busid *p = data;
78 if (!dev->driver->bus->irq_by_busid)
81 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
84 return dev->driver->bus->irq_by_busid(dev, p);
88 * Clear vblank timestamp buffer for a crtc.
90 static void clear_vblank_timestamps(struct drm_device *dev, int crtc)
92 memset(&dev->_vblank_time[crtc * DRM_VBLANKTIME_RBSIZE], 0,
93 DRM_VBLANKTIME_RBSIZE * sizeof(struct timeval));
97 * Disable vblank irq's on crtc, make sure that last vblank count
98 * of hardware and corresponding consistent software vblank counter
99 * are preserved, even if there are any spurious vblank irq's after
102 static void vblank_disable_and_save(struct drm_device *dev, int crtc)
104 unsigned long irqflags;
108 struct timeval tvblank;
110 /* Prevent vblank irq processing while disabling vblank irqs,
111 * so no updates of timestamps or count can happen after we've
112 * disabled. Needed to prevent races in case of delayed irq's.
114 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
116 dev->driver->disable_vblank(dev, crtc);
117 dev->vblank_enabled[crtc] = 0;
119 /* No further vblank irq's will be processed after
120 * this point. Get current hardware vblank count and
121 * vblank timestamp, repeat until they are consistent.
123 * FIXME: There is still a race condition here and in
124 * drm_update_vblank_count() which can cause off-by-one
125 * reinitialization of software vblank counter. If gpu
126 * vblank counter doesn't increment exactly at the leading
127 * edge of a vblank interval, then we can lose 1 count if
128 * we happen to execute between start of vblank and the
129 * delayed gpu counter increment.
132 dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc);
133 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
134 } while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc));
136 /* Compute time difference to stored timestamp of last vblank
137 * as updated by last invocation of drm_handle_vblank() in vblank irq.
139 vblcount = atomic_read(&dev->_vblank_count[crtc]);
140 diff_ns = timeval_to_ns(&tvblank) -
141 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
143 /* If there is at least 1 msec difference between the last stored
144 * timestamp and tvblank, then we are currently executing our
145 * disable inside a new vblank interval, the tvblank timestamp
146 * corresponds to this new vblank interval and the irq handler
147 * for this vblank didn't run yet and won't run due to our disable.
148 * Therefore we need to do the job of drm_handle_vblank() and
149 * increment the vblank counter by one to account for this vblank.
151 * Skip this step if there isn't any high precision timestamp
152 * available. In that case we can't account for this and just
155 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
156 atomic_inc(&dev->_vblank_count[crtc]);
157 smp_mb__after_atomic_inc();
160 /* Invalidate all timestamps while vblank irq's are off. */
161 clear_vblank_timestamps(dev, crtc);
163 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
166 static void vblank_disable_fn(unsigned long arg)
168 struct drm_device *dev = (struct drm_device *)arg;
169 unsigned long irqflags;
172 if (!dev->vblank_disable_allowed)
175 for (i = 0; i < dev->num_crtcs; i++) {
176 spin_lock_irqsave(&dev->vbl_lock, irqflags);
177 if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
178 dev->vblank_enabled[i]) {
179 DRM_DEBUG("disabling vblank on crtc %d\n", i);
180 vblank_disable_and_save(dev, i);
182 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
186 void drm_vblank_cleanup(struct drm_device *dev)
188 /* Bail if the driver didn't call drm_vblank_init() */
189 if (dev->num_crtcs == 0)
192 del_timer_sync(&dev->vblank_disable_timer);
194 vblank_disable_fn((unsigned long)dev);
196 kfree(dev->vbl_queue);
197 kfree(dev->_vblank_count);
198 kfree(dev->vblank_refcount);
199 kfree(dev->vblank_enabled);
200 kfree(dev->last_vblank);
201 kfree(dev->last_vblank_wait);
202 kfree(dev->vblank_inmodeset);
203 kfree(dev->_vblank_time);
207 EXPORT_SYMBOL(drm_vblank_cleanup);
209 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
211 int i, ret = -ENOMEM;
213 setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
215 spin_lock_init(&dev->vbl_lock);
216 spin_lock_init(&dev->vblank_time_lock);
218 dev->num_crtcs = num_crtcs;
220 dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs,
225 dev->_vblank_count = kmalloc(sizeof(atomic_t) * num_crtcs, GFP_KERNEL);
226 if (!dev->_vblank_count)
229 dev->vblank_refcount = kmalloc(sizeof(atomic_t) * num_crtcs,
231 if (!dev->vblank_refcount)
234 dev->vblank_enabled = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
235 if (!dev->vblank_enabled)
238 dev->last_vblank = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
239 if (!dev->last_vblank)
242 dev->last_vblank_wait = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
243 if (!dev->last_vblank_wait)
246 dev->vblank_inmodeset = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
247 if (!dev->vblank_inmodeset)
250 dev->_vblank_time = kcalloc(num_crtcs * DRM_VBLANKTIME_RBSIZE,
251 sizeof(struct timeval), GFP_KERNEL);
252 if (!dev->_vblank_time)
255 DRM_INFO("Supports vblank timestamp caching Rev 1 (10.10.2010).\n");
257 /* Driver specific high-precision vblank timestamping supported? */
258 if (dev->driver->get_vblank_timestamp)
259 DRM_INFO("Driver supports precise vblank timestamp query.\n");
261 DRM_INFO("No driver support for vblank timestamp query.\n");
263 /* Zero per-crtc vblank stuff */
264 for (i = 0; i < num_crtcs; i++) {
265 init_waitqueue_head(&dev->vbl_queue[i]);
266 atomic_set(&dev->_vblank_count[i], 0);
267 atomic_set(&dev->vblank_refcount[i], 0);
270 dev->vblank_disable_allowed = 0;
274 drm_vblank_cleanup(dev);
277 EXPORT_SYMBOL(drm_vblank_init);
279 static void drm_irq_vgaarb_nokms(void *cookie, bool state)
281 struct drm_device *dev = cookie;
283 if (dev->driver->vgaarb_irq) {
284 dev->driver->vgaarb_irq(dev, state);
288 if (!dev->irq_enabled)
292 if (dev->driver->irq_uninstall)
293 dev->driver->irq_uninstall(dev);
295 if (dev->driver->irq_preinstall)
296 dev->driver->irq_preinstall(dev);
297 if (dev->driver->irq_postinstall)
298 dev->driver->irq_postinstall(dev);
303 * Install IRQ handler.
305 * \param dev DRM device.
307 * Initializes the IRQ related data. Installs the handler, calling the driver
308 * \c irq_preinstall() and \c irq_postinstall() functions
309 * before and after the installation.
311 int drm_irq_install(struct drm_device *dev)
314 unsigned long sh_flags = 0;
317 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
320 if (drm_dev_to_irq(dev) == 0)
323 mutex_lock(&dev->struct_mutex);
325 /* Driver must have been initialized */
326 if (!dev->dev_private) {
327 mutex_unlock(&dev->struct_mutex);
331 if (dev->irq_enabled) {
332 mutex_unlock(&dev->struct_mutex);
335 dev->irq_enabled = 1;
336 mutex_unlock(&dev->struct_mutex);
338 DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
340 /* Before installing handler */
341 if (dev->driver->irq_preinstall)
342 dev->driver->irq_preinstall(dev);
344 /* Install handler */
345 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
346 sh_flags = IRQF_SHARED;
349 irqname = dev->devname;
351 irqname = dev->driver->name;
353 ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
354 sh_flags, irqname, dev);
357 mutex_lock(&dev->struct_mutex);
358 dev->irq_enabled = 0;
359 mutex_unlock(&dev->struct_mutex);
363 if (!drm_core_check_feature(dev, DRIVER_MODESET))
364 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
366 /* After installing handler */
367 if (dev->driver->irq_postinstall)
368 ret = dev->driver->irq_postinstall(dev);
371 mutex_lock(&dev->struct_mutex);
372 dev->irq_enabled = 0;
373 mutex_unlock(&dev->struct_mutex);
374 if (!drm_core_check_feature(dev, DRIVER_MODESET))
375 vga_client_register(dev->pdev, NULL, NULL, NULL);
376 free_irq(drm_dev_to_irq(dev), dev);
381 EXPORT_SYMBOL(drm_irq_install);
384 * Uninstall the IRQ handler.
386 * \param dev DRM device.
388 * Calls the driver's \c irq_uninstall() function, and stops the irq.
390 int drm_irq_uninstall(struct drm_device *dev)
392 unsigned long irqflags;
395 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
398 mutex_lock(&dev->struct_mutex);
399 irq_enabled = dev->irq_enabled;
400 dev->irq_enabled = 0;
401 mutex_unlock(&dev->struct_mutex);
404 * Wake up any waiters so they don't hang.
406 if (dev->num_crtcs) {
407 spin_lock_irqsave(&dev->vbl_lock, irqflags);
408 for (i = 0; i < dev->num_crtcs; i++) {
409 DRM_WAKEUP(&dev->vbl_queue[i]);
410 dev->vblank_enabled[i] = 0;
411 dev->last_vblank[i] =
412 dev->driver->get_vblank_counter(dev, i);
414 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
420 DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
422 if (!drm_core_check_feature(dev, DRIVER_MODESET))
423 vga_client_register(dev->pdev, NULL, NULL, NULL);
425 if (dev->driver->irq_uninstall)
426 dev->driver->irq_uninstall(dev);
428 free_irq(drm_dev_to_irq(dev), dev);
432 EXPORT_SYMBOL(drm_irq_uninstall);
437 * \param inode device inode.
438 * \param file_priv DRM file private.
439 * \param cmd command.
440 * \param arg user argument, pointing to a drm_control structure.
441 * \return zero on success or a negative number on failure.
443 * Calls irq_install() or irq_uninstall() according to \p arg.
445 int drm_control(struct drm_device *dev, void *data,
446 struct drm_file *file_priv)
448 struct drm_control *ctl = data;
450 /* if we haven't irq we fallback for compatibility reasons -
451 * this used to be a separate function in drm_dma.h
456 case DRM_INST_HANDLER:
457 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
459 if (drm_core_check_feature(dev, DRIVER_MODESET))
461 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
462 ctl->irq != drm_dev_to_irq(dev))
464 return drm_irq_install(dev);
465 case DRM_UNINST_HANDLER:
466 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
468 if (drm_core_check_feature(dev, DRIVER_MODESET))
470 return drm_irq_uninstall(dev);
477 * drm_calc_timestamping_constants - Calculate and
478 * store various constants which are later needed by
479 * vblank and swap-completion timestamping, e.g, by
480 * drm_calc_vbltimestamp_from_scanoutpos().
481 * They are derived from crtc's true scanout timing,
482 * so they take things like panel scaling or other
483 * adjustments into account.
485 * @crtc drm_crtc whose timestamp constants should be updated.
488 void drm_calc_timestamping_constants(struct drm_crtc *crtc)
490 s64 linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
493 /* Dot clock in Hz: */
494 dotclock = (u64) crtc->hwmode.clock * 1000;
496 /* Fields of interlaced scanout modes are only halve a frame duration.
497 * Double the dotclock to get halve the frame-/line-/pixelduration.
499 if (crtc->hwmode.flags & DRM_MODE_FLAG_INTERLACE)
502 /* Valid dotclock? */
504 /* Convert scanline length in pixels and video dot clock to
505 * line duration, frame duration and pixel duration in
508 pixeldur_ns = (s64) div64_u64(1000000000, dotclock);
509 linedur_ns = (s64) div64_u64(((u64) crtc->hwmode.crtc_htotal *
510 1000000000), dotclock);
511 framedur_ns = (s64) crtc->hwmode.crtc_vtotal * linedur_ns;
513 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
516 crtc->pixeldur_ns = pixeldur_ns;
517 crtc->linedur_ns = linedur_ns;
518 crtc->framedur_ns = framedur_ns;
520 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
521 crtc->base.id, crtc->hwmode.crtc_htotal,
522 crtc->hwmode.crtc_vtotal, crtc->hwmode.crtc_vdisplay);
523 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
524 crtc->base.id, (int) dotclock/1000, (int) framedur_ns,
525 (int) linedur_ns, (int) pixeldur_ns);
527 EXPORT_SYMBOL(drm_calc_timestamping_constants);
530 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
531 * drivers. Implements calculation of exact vblank timestamps from
532 * given drm_display_mode timings and current video scanout position
533 * of a crtc. This can be called from within get_vblank_timestamp()
534 * implementation of a kms driver to implement the actual timestamping.
536 * Should return timestamps conforming to the OML_sync_control OpenML
537 * extension specification. The timestamp corresponds to the end of
538 * the vblank interval, aka start of scanout of topmost-leftmost display
539 * pixel in the following video frame.
541 * Requires support for optional dev->driver->get_scanout_position()
542 * in kms driver, plus a bit of setup code to provide a drm_display_mode
543 * that corresponds to the true scanout timing.
545 * The current implementation only handles standard video modes. It
546 * returns as no operation if a doublescan or interlaced video mode is
547 * active. Higher level code is expected to handle this.
550 * @crtc: Which crtc's vblank timestamp to retrieve.
551 * @max_error: Desired maximum allowable error in timestamps (nanosecs).
552 * On return contains true maximum error of timestamp.
553 * @vblank_time: Pointer to struct timeval which should receive the timestamp.
554 * @flags: Flags to pass to driver:
556 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
557 * @refcrtc: drm_crtc* of crtc which defines scanout timing.
559 * Returns negative value on error, failure or if not supported in current
562 * -EINVAL - Invalid crtc.
563 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
564 * -ENOTSUPP - Function not supported in current display mode.
565 * -EIO - Failed, e.g., due to failed scanout position query.
567 * Returns or'ed positive status flags on success:
569 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
570 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
573 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
575 struct timeval *vblank_time,
577 struct drm_crtc *refcrtc)
579 ktime_t stime, etime, mono_time_offset;
580 struct timeval tv_etime;
581 struct drm_display_mode *mode;
582 int vbl_status, vtotal, vdisplay;
584 s64 framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
587 if (crtc < 0 || crtc >= dev->num_crtcs) {
588 DRM_ERROR("Invalid crtc %d\n", crtc);
592 /* Scanout position query not supported? Should not happen. */
593 if (!dev->driver->get_scanout_position) {
594 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
598 mode = &refcrtc->hwmode;
599 vtotal = mode->crtc_vtotal;
600 vdisplay = mode->crtc_vdisplay;
602 /* Durations of frames, lines, pixels in nanoseconds. */
603 framedur_ns = refcrtc->framedur_ns;
604 linedur_ns = refcrtc->linedur_ns;
605 pixeldur_ns = refcrtc->pixeldur_ns;
607 /* If mode timing undefined, just return as no-op:
608 * Happens during initial modesetting of a crtc.
610 if (vtotal <= 0 || vdisplay <= 0 || framedur_ns == 0) {
611 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
615 /* Get current scanout position with system timestamp.
616 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
617 * if single query takes longer than max_error nanoseconds.
619 * This guarantees a tight bound on maximum error if
620 * code gets preempted or delayed for some reason.
622 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
623 /* Disable preemption to make it very likely to
624 * succeed in the first iteration even on PREEMPT_RT kernel.
628 /* Get system timestamp before query. */
631 /* Get vertical and horizontal scanout pos. vpos, hpos. */
632 vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos);
634 /* Get system timestamp after query. */
636 mono_time_offset = ktime_get_monotonic_offset();
640 /* Return as no-op if scanout query unsupported or failed. */
641 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
642 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
647 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
649 /* Accept result with < max_error nsecs timing uncertainty. */
650 if (duration_ns <= (s64) *max_error)
654 /* Noisy system timing? */
655 if (i == DRM_TIMESTAMP_MAXRETRIES) {
656 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
657 crtc, (int) duration_ns/1000, *max_error/1000, i);
660 /* Return upper bound of timestamp precision error. */
661 *max_error = (int) duration_ns;
663 /* Check if in vblank area:
664 * vpos is >=0 in video scanout area, but negative
665 * within vblank area, counting down the number of lines until
668 invbl = vbl_status & DRM_SCANOUTPOS_INVBL;
670 /* Convert scanout position into elapsed time at raw_time query
671 * since start of scanout at first display scanline. delta_ns
672 * can be negative if start of scanout hasn't happened yet.
674 delta_ns = (s64) vpos * linedur_ns + (s64) hpos * pixeldur_ns;
676 /* Is vpos outside nominal vblank area, but less than
677 * 1/100 of a frame height away from start of vblank?
678 * If so, assume this isn't a massively delayed vblank
679 * interrupt, but a vblank interrupt that fired a few
680 * microseconds before true start of vblank. Compensate
681 * by adding a full frame duration to the final timestamp.
682 * Happens, e.g., on ATI R500, R600.
684 * We only do this if DRM_CALLED_FROM_VBLIRQ.
686 if ((flags & DRM_CALLED_FROM_VBLIRQ) && !invbl &&
687 ((vdisplay - vpos) < vtotal / 100)) {
688 delta_ns = delta_ns - framedur_ns;
690 /* Signal this correction as "applied". */
694 etime = ktime_sub(etime, mono_time_offset);
695 /* save this only for debugging purposes */
696 tv_etime = ktime_to_timeval(etime);
697 /* Subtract time delta from raw timestamp to get final
698 * vblank_time timestamp for end of vblank.
700 etime = ktime_sub_ns(etime, delta_ns);
701 *vblank_time = ktime_to_timeval(etime);
703 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
704 crtc, (int)vbl_status, hpos, vpos,
705 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
706 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
707 (int)duration_ns/1000, i);
709 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
711 vbl_status |= DRM_VBLANKTIME_INVBL;
715 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
718 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
722 * @crtc: which crtc's vblank timestamp to retrieve
723 * @tvblank: Pointer to target struct timeval which should receive the timestamp
724 * @flags: Flags to pass to driver:
726 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
728 * Fetches the system timestamp corresponding to the time of the most recent
729 * vblank interval on specified crtc. May call into kms-driver to
730 * compute the timestamp with a high-precision GPU specific method.
732 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
733 * call, i.e., it isn't very precisely locked to the true vblank.
735 * Returns non-zero if timestamp is considered to be very precise.
737 u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
738 struct timeval *tvblank, unsigned flags)
742 /* Define requested maximum error on timestamps (nanoseconds). */
743 int max_error = (int) drm_timestamp_precision * 1000;
745 /* Query driver if possible and precision timestamping enabled. */
746 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
747 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
753 /* GPU high precision timestamp query unsupported or failed.
754 * Return gettimeofday timestamp as best estimate.
756 do_gettimeofday(tvblank);
760 EXPORT_SYMBOL(drm_get_last_vbltimestamp);
763 * drm_vblank_count - retrieve "cooked" vblank counter value
765 * @crtc: which counter to retrieve
767 * Fetches the "cooked" vblank count value that represents the number of
768 * vblank events since the system was booted, including lost events due to
769 * modesetting activity.
771 u32 drm_vblank_count(struct drm_device *dev, int crtc)
773 return atomic_read(&dev->_vblank_count[crtc]);
775 EXPORT_SYMBOL(drm_vblank_count);
778 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
779 * and the system timestamp corresponding to that vblank counter value.
782 * @crtc: which counter to retrieve
783 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
785 * Fetches the "cooked" vblank count value that represents the number of
786 * vblank events since the system was booted, including lost events due to
787 * modesetting activity. Returns corresponding system timestamp of the time
788 * of the vblank interval that corresponds to the current value vblank counter
791 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
792 struct timeval *vblanktime)
796 /* Read timestamp from slot of _vblank_time ringbuffer
797 * that corresponds to current vblank count. Retry if
798 * count has incremented during readout. This works like
802 cur_vblank = atomic_read(&dev->_vblank_count[crtc]);
803 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
805 } while (cur_vblank != atomic_read(&dev->_vblank_count[crtc]));
809 EXPORT_SYMBOL(drm_vblank_count_and_time);
811 static void send_vblank_event(struct drm_device *dev,
812 struct drm_pending_vblank_event *e,
813 unsigned long seq, struct timeval *now)
815 WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
816 e->event.sequence = seq;
817 e->event.tv_sec = now->tv_sec;
818 e->event.tv_usec = now->tv_usec;
820 list_add_tail(&e->base.link,
821 &e->base.file_priv->event_list);
822 wake_up_interruptible(&e->base.file_priv->event_wait);
823 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
828 * drm_send_vblank_event - helper to send vblank event after pageflip
830 * @crtc: CRTC in question
831 * @e: the event to send
833 * Updates sequence # and timestamp on event, and sends it to userspace.
834 * Caller must hold event lock.
836 void drm_send_vblank_event(struct drm_device *dev, int crtc,
837 struct drm_pending_vblank_event *e)
842 seq = drm_vblank_count_and_time(dev, crtc, &now);
845 do_gettimeofday(&now);
847 send_vblank_event(dev, e, seq, &now);
849 EXPORT_SYMBOL(drm_send_vblank_event);
852 * drm_update_vblank_count - update the master vblank counter
854 * @crtc: counter to update
856 * Call back into the driver to update the appropriate vblank counter
857 * (specified by @crtc). Deal with wraparound, if it occurred, and
858 * update the last read value so we can deal with wraparound on the next
861 * Only necessary when going from off->on, to account for frames we
862 * didn't get an interrupt for.
864 * Note: caller must hold dev->vbl_lock since this reads & writes
865 * device vblank fields.
867 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
869 u32 cur_vblank, diff, tslot, rc;
870 struct timeval t_vblank;
873 * Interrupts were disabled prior to this call, so deal with counter
875 * NOTE! It's possible we lost a full dev->max_vblank_count events
876 * here if the register is small or we had vblank interrupts off for
879 * We repeat the hardware vblank counter & timestamp query until
880 * we get consistent results. This to prevent races between gpu
881 * updating its hardware counter while we are retrieving the
882 * corresponding vblank timestamp.
885 cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
886 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
887 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
889 /* Deal with counter wrap */
890 diff = cur_vblank - dev->last_vblank[crtc];
891 if (cur_vblank < dev->last_vblank[crtc]) {
892 diff += dev->max_vblank_count;
894 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
895 crtc, dev->last_vblank[crtc], cur_vblank, diff);
898 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
901 /* Reinitialize corresponding vblank timestamp if high-precision query
902 * available. Skip this step if query unsupported or failed. Will
903 * reinitialize delayed at next vblank interrupt in that case.
906 tslot = atomic_read(&dev->_vblank_count[crtc]) + diff;
907 vblanktimestamp(dev, crtc, tslot) = t_vblank;
910 smp_mb__before_atomic_inc();
911 atomic_add(diff, &dev->_vblank_count[crtc]);
912 smp_mb__after_atomic_inc();
916 * drm_vblank_get - get a reference count on vblank events
918 * @crtc: which CRTC to own
920 * Acquire a reference count on vblank events to avoid having them disabled
924 * Zero on success, nonzero on failure.
926 int drm_vblank_get(struct drm_device *dev, int crtc)
928 unsigned long irqflags, irqflags2;
931 spin_lock_irqsave(&dev->vbl_lock, irqflags);
932 /* Going from 0->1 means we have to enable interrupts again */
933 if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) {
934 spin_lock_irqsave(&dev->vblank_time_lock, irqflags2);
935 if (!dev->vblank_enabled[crtc]) {
936 /* Enable vblank irqs under vblank_time_lock protection.
937 * All vblank count & timestamp updates are held off
938 * until we are done reinitializing master counter and
939 * timestamps. Filtercode in drm_handle_vblank() will
940 * prevent double-accounting of same vblank interval.
942 ret = dev->driver->enable_vblank(dev, crtc);
943 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n",
946 atomic_dec(&dev->vblank_refcount[crtc]);
948 dev->vblank_enabled[crtc] = 1;
949 drm_update_vblank_count(dev, crtc);
952 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2);
954 if (!dev->vblank_enabled[crtc]) {
955 atomic_dec(&dev->vblank_refcount[crtc]);
959 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
963 EXPORT_SYMBOL(drm_vblank_get);
966 * drm_vblank_put - give up ownership of vblank events
968 * @crtc: which counter to give up
970 * Release ownership of a given vblank counter, turning off interrupts
971 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
973 void drm_vblank_put(struct drm_device *dev, int crtc)
975 BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0);
977 /* Last user schedules interrupt disable */
978 if (atomic_dec_and_test(&dev->vblank_refcount[crtc]) &&
979 (drm_vblank_offdelay > 0))
980 mod_timer(&dev->vblank_disable_timer,
981 jiffies + ((drm_vblank_offdelay * DRM_HZ)/1000));
983 EXPORT_SYMBOL(drm_vblank_put);
986 * drm_vblank_off - disable vblank events on a CRTC
988 * @crtc: CRTC in question
990 * Caller must hold event lock.
992 void drm_vblank_off(struct drm_device *dev, int crtc)
994 struct drm_pending_vblank_event *e, *t;
996 unsigned long irqflags;
999 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1000 vblank_disable_and_save(dev, crtc);
1001 DRM_WAKEUP(&dev->vbl_queue[crtc]);
1003 /* Send any queued vblank events, lest the natives grow disquiet */
1004 seq = drm_vblank_count_and_time(dev, crtc, &now);
1005 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1006 if (e->pipe != crtc)
1008 DRM_DEBUG("Sending premature vblank event on disable: \
1009 wanted %d, current %d\n",
1010 e->event.sequence, seq);
1011 list_del(&e->base.link);
1012 drm_vblank_put(dev, e->pipe);
1013 send_vblank_event(dev, e, seq, &now);
1016 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1018 EXPORT_SYMBOL(drm_vblank_off);
1021 * drm_vblank_pre_modeset - account for vblanks across mode sets
1023 * @crtc: CRTC in question
1025 * Account for vblank events across mode setting events, which will likely
1026 * reset the hardware frame counter.
1028 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
1030 /* vblank is not initialized (IRQ not installed ?) */
1031 if (!dev->num_crtcs)
1034 * To avoid all the problems that might happen if interrupts
1035 * were enabled/disabled around or between these calls, we just
1036 * have the kernel take a reference on the CRTC (just once though
1037 * to avoid corrupting the count if multiple, mismatch calls occur),
1038 * so that interrupts remain enabled in the interim.
1040 if (!dev->vblank_inmodeset[crtc]) {
1041 dev->vblank_inmodeset[crtc] = 0x1;
1042 if (drm_vblank_get(dev, crtc) == 0)
1043 dev->vblank_inmodeset[crtc] |= 0x2;
1046 EXPORT_SYMBOL(drm_vblank_pre_modeset);
1048 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
1050 unsigned long irqflags;
1052 if (dev->vblank_inmodeset[crtc]) {
1053 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1054 dev->vblank_disable_allowed = 1;
1055 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1057 if (dev->vblank_inmodeset[crtc] & 0x2)
1058 drm_vblank_put(dev, crtc);
1060 dev->vblank_inmodeset[crtc] = 0;
1063 EXPORT_SYMBOL(drm_vblank_post_modeset);
1066 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1067 * @DRM_IOCTL_ARGS: standard ioctl arguments
1069 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1070 * ioctls around modesetting so that any lost vblank events are accounted for.
1072 * Generally the counter will reset across mode sets. If interrupts are
1073 * enabled around this call, we don't have to do anything since the counter
1074 * will have already been incremented.
1076 int drm_modeset_ctl(struct drm_device *dev, void *data,
1077 struct drm_file *file_priv)
1079 struct drm_modeset_ctl *modeset = data;
1082 /* If drm_vblank_init() hasn't been called yet, just no-op */
1083 if (!dev->num_crtcs)
1086 /* KMS drivers handle this internally */
1087 if (drm_core_check_feature(dev, DRIVER_MODESET))
1090 crtc = modeset->crtc;
1091 if (crtc >= dev->num_crtcs)
1094 switch (modeset->cmd) {
1095 case _DRM_PRE_MODESET:
1096 drm_vblank_pre_modeset(dev, crtc);
1098 case _DRM_POST_MODESET:
1099 drm_vblank_post_modeset(dev, crtc);
1108 static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1109 union drm_wait_vblank *vblwait,
1110 struct drm_file *file_priv)
1112 struct drm_pending_vblank_event *e;
1114 unsigned long flags;
1118 e = kzalloc(sizeof *e, GFP_KERNEL);
1125 e->base.pid = current->pid;
1126 e->event.base.type = DRM_EVENT_VBLANK;
1127 e->event.base.length = sizeof e->event;
1128 e->event.user_data = vblwait->request.signal;
1129 e->base.event = &e->event.base;
1130 e->base.file_priv = file_priv;
1131 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
1133 spin_lock_irqsave(&dev->event_lock, flags);
1135 if (file_priv->event_space < sizeof e->event) {
1140 file_priv->event_space -= sizeof e->event;
1141 seq = drm_vblank_count_and_time(dev, pipe, &now);
1143 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1144 (seq - vblwait->request.sequence) <= (1 << 23)) {
1145 vblwait->request.sequence = seq + 1;
1146 vblwait->reply.sequence = vblwait->request.sequence;
1149 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1150 vblwait->request.sequence, seq, pipe);
1152 trace_drm_vblank_event_queued(current->pid, pipe,
1153 vblwait->request.sequence);
1155 e->event.sequence = vblwait->request.sequence;
1156 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1157 drm_vblank_put(dev, pipe);
1158 send_vblank_event(dev, e, seq, &now);
1159 vblwait->reply.sequence = seq;
1161 /* drm_handle_vblank_events will call drm_vblank_put */
1162 list_add_tail(&e->base.link, &dev->vblank_event_list);
1163 vblwait->reply.sequence = vblwait->request.sequence;
1166 spin_unlock_irqrestore(&dev->event_lock, flags);
1171 spin_unlock_irqrestore(&dev->event_lock, flags);
1174 drm_vblank_put(dev, pipe);
1181 * \param inode device inode.
1182 * \param file_priv DRM file private.
1183 * \param cmd command.
1184 * \param data user argument, pointing to a drm_wait_vblank structure.
1185 * \return zero on success or a negative number on failure.
1187 * This function enables the vblank interrupt on the pipe requested, then
1188 * sleeps waiting for the requested sequence number to occur, and drops
1189 * the vblank interrupt refcount afterwards. (vblank irq disable follows that
1190 * after a timeout with no further vblank waits scheduled).
1192 int drm_wait_vblank(struct drm_device *dev, void *data,
1193 struct drm_file *file_priv)
1195 union drm_wait_vblank *vblwait = data;
1197 unsigned int flags, seq, crtc, high_crtc;
1199 if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled))
1202 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1205 if (vblwait->request.type &
1206 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1207 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1208 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1209 vblwait->request.type,
1210 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1211 _DRM_VBLANK_HIGH_CRTC_MASK));
1215 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1216 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1218 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1220 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1221 if (crtc >= dev->num_crtcs)
1224 ret = drm_vblank_get(dev, crtc);
1226 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1229 seq = drm_vblank_count(dev, crtc);
1231 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1232 case _DRM_VBLANK_RELATIVE:
1233 vblwait->request.sequence += seq;
1234 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1235 case _DRM_VBLANK_ABSOLUTE:
1242 if (flags & _DRM_VBLANK_EVENT) {
1243 /* must hold on to the vblank ref until the event fires
1244 * drm_vblank_put will be called asynchronously
1246 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1249 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1250 (seq - vblwait->request.sequence) <= (1<<23)) {
1251 vblwait->request.sequence = seq + 1;
1254 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1255 vblwait->request.sequence, crtc);
1256 dev->last_vblank_wait[crtc] = vblwait->request.sequence;
1257 DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
1258 (((drm_vblank_count(dev, crtc) -
1259 vblwait->request.sequence) <= (1 << 23)) ||
1260 !dev->irq_enabled));
1262 if (ret != -EINTR) {
1265 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1266 vblwait->reply.tval_sec = now.tv_sec;
1267 vblwait->reply.tval_usec = now.tv_usec;
1269 DRM_DEBUG("returning %d to client\n",
1270 vblwait->reply.sequence);
1272 DRM_DEBUG("vblank wait interrupted by signal\n");
1276 drm_vblank_put(dev, crtc);
1280 static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1282 struct drm_pending_vblank_event *e, *t;
1284 unsigned long flags;
1287 seq = drm_vblank_count_and_time(dev, crtc, &now);
1289 spin_lock_irqsave(&dev->event_lock, flags);
1291 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1292 if (e->pipe != crtc)
1294 if ((seq - e->event.sequence) > (1<<23))
1297 DRM_DEBUG("vblank event on %d, current %d\n",
1298 e->event.sequence, seq);
1300 list_del(&e->base.link);
1301 drm_vblank_put(dev, e->pipe);
1302 send_vblank_event(dev, e, seq, &now);
1305 spin_unlock_irqrestore(&dev->event_lock, flags);
1307 trace_drm_vblank_event(crtc, seq);
1311 * drm_handle_vblank - handle a vblank event
1313 * @crtc: where this event occurred
1315 * Drivers should call this routine in their vblank interrupt handlers to
1316 * update the vblank counter and send any signals that may be pending.
1318 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1322 struct timeval tvblank;
1323 unsigned long irqflags;
1325 if (!dev->num_crtcs)
1328 /* Need timestamp lock to prevent concurrent execution with
1329 * vblank enable/disable, as this would cause inconsistent
1330 * or corrupted timestamps and vblank counts.
1332 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
1334 /* Vblank irq handling disabled. Nothing to do. */
1335 if (!dev->vblank_enabled[crtc]) {
1336 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1340 /* Fetch corresponding timestamp for this vblank interval from
1341 * driver and store it in proper slot of timestamp ringbuffer.
1344 /* Get current timestamp and count. */
1345 vblcount = atomic_read(&dev->_vblank_count[crtc]);
1346 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1348 /* Compute time difference to timestamp of last vblank */
1349 diff_ns = timeval_to_ns(&tvblank) -
1350 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1352 /* Update vblank timestamp and count if at least
1353 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1354 * difference between last stored timestamp and current
1355 * timestamp. A smaller difference means basically
1356 * identical timestamps. Happens if this vblank has
1357 * been already processed and this is a redundant call,
1358 * e.g., due to spurious vblank interrupts. We need to
1359 * ignore those for accounting.
1361 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1362 /* Store new timestamp in ringbuffer. */
1363 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1365 /* Increment cooked vblank count. This also atomically commits
1366 * the timestamp computed above.
1368 smp_mb__before_atomic_inc();
1369 atomic_inc(&dev->_vblank_count[crtc]);
1370 smp_mb__after_atomic_inc();
1372 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1373 crtc, (int) diff_ns);
1376 DRM_WAKEUP(&dev->vbl_queue[crtc]);
1377 drm_handle_vblank_events(dev, crtc);
1379 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1382 EXPORT_SYMBOL(drm_handle_vblank);