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1/*
2 * drm_irq.c IRQ and vblank support
3 *
4 * \author Rickard E. (Rik) Faith <faith@valinux.com>
5 * \author Gareth Hughes <gareth@valinux.com>
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the next
15 * paragraph) shall be included in all copies or substantial portions of the
16 * Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
22 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
23 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
24 * OTHER DEALINGS IN THE SOFTWARE.
25 */
26
27#include <drm/drm_vblank.h>
28#include <drm/drmP.h>
29#include <linux/export.h>
30
31#include "drm_trace.h"
32#include "drm_internal.h"
33
34/**
35 * DOC: vblank handling
36 *
37 * Vertical blanking plays a major role in graphics rendering. To achieve
38 * tear-free display, users must synchronize page flips and/or rendering to
39 * vertical blanking. The DRM API offers ioctls to perform page flips
40 * synchronized to vertical blanking and wait for vertical blanking.
41 *
42 * The DRM core handles most of the vertical blanking management logic, which
43 * involves filtering out spurious interrupts, keeping race-free blanking
44 * counters, coping with counter wrap-around and resets and keeping use counts.
45 * It relies on the driver to generate vertical blanking interrupts and
46 * optionally provide a hardware vertical blanking counter.
47 *
48 * Drivers must initialize the vertical blanking handling core with a call to
49 * drm_vblank_init(). Minimally, a driver needs to implement
50 * &drm_crtc_funcs.enable_vblank and &drm_crtc_funcs.disable_vblank plus call
51 * drm_crtc_handle_vblank() in it's vblank interrupt handler for working vblank
52 * support.
53 *
54 * Vertical blanking interrupts can be enabled by the DRM core or by drivers
55 * themselves (for instance to handle page flipping operations). The DRM core
56 * maintains a vertical blanking use count to ensure that the interrupts are not
57 * disabled while a user still needs them. To increment the use count, drivers
58 * call drm_crtc_vblank_get() and release the vblank reference again with
59 * drm_crtc_vblank_put(). In between these two calls vblank interrupts are
60 * guaranteed to be enabled.
61 *
62 * On many hardware disabling the vblank interrupt cannot be done in a race-free
63 * manner, see &drm_driver.vblank_disable_immediate and
64 * &drm_driver.max_vblank_count. In that case the vblank core only disables the
65 * vblanks after a timer has expired, which can be configured through the
66 * ``vblankoffdelay`` module parameter.
67 */
68
69/* Retry timestamp calculation up to 3 times to satisfy
70 * drm_timestamp_precision before giving up.
71 */
72#define DRM_TIMESTAMP_MAXRETRIES 3
73
74/* Threshold in nanoseconds for detection of redundant
75 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
76 */
77#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
78
79static bool
80drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
81 ktime_t *tvblank, bool in_vblank_irq);
82
83static unsigned int drm_timestamp_precision = 20; /* Default to 20 usecs. */
84
85static int drm_vblank_offdelay = 5000; /* Default to 5000 msecs. */
86
87module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
88module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
89MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs] (0: never disable, <0: disable immediately)");
90MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
91
92static void store_vblank(struct drm_device *dev, unsigned int pipe,
93 u32 vblank_count_inc,
94 ktime_t t_vblank, u32 last)
95{
96 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
97
98 assert_spin_locked(&dev->vblank_time_lock);
99
100 vblank->last = last;
101
102 write_seqlock(&vblank->seqlock);
103 vblank->time = t_vblank;
104 vblank->count += vblank_count_inc;
105 write_sequnlock(&vblank->seqlock);
106}
107
108/*
109 * "No hw counter" fallback implementation of .get_vblank_counter() hook,
110 * if there is no useable hardware frame counter available.
111 */
112static u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
113{
114 WARN_ON_ONCE(dev->max_vblank_count != 0);
115 return 0;
116}
117
118static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
119{
120 if (drm_core_check_feature(dev, DRIVER_MODESET)) {
121 struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
122
123 if (WARN_ON(!crtc))
124 return 0;
125
126 if (crtc->funcs->get_vblank_counter)
127 return crtc->funcs->get_vblank_counter(crtc);
128 }
129
130 if (dev->driver->get_vblank_counter)
131 return dev->driver->get_vblank_counter(dev, pipe);
132
133 return drm_vblank_no_hw_counter(dev, pipe);
134}
135
136/*
137 * Reset the stored timestamp for the current vblank count to correspond
138 * to the last vblank occurred.
139 *
140 * Only to be called from drm_crtc_vblank_on().
141 *
142 * Note: caller must hold &drm_device.vbl_lock since this reads & writes
143 * device vblank fields.
144 */
145static void drm_reset_vblank_timestamp(struct drm_device *dev, unsigned int pipe)
146{
147 u32 cur_vblank;
148 bool rc;
149 ktime_t t_vblank;
150 int count = DRM_TIMESTAMP_MAXRETRIES;
151
152 spin_lock(&dev->vblank_time_lock);
153
154 /*
155 * sample the current counter to avoid random jumps
156 * when drm_vblank_enable() applies the diff
157 */
158 do {
159 cur_vblank = __get_vblank_counter(dev, pipe);
160 rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
161 } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
162
163 /*
164 * Only reinitialize corresponding vblank timestamp if high-precision query
165 * available and didn't fail. Otherwise reinitialize delayed at next vblank
166 * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid.
167 */
168 if (!rc)
169 t_vblank = 0;
170
171 /*
172 * +1 to make sure user will never see the same
173 * vblank counter value before and after a modeset
174 */
175 store_vblank(dev, pipe, 1, t_vblank, cur_vblank);
176
177 spin_unlock(&dev->vblank_time_lock);
178}
179
180/*
181 * Call back into the driver to update the appropriate vblank counter
182 * (specified by @pipe). Deal with wraparound, if it occurred, and
183 * update the last read value so we can deal with wraparound on the next
184 * call if necessary.
185 *
186 * Only necessary when going from off->on, to account for frames we
187 * didn't get an interrupt for.
188 *
189 * Note: caller must hold &drm_device.vbl_lock since this reads & writes
190 * device vblank fields.
191 */
192static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
193 bool in_vblank_irq)
194{
195 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
196 u32 cur_vblank, diff;
197 bool rc;
198 ktime_t t_vblank;
199 int count = DRM_TIMESTAMP_MAXRETRIES;
200 int framedur_ns = vblank->framedur_ns;
201
202 /*
203 * Interrupts were disabled prior to this call, so deal with counter
204 * wrap if needed.
205 * NOTE! It's possible we lost a full dev->max_vblank_count + 1 events
206 * here if the register is small or we had vblank interrupts off for
207 * a long time.
208 *
209 * We repeat the hardware vblank counter & timestamp query until
210 * we get consistent results. This to prevent races between gpu
211 * updating its hardware counter while we are retrieving the
212 * corresponding vblank timestamp.
213 */
214 do {
215 cur_vblank = __get_vblank_counter(dev, pipe);
216 rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, in_vblank_irq);
217 } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
218
219 if (dev->max_vblank_count != 0) {
220 /* trust the hw counter when it's around */
221 diff = (cur_vblank - vblank->last) & dev->max_vblank_count;
222 } else if (rc && framedur_ns) {
223 u64 diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time));
224
225 /*
226 * Figure out how many vblanks we've missed based
227 * on the difference in the timestamps and the
228 * frame/field duration.
229 */
230 diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
231
232 if (diff == 0 && in_vblank_irq)
233 DRM_DEBUG_VBL("crtc %u: Redundant vblirq ignored."
234 " diff_ns = %lld, framedur_ns = %d)\n",
235 pipe, (long long) diff_ns, framedur_ns);
236 } else {
237 /* some kind of default for drivers w/o accurate vbl timestamping */
238 diff = in_vblank_irq ? 1 : 0;
239 }
240
241 /*
242 * Within a drm_vblank_pre_modeset - drm_vblank_post_modeset
243 * interval? If so then vblank irqs keep running and it will likely
244 * happen that the hardware vblank counter is not trustworthy as it
245 * might reset at some point in that interval and vblank timestamps
246 * are not trustworthy either in that interval. Iow. this can result
247 * in a bogus diff >> 1 which must be avoided as it would cause
248 * random large forward jumps of the software vblank counter.
249 */
250 if (diff > 1 && (vblank->inmodeset & 0x2)) {
251 DRM_DEBUG_VBL("clamping vblank bump to 1 on crtc %u: diffr=%u"
252 " due to pre-modeset.\n", pipe, diff);
253 diff = 1;
254 }
255
256 DRM_DEBUG_VBL("updating vblank count on crtc %u:"
257 " current=%llu, diff=%u, hw=%u hw_last=%u\n",
258 pipe, vblank->count, diff, cur_vblank, vblank->last);
259
260 if (diff == 0) {
261 WARN_ON_ONCE(cur_vblank != vblank->last);
262 return;
263 }
264
265 /*
266 * Only reinitialize corresponding vblank timestamp if high-precision query
267 * available and didn't fail, or we were called from the vblank interrupt.
268 * Otherwise reinitialize delayed at next vblank interrupt and assign 0
269 * for now, to mark the vblanktimestamp as invalid.
270 */
271 if (!rc && !in_vblank_irq)
272 t_vblank = 0;
273
274 store_vblank(dev, pipe, diff, t_vblank, cur_vblank);
275}
276
277static u64 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
278{
279 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
280
281 if (WARN_ON(pipe >= dev->num_crtcs))
282 return 0;
283
284 return vblank->count;
285}
286
287/**
288 * drm_crtc_accurate_vblank_count - retrieve the master vblank counter
289 * @crtc: which counter to retrieve
290 *
291 * This function is similar to drm_crtc_vblank_count() but this function
292 * interpolates to handle a race with vblank interrupts using the high precision
293 * timestamping support.
294 *
295 * This is mostly useful for hardware that can obtain the scanout position, but
296 * doesn't have a hardware frame counter.
297 */
298u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc)
299{
300 struct drm_device *dev = crtc->dev;
301 unsigned int pipe = drm_crtc_index(crtc);
302 u64 vblank;
303 unsigned long flags;
304
305 WARN_ONCE(drm_debug & DRM_UT_VBL && !dev->driver->get_vblank_timestamp,
306 "This function requires support for accurate vblank timestamps.");
307
308 spin_lock_irqsave(&dev->vblank_time_lock, flags);
309
310 drm_update_vblank_count(dev, pipe, false);
311 vblank = drm_vblank_count(dev, pipe);
312
313 spin_unlock_irqrestore(&dev->vblank_time_lock, flags);
314
315 return vblank;
316}
317EXPORT_SYMBOL(drm_crtc_accurate_vblank_count);
318
319static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
320{
321 if (drm_core_check_feature(dev, DRIVER_MODESET)) {
322 struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
323
324 if (WARN_ON(!crtc))
325 return;
326
327 if (crtc->funcs->disable_vblank) {
328 crtc->funcs->disable_vblank(crtc);
329 return;
330 }
331 }
332
333 dev->driver->disable_vblank(dev, pipe);
334}
335
336/*
337 * Disable vblank irq's on crtc, make sure that last vblank count
338 * of hardware and corresponding consistent software vblank counter
339 * are preserved, even if there are any spurious vblank irq's after
340 * disable.
341 */
342void drm_vblank_disable_and_save(struct drm_device *dev, unsigned int pipe)
343{
344 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
345 unsigned long irqflags;
346
347 assert_spin_locked(&dev->vbl_lock);
348
349 /* Prevent vblank irq processing while disabling vblank irqs,
350 * so no updates of timestamps or count can happen after we've
351 * disabled. Needed to prevent races in case of delayed irq's.
352 */
353 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
354
355 /*
356 * Update vblank count and disable vblank interrupts only if the
357 * interrupts were enabled. This avoids calling the ->disable_vblank()
358 * operation in atomic context with the hardware potentially runtime
359 * suspended.
360 */
361 if (!vblank->enabled)
362 goto out;
363
364 /*
365 * Update the count and timestamp to maintain the
366 * appearance that the counter has been ticking all along until
367 * this time. This makes the count account for the entire time
368 * between drm_crtc_vblank_on() and drm_crtc_vblank_off().
369 */
370 drm_update_vblank_count(dev, pipe, false);
371 __disable_vblank(dev, pipe);
372 vblank->enabled = false;
373
374out:
375 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
376}
377
378static void vblank_disable_fn(struct timer_list *t)
379{
380 struct drm_vblank_crtc *vblank = from_timer(vblank, t, disable_timer);
381 struct drm_device *dev = vblank->dev;
382 unsigned int pipe = vblank->pipe;
383 unsigned long irqflags;
384
385 spin_lock_irqsave(&dev->vbl_lock, irqflags);
386 if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
387 DRM_DEBUG("disabling vblank on crtc %u\n", pipe);
388 drm_vblank_disable_and_save(dev, pipe);
389 }
390 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
391}
392
393void drm_vblank_cleanup(struct drm_device *dev)
394{
395 unsigned int pipe;
396
397 /* Bail if the driver didn't call drm_vblank_init() */
398 if (dev->num_crtcs == 0)
399 return;
400
401 for (pipe = 0; pipe < dev->num_crtcs; pipe++) {
402 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
403
404 WARN_ON(READ_ONCE(vblank->enabled) &&
405 drm_core_check_feature(dev, DRIVER_MODESET));
406
407 del_timer_sync(&vblank->disable_timer);
408 }
409
410 kfree(dev->vblank);
411
412 dev->num_crtcs = 0;
413}
414
415/**
416 * drm_vblank_init - initialize vblank support
417 * @dev: DRM device
418 * @num_crtcs: number of CRTCs supported by @dev
419 *
420 * This function initializes vblank support for @num_crtcs display pipelines.
421 * Cleanup is handled by the DRM core, or through calling drm_dev_fini() for
422 * drivers with a &drm_driver.release callback.
423 *
424 * Returns:
425 * Zero on success or a negative error code on failure.
426 */
427int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
428{
429 int ret = -ENOMEM;
430 unsigned int i;
431
432 spin_lock_init(&dev->vbl_lock);
433 spin_lock_init(&dev->vblank_time_lock);
434
435 dev->num_crtcs = num_crtcs;
436
437 dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
438 if (!dev->vblank)
439 goto err;
440
441 for (i = 0; i < num_crtcs; i++) {
442 struct drm_vblank_crtc *vblank = &dev->vblank[i];
443
444 vblank->dev = dev;
445 vblank->pipe = i;
446 init_waitqueue_head(&vblank->queue);
447 timer_setup(&vblank->disable_timer, vblank_disable_fn, 0);
448 seqlock_init(&vblank->seqlock);
449 }
450
451 DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
452
453 /* Driver specific high-precision vblank timestamping supported? */
454 if (dev->driver->get_vblank_timestamp)
455 DRM_INFO("Driver supports precise vblank timestamp query.\n");
456 else
457 DRM_INFO("No driver support for vblank timestamp query.\n");
458
459 /* Must have precise timestamping for reliable vblank instant disable */
460 if (dev->vblank_disable_immediate && !dev->driver->get_vblank_timestamp) {
461 dev->vblank_disable_immediate = false;
462 DRM_INFO("Setting vblank_disable_immediate to false because "
463 "get_vblank_timestamp == NULL\n");
464 }
465
466 return 0;
467
468err:
469 dev->num_crtcs = 0;
470 return ret;
471}
472EXPORT_SYMBOL(drm_vblank_init);
473
474/**
475 * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC
476 * @crtc: which CRTC's vblank waitqueue to retrieve
477 *
478 * This function returns a pointer to the vblank waitqueue for the CRTC.
479 * Drivers can use this to implement vblank waits using wait_event() and related
480 * functions.
481 */
482wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc)
483{
484 return &crtc->dev->vblank[drm_crtc_index(crtc)].queue;
485}
486EXPORT_SYMBOL(drm_crtc_vblank_waitqueue);
487
488
489/**
490 * drm_calc_timestamping_constants - calculate vblank timestamp constants
491 * @crtc: drm_crtc whose timestamp constants should be updated.
492 * @mode: display mode containing the scanout timings
493 *
494 * Calculate and store various constants which are later needed by vblank and
495 * swap-completion timestamping, e.g, by
496 * drm_calc_vbltimestamp_from_scanoutpos(). They are derived from CRTC's true
497 * scanout timing, so they take things like panel scaling or other adjustments
498 * into account.
499 */
500void drm_calc_timestamping_constants(struct drm_crtc *crtc,
501 const struct drm_display_mode *mode)
502{
503 struct drm_device *dev = crtc->dev;
504 unsigned int pipe = drm_crtc_index(crtc);
505 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
506 int linedur_ns = 0, framedur_ns = 0;
507 int dotclock = mode->crtc_clock;
508
509 if (!dev->num_crtcs)
510 return;
511
512 if (WARN_ON(pipe >= dev->num_crtcs))
513 return;
514
515 /* Valid dotclock? */
516 if (dotclock > 0) {
517 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
518
519 /*
520 * Convert scanline length in pixels and video
521 * dot clock to line duration and frame duration
522 * in nanoseconds:
523 */
524 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
525 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
526
527 /*
528 * Fields of interlaced scanout modes are only half a frame duration.
529 */
530 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
531 framedur_ns /= 2;
532 } else
533 DRM_ERROR("crtc %u: Can't calculate constants, dotclock = 0!\n",
534 crtc->base.id);
535
536 vblank->linedur_ns = linedur_ns;
537 vblank->framedur_ns = framedur_ns;
538 vblank->hwmode = *mode;
539
540 DRM_DEBUG("crtc %u: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
541 crtc->base.id, mode->crtc_htotal,
542 mode->crtc_vtotal, mode->crtc_vdisplay);
543 DRM_DEBUG("crtc %u: clock %d kHz framedur %d linedur %d\n",
544 crtc->base.id, dotclock, framedur_ns, linedur_ns);
545}
546EXPORT_SYMBOL(drm_calc_timestamping_constants);
547
548/**
549 * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
550 * @dev: DRM device
551 * @pipe: index of CRTC whose vblank timestamp to retrieve
552 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
553 * On return contains true maximum error of timestamp
554 * @vblank_time: Pointer to time which should receive the timestamp
555 * @in_vblank_irq:
556 * True when called from drm_crtc_handle_vblank(). Some drivers
557 * need to apply some workarounds for gpu-specific vblank irq quirks
558 * if flag is set.
559 *
560 * Implements calculation of exact vblank timestamps from given drm_display_mode
561 * timings and current video scanout position of a CRTC. This can be directly
562 * used as the &drm_driver.get_vblank_timestamp implementation of a kms driver
563 * if &drm_driver.get_scanout_position is implemented.
564 *
565 * The current implementation only handles standard video modes. For double scan
566 * and interlaced modes the driver is supposed to adjust the hardware mode
567 * (taken from &drm_crtc_state.adjusted mode for atomic modeset drivers) to
568 * match the scanout position reported.
569 *
570 * Note that atomic drivers must call drm_calc_timestamping_constants() before
571 * enabling a CRTC. The atomic helpers already take care of that in
572 * drm_atomic_helper_update_legacy_modeset_state().
573 *
574 * Returns:
575 *
576 * Returns true on success, and false on failure, i.e. when no accurate
577 * timestamp could be acquired.
578 */
579bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
580 unsigned int pipe,
581 int *max_error,
582 ktime_t *vblank_time,
583 bool in_vblank_irq)
584{
585 struct timespec64 ts_etime, ts_vblank_time;
586 ktime_t stime, etime;
587 bool vbl_status;
588 struct drm_crtc *crtc;
589 const struct drm_display_mode *mode;
590 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
591 int vpos, hpos, i;
592 int delta_ns, duration_ns;
593
594 if (!drm_core_check_feature(dev, DRIVER_MODESET))
595 return false;
596
597 crtc = drm_crtc_from_index(dev, pipe);
598
599 if (pipe >= dev->num_crtcs || !crtc) {
600 DRM_ERROR("Invalid crtc %u\n", pipe);
601 return false;
602 }
603
604 /* Scanout position query not supported? Should not happen. */
605 if (!dev->driver->get_scanout_position) {
606 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
607 return false;
608 }
609
610 if (drm_drv_uses_atomic_modeset(dev))
611 mode = &vblank->hwmode;
612 else
613 mode = &crtc->hwmode;
614
615 /* If mode timing undefined, just return as no-op:
616 * Happens during initial modesetting of a crtc.
617 */
618 if (mode->crtc_clock == 0) {
619 DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
620 WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev));
621
622 return false;
623 }
624
625 /* Get current scanout position with system timestamp.
626 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
627 * if single query takes longer than max_error nanoseconds.
628 *
629 * This guarantees a tight bound on maximum error if
630 * code gets preempted or delayed for some reason.
631 */
632 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
633 /*
634 * Get vertical and horizontal scanout position vpos, hpos,
635 * and bounding timestamps stime, etime, pre/post query.
636 */
637 vbl_status = dev->driver->get_scanout_position(dev, pipe,
638 in_vblank_irq,
639 &vpos, &hpos,
640 &stime, &etime,
641 mode);
642
643 /* Return as no-op if scanout query unsupported or failed. */
644 if (!vbl_status) {
645 DRM_DEBUG("crtc %u : scanoutpos query failed.\n",
646 pipe);
647 return false;
648 }
649
650 /* Compute uncertainty in timestamp of scanout position query. */
651 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
652
653 /* Accept result with < max_error nsecs timing uncertainty. */
654 if (duration_ns <= *max_error)
655 break;
656 }
657
658 /* Noisy system timing? */
659 if (i == DRM_TIMESTAMP_MAXRETRIES) {
660 DRM_DEBUG("crtc %u: Noisy timestamp %d us > %d us [%d reps].\n",
661 pipe, duration_ns/1000, *max_error/1000, i);
662 }
663
664 /* Return upper bound of timestamp precision error. */
665 *max_error = duration_ns;
666
667 /* Convert scanout position into elapsed time at raw_time query
668 * since start of scanout at first display scanline. delta_ns
669 * can be negative if start of scanout hasn't happened yet.
670 */
671 delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos),
672 mode->crtc_clock);
673
674 /* Subtract time delta from raw timestamp to get final
675 * vblank_time timestamp for end of vblank.
676 */
677 *vblank_time = ktime_sub_ns(etime, delta_ns);
678
679 if ((drm_debug & DRM_UT_VBL) == 0)
680 return true;
681
682 ts_etime = ktime_to_timespec64(etime);
683 ts_vblank_time = ktime_to_timespec64(*vblank_time);
684
685 DRM_DEBUG_VBL("crtc %u : v p(%d,%d)@ %lld.%06ld -> %lld.%06ld [e %d us, %d rep]\n",
686 pipe, hpos, vpos,
687 (u64)ts_etime.tv_sec, ts_etime.tv_nsec / 1000,
688 (u64)ts_vblank_time.tv_sec, ts_vblank_time.tv_nsec / 1000,
689 duration_ns / 1000, i);
690
691 return true;
692}
693EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
694
695/**
696 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
697 * vblank interval
698 * @dev: DRM device
699 * @pipe: index of CRTC whose vblank timestamp to retrieve
700 * @tvblank: Pointer to target time which should receive the timestamp
701 * @in_vblank_irq:
702 * True when called from drm_crtc_handle_vblank(). Some drivers
703 * need to apply some workarounds for gpu-specific vblank irq quirks
704 * if flag is set.
705 *
706 * Fetches the system timestamp corresponding to the time of the most recent
707 * vblank interval on specified CRTC. May call into kms-driver to
708 * compute the timestamp with a high-precision GPU specific method.
709 *
710 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
711 * call, i.e., it isn't very precisely locked to the true vblank.
712 *
713 * Returns:
714 * True if timestamp is considered to be very precise, false otherwise.
715 */
716static bool
717drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
718 ktime_t *tvblank, bool in_vblank_irq)
719{
720 bool ret = false;
721
722 /* Define requested maximum error on timestamps (nanoseconds). */
723 int max_error = (int) drm_timestamp_precision * 1000;
724
725 /* Query driver if possible and precision timestamping enabled. */
726 if (dev->driver->get_vblank_timestamp && (max_error > 0))
727 ret = dev->driver->get_vblank_timestamp(dev, pipe, &max_error,
728 tvblank, in_vblank_irq);
729
730 /* GPU high precision timestamp query unsupported or failed.
731 * Return current monotonic/gettimeofday timestamp as best estimate.
732 */
733 if (!ret)
734 *tvblank = ktime_get();
735
736 return ret;
737}
738
739/**
740 * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
741 * @crtc: which counter to retrieve
742 *
743 * Fetches the "cooked" vblank count value that represents the number of
744 * vblank events since the system was booted, including lost events due to
745 * modesetting activity. Note that this timer isn't correct against a racing
746 * vblank interrupt (since it only reports the software vblank counter), see
747 * drm_crtc_accurate_vblank_count() for such use-cases.
748 *
749 * Returns:
750 * The software vblank counter.
751 */
752u64 drm_crtc_vblank_count(struct drm_crtc *crtc)
753{
754 return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
755}
756EXPORT_SYMBOL(drm_crtc_vblank_count);
757
758/**
759 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value and the
760 * system timestamp corresponding to that vblank counter value.
761 * @dev: DRM device
762 * @pipe: index of CRTC whose counter to retrieve
763 * @vblanktime: Pointer to ktime_t to receive the vblank timestamp.
764 *
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. Returns corresponding system timestamp of the time
768 * of the vblank interval that corresponds to the current vblank counter value.
769 *
770 * This is the legacy version of drm_crtc_vblank_count_and_time().
771 */
772static u64 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
773 ktime_t *vblanktime)
774{
775 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
776 u64 vblank_count;
777 unsigned int seq;
778
779 if (WARN_ON(pipe >= dev->num_crtcs)) {
780 *vblanktime = 0;
781 return 0;
782 }
783
784 do {
785 seq = read_seqbegin(&vblank->seqlock);
786 vblank_count = vblank->count;
787 *vblanktime = vblank->time;
788 } while (read_seqretry(&vblank->seqlock, seq));
789
790 return vblank_count;
791}
792
793/**
794 * drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value
795 * and the system timestamp corresponding to that vblank counter value
796 * @crtc: which counter to retrieve
797 * @vblanktime: Pointer to time to receive the vblank timestamp.
798 *
799 * Fetches the "cooked" vblank count value that represents the number of
800 * vblank events since the system was booted, including lost events due to
801 * modesetting activity. Returns corresponding system timestamp of the time
802 * of the vblank interval that corresponds to the current vblank counter value.
803 */
804u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
805 ktime_t *vblanktime)
806{
807 return drm_vblank_count_and_time(crtc->dev, drm_crtc_index(crtc),
808 vblanktime);
809}
810EXPORT_SYMBOL(drm_crtc_vblank_count_and_time);
811
812static void send_vblank_event(struct drm_device *dev,
813 struct drm_pending_vblank_event *e,
814 u64 seq, ktime_t now)
815{
816 struct timespec64 tv;
817
818 switch (e->event.base.type) {
819 case DRM_EVENT_VBLANK:
820 case DRM_EVENT_FLIP_COMPLETE:
821 tv = ktime_to_timespec64(now);
822 e->event.vbl.sequence = seq;
823 /*
824 * e->event is a user space structure, with hardcoded unsigned
825 * 32-bit seconds/microseconds. This is safe as we always use
826 * monotonic timestamps since linux-4.15
827 */
828 e->event.vbl.tv_sec = tv.tv_sec;
829 e->event.vbl.tv_usec = tv.tv_nsec / 1000;
830 break;
831 case DRM_EVENT_CRTC_SEQUENCE:
832 if (seq)
833 e->event.seq.sequence = seq;
834 e->event.seq.time_ns = ktime_to_ns(now);
835 break;
836 }
837 trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe, seq);
838 drm_send_event_locked(dev, &e->base);
839}
840
841/**
842 * drm_crtc_arm_vblank_event - arm vblank event after pageflip
843 * @crtc: the source CRTC of the vblank event
844 * @e: the event to send
845 *
846 * A lot of drivers need to generate vblank events for the very next vblank
847 * interrupt. For example when the page flip interrupt happens when the page
848 * flip gets armed, but not when it actually executes within the next vblank
849 * period. This helper function implements exactly the required vblank arming
850 * behaviour.
851 *
852 * NOTE: Drivers using this to send out the &drm_crtc_state.event as part of an
853 * atomic commit must ensure that the next vblank happens at exactly the same
854 * time as the atomic commit is committed to the hardware. This function itself
855 * does **not** protect against the next vblank interrupt racing with either this
856 * function call or the atomic commit operation. A possible sequence could be:
857 *
858 * 1. Driver commits new hardware state into vblank-synchronized registers.
859 * 2. A vblank happens, committing the hardware state. Also the corresponding
860 * vblank interrupt is fired off and fully processed by the interrupt
861 * handler.
862 * 3. The atomic commit operation proceeds to call drm_crtc_arm_vblank_event().
863 * 4. The event is only send out for the next vblank, which is wrong.
864 *
865 * An equivalent race can happen when the driver calls
866 * drm_crtc_arm_vblank_event() before writing out the new hardware state.
867 *
868 * The only way to make this work safely is to prevent the vblank from firing
869 * (and the hardware from committing anything else) until the entire atomic
870 * commit sequence has run to completion. If the hardware does not have such a
871 * feature (e.g. using a "go" bit), then it is unsafe to use this functions.
872 * Instead drivers need to manually send out the event from their interrupt
873 * handler by calling drm_crtc_send_vblank_event() and make sure that there's no
874 * possible race with the hardware committing the atomic update.
875 *
876 * Caller must hold a vblank reference for the event @e, which will be dropped
877 * when the next vblank arrives.
878 */
879void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
880 struct drm_pending_vblank_event *e)
881{
882 struct drm_device *dev = crtc->dev;
883 unsigned int pipe = drm_crtc_index(crtc);
884
885 assert_spin_locked(&dev->event_lock);
886
887 e->pipe = pipe;
888 e->sequence = drm_crtc_accurate_vblank_count(crtc) + 1;
889 list_add_tail(&e->base.link, &dev->vblank_event_list);
890}
891EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
892
893/**
894 * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
895 * @crtc: the source CRTC of the vblank event
896 * @e: the event to send
897 *
898 * Updates sequence # and timestamp on event for the most recently processed
899 * vblank, and sends it to userspace. Caller must hold event lock.
900 *
901 * See drm_crtc_arm_vblank_event() for a helper which can be used in certain
902 * situation, especially to send out events for atomic commit operations.
903 */
904void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
905 struct drm_pending_vblank_event *e)
906{
907 struct drm_device *dev = crtc->dev;
908 u64 seq;
909 unsigned int pipe = drm_crtc_index(crtc);
910 ktime_t now;
911
912 if (dev->num_crtcs > 0) {
913 seq = drm_vblank_count_and_time(dev, pipe, &now);
914 } else {
915 seq = 0;
916
917 now = ktime_get();
918 }
919 e->pipe = pipe;
920 send_vblank_event(dev, e, seq, now);
921}
922EXPORT_SYMBOL(drm_crtc_send_vblank_event);
923
924static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
925{
926 if (drm_core_check_feature(dev, DRIVER_MODESET)) {
927 struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
928
929 if (WARN_ON(!crtc))
930 return 0;
931
932 if (crtc->funcs->enable_vblank)
933 return crtc->funcs->enable_vblank(crtc);
934 }
935
936 return dev->driver->enable_vblank(dev, pipe);
937}
938
939static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
940{
941 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
942 int ret = 0;
943
944 assert_spin_locked(&dev->vbl_lock);
945
946 spin_lock(&dev->vblank_time_lock);
947
948 if (!vblank->enabled) {
949 /*
950 * Enable vblank irqs under vblank_time_lock protection.
951 * All vblank count & timestamp updates are held off
952 * until we are done reinitializing master counter and
953 * timestamps. Filtercode in drm_handle_vblank() will
954 * prevent double-accounting of same vblank interval.
955 */
956 ret = __enable_vblank(dev, pipe);
957 DRM_DEBUG("enabling vblank on crtc %u, ret: %d\n", pipe, ret);
958 if (ret) {
959 atomic_dec(&vblank->refcount);
960 } else {
961 drm_update_vblank_count(dev, pipe, 0);
962 /* drm_update_vblank_count() includes a wmb so we just
963 * need to ensure that the compiler emits the write
964 * to mark the vblank as enabled after the call
965 * to drm_update_vblank_count().
966 */
967 WRITE_ONCE(vblank->enabled, true);
968 }
969 }
970
971 spin_unlock(&dev->vblank_time_lock);
972
973 return ret;
974}
975
976static int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
977{
978 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
979 unsigned long irqflags;
980 int ret = 0;
981
982 if (!dev->num_crtcs)
983 return -EINVAL;
984
985 if (WARN_ON(pipe >= dev->num_crtcs))
986 return -EINVAL;
987
988 spin_lock_irqsave(&dev->vbl_lock, irqflags);
989 /* Going from 0->1 means we have to enable interrupts again */
990 if (atomic_add_return(1, &vblank->refcount) == 1) {
991 ret = drm_vblank_enable(dev, pipe);
992 } else {
993 if (!vblank->enabled) {
994 atomic_dec(&vblank->refcount);
995 ret = -EINVAL;
996 }
997 }
998 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
999
1000 return ret;
1001}
1002
1003/**
1004 * drm_crtc_vblank_get - get a reference count on vblank events
1005 * @crtc: which CRTC to own
1006 *
1007 * Acquire a reference count on vblank events to avoid having them disabled
1008 * while in use.
1009 *
1010 * Returns:
1011 * Zero on success or a negative error code on failure.
1012 */
1013int drm_crtc_vblank_get(struct drm_crtc *crtc)
1014{
1015 return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
1016}
1017EXPORT_SYMBOL(drm_crtc_vblank_get);
1018
1019static void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
1020{
1021 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1022
1023 if (WARN_ON(pipe >= dev->num_crtcs))
1024 return;
1025
1026 if (WARN_ON(atomic_read(&vblank->refcount) == 0))
1027 return;
1028
1029 /* Last user schedules interrupt disable */
1030 if (atomic_dec_and_test(&vblank->refcount)) {
1031 if (drm_vblank_offdelay == 0)
1032 return;
1033 else if (drm_vblank_offdelay < 0)
1034 vblank_disable_fn(&vblank->disable_timer);
1035 else if (!dev->vblank_disable_immediate)
1036 mod_timer(&vblank->disable_timer,
1037 jiffies + ((drm_vblank_offdelay * HZ)/1000));
1038 }
1039}
1040
1041/**
1042 * drm_crtc_vblank_put - give up ownership of vblank events
1043 * @crtc: which counter to give up
1044 *
1045 * Release ownership of a given vblank counter, turning off interrupts
1046 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1047 */
1048void drm_crtc_vblank_put(struct drm_crtc *crtc)
1049{
1050 drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
1051}
1052EXPORT_SYMBOL(drm_crtc_vblank_put);
1053
1054/**
1055 * drm_wait_one_vblank - wait for one vblank
1056 * @dev: DRM device
1057 * @pipe: CRTC index
1058 *
1059 * This waits for one vblank to pass on @pipe, using the irq driver interfaces.
1060 * It is a failure to call this when the vblank irq for @pipe is disabled, e.g.
1061 * due to lack of driver support or because the crtc is off.
1062 *
1063 * This is the legacy version of drm_crtc_wait_one_vblank().
1064 */
1065void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe)
1066{
1067 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1068 int ret;
1069 u64 last;
1070
1071 if (WARN_ON(pipe >= dev->num_crtcs))
1072 return;
1073
1074 ret = drm_vblank_get(dev, pipe);
1075 if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", pipe, ret))
1076 return;
1077
1078 last = drm_vblank_count(dev, pipe);
1079
1080 ret = wait_event_timeout(vblank->queue,
1081 last != drm_vblank_count(dev, pipe),
1082 msecs_to_jiffies(100));
1083
1084 WARN(ret == 0, "vblank wait timed out on crtc %i\n", pipe);
1085
1086 drm_vblank_put(dev, pipe);
1087}
1088EXPORT_SYMBOL(drm_wait_one_vblank);
1089
1090/**
1091 * drm_crtc_wait_one_vblank - wait for one vblank
1092 * @crtc: DRM crtc
1093 *
1094 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
1095 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
1096 * due to lack of driver support or because the crtc is off.
1097 */
1098void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
1099{
1100 drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
1101}
1102EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
1103
1104/**
1105 * drm_crtc_vblank_off - disable vblank events on a CRTC
1106 * @crtc: CRTC in question
1107 *
1108 * Drivers can use this function to shut down the vblank interrupt handling when
1109 * disabling a crtc. This function ensures that the latest vblank frame count is
1110 * stored so that drm_vblank_on can restore it again.
1111 *
1112 * Drivers must use this function when the hardware vblank counter can get
1113 * reset, e.g. when suspending or disabling the @crtc in general.
1114 */
1115void drm_crtc_vblank_off(struct drm_crtc *crtc)
1116{
1117 struct drm_device *dev = crtc->dev;
1118 unsigned int pipe = drm_crtc_index(crtc);
1119 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1120 struct drm_pending_vblank_event *e, *t;
1121
1122 ktime_t now;
1123 unsigned long irqflags;
1124 u64 seq;
1125
1126 if (WARN_ON(pipe >= dev->num_crtcs))
1127 return;
1128
1129 spin_lock_irqsave(&dev->event_lock, irqflags);
1130
1131 spin_lock(&dev->vbl_lock);
1132 DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
1133 pipe, vblank->enabled, vblank->inmodeset);
1134
1135 /* Avoid redundant vblank disables without previous
1136 * drm_crtc_vblank_on(). */
1137 if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset)
1138 drm_vblank_disable_and_save(dev, pipe);
1139
1140 wake_up(&vblank->queue);
1141
1142 /*
1143 * Prevent subsequent drm_vblank_get() from re-enabling
1144 * the vblank interrupt by bumping the refcount.
1145 */
1146 if (!vblank->inmodeset) {
1147 atomic_inc(&vblank->refcount);
1148 vblank->inmodeset = 1;
1149 }
1150 spin_unlock(&dev->vbl_lock);
1151
1152 /* Send any queued vblank events, lest the natives grow disquiet */
1153 seq = drm_vblank_count_and_time(dev, pipe, &now);
1154
1155 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1156 if (e->pipe != pipe)
1157 continue;
1158 DRM_DEBUG("Sending premature vblank event on disable: "
1159 "wanted %llu, current %llu\n",
1160 e->sequence, seq);
1161 list_del(&e->base.link);
1162 drm_vblank_put(dev, pipe);
1163 send_vblank_event(dev, e, seq, now);
1164 }
1165 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1166
1167 /* Will be reset by the modeset helpers when re-enabling the crtc by
1168 * calling drm_calc_timestamping_constants(). */
1169 vblank->hwmode.crtc_clock = 0;
1170}
1171EXPORT_SYMBOL(drm_crtc_vblank_off);
1172
1173/**
1174 * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
1175 * @crtc: CRTC in question
1176 *
1177 * Drivers can use this function to reset the vblank state to off at load time.
1178 * Drivers should use this together with the drm_crtc_vblank_off() and
1179 * drm_crtc_vblank_on() functions. The difference compared to
1180 * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
1181 * and hence doesn't need to call any driver hooks.
1182 *
1183 * This is useful for recovering driver state e.g. on driver load, or on resume.
1184 */
1185void drm_crtc_vblank_reset(struct drm_crtc *crtc)
1186{
1187 struct drm_device *dev = crtc->dev;
1188 unsigned long irqflags;
1189 unsigned int pipe = drm_crtc_index(crtc);
1190 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1191
1192 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1193 /*
1194 * Prevent subsequent drm_vblank_get() from enabling the vblank
1195 * interrupt by bumping the refcount.
1196 */
1197 if (!vblank->inmodeset) {
1198 atomic_inc(&vblank->refcount);
1199 vblank->inmodeset = 1;
1200 }
1201 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1202
1203 WARN_ON(!list_empty(&dev->vblank_event_list));
1204}
1205EXPORT_SYMBOL(drm_crtc_vblank_reset);
1206
1207/**
1208 * drm_crtc_vblank_on - enable vblank events on a CRTC
1209 * @crtc: CRTC in question
1210 *
1211 * This functions restores the vblank interrupt state captured with
1212 * drm_crtc_vblank_off() again and is generally called when enabling @crtc. Note
1213 * that calls to drm_crtc_vblank_on() and drm_crtc_vblank_off() can be
1214 * unbalanced and so can also be unconditionally called in driver load code to
1215 * reflect the current hardware state of the crtc.
1216 */
1217void drm_crtc_vblank_on(struct drm_crtc *crtc)
1218{
1219 struct drm_device *dev = crtc->dev;
1220 unsigned int pipe = drm_crtc_index(crtc);
1221 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1222 unsigned long irqflags;
1223
1224 if (WARN_ON(pipe >= dev->num_crtcs))
1225 return;
1226
1227 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1228 DRM_DEBUG_VBL("crtc %d, vblank enabled %d, inmodeset %d\n",
1229 pipe, vblank->enabled, vblank->inmodeset);
1230
1231 /* Drop our private "prevent drm_vblank_get" refcount */
1232 if (vblank->inmodeset) {
1233 atomic_dec(&vblank->refcount);
1234 vblank->inmodeset = 0;
1235 }
1236
1237 drm_reset_vblank_timestamp(dev, pipe);
1238
1239 /*
1240 * re-enable interrupts if there are users left, or the
1241 * user wishes vblank interrupts to be enabled all the time.
1242 */
1243 if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0)
1244 WARN_ON(drm_vblank_enable(dev, pipe));
1245 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1246}
1247EXPORT_SYMBOL(drm_crtc_vblank_on);
1248
1249/**
1250 * drm_vblank_restore - estimate missed vblanks and update vblank count.
1251 * @dev: DRM device
1252 * @pipe: CRTC index
1253 *
1254 * Power manamement features can cause frame counter resets between vblank
1255 * disable and enable. Drivers can use this function in their
1256 * &drm_crtc_funcs.enable_vblank implementation to estimate missed vblanks since
1257 * the last &drm_crtc_funcs.disable_vblank using timestamps and update the
1258 * vblank counter.
1259 *
1260 * This function is the legacy version of drm_crtc_vblank_restore().
1261 */
1262void drm_vblank_restore(struct drm_device *dev, unsigned int pipe)
1263{
1264 ktime_t t_vblank;
1265 struct drm_vblank_crtc *vblank;
1266 int framedur_ns;
1267 u64 diff_ns;
1268 u32 cur_vblank, diff = 1;
1269 int count = DRM_TIMESTAMP_MAXRETRIES;
1270
1271 if (WARN_ON(pipe >= dev->num_crtcs))
1272 return;
1273
1274 assert_spin_locked(&dev->vbl_lock);
1275 assert_spin_locked(&dev->vblank_time_lock);
1276
1277 vblank = &dev->vblank[pipe];
1278 WARN_ONCE((drm_debug & DRM_UT_VBL) && !vblank->framedur_ns,
1279 "Cannot compute missed vblanks without frame duration\n");
1280 framedur_ns = vblank->framedur_ns;
1281
1282 do {
1283 cur_vblank = __get_vblank_counter(dev, pipe);
1284 drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
1285 } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
1286
1287 diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time));
1288 if (framedur_ns)
1289 diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
1290
1291
1292 DRM_DEBUG_VBL("missed %d vblanks in %lld ns, frame duration=%d ns, hw_diff=%d\n",
1293 diff, diff_ns, framedur_ns, cur_vblank - vblank->last);
1294 store_vblank(dev, pipe, diff, t_vblank, cur_vblank);
1295}
1296EXPORT_SYMBOL(drm_vblank_restore);
1297
1298/**
1299 * drm_crtc_vblank_restore - estimate missed vblanks and update vblank count.
1300 * @crtc: CRTC in question
1301 *
1302 * Power manamement features can cause frame counter resets between vblank
1303 * disable and enable. Drivers can use this function in their
1304 * &drm_crtc_funcs.enable_vblank implementation to estimate missed vblanks since
1305 * the last &drm_crtc_funcs.disable_vblank using timestamps and update the
1306 * vblank counter.
1307 */
1308void drm_crtc_vblank_restore(struct drm_crtc *crtc)
1309{
1310 drm_vblank_restore(crtc->dev, drm_crtc_index(crtc));
1311}
1312EXPORT_SYMBOL(drm_crtc_vblank_restore);
1313
1314static void drm_legacy_vblank_pre_modeset(struct drm_device *dev,
1315 unsigned int pipe)
1316{
1317 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1318
1319 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1320 if (!dev->num_crtcs)
1321 return;
1322
1323 if (WARN_ON(pipe >= dev->num_crtcs))
1324 return;
1325
1326 /*
1327 * To avoid all the problems that might happen if interrupts
1328 * were enabled/disabled around or between these calls, we just
1329 * have the kernel take a reference on the CRTC (just once though
1330 * to avoid corrupting the count if multiple, mismatch calls occur),
1331 * so that interrupts remain enabled in the interim.
1332 */
1333 if (!vblank->inmodeset) {
1334 vblank->inmodeset = 0x1;
1335 if (drm_vblank_get(dev, pipe) == 0)
1336 vblank->inmodeset |= 0x2;
1337 }
1338}
1339
1340static void drm_legacy_vblank_post_modeset(struct drm_device *dev,
1341 unsigned int pipe)
1342{
1343 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1344 unsigned long irqflags;
1345
1346 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1347 if (!dev->num_crtcs)
1348 return;
1349
1350 if (WARN_ON(pipe >= dev->num_crtcs))
1351 return;
1352
1353 if (vblank->inmodeset) {
1354 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1355 drm_reset_vblank_timestamp(dev, pipe);
1356 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1357
1358 if (vblank->inmodeset & 0x2)
1359 drm_vblank_put(dev, pipe);
1360
1361 vblank->inmodeset = 0;
1362 }
1363}
1364
1365int drm_legacy_modeset_ctl_ioctl(struct drm_device *dev, void *data,
1366 struct drm_file *file_priv)
1367{
1368 struct drm_modeset_ctl *modeset = data;
1369 unsigned int pipe;
1370
1371 /* If drm_vblank_init() hasn't been called yet, just no-op */
1372 if (!dev->num_crtcs)
1373 return 0;
1374
1375 /* KMS drivers handle this internally */
1376 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
1377 return 0;
1378
1379 pipe = modeset->crtc;
1380 if (pipe >= dev->num_crtcs)
1381 return -EINVAL;
1382
1383 switch (modeset->cmd) {
1384 case _DRM_PRE_MODESET:
1385 drm_legacy_vblank_pre_modeset(dev, pipe);
1386 break;
1387 case _DRM_POST_MODESET:
1388 drm_legacy_vblank_post_modeset(dev, pipe);
1389 break;
1390 default:
1391 return -EINVAL;
1392 }
1393
1394 return 0;
1395}
1396
1397static inline bool vblank_passed(u64 seq, u64 ref)
1398{
1399 return (seq - ref) <= (1 << 23);
1400}
1401
1402static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
1403 u64 req_seq,
1404 union drm_wait_vblank *vblwait,
1405 struct drm_file *file_priv)
1406{
1407 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1408 struct drm_pending_vblank_event *e;
1409 ktime_t now;
1410 unsigned long flags;
1411 u64 seq;
1412 int ret;
1413
1414 e = kzalloc(sizeof(*e), GFP_KERNEL);
1415 if (e == NULL) {
1416 ret = -ENOMEM;
1417 goto err_put;
1418 }
1419
1420 e->pipe = pipe;
1421 e->event.base.type = DRM_EVENT_VBLANK;
1422 e->event.base.length = sizeof(e->event.vbl);
1423 e->event.vbl.user_data = vblwait->request.signal;
1424 e->event.vbl.crtc_id = 0;
1425 if (drm_core_check_feature(dev, DRIVER_MODESET)) {
1426 struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
1427 if (crtc)
1428 e->event.vbl.crtc_id = crtc->base.id;
1429 }
1430
1431 spin_lock_irqsave(&dev->event_lock, flags);
1432
1433 /*
1434 * drm_crtc_vblank_off() might have been called after we called
1435 * drm_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
1436 * vblank disable, so no need for further locking. The reference from
1437 * drm_vblank_get() protects against vblank disable from another source.
1438 */
1439 if (!READ_ONCE(vblank->enabled)) {
1440 ret = -EINVAL;
1441 goto err_unlock;
1442 }
1443
1444 ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
1445 &e->event.base);
1446
1447 if (ret)
1448 goto err_unlock;
1449
1450 seq = drm_vblank_count_and_time(dev, pipe, &now);
1451
1452 DRM_DEBUG("event on vblank count %llu, current %llu, crtc %u\n",
1453 req_seq, seq, pipe);
1454
1455 trace_drm_vblank_event_queued(file_priv, pipe, req_seq);
1456
1457 e->sequence = req_seq;
1458 if (vblank_passed(seq, req_seq)) {
1459 drm_vblank_put(dev, pipe);
1460 send_vblank_event(dev, e, seq, now);
1461 vblwait->reply.sequence = seq;
1462 } else {
1463 /* drm_handle_vblank_events will call drm_vblank_put */
1464 list_add_tail(&e->base.link, &dev->vblank_event_list);
1465 vblwait->reply.sequence = req_seq;
1466 }
1467
1468 spin_unlock_irqrestore(&dev->event_lock, flags);
1469
1470 return 0;
1471
1472err_unlock:
1473 spin_unlock_irqrestore(&dev->event_lock, flags);
1474 kfree(e);
1475err_put:
1476 drm_vblank_put(dev, pipe);
1477 return ret;
1478}
1479
1480static bool drm_wait_vblank_is_query(union drm_wait_vblank *vblwait)
1481{
1482 if (vblwait->request.sequence)
1483 return false;
1484
1485 return _DRM_VBLANK_RELATIVE ==
1486 (vblwait->request.type & (_DRM_VBLANK_TYPES_MASK |
1487 _DRM_VBLANK_EVENT |
1488 _DRM_VBLANK_NEXTONMISS));
1489}
1490
1491/*
1492 * Widen a 32-bit param to 64-bits.
1493 *
1494 * \param narrow 32-bit value (missing upper 32 bits)
1495 * \param near 64-bit value that should be 'close' to near
1496 *
1497 * This function returns a 64-bit value using the lower 32-bits from
1498 * 'narrow' and constructing the upper 32-bits so that the result is
1499 * as close as possible to 'near'.
1500 */
1501
1502static u64 widen_32_to_64(u32 narrow, u64 near)
1503{
1504 return near + (s32) (narrow - near);
1505}
1506
1507static void drm_wait_vblank_reply(struct drm_device *dev, unsigned int pipe,
1508 struct drm_wait_vblank_reply *reply)
1509{
1510 ktime_t now;
1511 struct timespec64 ts;
1512
1513 /*
1514 * drm_wait_vblank_reply is a UAPI structure that uses 'long'
1515 * to store the seconds. This is safe as we always use monotonic
1516 * timestamps since linux-4.15.
1517 */
1518 reply->sequence = drm_vblank_count_and_time(dev, pipe, &now);
1519 ts = ktime_to_timespec64(now);
1520 reply->tval_sec = (u32)ts.tv_sec;
1521 reply->tval_usec = ts.tv_nsec / 1000;
1522}
1523
1524int drm_wait_vblank_ioctl(struct drm_device *dev, void *data,
1525 struct drm_file *file_priv)
1526{
1527 struct drm_crtc *crtc;
1528 struct drm_vblank_crtc *vblank;
1529 union drm_wait_vblank *vblwait = data;
1530 int ret;
1531 u64 req_seq, seq;
1532 unsigned int pipe_index;
1533 unsigned int flags, pipe, high_pipe;
1534
1535 if (!dev->irq_enabled)
1536 return -EINVAL;
1537
1538 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1539 return -EINVAL;
1540
1541 if (vblwait->request.type &
1542 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1543 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1544 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1545 vblwait->request.type,
1546 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1547 _DRM_VBLANK_HIGH_CRTC_MASK));
1548 return -EINVAL;
1549 }
1550
1551 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1552 high_pipe = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1553 if (high_pipe)
1554 pipe_index = high_pipe >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1555 else
1556 pipe_index = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1557
1558 /* Convert lease-relative crtc index into global crtc index */
1559 if (drm_core_check_feature(dev, DRIVER_MODESET)) {
1560 pipe = 0;
1561 drm_for_each_crtc(crtc, dev) {
1562 if (drm_lease_held(file_priv, crtc->base.id)) {
1563 if (pipe_index == 0)
1564 break;
1565 pipe_index--;
1566 }
1567 pipe++;
1568 }
1569 } else {
1570 pipe = pipe_index;
1571 }
1572
1573 if (pipe >= dev->num_crtcs)
1574 return -EINVAL;
1575
1576 vblank = &dev->vblank[pipe];
1577
1578 /* If the counter is currently enabled and accurate, short-circuit
1579 * queries to return the cached timestamp of the last vblank.
1580 */
1581 if (dev->vblank_disable_immediate &&
1582 drm_wait_vblank_is_query(vblwait) &&
1583 READ_ONCE(vblank->enabled)) {
1584 drm_wait_vblank_reply(dev, pipe, &vblwait->reply);
1585 return 0;
1586 }
1587
1588 ret = drm_vblank_get(dev, pipe);
1589 if (ret) {
1590 DRM_DEBUG("crtc %d failed to acquire vblank counter, %d\n", pipe, ret);
1591 return ret;
1592 }
1593 seq = drm_vblank_count(dev, pipe);
1594
1595 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1596 case _DRM_VBLANK_RELATIVE:
1597 req_seq = seq + vblwait->request.sequence;
1598 vblwait->request.sequence = req_seq;
1599 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1600 break;
1601 case _DRM_VBLANK_ABSOLUTE:
1602 req_seq = widen_32_to_64(vblwait->request.sequence, seq);
1603 break;
1604 default:
1605 ret = -EINVAL;
1606 goto done;
1607 }
1608
1609 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1610 vblank_passed(seq, req_seq)) {
1611 req_seq = seq + 1;
1612 vblwait->request.type &= ~_DRM_VBLANK_NEXTONMISS;
1613 vblwait->request.sequence = req_seq;
1614 }
1615
1616 if (flags & _DRM_VBLANK_EVENT) {
1617 /* must hold on to the vblank ref until the event fires
1618 * drm_vblank_put will be called asynchronously
1619 */
1620 return drm_queue_vblank_event(dev, pipe, req_seq, vblwait, file_priv);
1621 }
1622
1623 if (req_seq != seq) {
1624 DRM_DEBUG("waiting on vblank count %llu, crtc %u\n",
1625 req_seq, pipe);
1626 DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
1627 vblank_passed(drm_vblank_count(dev, pipe),
1628 req_seq) ||
1629 !READ_ONCE(vblank->enabled));
1630 }
1631
1632 if (ret != -EINTR) {
1633 drm_wait_vblank_reply(dev, pipe, &vblwait->reply);
1634
1635 DRM_DEBUG("crtc %d returning %u to client\n",
1636 pipe, vblwait->reply.sequence);
1637 } else {
1638 DRM_DEBUG("crtc %d vblank wait interrupted by signal\n", pipe);
1639 }
1640
1641done:
1642 drm_vblank_put(dev, pipe);
1643 return ret;
1644}
1645
1646static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
1647{
1648 struct drm_pending_vblank_event *e, *t;
1649 ktime_t now;
1650 u64 seq;
1651
1652 assert_spin_locked(&dev->event_lock);
1653
1654 seq = drm_vblank_count_and_time(dev, pipe, &now);
1655
1656 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1657 if (e->pipe != pipe)
1658 continue;
1659 if (!vblank_passed(seq, e->sequence))
1660 continue;
1661
1662 DRM_DEBUG("vblank event on %llu, current %llu\n",
1663 e->sequence, seq);
1664
1665 list_del(&e->base.link);
1666 drm_vblank_put(dev, pipe);
1667 send_vblank_event(dev, e, seq, now);
1668 }
1669
1670 trace_drm_vblank_event(pipe, seq);
1671}
1672
1673/**
1674 * drm_handle_vblank - handle a vblank event
1675 * @dev: DRM device
1676 * @pipe: index of CRTC where this event occurred
1677 *
1678 * Drivers should call this routine in their vblank interrupt handlers to
1679 * update the vblank counter and send any signals that may be pending.
1680 *
1681 * This is the legacy version of drm_crtc_handle_vblank().
1682 */
1683bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
1684{
1685 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1686 unsigned long irqflags;
1687 bool disable_irq;
1688
1689 if (WARN_ON_ONCE(!dev->num_crtcs))
1690 return false;
1691
1692 if (WARN_ON(pipe >= dev->num_crtcs))
1693 return false;
1694
1695 spin_lock_irqsave(&dev->event_lock, irqflags);
1696
1697 /* Need timestamp lock to prevent concurrent execution with
1698 * vblank enable/disable, as this would cause inconsistent
1699 * or corrupted timestamps and vblank counts.
1700 */
1701 spin_lock(&dev->vblank_time_lock);
1702
1703 /* Vblank irq handling disabled. Nothing to do. */
1704 if (!vblank->enabled) {
1705 spin_unlock(&dev->vblank_time_lock);
1706 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1707 return false;
1708 }
1709
1710 drm_update_vblank_count(dev, pipe, true);
1711
1712 spin_unlock(&dev->vblank_time_lock);
1713
1714 wake_up(&vblank->queue);
1715
1716 /* With instant-off, we defer disabling the interrupt until after
1717 * we finish processing the following vblank after all events have
1718 * been signaled. The disable has to be last (after
1719 * drm_handle_vblank_events) so that the timestamp is always accurate.
1720 */
1721 disable_irq = (dev->vblank_disable_immediate &&
1722 drm_vblank_offdelay > 0 &&
1723 !atomic_read(&vblank->refcount));
1724
1725 drm_handle_vblank_events(dev, pipe);
1726
1727 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1728
1729 if (disable_irq)
1730 vblank_disable_fn(&vblank->disable_timer);
1731
1732 return true;
1733}
1734EXPORT_SYMBOL(drm_handle_vblank);
1735
1736/**
1737 * drm_crtc_handle_vblank - handle a vblank event
1738 * @crtc: where this event occurred
1739 *
1740 * Drivers should call this routine in their vblank interrupt handlers to
1741 * update the vblank counter and send any signals that may be pending.
1742 *
1743 * This is the native KMS version of drm_handle_vblank().
1744 *
1745 * Returns:
1746 * True if the event was successfully handled, false on failure.
1747 */
1748bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
1749{
1750 return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
1751}
1752EXPORT_SYMBOL(drm_crtc_handle_vblank);
1753
1754/*
1755 * Get crtc VBLANK count.
1756 *
1757 * \param dev DRM device
1758 * \param data user arguement, pointing to a drm_crtc_get_sequence structure.
1759 * \param file_priv drm file private for the user's open file descriptor
1760 */
1761
1762int drm_crtc_get_sequence_ioctl(struct drm_device *dev, void *data,
1763 struct drm_file *file_priv)
1764{
1765 struct drm_crtc *crtc;
1766 struct drm_vblank_crtc *vblank;
1767 int pipe;
1768 struct drm_crtc_get_sequence *get_seq = data;
1769 ktime_t now;
1770 bool vblank_enabled;
1771 int ret;
1772
1773 if (!drm_core_check_feature(dev, DRIVER_MODESET))
1774 return -EINVAL;
1775
1776 if (!dev->irq_enabled)
1777 return -EINVAL;
1778
1779 crtc = drm_crtc_find(dev, file_priv, get_seq->crtc_id);
1780 if (!crtc)
1781 return -ENOENT;
1782
1783 pipe = drm_crtc_index(crtc);
1784
1785 vblank = &dev->vblank[pipe];
1786 vblank_enabled = dev->vblank_disable_immediate && READ_ONCE(vblank->enabled);
1787
1788 if (!vblank_enabled) {
1789 ret = drm_crtc_vblank_get(crtc);
1790 if (ret) {
1791 DRM_DEBUG("crtc %d failed to acquire vblank counter, %d\n", pipe, ret);
1792 return ret;
1793 }
1794 }
1795 drm_modeset_lock(&crtc->mutex, NULL);
1796 if (crtc->state)
1797 get_seq->active = crtc->state->enable;
1798 else
1799 get_seq->active = crtc->enabled;
1800 drm_modeset_unlock(&crtc->mutex);
1801 get_seq->sequence = drm_vblank_count_and_time(dev, pipe, &now);
1802 get_seq->sequence_ns = ktime_to_ns(now);
1803 if (!vblank_enabled)
1804 drm_crtc_vblank_put(crtc);
1805 return 0;
1806}
1807
1808/*
1809 * Queue a event for VBLANK sequence
1810 *
1811 * \param dev DRM device
1812 * \param data user arguement, pointing to a drm_crtc_queue_sequence structure.
1813 * \param file_priv drm file private for the user's open file descriptor
1814 */
1815
1816int drm_crtc_queue_sequence_ioctl(struct drm_device *dev, void *data,
1817 struct drm_file *file_priv)
1818{
1819 struct drm_crtc *crtc;
1820 struct drm_vblank_crtc *vblank;
1821 int pipe;
1822 struct drm_crtc_queue_sequence *queue_seq = data;
1823 ktime_t now;
1824 struct drm_pending_vblank_event *e;
1825 u32 flags;
1826 u64 seq;
1827 u64 req_seq;
1828 int ret;
1829 unsigned long spin_flags;
1830
1831 if (!drm_core_check_feature(dev, DRIVER_MODESET))
1832 return -EINVAL;
1833
1834 if (!dev->irq_enabled)
1835 return -EINVAL;
1836
1837 crtc = drm_crtc_find(dev, file_priv, queue_seq->crtc_id);
1838 if (!crtc)
1839 return -ENOENT;
1840
1841 flags = queue_seq->flags;
1842 /* Check valid flag bits */
1843 if (flags & ~(DRM_CRTC_SEQUENCE_RELATIVE|
1844 DRM_CRTC_SEQUENCE_NEXT_ON_MISS))
1845 return -EINVAL;
1846
1847 pipe = drm_crtc_index(crtc);
1848
1849 vblank = &dev->vblank[pipe];
1850
1851 e = kzalloc(sizeof(*e), GFP_KERNEL);
1852 if (e == NULL)
1853 return -ENOMEM;
1854
1855 ret = drm_crtc_vblank_get(crtc);
1856 if (ret) {
1857 DRM_DEBUG("crtc %d failed to acquire vblank counter, %d\n", pipe, ret);
1858 goto err_free;
1859 }
1860
1861 seq = drm_vblank_count_and_time(dev, pipe, &now);
1862 req_seq = queue_seq->sequence;
1863
1864 if (flags & DRM_CRTC_SEQUENCE_RELATIVE)
1865 req_seq += seq;
1866
1867 if ((flags & DRM_CRTC_SEQUENCE_NEXT_ON_MISS) && vblank_passed(seq, req_seq))
1868 req_seq = seq + 1;
1869
1870 e->pipe = pipe;
1871 e->event.base.type = DRM_EVENT_CRTC_SEQUENCE;
1872 e->event.base.length = sizeof(e->event.seq);
1873 e->event.seq.user_data = queue_seq->user_data;
1874
1875 spin_lock_irqsave(&dev->event_lock, spin_flags);
1876
1877 /*
1878 * drm_crtc_vblank_off() might have been called after we called
1879 * drm_crtc_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
1880 * vblank disable, so no need for further locking. The reference from
1881 * drm_crtc_vblank_get() protects against vblank disable from another source.
1882 */
1883 if (!READ_ONCE(vblank->enabled)) {
1884 ret = -EINVAL;
1885 goto err_unlock;
1886 }
1887
1888 ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
1889 &e->event.base);
1890
1891 if (ret)
1892 goto err_unlock;
1893
1894 e->sequence = req_seq;
1895
1896 if (vblank_passed(seq, req_seq)) {
1897 drm_crtc_vblank_put(crtc);
1898 send_vblank_event(dev, e, seq, now);
1899 queue_seq->sequence = seq;
1900 } else {
1901 /* drm_handle_vblank_events will call drm_vblank_put */
1902 list_add_tail(&e->base.link, &dev->vblank_event_list);
1903 queue_seq->sequence = req_seq;
1904 }
1905
1906 spin_unlock_irqrestore(&dev->event_lock, spin_flags);
1907 return 0;
1908
1909err_unlock:
1910 spin_unlock_irqrestore(&dev->event_lock, spin_flags);
1911 drm_crtc_vblank_put(crtc);
1912err_free:
1913 kfree(e);
1914 return ret;
1915}