2 * drm_irq.c IRQ and vblank support
4 * \author Rickard E. (Rik) Faith <faith@valinux.com>
5 * \author Gareth Hughes <gareth@valinux.com>
9 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
11 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
12 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
13 * All Rights Reserved.
15 * Permission is hereby granted, free of charge, to any person obtaining a
16 * copy of this software and associated documentation files (the "Software"),
17 * to deal in the Software without restriction, including without limitation
18 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
19 * and/or sell copies of the Software, and to permit persons to whom the
20 * Software is furnished to do so, subject to the following conditions:
22 * The above copyright notice and this permission notice (including the next
23 * paragraph) shall be included in all copies or substantial portions of the
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
29 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
30 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
31 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
32 * OTHER DEALINGS IN THE SOFTWARE.
36 #include "drm_trace.h"
37 #include "drm_internal.h"
39 #include <linux/interrupt.h> /* For task queue support */
40 #include <linux/slab.h>
42 #include <linux/vgaarb.h>
43 #include <linux/export.h>
45 /* Access macro for slots in vblank timestamp ringbuffer. */
46 #define vblanktimestamp(dev, pipe, count) \
47 ((dev)->vblank[pipe].time[(count) % DRM_VBLANKTIME_RBSIZE])
49 /* Retry timestamp calculation up to 3 times to satisfy
50 * drm_timestamp_precision before giving up.
52 #define DRM_TIMESTAMP_MAXRETRIES 3
54 /* Threshold in nanoseconds for detection of redundant
55 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
57 #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
60 drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
61 struct timeval *tvblank, unsigned flags);
63 static unsigned int drm_timestamp_precision = 20; /* Default to 20 usecs. */
66 * Default to use monotonic timestamps for wait-for-vblank and page-flip
69 unsigned int drm_timestamp_monotonic = 1;
71 static int drm_vblank_offdelay = 5000; /* Default to 5000 msecs. */
73 module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
74 module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
75 module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);
77 static void store_vblank(struct drm_device *dev, unsigned int pipe,
79 struct timeval *t_vblank, u32 last)
81 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
84 assert_spin_locked(&dev->vblank_time_lock);
88 /* All writers hold the spinlock, but readers are serialized by
89 * the latching of vblank->count below.
91 tslot = vblank->count + vblank_count_inc;
92 vblanktimestamp(dev, pipe, tslot) = *t_vblank;
95 * vblank timestamp updates are protected on the write side with
96 * vblank_time_lock, but on the read side done locklessly using a
97 * sequence-lock on the vblank counter. Ensure correct ordering using
98 * memory barrriers. We need the barrier both before and also after the
99 * counter update to synchronize with the next timestamp write.
100 * The read-side barriers for this are in drm_vblank_count_and_time.
103 vblank->count += vblank_count_inc;
108 * drm_reset_vblank_timestamp - reset the last timestamp to the last vblank
110 * @pipe: index of CRTC for which to reset the timestamp
112 * Reset the stored timestamp for the current vblank count to correspond
113 * to the last vblank occurred.
115 * Only to be called from drm_vblank_on().
117 * Note: caller must hold dev->vbl_lock since this reads & writes
118 * device vblank fields.
120 static void drm_reset_vblank_timestamp(struct drm_device *dev, unsigned int pipe)
124 struct timeval t_vblank;
125 int count = DRM_TIMESTAMP_MAXRETRIES;
127 spin_lock(&dev->vblank_time_lock);
130 * sample the current counter to avoid random jumps
131 * when drm_vblank_enable() applies the diff
134 cur_vblank = dev->driver->get_vblank_counter(dev, pipe);
135 rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, 0);
136 } while (cur_vblank != dev->driver->get_vblank_counter(dev, pipe) && --count > 0);
139 * Only reinitialize corresponding vblank timestamp if high-precision query
140 * available and didn't fail. Otherwise reinitialize delayed at next vblank
141 * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid.
144 t_vblank = (struct timeval) {0, 0};
147 * +1 to make sure user will never see the same
148 * vblank counter value before and after a modeset
150 store_vblank(dev, pipe, 1, &t_vblank, cur_vblank);
152 spin_unlock(&dev->vblank_time_lock);
156 * drm_update_vblank_count - update the master vblank counter
158 * @pipe: counter to update
160 * Call back into the driver to update the appropriate vblank counter
161 * (specified by @pipe). Deal with wraparound, if it occurred, and
162 * update the last read value so we can deal with wraparound on the next
165 * Only necessary when going from off->on, to account for frames we
166 * didn't get an interrupt for.
168 * Note: caller must hold dev->vbl_lock since this reads & writes
169 * device vblank fields.
171 static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
174 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
175 u32 cur_vblank, diff;
177 struct timeval t_vblank;
178 int count = DRM_TIMESTAMP_MAXRETRIES;
179 int framedur_ns = vblank->framedur_ns;
182 * Interrupts were disabled prior to this call, so deal with counter
184 * NOTE! It's possible we lost a full dev->max_vblank_count + 1 events
185 * here if the register is small or we had vblank interrupts off for
188 * We repeat the hardware vblank counter & timestamp query until
189 * we get consistent results. This to prevent races between gpu
190 * updating its hardware counter while we are retrieving the
191 * corresponding vblank timestamp.
194 cur_vblank = dev->driver->get_vblank_counter(dev, pipe);
195 rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, flags);
196 } while (cur_vblank != dev->driver->get_vblank_counter(dev, pipe) && --count > 0);
198 if (dev->max_vblank_count != 0) {
199 /* trust the hw counter when it's around */
200 diff = (cur_vblank - vblank->last) & dev->max_vblank_count;
201 } else if (rc && framedur_ns) {
202 const struct timeval *t_old;
205 t_old = &vblanktimestamp(dev, pipe, vblank->count);
206 diff_ns = timeval_to_ns(&t_vblank) - timeval_to_ns(t_old);
209 * Figure out how many vblanks we've missed based
210 * on the difference in the timestamps and the
211 * frame/field duration.
213 diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
215 if (diff == 0 && flags & DRM_CALLED_FROM_VBLIRQ)
216 DRM_DEBUG_VBL("crtc %u: Redundant vblirq ignored."
217 " diff_ns = %lld, framedur_ns = %d)\n",
218 pipe, (long long) diff_ns, framedur_ns);
220 /* some kind of default for drivers w/o accurate vbl timestamping */
221 diff = (flags & DRM_CALLED_FROM_VBLIRQ) != 0;
225 * Within a drm_vblank_pre_modeset - drm_vblank_post_modeset
226 * interval? If so then vblank irqs keep running and it will likely
227 * happen that the hardware vblank counter is not trustworthy as it
228 * might reset at some point in that interval and vblank timestamps
229 * are not trustworthy either in that interval. Iow. this can result
230 * in a bogus diff >> 1 which must be avoided as it would cause
231 * random large forward jumps of the software vblank counter.
233 if (diff > 1 && (vblank->inmodeset & 0x2)) {
234 DRM_DEBUG_VBL("clamping vblank bump to 1 on crtc %u: diffr=%u"
235 " due to pre-modeset.\n", pipe, diff);
240 * FIMXE: Need to replace this hack with proper seqlocks.
242 * Restrict the bump of the software vblank counter to a safe maximum
243 * value of +1 whenever there is the possibility that concurrent readers
244 * of vblank timestamps could be active at the moment, as the current
245 * implementation of the timestamp caching and updating is not safe
246 * against concurrent readers for calls to store_vblank() with a bump
247 * of anything but +1. A bump != 1 would very likely return corrupted
248 * timestamps to userspace, because the same slot in the cache could
249 * be concurrently written by store_vblank() and read by one of those
250 * readers without the read-retry logic detecting the collision.
252 * Concurrent readers can exist when we are called from the
253 * drm_vblank_off() or drm_vblank_on() functions and other non-vblank-
254 * irq callers. However, all those calls to us are happening with the
255 * vbl_lock locked to prevent drm_vblank_get(), so the vblank refcount
256 * can't increase while we are executing. Therefore a zero refcount at
257 * this point is safe for arbitrary counter bumps if we are called
258 * outside vblank irq, a non-zero count is not 100% safe. Unfortunately
259 * we must also accept a refcount of 1, as whenever we are called from
260 * drm_vblank_get() -> drm_vblank_enable() the refcount will be 1 and
261 * we must let that one pass through in order to not lose vblank counts
262 * during vblank irq off - which would completely defeat the whole
263 * point of this routine.
265 * Whenever we are called from vblank irq, we have to assume concurrent
266 * readers exist or can show up any time during our execution, even if
267 * the refcount is currently zero, as vblank irqs are usually only
268 * enabled due to the presence of readers, and because when we are called
269 * from vblank irq we can't hold the vbl_lock to protect us from sudden
270 * bumps in vblank refcount. Therefore also restrict bumps to +1 when
271 * called from vblank irq.
273 if ((diff > 1) && (atomic_read(&vblank->refcount) > 1 ||
274 (flags & DRM_CALLED_FROM_VBLIRQ))) {
275 DRM_DEBUG_VBL("clamping vblank bump to 1 on crtc %u: diffr=%u "
276 "refcount %u, vblirq %u\n", pipe, diff,
277 atomic_read(&vblank->refcount),
278 (flags & DRM_CALLED_FROM_VBLIRQ) != 0);
282 DRM_DEBUG_VBL("updating vblank count on crtc %u:"
283 " current=%u, diff=%u, hw=%u hw_last=%u\n",
284 pipe, vblank->count, diff, cur_vblank, vblank->last);
287 WARN_ON_ONCE(cur_vblank != vblank->last);
292 * Only reinitialize corresponding vblank timestamp if high-precision query
293 * available and didn't fail, or we were called from the vblank interrupt.
294 * Otherwise reinitialize delayed at next vblank interrupt and assign 0
295 * for now, to mark the vblanktimestamp as invalid.
297 if (!rc && (flags & DRM_CALLED_FROM_VBLIRQ) == 0)
298 t_vblank = (struct timeval) {0, 0};
300 store_vblank(dev, pipe, diff, &t_vblank, cur_vblank);
304 * Disable vblank irq's on crtc, make sure that last vblank count
305 * of hardware and corresponding consistent software vblank counter
306 * are preserved, even if there are any spurious vblank irq's after
309 static void vblank_disable_and_save(struct drm_device *dev, unsigned int pipe)
311 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
312 unsigned long irqflags;
314 /* Prevent vblank irq processing while disabling vblank irqs,
315 * so no updates of timestamps or count can happen after we've
316 * disabled. Needed to prevent races in case of delayed irq's.
318 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
321 * Only disable vblank interrupts if they're enabled. This avoids
322 * calling the ->disable_vblank() operation in atomic context with the
323 * hardware potentially runtime suspended.
325 if (vblank->enabled) {
326 dev->driver->disable_vblank(dev, pipe);
327 vblank->enabled = false;
331 * Always update the count and timestamp to maintain the
332 * appearance that the counter has been ticking all along until
333 * this time. This makes the count account for the entire time
334 * between drm_vblank_on() and drm_vblank_off().
336 drm_update_vblank_count(dev, pipe, 0);
338 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
341 static void vblank_disable_fn(unsigned long arg)
343 struct drm_vblank_crtc *vblank = (void *)arg;
344 struct drm_device *dev = vblank->dev;
345 unsigned int pipe = vblank->pipe;
346 unsigned long irqflags;
348 if (!dev->vblank_disable_allowed)
351 spin_lock_irqsave(&dev->vbl_lock, irqflags);
352 if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
353 DRM_DEBUG("disabling vblank on crtc %u\n", pipe);
354 vblank_disable_and_save(dev, pipe);
356 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
360 * drm_vblank_cleanup - cleanup vblank support
363 * This function cleans up any resources allocated in drm_vblank_init.
365 void drm_vblank_cleanup(struct drm_device *dev)
369 /* Bail if the driver didn't call drm_vblank_init() */
370 if (dev->num_crtcs == 0)
373 for (pipe = 0; pipe < dev->num_crtcs; pipe++) {
374 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
376 WARN_ON(vblank->enabled &&
377 drm_core_check_feature(dev, DRIVER_MODESET));
379 del_timer_sync(&vblank->disable_timer);
386 EXPORT_SYMBOL(drm_vblank_cleanup);
389 * drm_vblank_init - initialize vblank support
391 * @num_crtcs: number of CRTCs supported by @dev
393 * This function initializes vblank support for @num_crtcs display pipelines.
396 * Zero on success or a negative error code on failure.
398 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
403 spin_lock_init(&dev->vbl_lock);
404 spin_lock_init(&dev->vblank_time_lock);
406 dev->num_crtcs = num_crtcs;
408 dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
412 for (i = 0; i < num_crtcs; i++) {
413 struct drm_vblank_crtc *vblank = &dev->vblank[i];
417 init_waitqueue_head(&vblank->queue);
418 setup_timer(&vblank->disable_timer, vblank_disable_fn,
419 (unsigned long)vblank);
422 DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
424 /* Driver specific high-precision vblank timestamping supported? */
425 if (dev->driver->get_vblank_timestamp)
426 DRM_INFO("Driver supports precise vblank timestamp query.\n");
428 DRM_INFO("No driver support for vblank timestamp query.\n");
430 /* Must have precise timestamping for reliable vblank instant disable */
431 if (dev->vblank_disable_immediate && !dev->driver->get_vblank_timestamp) {
432 dev->vblank_disable_immediate = false;
433 DRM_INFO("Setting vblank_disable_immediate to false because "
434 "get_vblank_timestamp == NULL\n");
437 dev->vblank_disable_allowed = false;
445 EXPORT_SYMBOL(drm_vblank_init);
447 static void drm_irq_vgaarb_nokms(void *cookie, bool state)
449 struct drm_device *dev = cookie;
451 if (dev->driver->vgaarb_irq) {
452 dev->driver->vgaarb_irq(dev, state);
456 if (!dev->irq_enabled)
460 if (dev->driver->irq_uninstall)
461 dev->driver->irq_uninstall(dev);
463 if (dev->driver->irq_preinstall)
464 dev->driver->irq_preinstall(dev);
465 if (dev->driver->irq_postinstall)
466 dev->driver->irq_postinstall(dev);
471 * drm_irq_install - install IRQ handler
473 * @irq: IRQ number to install the handler for
475 * Initializes the IRQ related data. Installs the handler, calling the driver
476 * irq_preinstall() and irq_postinstall() functions before and after the
479 * This is the simplified helper interface provided for drivers with no special
480 * needs. Drivers which need to install interrupt handlers for multiple
481 * interrupts must instead set drm_device->irq_enabled to signal the DRM core
482 * that vblank interrupts are available.
485 * Zero on success or a negative error code on failure.
487 int drm_irq_install(struct drm_device *dev, int irq)
490 unsigned long sh_flags = 0;
492 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
498 /* Driver must have been initialized */
499 if (!dev->dev_private)
502 if (dev->irq_enabled)
504 dev->irq_enabled = true;
506 DRM_DEBUG("irq=%d\n", irq);
508 /* Before installing handler */
509 if (dev->driver->irq_preinstall)
510 dev->driver->irq_preinstall(dev);
512 /* Install handler */
513 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
514 sh_flags = IRQF_SHARED;
516 ret = request_irq(irq, dev->driver->irq_handler,
517 sh_flags, dev->driver->name, dev);
520 dev->irq_enabled = false;
524 if (!drm_core_check_feature(dev, DRIVER_MODESET))
525 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
527 /* After installing handler */
528 if (dev->driver->irq_postinstall)
529 ret = dev->driver->irq_postinstall(dev);
532 dev->irq_enabled = false;
533 if (!drm_core_check_feature(dev, DRIVER_MODESET))
534 vga_client_register(dev->pdev, NULL, NULL, NULL);
542 EXPORT_SYMBOL(drm_irq_install);
545 * drm_irq_uninstall - uninstall the IRQ handler
548 * Calls the driver's irq_uninstall() function and unregisters the IRQ handler.
549 * This should only be called by drivers which used drm_irq_install() to set up
550 * their interrupt handler. Other drivers must only reset
551 * drm_device->irq_enabled to false.
553 * Note that for kernel modesetting drivers it is a bug if this function fails.
554 * The sanity checks are only to catch buggy user modesetting drivers which call
555 * the same function through an ioctl.
558 * Zero on success or a negative error code on failure.
560 int drm_irq_uninstall(struct drm_device *dev)
562 unsigned long irqflags;
566 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
569 irq_enabled = dev->irq_enabled;
570 dev->irq_enabled = false;
573 * Wake up any waiters so they don't hang. This is just to paper over
574 * isssues for UMS drivers which aren't in full control of their
575 * vblank/irq handling. KMS drivers must ensure that vblanks are all
576 * disabled when uninstalling the irq handler.
578 if (dev->num_crtcs) {
579 spin_lock_irqsave(&dev->vbl_lock, irqflags);
580 for (i = 0; i < dev->num_crtcs; i++) {
581 struct drm_vblank_crtc *vblank = &dev->vblank[i];
583 if (!vblank->enabled)
586 WARN_ON(drm_core_check_feature(dev, DRIVER_MODESET));
588 vblank_disable_and_save(dev, i);
589 wake_up(&vblank->queue);
591 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
597 DRM_DEBUG("irq=%d\n", dev->irq);
599 if (!drm_core_check_feature(dev, DRIVER_MODESET))
600 vga_client_register(dev->pdev, NULL, NULL, NULL);
602 if (dev->driver->irq_uninstall)
603 dev->driver->irq_uninstall(dev);
605 free_irq(dev->irq, dev);
609 EXPORT_SYMBOL(drm_irq_uninstall);
614 * \param inode device inode.
615 * \param file_priv DRM file private.
616 * \param cmd command.
617 * \param arg user argument, pointing to a drm_control structure.
618 * \return zero on success or a negative number on failure.
620 * Calls irq_install() or irq_uninstall() according to \p arg.
622 int drm_control(struct drm_device *dev, void *data,
623 struct drm_file *file_priv)
625 struct drm_control *ctl = data;
628 /* if we haven't irq we fallback for compatibility reasons -
629 * this used to be a separate function in drm_dma.h
632 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
634 if (drm_core_check_feature(dev, DRIVER_MODESET))
636 /* UMS was only ever support on pci devices. */
637 if (WARN_ON(!dev->pdev))
641 case DRM_INST_HANDLER:
642 irq = dev->pdev->irq;
644 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
647 mutex_lock(&dev->struct_mutex);
648 ret = drm_irq_install(dev, irq);
649 mutex_unlock(&dev->struct_mutex);
652 case DRM_UNINST_HANDLER:
653 mutex_lock(&dev->struct_mutex);
654 ret = drm_irq_uninstall(dev);
655 mutex_unlock(&dev->struct_mutex);
664 * drm_calc_timestamping_constants - calculate vblank timestamp constants
665 * @crtc: drm_crtc whose timestamp constants should be updated.
666 * @mode: display mode containing the scanout timings
668 * Calculate and store various constants which are later
669 * needed by vblank and swap-completion timestamping, e.g,
670 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
671 * derived from CRTC's true scanout timing, so they take
672 * things like panel scaling or other adjustments into account.
674 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
675 const struct drm_display_mode *mode)
677 struct drm_device *dev = crtc->dev;
678 unsigned int pipe = drm_crtc_index(crtc);
679 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
680 int linedur_ns = 0, framedur_ns = 0;
681 int dotclock = mode->crtc_clock;
686 if (WARN_ON(pipe >= dev->num_crtcs))
689 /* Valid dotclock? */
691 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
694 * Convert scanline length in pixels and video
695 * dot clock to line duration and frame duration
698 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
699 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
702 * Fields of interlaced scanout modes are only half a frame duration.
704 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
707 DRM_ERROR("crtc %u: Can't calculate constants, dotclock = 0!\n",
710 vblank->linedur_ns = linedur_ns;
711 vblank->framedur_ns = framedur_ns;
713 DRM_DEBUG("crtc %u: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
714 crtc->base.id, mode->crtc_htotal,
715 mode->crtc_vtotal, mode->crtc_vdisplay);
716 DRM_DEBUG("crtc %u: clock %d kHz framedur %d linedur %d\n",
717 crtc->base.id, dotclock, framedur_ns, linedur_ns);
719 EXPORT_SYMBOL(drm_calc_timestamping_constants);
722 * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
724 * @pipe: index of CRTC whose vblank timestamp to retrieve
725 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
726 * On return contains true maximum error of timestamp
727 * @vblank_time: Pointer to struct timeval which should receive the timestamp
728 * @flags: Flags to pass to driver:
730 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
731 * @mode: mode which defines the scanout timings
733 * Implements calculation of exact vblank timestamps from given drm_display_mode
734 * timings and current video scanout position of a CRTC. This can be called from
735 * within get_vblank_timestamp() implementation of a kms driver to implement the
736 * actual timestamping.
738 * Should return timestamps conforming to the OML_sync_control OpenML
739 * extension specification. The timestamp corresponds to the end of
740 * the vblank interval, aka start of scanout of topmost-leftmost display
741 * pixel in the following video frame.
743 * Requires support for optional dev->driver->get_scanout_position()
744 * in kms driver, plus a bit of setup code to provide a drm_display_mode
745 * that corresponds to the true scanout timing.
747 * The current implementation only handles standard video modes. It
748 * returns as no operation if a doublescan or interlaced video mode is
749 * active. Higher level code is expected to handle this.
752 * Negative value on error, failure or if not supported in current
755 * -EINVAL - Invalid CRTC.
756 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
757 * -ENOTSUPP - Function not supported in current display mode.
758 * -EIO - Failed, e.g., due to failed scanout position query.
760 * Returns or'ed positive status flags on success:
762 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
763 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
766 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
769 struct timeval *vblank_time,
771 const struct drm_display_mode *mode)
773 struct timeval tv_etime;
774 ktime_t stime, etime;
775 unsigned int vbl_status;
776 int ret = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
778 int delta_ns, duration_ns;
780 if (pipe >= dev->num_crtcs) {
781 DRM_ERROR("Invalid crtc %u\n", pipe);
785 /* Scanout position query not supported? Should not happen. */
786 if (!dev->driver->get_scanout_position) {
787 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
791 /* If mode timing undefined, just return as no-op:
792 * Happens during initial modesetting of a crtc.
794 if (mode->crtc_clock == 0) {
795 DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
799 /* Get current scanout position with system timestamp.
800 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
801 * if single query takes longer than max_error nanoseconds.
803 * This guarantees a tight bound on maximum error if
804 * code gets preempted or delayed for some reason.
806 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
808 * Get vertical and horizontal scanout position vpos, hpos,
809 * and bounding timestamps stime, etime, pre/post query.
811 vbl_status = dev->driver->get_scanout_position(dev, pipe, flags,
816 /* Return as no-op if scanout query unsupported or failed. */
817 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
818 DRM_DEBUG("crtc %u : scanoutpos query failed [0x%x].\n",
823 /* Compute uncertainty in timestamp of scanout position query. */
824 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
826 /* Accept result with < max_error nsecs timing uncertainty. */
827 if (duration_ns <= *max_error)
831 /* Noisy system timing? */
832 if (i == DRM_TIMESTAMP_MAXRETRIES) {
833 DRM_DEBUG("crtc %u: Noisy timestamp %d us > %d us [%d reps].\n",
834 pipe, duration_ns/1000, *max_error/1000, i);
837 /* Return upper bound of timestamp precision error. */
838 *max_error = duration_ns;
840 /* Check if in vblank area:
841 * vpos is >=0 in video scanout area, but negative
842 * within vblank area, counting down the number of lines until
845 if (vbl_status & DRM_SCANOUTPOS_IN_VBLANK)
846 ret |= DRM_VBLANKTIME_IN_VBLANK;
848 /* Convert scanout position into elapsed time at raw_time query
849 * since start of scanout at first display scanline. delta_ns
850 * can be negative if start of scanout hasn't happened yet.
852 delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos),
855 if (!drm_timestamp_monotonic)
856 etime = ktime_mono_to_real(etime);
858 /* save this only for debugging purposes */
859 tv_etime = ktime_to_timeval(etime);
860 /* Subtract time delta from raw timestamp to get final
861 * vblank_time timestamp for end of vblank.
864 etime = ktime_add_ns(etime, -delta_ns);
866 etime = ktime_sub_ns(etime, delta_ns);
867 *vblank_time = ktime_to_timeval(etime);
869 DRM_DEBUG_VBL("crtc %u : v 0x%x p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
870 pipe, vbl_status, hpos, vpos,
871 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
872 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
873 duration_ns/1000, i);
877 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
879 static struct timeval get_drm_timestamp(void)
883 now = drm_timestamp_monotonic ? ktime_get() : ktime_get_real();
884 return ktime_to_timeval(now);
888 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
891 * @pipe: index of CRTC whose vblank timestamp to retrieve
892 * @tvblank: Pointer to target struct timeval which should receive the timestamp
893 * @flags: Flags to pass to driver:
895 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
897 * Fetches the system timestamp corresponding to the time of the most recent
898 * vblank interval on specified CRTC. May call into kms-driver to
899 * compute the timestamp with a high-precision GPU specific method.
901 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
902 * call, i.e., it isn't very precisely locked to the true vblank.
905 * True if timestamp is considered to be very precise, false otherwise.
908 drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
909 struct timeval *tvblank, unsigned flags)
913 /* Define requested maximum error on timestamps (nanoseconds). */
914 int max_error = (int) drm_timestamp_precision * 1000;
916 /* Query driver if possible and precision timestamping enabled. */
917 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
918 ret = dev->driver->get_vblank_timestamp(dev, pipe, &max_error,
924 /* GPU high precision timestamp query unsupported or failed.
925 * Return current monotonic/gettimeofday timestamp as best estimate.
927 *tvblank = get_drm_timestamp();
933 * drm_vblank_count - retrieve "cooked" vblank counter value
935 * @pipe: index of CRTC for which to retrieve the counter
937 * Fetches the "cooked" vblank count value that represents the number of
938 * vblank events since the system was booted, including lost events due to
939 * modesetting activity.
941 * This is the legacy version of drm_crtc_vblank_count().
944 * The software vblank counter.
946 u32 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
948 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
950 if (WARN_ON(pipe >= dev->num_crtcs))
953 return vblank->count;
955 EXPORT_SYMBOL(drm_vblank_count);
958 * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
959 * @crtc: which counter to retrieve
961 * Fetches the "cooked" vblank count value that represents the number of
962 * vblank events since the system was booted, including lost events due to
963 * modesetting activity.
965 * This is the native KMS version of drm_vblank_count().
968 * The software vblank counter.
970 u32 drm_crtc_vblank_count(struct drm_crtc *crtc)
972 return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
974 EXPORT_SYMBOL(drm_crtc_vblank_count);
977 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value and the
978 * system timestamp corresponding to that vblank counter value.
980 * @pipe: index of CRTC whose counter to retrieve
981 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
983 * Fetches the "cooked" vblank count value that represents the number of
984 * vblank events since the system was booted, including lost events due to
985 * modesetting activity. Returns corresponding system timestamp of the time
986 * of the vblank interval that corresponds to the current vblank counter value.
988 * This is the legacy version of drm_crtc_vblank_count_and_time().
990 u32 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
991 struct timeval *vblanktime)
993 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
994 int count = DRM_TIMESTAMP_MAXRETRIES;
997 if (WARN_ON(pipe >= dev->num_crtcs))
1001 * Vblank timestamps are read lockless. To ensure consistency the vblank
1002 * counter is rechecked and ordering is ensured using memory barriers.
1003 * This works like a seqlock. The write-side barriers are in store_vblank.
1006 cur_vblank = vblank->count;
1008 *vblanktime = vblanktimestamp(dev, pipe, cur_vblank);
1010 } while (cur_vblank != vblank->count && --count > 0);
1014 EXPORT_SYMBOL(drm_vblank_count_and_time);
1017 * drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value
1018 * and the system timestamp corresponding to that vblank counter value
1019 * @crtc: which counter to retrieve
1020 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
1022 * Fetches the "cooked" vblank count value that represents the number of
1023 * vblank events since the system was booted, including lost events due to
1024 * modesetting activity. Returns corresponding system timestamp of the time
1025 * of the vblank interval that corresponds to the current vblank counter value.
1027 * This is the native KMS version of drm_vblank_count_and_time().
1029 u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
1030 struct timeval *vblanktime)
1032 return drm_vblank_count_and_time(crtc->dev, drm_crtc_index(crtc),
1035 EXPORT_SYMBOL(drm_crtc_vblank_count_and_time);
1037 static void send_vblank_event(struct drm_device *dev,
1038 struct drm_pending_vblank_event *e,
1039 unsigned long seq, struct timeval *now)
1041 assert_spin_locked(&dev->event_lock);
1043 e->event.sequence = seq;
1044 e->event.tv_sec = now->tv_sec;
1045 e->event.tv_usec = now->tv_usec;
1047 list_add_tail(&e->base.link,
1048 &e->base.file_priv->event_list);
1049 wake_up_interruptible(&e->base.file_priv->event_wait);
1050 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
1055 * drm_arm_vblank_event - arm vblank event after pageflip
1058 * @e: the event to prepare to send
1060 * A lot of drivers need to generate vblank events for the very next vblank
1061 * interrupt. For example when the page flip interrupt happens when the page
1062 * flip gets armed, but not when it actually executes within the next vblank
1063 * period. This helper function implements exactly the required vblank arming
1066 * Caller must hold event lock. Caller must also hold a vblank reference for
1067 * the event @e, which will be dropped when the next vblank arrives.
1069 * This is the legacy version of drm_crtc_arm_vblank_event().
1071 void drm_arm_vblank_event(struct drm_device *dev, unsigned int pipe,
1072 struct drm_pending_vblank_event *e)
1074 assert_spin_locked(&dev->event_lock);
1077 e->event.sequence = drm_vblank_count(dev, pipe);
1078 list_add_tail(&e->base.link, &dev->vblank_event_list);
1080 EXPORT_SYMBOL(drm_arm_vblank_event);
1083 * drm_crtc_arm_vblank_event - arm vblank event after pageflip
1084 * @crtc: the source CRTC of the vblank event
1085 * @e: the event to send
1087 * A lot of drivers need to generate vblank events for the very next vblank
1088 * interrupt. For example when the page flip interrupt happens when the page
1089 * flip gets armed, but not when it actually executes within the next vblank
1090 * period. This helper function implements exactly the required vblank arming
1093 * Caller must hold event lock. Caller must also hold a vblank reference for
1094 * the event @e, which will be dropped when the next vblank arrives.
1096 * This is the native KMS version of drm_arm_vblank_event().
1098 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
1099 struct drm_pending_vblank_event *e)
1101 drm_arm_vblank_event(crtc->dev, drm_crtc_index(crtc), e);
1103 EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
1106 * drm_send_vblank_event - helper to send vblank event after pageflip
1109 * @e: the event to send
1111 * Updates sequence # and timestamp on event, and sends it to userspace.
1112 * Caller must hold event lock.
1114 * This is the legacy version of drm_crtc_send_vblank_event().
1116 void drm_send_vblank_event(struct drm_device *dev, unsigned int pipe,
1117 struct drm_pending_vblank_event *e)
1122 if (dev->num_crtcs > 0) {
1123 seq = drm_vblank_count_and_time(dev, pipe, &now);
1127 now = get_drm_timestamp();
1130 send_vblank_event(dev, e, seq, &now);
1132 EXPORT_SYMBOL(drm_send_vblank_event);
1135 * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
1136 * @crtc: the source CRTC of the vblank event
1137 * @e: the event to send
1139 * Updates sequence # and timestamp on event, and sends it to userspace.
1140 * Caller must hold event lock.
1142 * This is the native KMS version of drm_send_vblank_event().
1144 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
1145 struct drm_pending_vblank_event *e)
1147 drm_send_vblank_event(crtc->dev, drm_crtc_index(crtc), e);
1149 EXPORT_SYMBOL(drm_crtc_send_vblank_event);
1152 * drm_vblank_enable - enable the vblank interrupt on a CRTC
1157 * Zero on success or a negative error code on failure.
1159 static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
1161 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1164 assert_spin_locked(&dev->vbl_lock);
1166 spin_lock(&dev->vblank_time_lock);
1168 if (!vblank->enabled) {
1170 * Enable vblank irqs under vblank_time_lock protection.
1171 * All vblank count & timestamp updates are held off
1172 * until we are done reinitializing master counter and
1173 * timestamps. Filtercode in drm_handle_vblank() will
1174 * prevent double-accounting of same vblank interval.
1176 ret = dev->driver->enable_vblank(dev, pipe);
1177 DRM_DEBUG("enabling vblank on crtc %u, ret: %d\n", pipe, ret);
1179 atomic_dec(&vblank->refcount);
1181 vblank->enabled = true;
1182 drm_update_vblank_count(dev, pipe, 0);
1186 spin_unlock(&dev->vblank_time_lock);
1192 * drm_vblank_get - get a reference count on vblank events
1194 * @pipe: index of CRTC to own
1196 * Acquire a reference count on vblank events to avoid having them disabled
1199 * This is the legacy version of drm_crtc_vblank_get().
1202 * Zero on success or a negative error code on failure.
1204 int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
1206 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1207 unsigned long irqflags;
1210 if (!dev->num_crtcs)
1213 if (WARN_ON(pipe >= dev->num_crtcs))
1216 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1217 /* Going from 0->1 means we have to enable interrupts again */
1218 if (atomic_add_return(1, &vblank->refcount) == 1) {
1219 ret = drm_vblank_enable(dev, pipe);
1221 if (!vblank->enabled) {
1222 atomic_dec(&vblank->refcount);
1226 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1230 EXPORT_SYMBOL(drm_vblank_get);
1233 * drm_crtc_vblank_get - get a reference count on vblank events
1234 * @crtc: which CRTC to own
1236 * Acquire a reference count on vblank events to avoid having them disabled
1239 * This is the native kms version of drm_vblank_get().
1242 * Zero on success or a negative error code on failure.
1244 int drm_crtc_vblank_get(struct drm_crtc *crtc)
1246 return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
1248 EXPORT_SYMBOL(drm_crtc_vblank_get);
1251 * drm_vblank_put - release ownership of vblank events
1253 * @pipe: index of CRTC to release
1255 * Release ownership of a given vblank counter, turning off interrupts
1256 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1258 * This is the legacy version of drm_crtc_vblank_put().
1260 void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
1262 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1264 if (WARN_ON(pipe >= dev->num_crtcs))
1267 if (WARN_ON(atomic_read(&vblank->refcount) == 0))
1270 /* Last user schedules interrupt disable */
1271 if (atomic_dec_and_test(&vblank->refcount)) {
1272 if (drm_vblank_offdelay == 0)
1274 else if (drm_vblank_offdelay < 0)
1275 vblank_disable_fn((unsigned long)vblank);
1276 else if (!dev->vblank_disable_immediate)
1277 mod_timer(&vblank->disable_timer,
1278 jiffies + ((drm_vblank_offdelay * HZ)/1000));
1281 EXPORT_SYMBOL(drm_vblank_put);
1284 * drm_crtc_vblank_put - give up ownership of vblank events
1285 * @crtc: which counter to give up
1287 * Release ownership of a given vblank counter, turning off interrupts
1288 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1290 * This is the native kms version of drm_vblank_put().
1292 void drm_crtc_vblank_put(struct drm_crtc *crtc)
1294 drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
1296 EXPORT_SYMBOL(drm_crtc_vblank_put);
1299 * drm_wait_one_vblank - wait for one vblank
1303 * This waits for one vblank to pass on @pipe, using the irq driver interfaces.
1304 * It is a failure to call this when the vblank irq for @pipe is disabled, e.g.
1305 * due to lack of driver support or because the crtc is off.
1307 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe)
1309 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1313 if (WARN_ON(pipe >= dev->num_crtcs))
1316 ret = drm_vblank_get(dev, pipe);
1317 if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", pipe, ret))
1320 last = drm_vblank_count(dev, pipe);
1322 ret = wait_event_timeout(vblank->queue,
1323 last != drm_vblank_count(dev, pipe),
1324 msecs_to_jiffies(100));
1326 WARN(ret == 0, "vblank wait timed out on crtc %i\n", pipe);
1328 drm_vblank_put(dev, pipe);
1330 EXPORT_SYMBOL(drm_wait_one_vblank);
1333 * drm_crtc_wait_one_vblank - wait for one vblank
1336 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
1337 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
1338 * due to lack of driver support or because the crtc is off.
1340 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
1342 drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
1344 EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
1347 * drm_vblank_off - disable vblank events on a CRTC
1351 * Drivers can use this function to shut down the vblank interrupt handling when
1352 * disabling a crtc. This function ensures that the latest vblank frame count is
1353 * stored so that drm_vblank_on() can restore it again.
1355 * Drivers must use this function when the hardware vblank counter can get
1356 * reset, e.g. when suspending.
1358 * This is the legacy version of drm_crtc_vblank_off().
1360 void drm_vblank_off(struct drm_device *dev, unsigned int pipe)
1362 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1363 struct drm_pending_vblank_event *e, *t;
1365 unsigned long irqflags;
1368 if (WARN_ON(pipe >= dev->num_crtcs))
1371 spin_lock_irqsave(&dev->event_lock, irqflags);
1373 spin_lock(&dev->vbl_lock);
1374 DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
1375 pipe, vblank->enabled, vblank->inmodeset);
1377 /* Avoid redundant vblank disables without previous drm_vblank_on(). */
1378 if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset)
1379 vblank_disable_and_save(dev, pipe);
1381 wake_up(&vblank->queue);
1384 * Prevent subsequent drm_vblank_get() from re-enabling
1385 * the vblank interrupt by bumping the refcount.
1387 if (!vblank->inmodeset) {
1388 atomic_inc(&vblank->refcount);
1389 vblank->inmodeset = 1;
1391 spin_unlock(&dev->vbl_lock);
1393 /* Send any queued vblank events, lest the natives grow disquiet */
1394 seq = drm_vblank_count_and_time(dev, pipe, &now);
1396 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1397 if (e->pipe != pipe)
1399 DRM_DEBUG("Sending premature vblank event on disable: "
1400 "wanted %d, current %d\n",
1401 e->event.sequence, seq);
1402 list_del(&e->base.link);
1403 drm_vblank_put(dev, pipe);
1404 send_vblank_event(dev, e, seq, &now);
1406 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1408 EXPORT_SYMBOL(drm_vblank_off);
1411 * drm_crtc_vblank_off - disable vblank events on a CRTC
1412 * @crtc: CRTC in question
1414 * Drivers can use this function to shut down the vblank interrupt handling when
1415 * disabling a crtc. This function ensures that the latest vblank frame count is
1416 * stored so that drm_vblank_on can restore it again.
1418 * Drivers must use this function when the hardware vblank counter can get
1419 * reset, e.g. when suspending.
1421 * This is the native kms version of drm_vblank_off().
1423 void drm_crtc_vblank_off(struct drm_crtc *crtc)
1425 drm_vblank_off(crtc->dev, drm_crtc_index(crtc));
1427 EXPORT_SYMBOL(drm_crtc_vblank_off);
1430 * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
1431 * @crtc: CRTC in question
1433 * Drivers can use this function to reset the vblank state to off at load time.
1434 * Drivers should use this together with the drm_crtc_vblank_off() and
1435 * drm_crtc_vblank_on() functions. The difference compared to
1436 * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
1437 * and hence doesn't need to call any driver hooks.
1439 void drm_crtc_vblank_reset(struct drm_crtc *crtc)
1441 struct drm_device *dev = crtc->dev;
1442 unsigned long irqflags;
1443 unsigned int pipe = drm_crtc_index(crtc);
1444 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1446 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1448 * Prevent subsequent drm_vblank_get() from enabling the vblank
1449 * interrupt by bumping the refcount.
1451 if (!vblank->inmodeset) {
1452 atomic_inc(&vblank->refcount);
1453 vblank->inmodeset = 1;
1455 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1457 WARN_ON(!list_empty(&dev->vblank_event_list));
1459 EXPORT_SYMBOL(drm_crtc_vblank_reset);
1462 * drm_vblank_on - enable vblank events on a CRTC
1466 * This functions restores the vblank interrupt state captured with
1467 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1468 * drm_vblank_off() can be unbalanced and so can also be unconditionally called
1469 * in driver load code to reflect the current hardware state of the crtc.
1471 * This is the legacy version of drm_crtc_vblank_on().
1473 void drm_vblank_on(struct drm_device *dev, unsigned int pipe)
1475 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1476 unsigned long irqflags;
1478 if (WARN_ON(pipe >= dev->num_crtcs))
1481 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1482 DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
1483 pipe, vblank->enabled, vblank->inmodeset);
1485 /* Drop our private "prevent drm_vblank_get" refcount */
1486 if (vblank->inmodeset) {
1487 atomic_dec(&vblank->refcount);
1488 vblank->inmodeset = 0;
1491 drm_reset_vblank_timestamp(dev, pipe);
1494 * re-enable interrupts if there are users left, or the
1495 * user wishes vblank interrupts to be enabled all the time.
1497 if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0)
1498 WARN_ON(drm_vblank_enable(dev, pipe));
1499 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1501 EXPORT_SYMBOL(drm_vblank_on);
1504 * drm_crtc_vblank_on - enable vblank events on a CRTC
1505 * @crtc: CRTC in question
1507 * This functions restores the vblank interrupt state captured with
1508 * drm_vblank_off() again. Note that calls to drm_vblank_on() and
1509 * drm_vblank_off() can be unbalanced and so can also be unconditionally called
1510 * in driver load code to reflect the current hardware state of the crtc.
1512 * This is the native kms version of drm_vblank_on().
1514 void drm_crtc_vblank_on(struct drm_crtc *crtc)
1516 drm_vblank_on(crtc->dev, drm_crtc_index(crtc));
1518 EXPORT_SYMBOL(drm_crtc_vblank_on);
1521 * drm_vblank_pre_modeset - account for vblanks across mode sets
1525 * Account for vblank events across mode setting events, which will likely
1526 * reset the hardware frame counter.
1528 * This is done by grabbing a temporary vblank reference to ensure that the
1529 * vblank interrupt keeps running across the modeset sequence. With this the
1530 * software-side vblank frame counting will ensure that there are no jumps or
1533 * Unfortunately this approach is racy and also doesn't work when the vblank
1534 * interrupt stops running, e.g. across system suspend resume. It is therefore
1535 * highly recommended that drivers use the newer drm_vblank_off() and
1536 * drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when
1537 * using "cooked" software vblank frame counters and not relying on any hardware
1540 * Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc
1543 void drm_vblank_pre_modeset(struct drm_device *dev, unsigned int pipe)
1545 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1547 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1548 if (!dev->num_crtcs)
1551 if (WARN_ON(pipe >= dev->num_crtcs))
1555 * To avoid all the problems that might happen if interrupts
1556 * were enabled/disabled around or between these calls, we just
1557 * have the kernel take a reference on the CRTC (just once though
1558 * to avoid corrupting the count if multiple, mismatch calls occur),
1559 * so that interrupts remain enabled in the interim.
1561 if (!vblank->inmodeset) {
1562 vblank->inmodeset = 0x1;
1563 if (drm_vblank_get(dev, pipe) == 0)
1564 vblank->inmodeset |= 0x2;
1567 EXPORT_SYMBOL(drm_vblank_pre_modeset);
1570 * drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes
1574 * This function again drops the temporary vblank reference acquired in
1575 * drm_vblank_pre_modeset.
1577 void drm_vblank_post_modeset(struct drm_device *dev, unsigned int pipe)
1579 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1580 unsigned long irqflags;
1582 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1583 if (!dev->num_crtcs)
1586 if (WARN_ON(pipe >= dev->num_crtcs))
1589 if (vblank->inmodeset) {
1590 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1591 dev->vblank_disable_allowed = true;
1592 drm_reset_vblank_timestamp(dev, pipe);
1593 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1595 if (vblank->inmodeset & 0x2)
1596 drm_vblank_put(dev, pipe);
1598 vblank->inmodeset = 0;
1601 EXPORT_SYMBOL(drm_vblank_post_modeset);
1604 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1605 * @DRM_IOCTL_ARGS: standard ioctl arguments
1607 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1608 * ioctls around modesetting so that any lost vblank events are accounted for.
1610 * Generally the counter will reset across mode sets. If interrupts are
1611 * enabled around this call, we don't have to do anything since the counter
1612 * will have already been incremented.
1614 int drm_modeset_ctl(struct drm_device *dev, void *data,
1615 struct drm_file *file_priv)
1617 struct drm_modeset_ctl *modeset = data;
1620 /* If drm_vblank_init() hasn't been called yet, just no-op */
1621 if (!dev->num_crtcs)
1624 /* KMS drivers handle this internally */
1625 if (drm_core_check_feature(dev, DRIVER_MODESET))
1628 pipe = modeset->crtc;
1629 if (pipe >= dev->num_crtcs)
1632 switch (modeset->cmd) {
1633 case _DRM_PRE_MODESET:
1634 drm_vblank_pre_modeset(dev, pipe);
1636 case _DRM_POST_MODESET:
1637 drm_vblank_post_modeset(dev, pipe);
1646 static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
1647 union drm_wait_vblank *vblwait,
1648 struct drm_file *file_priv)
1650 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1651 struct drm_pending_vblank_event *e;
1653 unsigned long flags;
1657 e = kzalloc(sizeof(*e), GFP_KERNEL);
1664 e->base.pid = current->pid;
1665 e->event.base.type = DRM_EVENT_VBLANK;
1666 e->event.base.length = sizeof(e->event);
1667 e->event.user_data = vblwait->request.signal;
1668 e->base.event = &e->event.base;
1669 e->base.file_priv = file_priv;
1670 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
1672 spin_lock_irqsave(&dev->event_lock, flags);
1675 * drm_vblank_off() might have been called after we called
1676 * drm_vblank_get(). drm_vblank_off() holds event_lock
1677 * around the vblank disable, so no need for further locking.
1678 * The reference from drm_vblank_get() protects against
1679 * vblank disable from another source.
1681 if (!vblank->enabled) {
1686 if (file_priv->event_space < sizeof(e->event)) {
1691 file_priv->event_space -= sizeof(e->event);
1692 seq = drm_vblank_count_and_time(dev, pipe, &now);
1694 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1695 (seq - vblwait->request.sequence) <= (1 << 23)) {
1696 vblwait->request.sequence = seq + 1;
1697 vblwait->reply.sequence = vblwait->request.sequence;
1700 DRM_DEBUG("event on vblank count %d, current %d, crtc %u\n",
1701 vblwait->request.sequence, seq, pipe);
1703 trace_drm_vblank_event_queued(current->pid, pipe,
1704 vblwait->request.sequence);
1706 e->event.sequence = vblwait->request.sequence;
1707 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1708 drm_vblank_put(dev, pipe);
1709 send_vblank_event(dev, e, seq, &now);
1710 vblwait->reply.sequence = seq;
1712 /* drm_handle_vblank_events will call drm_vblank_put */
1713 list_add_tail(&e->base.link, &dev->vblank_event_list);
1714 vblwait->reply.sequence = vblwait->request.sequence;
1717 spin_unlock_irqrestore(&dev->event_lock, flags);
1722 spin_unlock_irqrestore(&dev->event_lock, flags);
1725 drm_vblank_put(dev, pipe);
1732 * \param inode device inode.
1733 * \param file_priv DRM file private.
1734 * \param cmd command.
1735 * \param data user argument, pointing to a drm_wait_vblank structure.
1736 * \return zero on success or a negative number on failure.
1738 * This function enables the vblank interrupt on the pipe requested, then
1739 * sleeps waiting for the requested sequence number to occur, and drops
1740 * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
1741 * after a timeout with no further vblank waits scheduled).
1743 int drm_wait_vblank(struct drm_device *dev, void *data,
1744 struct drm_file *file_priv)
1746 struct drm_vblank_crtc *vblank;
1747 union drm_wait_vblank *vblwait = data;
1749 unsigned int flags, seq, pipe, high_pipe;
1751 if (!dev->irq_enabled)
1754 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1757 if (vblwait->request.type &
1758 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1759 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1760 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1761 vblwait->request.type,
1762 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1763 _DRM_VBLANK_HIGH_CRTC_MASK));
1767 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1768 high_pipe = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1770 pipe = high_pipe >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1772 pipe = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1773 if (pipe >= dev->num_crtcs)
1776 vblank = &dev->vblank[pipe];
1778 ret = drm_vblank_get(dev, pipe);
1780 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1783 seq = drm_vblank_count(dev, pipe);
1785 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1786 case _DRM_VBLANK_RELATIVE:
1787 vblwait->request.sequence += seq;
1788 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1789 case _DRM_VBLANK_ABSOLUTE:
1796 if (flags & _DRM_VBLANK_EVENT) {
1797 /* must hold on to the vblank ref until the event fires
1798 * drm_vblank_put will be called asynchronously
1800 return drm_queue_vblank_event(dev, pipe, vblwait, file_priv);
1803 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1804 (seq - vblwait->request.sequence) <= (1<<23)) {
1805 vblwait->request.sequence = seq + 1;
1808 DRM_DEBUG("waiting on vblank count %d, crtc %u\n",
1809 vblwait->request.sequence, pipe);
1810 vblank->last_wait = vblwait->request.sequence;
1811 DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
1812 (((drm_vblank_count(dev, pipe) -
1813 vblwait->request.sequence) <= (1 << 23)) ||
1815 !dev->irq_enabled));
1817 if (ret != -EINTR) {
1820 vblwait->reply.sequence = drm_vblank_count_and_time(dev, pipe, &now);
1821 vblwait->reply.tval_sec = now.tv_sec;
1822 vblwait->reply.tval_usec = now.tv_usec;
1824 DRM_DEBUG("returning %d to client\n",
1825 vblwait->reply.sequence);
1827 DRM_DEBUG("vblank wait interrupted by signal\n");
1831 drm_vblank_put(dev, pipe);
1835 static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
1837 struct drm_pending_vblank_event *e, *t;
1841 assert_spin_locked(&dev->event_lock);
1843 seq = drm_vblank_count_and_time(dev, pipe, &now);
1845 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1846 if (e->pipe != pipe)
1848 if ((seq - e->event.sequence) > (1<<23))
1851 DRM_DEBUG("vblank event on %d, current %d\n",
1852 e->event.sequence, seq);
1854 list_del(&e->base.link);
1855 drm_vblank_put(dev, pipe);
1856 send_vblank_event(dev, e, seq, &now);
1859 trace_drm_vblank_event(pipe, seq);
1863 * drm_handle_vblank - handle a vblank event
1865 * @pipe: index of CRTC where this event occurred
1867 * Drivers should call this routine in their vblank interrupt handlers to
1868 * update the vblank counter and send any signals that may be pending.
1870 * This is the legacy version of drm_crtc_handle_vblank().
1872 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
1874 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1875 unsigned long irqflags;
1877 if (WARN_ON_ONCE(!dev->num_crtcs))
1880 if (WARN_ON(pipe >= dev->num_crtcs))
1883 spin_lock_irqsave(&dev->event_lock, irqflags);
1885 /* Need timestamp lock to prevent concurrent execution with
1886 * vblank enable/disable, as this would cause inconsistent
1887 * or corrupted timestamps and vblank counts.
1889 spin_lock(&dev->vblank_time_lock);
1891 /* Vblank irq handling disabled. Nothing to do. */
1892 if (!vblank->enabled) {
1893 spin_unlock(&dev->vblank_time_lock);
1894 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1898 drm_update_vblank_count(dev, pipe, DRM_CALLED_FROM_VBLIRQ);
1900 spin_unlock(&dev->vblank_time_lock);
1902 wake_up(&vblank->queue);
1903 drm_handle_vblank_events(dev, pipe);
1905 /* With instant-off, we defer disabling the interrupt until after
1906 * we finish processing the following vblank. The disable has to
1907 * be last (after drm_handle_vblank_events) so that the timestamp
1908 * is always accurate.
1910 if (dev->vblank_disable_immediate &&
1911 drm_vblank_offdelay > 0 &&
1912 !atomic_read(&vblank->refcount))
1913 vblank_disable_fn((unsigned long)vblank);
1915 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1919 EXPORT_SYMBOL(drm_handle_vblank);
1922 * drm_crtc_handle_vblank - handle a vblank event
1923 * @crtc: where this event occurred
1925 * Drivers should call this routine in their vblank interrupt handlers to
1926 * update the vblank counter and send any signals that may be pending.
1928 * This is the native KMS version of drm_handle_vblank().
1931 * True if the event was successfully handled, false on failure.
1933 bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
1935 return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
1937 EXPORT_SYMBOL(drm_crtc_handle_vblank);
1940 * drm_vblank_no_hw_counter - "No hw counter" implementation of .get_vblank_counter()
1942 * @pipe: CRTC for which to read the counter
1944 * Drivers can plug this into the .get_vblank_counter() function if
1945 * there is no useable hardware frame counter available.
1950 u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
1954 EXPORT_SYMBOL(drm_vblank_no_hw_counter);