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.
113 * Disable preemption, so vblank_time_lock is held as short as
114 * possible, even under a kernel with PREEMPT_RT patches.
117 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
119 dev->driver->disable_vblank(dev, crtc);
120 dev->vblank_enabled[crtc] = 0;
122 /* No further vblank irq's will be processed after
123 * this point. Get current hardware vblank count and
124 * vblank timestamp, repeat until they are consistent.
126 * FIXME: There is still a race condition here and in
127 * drm_update_vblank_count() which can cause off-by-one
128 * reinitialization of software vblank counter. If gpu
129 * vblank counter doesn't increment exactly at the leading
130 * edge of a vblank interval, then we can lose 1 count if
131 * we happen to execute between start of vblank and the
132 * delayed gpu counter increment.
135 dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc);
136 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
137 } while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc));
139 /* Compute time difference to stored timestamp of last vblank
140 * as updated by last invocation of drm_handle_vblank() in vblank irq.
142 vblcount = atomic_read(&dev->_vblank_count[crtc]);
143 diff_ns = timeval_to_ns(&tvblank) -
144 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
146 /* If there is at least 1 msec difference between the last stored
147 * timestamp and tvblank, then we are currently executing our
148 * disable inside a new vblank interval, the tvblank timestamp
149 * corresponds to this new vblank interval and the irq handler
150 * for this vblank didn't run yet and won't run due to our disable.
151 * Therefore we need to do the job of drm_handle_vblank() and
152 * increment the vblank counter by one to account for this vblank.
154 * Skip this step if there isn't any high precision timestamp
155 * available. In that case we can't account for this and just
158 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
159 atomic_inc(&dev->_vblank_count[crtc]);
160 smp_mb__after_atomic_inc();
163 /* Invalidate all timestamps while vblank irq's are off. */
164 clear_vblank_timestamps(dev, crtc);
166 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
170 static void vblank_disable_fn(unsigned long arg)
172 struct drm_device *dev = (struct drm_device *)arg;
173 unsigned long irqflags;
176 if (!dev->vblank_disable_allowed)
179 for (i = 0; i < dev->num_crtcs; i++) {
180 spin_lock_irqsave(&dev->vbl_lock, irqflags);
181 if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
182 dev->vblank_enabled[i]) {
183 DRM_DEBUG("disabling vblank on crtc %d\n", i);
184 vblank_disable_and_save(dev, i);
186 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
190 void drm_vblank_cleanup(struct drm_device *dev)
192 /* Bail if the driver didn't call drm_vblank_init() */
193 if (dev->num_crtcs == 0)
196 del_timer(&dev->vblank_disable_timer);
198 vblank_disable_fn((unsigned long)dev);
200 kfree(dev->vbl_queue);
201 kfree(dev->_vblank_count);
202 kfree(dev->vblank_refcount);
203 kfree(dev->vblank_enabled);
204 kfree(dev->last_vblank);
205 kfree(dev->last_vblank_wait);
206 kfree(dev->vblank_inmodeset);
207 kfree(dev->_vblank_time);
211 EXPORT_SYMBOL(drm_vblank_cleanup);
213 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
215 int i, ret = -ENOMEM;
217 setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
219 spin_lock_init(&dev->vbl_lock);
220 spin_lock_init(&dev->vblank_time_lock);
222 dev->num_crtcs = num_crtcs;
224 dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs,
229 dev->_vblank_count = kmalloc(sizeof(atomic_t) * num_crtcs, GFP_KERNEL);
230 if (!dev->_vblank_count)
233 dev->vblank_refcount = kmalloc(sizeof(atomic_t) * num_crtcs,
235 if (!dev->vblank_refcount)
238 dev->vblank_enabled = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
239 if (!dev->vblank_enabled)
242 dev->last_vblank = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
243 if (!dev->last_vblank)
246 dev->last_vblank_wait = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
247 if (!dev->last_vblank_wait)
250 dev->vblank_inmodeset = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
251 if (!dev->vblank_inmodeset)
254 dev->_vblank_time = kcalloc(num_crtcs * DRM_VBLANKTIME_RBSIZE,
255 sizeof(struct timeval), GFP_KERNEL);
256 if (!dev->_vblank_time)
259 DRM_INFO("Supports vblank timestamp caching Rev 1 (10.10.2010).\n");
261 /* Driver specific high-precision vblank timestamping supported? */
262 if (dev->driver->get_vblank_timestamp)
263 DRM_INFO("Driver supports precise vblank timestamp query.\n");
265 DRM_INFO("No driver support for vblank timestamp query.\n");
267 /* Zero per-crtc vblank stuff */
268 for (i = 0; i < num_crtcs; i++) {
269 init_waitqueue_head(&dev->vbl_queue[i]);
270 atomic_set(&dev->_vblank_count[i], 0);
271 atomic_set(&dev->vblank_refcount[i], 0);
274 dev->vblank_disable_allowed = 0;
278 drm_vblank_cleanup(dev);
281 EXPORT_SYMBOL(drm_vblank_init);
283 static void drm_irq_vgaarb_nokms(void *cookie, bool state)
285 struct drm_device *dev = cookie;
287 if (dev->driver->vgaarb_irq) {
288 dev->driver->vgaarb_irq(dev, state);
292 if (!dev->irq_enabled)
296 if (dev->driver->irq_uninstall)
297 dev->driver->irq_uninstall(dev);
299 if (dev->driver->irq_preinstall)
300 dev->driver->irq_preinstall(dev);
301 if (dev->driver->irq_postinstall)
302 dev->driver->irq_postinstall(dev);
307 * Install IRQ handler.
309 * \param dev DRM device.
311 * Initializes the IRQ related data. Installs the handler, calling the driver
312 * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
313 * before and after the installation.
315 int drm_irq_install(struct drm_device *dev)
318 unsigned long sh_flags = 0;
321 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
324 if (drm_dev_to_irq(dev) == 0)
327 mutex_lock(&dev->struct_mutex);
329 /* Driver must have been initialized */
330 if (!dev->dev_private) {
331 mutex_unlock(&dev->struct_mutex);
335 if (dev->irq_enabled) {
336 mutex_unlock(&dev->struct_mutex);
339 dev->irq_enabled = 1;
340 mutex_unlock(&dev->struct_mutex);
342 DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
344 /* Before installing handler */
345 if (dev->driver->irq_preinstall)
346 dev->driver->irq_preinstall(dev);
348 /* Install handler */
349 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
350 sh_flags = IRQF_SHARED;
353 irqname = dev->devname;
355 irqname = dev->driver->name;
357 ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
358 sh_flags, irqname, dev);
361 mutex_lock(&dev->struct_mutex);
362 dev->irq_enabled = 0;
363 mutex_unlock(&dev->struct_mutex);
367 if (!drm_core_check_feature(dev, DRIVER_MODESET))
368 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
370 /* After installing handler */
371 if (dev->driver->irq_postinstall)
372 ret = dev->driver->irq_postinstall(dev);
375 mutex_lock(&dev->struct_mutex);
376 dev->irq_enabled = 0;
377 mutex_unlock(&dev->struct_mutex);
378 if (!drm_core_check_feature(dev, DRIVER_MODESET))
379 vga_client_register(dev->pdev, NULL, NULL, NULL);
380 free_irq(drm_dev_to_irq(dev), dev);
385 EXPORT_SYMBOL(drm_irq_install);
388 * Uninstall the IRQ handler.
390 * \param dev DRM device.
392 * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq.
394 int drm_irq_uninstall(struct drm_device *dev)
396 unsigned long irqflags;
399 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
402 mutex_lock(&dev->struct_mutex);
403 irq_enabled = dev->irq_enabled;
404 dev->irq_enabled = 0;
405 mutex_unlock(&dev->struct_mutex);
408 * Wake up any waiters so they don't hang.
410 if (dev->num_crtcs) {
411 spin_lock_irqsave(&dev->vbl_lock, irqflags);
412 for (i = 0; i < dev->num_crtcs; i++) {
413 DRM_WAKEUP(&dev->vbl_queue[i]);
414 dev->vblank_enabled[i] = 0;
415 dev->last_vblank[i] =
416 dev->driver->get_vblank_counter(dev, i);
418 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
424 DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
426 if (!drm_core_check_feature(dev, DRIVER_MODESET))
427 vga_client_register(dev->pdev, NULL, NULL, NULL);
429 if (dev->driver->irq_uninstall)
430 dev->driver->irq_uninstall(dev);
432 free_irq(drm_dev_to_irq(dev), dev);
436 EXPORT_SYMBOL(drm_irq_uninstall);
441 * \param inode device inode.
442 * \param file_priv DRM file private.
443 * \param cmd command.
444 * \param arg user argument, pointing to a drm_control structure.
445 * \return zero on success or a negative number on failure.
447 * Calls irq_install() or irq_uninstall() according to \p arg.
449 int drm_control(struct drm_device *dev, void *data,
450 struct drm_file *file_priv)
452 struct drm_control *ctl = data;
454 /* if we haven't irq we fallback for compatibility reasons -
455 * this used to be a separate function in drm_dma.h
460 case DRM_INST_HANDLER:
461 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
463 if (drm_core_check_feature(dev, DRIVER_MODESET))
465 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
466 ctl->irq != drm_dev_to_irq(dev))
468 return drm_irq_install(dev);
469 case DRM_UNINST_HANDLER:
470 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
472 if (drm_core_check_feature(dev, DRIVER_MODESET))
474 return drm_irq_uninstall(dev);
481 * drm_calc_timestamping_constants - Calculate and
482 * store various constants which are later needed by
483 * vblank and swap-completion timestamping, e.g, by
484 * drm_calc_vbltimestamp_from_scanoutpos().
485 * They are derived from crtc's true scanout timing,
486 * so they take things like panel scaling or other
487 * adjustments into account.
489 * @crtc drm_crtc whose timestamp constants should be updated.
492 void drm_calc_timestamping_constants(struct drm_crtc *crtc)
494 s64 linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
497 /* Dot clock in Hz: */
498 dotclock = (u64) crtc->hwmode.clock * 1000;
500 /* Fields of interlaced scanout modes are only halve a frame duration.
501 * Double the dotclock to get halve the frame-/line-/pixelduration.
503 if (crtc->hwmode.flags & DRM_MODE_FLAG_INTERLACE)
506 /* Valid dotclock? */
508 /* Convert scanline length in pixels and video dot clock to
509 * line duration, frame duration and pixel duration in
512 pixeldur_ns = (s64) div64_u64(1000000000, dotclock);
513 linedur_ns = (s64) div64_u64(((u64) crtc->hwmode.crtc_htotal *
514 1000000000), dotclock);
515 framedur_ns = (s64) crtc->hwmode.crtc_vtotal * linedur_ns;
517 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
520 crtc->pixeldur_ns = pixeldur_ns;
521 crtc->linedur_ns = linedur_ns;
522 crtc->framedur_ns = framedur_ns;
524 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
525 crtc->base.id, crtc->hwmode.crtc_htotal,
526 crtc->hwmode.crtc_vtotal, crtc->hwmode.crtc_vdisplay);
527 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
528 crtc->base.id, (int) dotclock/1000, (int) framedur_ns,
529 (int) linedur_ns, (int) pixeldur_ns);
531 EXPORT_SYMBOL(drm_calc_timestamping_constants);
534 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
535 * drivers. Implements calculation of exact vblank timestamps from
536 * given drm_display_mode timings and current video scanout position
537 * of a crtc. This can be called from within get_vblank_timestamp()
538 * implementation of a kms driver to implement the actual timestamping.
540 * Should return timestamps conforming to the OML_sync_control OpenML
541 * extension specification. The timestamp corresponds to the end of
542 * the vblank interval, aka start of scanout of topmost-leftmost display
543 * pixel in the following video frame.
545 * Requires support for optional dev->driver->get_scanout_position()
546 * in kms driver, plus a bit of setup code to provide a drm_display_mode
547 * that corresponds to the true scanout timing.
549 * The current implementation only handles standard video modes. It
550 * returns as no operation if a doublescan or interlaced video mode is
551 * active. Higher level code is expected to handle this.
554 * @crtc: Which crtc's vblank timestamp to retrieve.
555 * @max_error: Desired maximum allowable error in timestamps (nanosecs).
556 * On return contains true maximum error of timestamp.
557 * @vblank_time: Pointer to struct timeval which should receive the timestamp.
558 * @flags: Flags to pass to driver:
560 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
561 * @refcrtc: drm_crtc* of crtc which defines scanout timing.
563 * Returns negative value on error, failure or if not supported in current
566 * -EINVAL - Invalid crtc.
567 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
568 * -ENOTSUPP - Function not supported in current display mode.
569 * -EIO - Failed, e.g., due to failed scanout position query.
571 * Returns or'ed positive status flags on success:
573 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
574 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
577 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
579 struct timeval *vblank_time,
581 struct drm_crtc *refcrtc)
583 struct timeval stime, raw_time;
584 struct drm_display_mode *mode;
585 int vbl_status, vtotal, vdisplay;
587 s64 framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
590 if (crtc < 0 || crtc >= dev->num_crtcs) {
591 DRM_ERROR("Invalid crtc %d\n", crtc);
595 /* Scanout position query not supported? Should not happen. */
596 if (!dev->driver->get_scanout_position) {
597 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
601 mode = &refcrtc->hwmode;
602 vtotal = mode->crtc_vtotal;
603 vdisplay = mode->crtc_vdisplay;
605 /* Durations of frames, lines, pixels in nanoseconds. */
606 framedur_ns = refcrtc->framedur_ns;
607 linedur_ns = refcrtc->linedur_ns;
608 pixeldur_ns = refcrtc->pixeldur_ns;
610 /* If mode timing undefined, just return as no-op:
611 * Happens during initial modesetting of a crtc.
613 if (vtotal <= 0 || vdisplay <= 0 || framedur_ns == 0) {
614 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
618 /* Get current scanout position with system timestamp.
619 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
620 * if single query takes longer than max_error nanoseconds.
622 * This guarantees a tight bound on maximum error if
623 * code gets preempted or delayed for some reason.
625 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
626 /* Disable preemption to make it very likely to
627 * succeed in the first iteration even on PREEMPT_RT kernel.
631 /* Get system timestamp before query. */
632 do_gettimeofday(&stime);
634 /* Get vertical and horizontal scanout pos. vpos, hpos. */
635 vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos);
637 /* Get system timestamp after query. */
638 do_gettimeofday(&raw_time);
642 /* Return as no-op if scanout query unsupported or failed. */
643 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
644 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
649 duration_ns = timeval_to_ns(&raw_time) - timeval_to_ns(&stime);
651 /* Accept result with < max_error nsecs timing uncertainty. */
652 if (duration_ns <= (s64) *max_error)
656 /* Noisy system timing? */
657 if (i == DRM_TIMESTAMP_MAXRETRIES) {
658 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
659 crtc, (int) duration_ns/1000, *max_error/1000, i);
662 /* Return upper bound of timestamp precision error. */
663 *max_error = (int) duration_ns;
665 /* Check if in vblank area:
666 * vpos is >=0 in video scanout area, but negative
667 * within vblank area, counting down the number of lines until
670 invbl = vbl_status & DRM_SCANOUTPOS_INVBL;
672 /* Convert scanout position into elapsed time at raw_time query
673 * since start of scanout at first display scanline. delta_ns
674 * can be negative if start of scanout hasn't happened yet.
676 delta_ns = (s64) vpos * linedur_ns + (s64) hpos * pixeldur_ns;
678 /* Is vpos outside nominal vblank area, but less than
679 * 1/100 of a frame height away from start of vblank?
680 * If so, assume this isn't a massively delayed vblank
681 * interrupt, but a vblank interrupt that fired a few
682 * microseconds before true start of vblank. Compensate
683 * by adding a full frame duration to the final timestamp.
684 * Happens, e.g., on ATI R500, R600.
686 * We only do this if DRM_CALLED_FROM_VBLIRQ.
688 if ((flags & DRM_CALLED_FROM_VBLIRQ) && !invbl &&
689 ((vdisplay - vpos) < vtotal / 100)) {
690 delta_ns = delta_ns - framedur_ns;
692 /* Signal this correction as "applied". */
696 /* Subtract time delta from raw timestamp to get final
697 * vblank_time timestamp for end of vblank.
699 *vblank_time = ns_to_timeval(timeval_to_ns(&raw_time) - delta_ns);
701 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
702 crtc, (int)vbl_status, hpos, vpos,
703 (long)raw_time.tv_sec, (long)raw_time.tv_usec,
704 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
705 (int)duration_ns/1000, i);
707 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
709 vbl_status |= DRM_VBLANKTIME_INVBL;
713 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
716 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
720 * @crtc: which crtc's vblank timestamp to retrieve
721 * @tvblank: Pointer to target struct timeval which should receive the timestamp
722 * @flags: Flags to pass to driver:
724 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
726 * Fetches the system timestamp corresponding to the time of the most recent
727 * vblank interval on specified crtc. May call into kms-driver to
728 * compute the timestamp with a high-precision GPU specific method.
730 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
731 * call, i.e., it isn't very precisely locked to the true vblank.
733 * Returns non-zero if timestamp is considered to be very precise.
735 u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
736 struct timeval *tvblank, unsigned flags)
740 /* Define requested maximum error on timestamps (nanoseconds). */
741 int max_error = (int) drm_timestamp_precision * 1000;
743 /* Query driver if possible and precision timestamping enabled. */
744 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
745 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
751 /* GPU high precision timestamp query unsupported or failed.
752 * Return gettimeofday timestamp as best estimate.
754 do_gettimeofday(tvblank);
758 EXPORT_SYMBOL(drm_get_last_vbltimestamp);
761 * drm_vblank_count - retrieve "cooked" vblank counter value
763 * @crtc: which counter to retrieve
765 * Fetches the "cooked" vblank count value that represents the number of
766 * vblank events since the system was booted, including lost events due to
767 * modesetting activity.
769 u32 drm_vblank_count(struct drm_device *dev, int crtc)
771 return atomic_read(&dev->_vblank_count[crtc]);
773 EXPORT_SYMBOL(drm_vblank_count);
776 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
777 * and the system timestamp corresponding to that vblank counter value.
780 * @crtc: which counter to retrieve
781 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
783 * Fetches the "cooked" vblank count value that represents the number of
784 * vblank events since the system was booted, including lost events due to
785 * modesetting activity. Returns corresponding system timestamp of the time
786 * of the vblank interval that corresponds to the current value vblank counter
789 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
790 struct timeval *vblanktime)
794 /* Read timestamp from slot of _vblank_time ringbuffer
795 * that corresponds to current vblank count. Retry if
796 * count has incremented during readout. This works like
800 cur_vblank = atomic_read(&dev->_vblank_count[crtc]);
801 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
803 } while (cur_vblank != atomic_read(&dev->_vblank_count[crtc]));
807 EXPORT_SYMBOL(drm_vblank_count_and_time);
810 * drm_update_vblank_count - update the master vblank counter
812 * @crtc: counter to update
814 * Call back into the driver to update the appropriate vblank counter
815 * (specified by @crtc). Deal with wraparound, if it occurred, and
816 * update the last read value so we can deal with wraparound on the next
819 * Only necessary when going from off->on, to account for frames we
820 * didn't get an interrupt for.
822 * Note: caller must hold dev->vbl_lock since this reads & writes
823 * device vblank fields.
825 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
827 u32 cur_vblank, diff, tslot, rc;
828 struct timeval t_vblank;
831 * Interrupts were disabled prior to this call, so deal with counter
833 * NOTE! It's possible we lost a full dev->max_vblank_count events
834 * here if the register is small or we had vblank interrupts off for
837 * We repeat the hardware vblank counter & timestamp query until
838 * we get consistent results. This to prevent races between gpu
839 * updating its hardware counter while we are retrieving the
840 * corresponding vblank timestamp.
843 cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
844 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
845 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
847 /* Deal with counter wrap */
848 diff = cur_vblank - dev->last_vblank[crtc];
849 if (cur_vblank < dev->last_vblank[crtc]) {
850 diff += dev->max_vblank_count;
852 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
853 crtc, dev->last_vblank[crtc], cur_vblank, diff);
856 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
859 /* Reinitialize corresponding vblank timestamp if high-precision query
860 * available. Skip this step if query unsupported or failed. Will
861 * reinitialize delayed at next vblank interrupt in that case.
864 tslot = atomic_read(&dev->_vblank_count[crtc]) + diff;
865 vblanktimestamp(dev, crtc, tslot) = t_vblank;
868 smp_mb__before_atomic_inc();
869 atomic_add(diff, &dev->_vblank_count[crtc]);
870 smp_mb__after_atomic_inc();
874 * drm_vblank_get - get a reference count on vblank events
876 * @crtc: which CRTC to own
878 * Acquire a reference count on vblank events to avoid having them disabled
882 * Zero on success, nonzero on failure.
884 int drm_vblank_get(struct drm_device *dev, int crtc)
886 unsigned long irqflags, irqflags2;
889 spin_lock_irqsave(&dev->vbl_lock, irqflags);
890 /* Going from 0->1 means we have to enable interrupts again */
891 if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) {
892 /* Disable preemption while holding vblank_time_lock. Do
893 * it explicitely to guard against PREEMPT_RT kernel.
896 spin_lock_irqsave(&dev->vblank_time_lock, irqflags2);
897 if (!dev->vblank_enabled[crtc]) {
898 /* Enable vblank irqs under vblank_time_lock protection.
899 * All vblank count & timestamp updates are held off
900 * until we are done reinitializing master counter and
901 * timestamps. Filtercode in drm_handle_vblank() will
902 * prevent double-accounting of same vblank interval.
904 ret = dev->driver->enable_vblank(dev, crtc);
905 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n",
908 atomic_dec(&dev->vblank_refcount[crtc]);
910 dev->vblank_enabled[crtc] = 1;
911 drm_update_vblank_count(dev, crtc);
914 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2);
917 if (!dev->vblank_enabled[crtc]) {
918 atomic_dec(&dev->vblank_refcount[crtc]);
922 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
926 EXPORT_SYMBOL(drm_vblank_get);
929 * drm_vblank_put - give up ownership of vblank events
931 * @crtc: which counter to give up
933 * Release ownership of a given vblank counter, turning off interrupts
934 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
936 void drm_vblank_put(struct drm_device *dev, int crtc)
938 BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0);
940 /* Last user schedules interrupt disable */
941 if (atomic_dec_and_test(&dev->vblank_refcount[crtc]) &&
942 (drm_vblank_offdelay > 0))
943 mod_timer(&dev->vblank_disable_timer,
944 jiffies + ((drm_vblank_offdelay * DRM_HZ)/1000));
946 EXPORT_SYMBOL(drm_vblank_put);
948 void drm_vblank_off(struct drm_device *dev, int crtc)
950 struct drm_pending_vblank_event *e, *t;
952 unsigned long irqflags;
955 spin_lock_irqsave(&dev->vbl_lock, irqflags);
956 vblank_disable_and_save(dev, crtc);
957 DRM_WAKEUP(&dev->vbl_queue[crtc]);
959 /* Send any queued vblank events, lest the natives grow disquiet */
960 seq = drm_vblank_count_and_time(dev, crtc, &now);
961 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
964 DRM_DEBUG("Sending premature vblank event on disable: \
965 wanted %d, current %d\n",
966 e->event.sequence, seq);
968 e->event.sequence = seq;
969 e->event.tv_sec = now.tv_sec;
970 e->event.tv_usec = now.tv_usec;
971 drm_vblank_put(dev, e->pipe);
972 list_move_tail(&e->base.link, &e->base.file_priv->event_list);
973 wake_up_interruptible(&e->base.file_priv->event_wait);
974 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
978 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
980 EXPORT_SYMBOL(drm_vblank_off);
983 * drm_vblank_pre_modeset - account for vblanks across mode sets
985 * @crtc: CRTC in question
986 * @post: post or pre mode set?
988 * Account for vblank events across mode setting events, which will likely
989 * reset the hardware frame counter.
991 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
993 /* vblank is not initialized (IRQ not installed ?) */
997 * To avoid all the problems that might happen if interrupts
998 * were enabled/disabled around or between these calls, we just
999 * have the kernel take a reference on the CRTC (just once though
1000 * to avoid corrupting the count if multiple, mismatch calls occur),
1001 * so that interrupts remain enabled in the interim.
1003 if (!dev->vblank_inmodeset[crtc]) {
1004 dev->vblank_inmodeset[crtc] = 0x1;
1005 if (drm_vblank_get(dev, crtc) == 0)
1006 dev->vblank_inmodeset[crtc] |= 0x2;
1009 EXPORT_SYMBOL(drm_vblank_pre_modeset);
1011 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
1013 unsigned long irqflags;
1015 if (dev->vblank_inmodeset[crtc]) {
1016 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1017 dev->vblank_disable_allowed = 1;
1018 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1020 if (dev->vblank_inmodeset[crtc] & 0x2)
1021 drm_vblank_put(dev, crtc);
1023 dev->vblank_inmodeset[crtc] = 0;
1026 EXPORT_SYMBOL(drm_vblank_post_modeset);
1029 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1030 * @DRM_IOCTL_ARGS: standard ioctl arguments
1032 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1033 * ioctls around modesetting so that any lost vblank events are accounted for.
1035 * Generally the counter will reset across mode sets. If interrupts are
1036 * enabled around this call, we don't have to do anything since the counter
1037 * will have already been incremented.
1039 int drm_modeset_ctl(struct drm_device *dev, void *data,
1040 struct drm_file *file_priv)
1042 struct drm_modeset_ctl *modeset = data;
1046 /* If drm_vblank_init() hasn't been called yet, just no-op */
1047 if (!dev->num_crtcs)
1050 crtc = modeset->crtc;
1051 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);
1072 static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1073 union drm_wait_vblank *vblwait,
1074 struct drm_file *file_priv)
1076 struct drm_pending_vblank_event *e;
1078 unsigned long flags;
1082 e = kzalloc(sizeof *e, GFP_KERNEL);
1089 e->base.pid = current->pid;
1090 e->event.base.type = DRM_EVENT_VBLANK;
1091 e->event.base.length = sizeof e->event;
1092 e->event.user_data = vblwait->request.signal;
1093 e->base.event = &e->event.base;
1094 e->base.file_priv = file_priv;
1095 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
1097 spin_lock_irqsave(&dev->event_lock, flags);
1099 if (file_priv->event_space < sizeof e->event) {
1104 file_priv->event_space -= sizeof e->event;
1105 seq = drm_vblank_count_and_time(dev, pipe, &now);
1107 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1108 (seq - vblwait->request.sequence) <= (1 << 23)) {
1109 vblwait->request.sequence = seq + 1;
1110 vblwait->reply.sequence = vblwait->request.sequence;
1113 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1114 vblwait->request.sequence, seq, pipe);
1116 trace_drm_vblank_event_queued(current->pid, pipe,
1117 vblwait->request.sequence);
1119 e->event.sequence = vblwait->request.sequence;
1120 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1121 e->event.sequence = seq;
1122 e->event.tv_sec = now.tv_sec;
1123 e->event.tv_usec = now.tv_usec;
1124 drm_vblank_put(dev, pipe);
1125 list_add_tail(&e->base.link, &e->base.file_priv->event_list);
1126 wake_up_interruptible(&e->base.file_priv->event_wait);
1127 vblwait->reply.sequence = seq;
1128 trace_drm_vblank_event_delivered(current->pid, pipe,
1129 vblwait->request.sequence);
1131 list_add_tail(&e->base.link, &dev->vblank_event_list);
1132 vblwait->reply.sequence = vblwait->request.sequence;
1135 spin_unlock_irqrestore(&dev->event_lock, flags);
1140 spin_unlock_irqrestore(&dev->event_lock, flags);
1143 drm_vblank_put(dev, pipe);
1150 * \param inode device inode.
1151 * \param file_priv DRM file private.
1152 * \param cmd command.
1153 * \param data user argument, pointing to a drm_wait_vblank structure.
1154 * \return zero on success or a negative number on failure.
1156 * This function enables the vblank interrupt on the pipe requested, then
1157 * sleeps waiting for the requested sequence number to occur, and drops
1158 * the vblank interrupt refcount afterwards. (vblank irq disable follows that
1159 * after a timeout with no further vblank waits scheduled).
1161 int drm_wait_vblank(struct drm_device *dev, void *data,
1162 struct drm_file *file_priv)
1164 union drm_wait_vblank *vblwait = data;
1166 unsigned int flags, seq, crtc, high_crtc;
1168 if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled))
1171 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1174 if (vblwait->request.type &
1175 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1176 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1177 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1178 vblwait->request.type,
1179 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1180 _DRM_VBLANK_HIGH_CRTC_MASK));
1184 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1185 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1187 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1189 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1190 if (crtc >= dev->num_crtcs)
1193 ret = drm_vblank_get(dev, crtc);
1195 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1198 seq = drm_vblank_count(dev, crtc);
1200 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1201 case _DRM_VBLANK_RELATIVE:
1202 vblwait->request.sequence += seq;
1203 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1204 case _DRM_VBLANK_ABSOLUTE:
1211 if (flags & _DRM_VBLANK_EVENT)
1212 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1214 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1215 (seq - vblwait->request.sequence) <= (1<<23)) {
1216 vblwait->request.sequence = seq + 1;
1219 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1220 vblwait->request.sequence, crtc);
1221 dev->last_vblank_wait[crtc] = vblwait->request.sequence;
1222 DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
1223 (((drm_vblank_count(dev, crtc) -
1224 vblwait->request.sequence) <= (1 << 23)) ||
1225 !dev->irq_enabled));
1227 if (ret != -EINTR) {
1230 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1231 vblwait->reply.tval_sec = now.tv_sec;
1232 vblwait->reply.tval_usec = now.tv_usec;
1234 DRM_DEBUG("returning %d to client\n",
1235 vblwait->reply.sequence);
1237 DRM_DEBUG("vblank wait interrupted by signal\n");
1241 drm_vblank_put(dev, crtc);
1245 void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1247 struct drm_pending_vblank_event *e, *t;
1249 unsigned long flags;
1252 seq = drm_vblank_count_and_time(dev, crtc, &now);
1254 spin_lock_irqsave(&dev->event_lock, flags);
1256 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1257 if (e->pipe != crtc)
1259 if ((seq - e->event.sequence) > (1<<23))
1262 DRM_DEBUG("vblank event on %d, current %d\n",
1263 e->event.sequence, seq);
1265 e->event.sequence = seq;
1266 e->event.tv_sec = now.tv_sec;
1267 e->event.tv_usec = now.tv_usec;
1268 drm_vblank_put(dev, e->pipe);
1269 list_move_tail(&e->base.link, &e->base.file_priv->event_list);
1270 wake_up_interruptible(&e->base.file_priv->event_wait);
1271 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
1275 spin_unlock_irqrestore(&dev->event_lock, flags);
1277 trace_drm_vblank_event(crtc, seq);
1281 * drm_handle_vblank - handle a vblank event
1283 * @crtc: where this event occurred
1285 * Drivers should call this routine in their vblank interrupt handlers to
1286 * update the vblank counter and send any signals that may be pending.
1288 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1292 struct timeval tvblank;
1293 unsigned long irqflags;
1295 if (!dev->num_crtcs)
1298 /* Need timestamp lock to prevent concurrent execution with
1299 * vblank enable/disable, as this would cause inconsistent
1300 * or corrupted timestamps and vblank counts.
1302 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
1304 /* Vblank irq handling disabled. Nothing to do. */
1305 if (!dev->vblank_enabled[crtc]) {
1306 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1310 /* Fetch corresponding timestamp for this vblank interval from
1311 * driver and store it in proper slot of timestamp ringbuffer.
1314 /* Get current timestamp and count. */
1315 vblcount = atomic_read(&dev->_vblank_count[crtc]);
1316 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1318 /* Compute time difference to timestamp of last vblank */
1319 diff_ns = timeval_to_ns(&tvblank) -
1320 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1322 /* Update vblank timestamp and count if at least
1323 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1324 * difference between last stored timestamp and current
1325 * timestamp. A smaller difference means basically
1326 * identical timestamps. Happens if this vblank has
1327 * been already processed and this is a redundant call,
1328 * e.g., due to spurious vblank interrupts. We need to
1329 * ignore those for accounting.
1331 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1332 /* Store new timestamp in ringbuffer. */
1333 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1335 /* Increment cooked vblank count. This also atomically commits
1336 * the timestamp computed above.
1338 smp_mb__before_atomic_inc();
1339 atomic_inc(&dev->_vblank_count[crtc]);
1340 smp_mb__after_atomic_inc();
1342 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1343 crtc, (int) diff_ns);
1346 DRM_WAKEUP(&dev->vbl_queue[crtc]);
1347 drm_handle_vblank_events(dev, crtc);
1349 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1352 EXPORT_SYMBOL(drm_handle_vblank);