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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 <linux/export.h>
28#include <linux/kthread.h>
29#include <linux/moduleparam.h>
30
31#include <drm/drm_crtc.h>
32#include <drm/drm_drv.h>
33#include <drm/drm_framebuffer.h>
34#include <drm/drm_managed.h>
35#include <drm/drm_modeset_helper_vtables.h>
36#include <drm/drm_print.h>
37#include <drm/drm_vblank.h>
38
39#include "drm_internal.h"
40#include "drm_trace.h"
41
42/**
43 * DOC: vblank handling
44 *
45 * From the computer's perspective, every time the monitor displays
46 * a new frame the scanout engine has "scanned out" the display image
47 * from top to bottom, one row of pixels at a time. The current row
48 * of pixels is referred to as the current scanline.
49 *
50 * In addition to the display's visible area, there's usually a couple of
51 * extra scanlines which aren't actually displayed on the screen.
52 * These extra scanlines don't contain image data and are occasionally used
53 * for features like audio and infoframes. The region made up of these
54 * scanlines is referred to as the vertical blanking region, or vblank for
55 * short.
56 *
57 * For historical reference, the vertical blanking period was designed to
58 * give the electron gun (on CRTs) enough time to move back to the top of
59 * the screen to start scanning out the next frame. Similar for horizontal
60 * blanking periods. They were designed to give the electron gun enough
61 * time to move back to the other side of the screen to start scanning the
62 * next scanline.
63 *
64 * ::
65 *
66 *
67 * physical → ⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽
68 * top of | |
69 * display | |
70 * | New frame |
71 * | |
72 * |↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓|
73 * |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| ← Scanline,
74 * |↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓| updates the
75 * | | frame as it
76 * | | travels down
77 * | | ("scan out")
78 * | Old frame |
79 * | |
80 * | |
81 * | |
82 * | | physical
83 * | | bottom of
84 * vertical |⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽| ← display
85 * blanking ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆
86 * region → ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆
87 * ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆
88 * start of → ⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽
89 * new frame
90 *
91 * "Physical top of display" is the reference point for the high-precision/
92 * corrected timestamp.
93 *
94 * On a lot of display hardware, programming needs to take effect during the
95 * vertical blanking period so that settings like gamma, the image buffer
96 * buffer to be scanned out, etc. can safely be changed without showing
97 * any visual artifacts on the screen. In some unforgiving hardware, some of
98 * this programming has to both start and end in the same vblank. To help
99 * with the timing of the hardware programming, an interrupt is usually
100 * available to notify the driver when it can start the updating of registers.
101 * The interrupt is in this context named the vblank interrupt.
102 *
103 * The vblank interrupt may be fired at different points depending on the
104 * hardware. Some hardware implementations will fire the interrupt when the
105 * new frame start, other implementations will fire the interrupt at different
106 * points in time.
107 *
108 * Vertical blanking plays a major role in graphics rendering. To achieve
109 * tear-free display, users must synchronize page flips and/or rendering to
110 * vertical blanking. The DRM API offers ioctls to perform page flips
111 * synchronized to vertical blanking and wait for vertical blanking.
112 *
113 * The DRM core handles most of the vertical blanking management logic, which
114 * involves filtering out spurious interrupts, keeping race-free blanking
115 * counters, coping with counter wrap-around and resets and keeping use counts.
116 * It relies on the driver to generate vertical blanking interrupts and
117 * optionally provide a hardware vertical blanking counter.
118 *
119 * Drivers must initialize the vertical blanking handling core with a call to
120 * drm_vblank_init(). Minimally, a driver needs to implement
121 * &drm_crtc_funcs.enable_vblank and &drm_crtc_funcs.disable_vblank plus call
122 * drm_crtc_handle_vblank() in its vblank interrupt handler for working vblank
123 * support.
124 *
125 * Vertical blanking interrupts can be enabled by the DRM core or by drivers
126 * themselves (for instance to handle page flipping operations). The DRM core
127 * maintains a vertical blanking use count to ensure that the interrupts are not
128 * disabled while a user still needs them. To increment the use count, drivers
129 * call drm_crtc_vblank_get() and release the vblank reference again with
130 * drm_crtc_vblank_put(). In between these two calls vblank interrupts are
131 * guaranteed to be enabled.
132 *
133 * On many hardware disabling the vblank interrupt cannot be done in a race-free
134 * manner, see &drm_vblank_crtc_config.disable_immediate and
135 * &drm_driver.max_vblank_count. In that case the vblank core only disables the
136 * vblanks after a timer has expired, which can be configured through the
137 * ``vblankoffdelay`` module parameter.
138 *
139 * Drivers for hardware without support for vertical-blanking interrupts
140 * must not call drm_vblank_init(). For such drivers, atomic helpers will
141 * automatically generate fake vblank events as part of the display update.
142 * This functionality also can be controlled by the driver by enabling and
143 * disabling struct drm_crtc_state.no_vblank.
144 */
145
146/* Retry timestamp calculation up to 3 times to satisfy
147 * drm_timestamp_precision before giving up.
148 */
149#define DRM_TIMESTAMP_MAXRETRIES 3
150
151/* Threshold in nanoseconds for detection of redundant
152 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
153 */
154#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
155
156static bool
157drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
158 ktime_t *tvblank, bool in_vblank_irq);
159
160static unsigned int drm_timestamp_precision = 20; /* Default to 20 usecs. */
161
162static int drm_vblank_offdelay = 5000; /* Default to 5000 msecs. */
163
164module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
165module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
166MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs] (0: never disable, <0: disable immediately)");
167MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
168
169static struct drm_vblank_crtc *
170drm_vblank_crtc(struct drm_device *dev, unsigned int pipe)
171{
172 return &dev->vblank[pipe];
173}
174
175struct drm_vblank_crtc *
176drm_crtc_vblank_crtc(struct drm_crtc *crtc)
177{
178 return drm_vblank_crtc(crtc->dev, drm_crtc_index(crtc));
179}
180EXPORT_SYMBOL(drm_crtc_vblank_crtc);
181
182static void store_vblank(struct drm_device *dev, unsigned int pipe,
183 u32 vblank_count_inc,
184 ktime_t t_vblank, u32 last)
185{
186 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
187
188 assert_spin_locked(&dev->vblank_time_lock);
189
190 vblank->last = last;
191
192 write_seqlock(&vblank->seqlock);
193 vblank->time = t_vblank;
194 atomic64_add(vblank_count_inc, &vblank->count);
195 write_sequnlock(&vblank->seqlock);
196}
197
198static u32 drm_max_vblank_count(struct drm_device *dev, unsigned int pipe)
199{
200 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
201
202 return vblank->max_vblank_count ?: dev->max_vblank_count;
203}
204
205/*
206 * "No hw counter" fallback implementation of .get_vblank_counter() hook,
207 * if there is no usable hardware frame counter available.
208 */
209static u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
210{
211 drm_WARN_ON_ONCE(dev, drm_max_vblank_count(dev, pipe) != 0);
212 return 0;
213}
214
215static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
216{
217 if (drm_core_check_feature(dev, DRIVER_MODESET)) {
218 struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
219
220 if (drm_WARN_ON(dev, !crtc))
221 return 0;
222
223 if (crtc->funcs->get_vblank_counter)
224 return crtc->funcs->get_vblank_counter(crtc);
225 }
226
227 return drm_vblank_no_hw_counter(dev, pipe);
228}
229
230/*
231 * Reset the stored timestamp for the current vblank count to correspond
232 * to the last vblank occurred.
233 *
234 * Only to be called from drm_crtc_vblank_on().
235 *
236 * Note: caller must hold &drm_device.vbl_lock since this reads & writes
237 * device vblank fields.
238 */
239static void drm_reset_vblank_timestamp(struct drm_device *dev, unsigned int pipe)
240{
241 u32 cur_vblank;
242 bool rc;
243 ktime_t t_vblank;
244 int count = DRM_TIMESTAMP_MAXRETRIES;
245
246 spin_lock(&dev->vblank_time_lock);
247
248 /*
249 * sample the current counter to avoid random jumps
250 * when drm_vblank_enable() applies the diff
251 */
252 do {
253 cur_vblank = __get_vblank_counter(dev, pipe);
254 rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
255 } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
256
257 /*
258 * Only reinitialize corresponding vblank timestamp if high-precision query
259 * available and didn't fail. Otherwise reinitialize delayed at next vblank
260 * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid.
261 */
262 if (!rc)
263 t_vblank = 0;
264
265 /*
266 * +1 to make sure user will never see the same
267 * vblank counter value before and after a modeset
268 */
269 store_vblank(dev, pipe, 1, t_vblank, cur_vblank);
270
271 spin_unlock(&dev->vblank_time_lock);
272}
273
274/*
275 * Call back into the driver to update the appropriate vblank counter
276 * (specified by @pipe). Deal with wraparound, if it occurred, and
277 * update the last read value so we can deal with wraparound on the next
278 * call if necessary.
279 *
280 * Only necessary when going from off->on, to account for frames we
281 * didn't get an interrupt for.
282 *
283 * Note: caller must hold &drm_device.vbl_lock since this reads & writes
284 * device vblank fields.
285 */
286static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
287 bool in_vblank_irq)
288{
289 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
290 u32 cur_vblank, diff;
291 bool rc;
292 ktime_t t_vblank;
293 int count = DRM_TIMESTAMP_MAXRETRIES;
294 int framedur_ns = vblank->framedur_ns;
295 u32 max_vblank_count = drm_max_vblank_count(dev, pipe);
296
297 /*
298 * Interrupts were disabled prior to this call, so deal with counter
299 * wrap if needed.
300 * NOTE! It's possible we lost a full dev->max_vblank_count + 1 events
301 * here if the register is small or we had vblank interrupts off for
302 * a long time.
303 *
304 * We repeat the hardware vblank counter & timestamp query until
305 * we get consistent results. This to prevent races between gpu
306 * updating its hardware counter while we are retrieving the
307 * corresponding vblank timestamp.
308 */
309 do {
310 cur_vblank = __get_vblank_counter(dev, pipe);
311 rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, in_vblank_irq);
312 } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
313
314 if (max_vblank_count) {
315 /* trust the hw counter when it's around */
316 diff = (cur_vblank - vblank->last) & max_vblank_count;
317 } else if (rc && framedur_ns) {
318 u64 diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time));
319
320 /*
321 * Figure out how many vblanks we've missed based
322 * on the difference in the timestamps and the
323 * frame/field duration.
324 */
325
326 drm_dbg_vbl(dev, "crtc %u: Calculating number of vblanks."
327 " diff_ns = %lld, framedur_ns = %d)\n",
328 pipe, (long long)diff_ns, framedur_ns);
329
330 diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
331
332 if (diff == 0 && in_vblank_irq)
333 drm_dbg_vbl(dev, "crtc %u: Redundant vblirq ignored\n",
334 pipe);
335 } else {
336 /* some kind of default for drivers w/o accurate vbl timestamping */
337 diff = in_vblank_irq ? 1 : 0;
338 }
339
340 /*
341 * Within a drm_vblank_pre_modeset - drm_vblank_post_modeset
342 * interval? If so then vblank irqs keep running and it will likely
343 * happen that the hardware vblank counter is not trustworthy as it
344 * might reset at some point in that interval and vblank timestamps
345 * are not trustworthy either in that interval. Iow. this can result
346 * in a bogus diff >> 1 which must be avoided as it would cause
347 * random large forward jumps of the software vblank counter.
348 */
349 if (diff > 1 && (vblank->inmodeset & 0x2)) {
350 drm_dbg_vbl(dev,
351 "clamping vblank bump to 1 on crtc %u: diffr=%u"
352 " due to pre-modeset.\n", pipe, diff);
353 diff = 1;
354 }
355
356 drm_dbg_vbl(dev, "updating vblank count on crtc %u:"
357 " current=%llu, diff=%u, hw=%u hw_last=%u\n",
358 pipe, (unsigned long long)atomic64_read(&vblank->count),
359 diff, cur_vblank, vblank->last);
360
361 if (diff == 0) {
362 drm_WARN_ON_ONCE(dev, cur_vblank != vblank->last);
363 return;
364 }
365
366 /*
367 * Only reinitialize corresponding vblank timestamp if high-precision query
368 * available and didn't fail, or we were called from the vblank interrupt.
369 * Otherwise reinitialize delayed at next vblank interrupt and assign 0
370 * for now, to mark the vblanktimestamp as invalid.
371 */
372 if (!rc && !in_vblank_irq)
373 t_vblank = 0;
374
375 store_vblank(dev, pipe, diff, t_vblank, cur_vblank);
376}
377
378u64 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
379{
380 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
381 u64 count;
382
383 if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
384 return 0;
385
386 count = atomic64_read(&vblank->count);
387
388 /*
389 * This read barrier corresponds to the implicit write barrier of the
390 * write seqlock in store_vblank(). Note that this is the only place
391 * where we need an explicit barrier, since all other access goes
392 * through drm_vblank_count_and_time(), which already has the required
393 * read barrier curtesy of the read seqlock.
394 */
395 smp_rmb();
396
397 return count;
398}
399
400/**
401 * drm_crtc_accurate_vblank_count - retrieve the master vblank counter
402 * @crtc: which counter to retrieve
403 *
404 * This function is similar to drm_crtc_vblank_count() but this function
405 * interpolates to handle a race with vblank interrupts using the high precision
406 * timestamping support.
407 *
408 * This is mostly useful for hardware that can obtain the scanout position, but
409 * doesn't have a hardware frame counter.
410 */
411u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc)
412{
413 struct drm_device *dev = crtc->dev;
414 unsigned int pipe = drm_crtc_index(crtc);
415 u64 vblank;
416 unsigned long flags;
417
418 drm_WARN_ONCE(dev, drm_debug_enabled(DRM_UT_VBL) &&
419 !crtc->funcs->get_vblank_timestamp,
420 "This function requires support for accurate vblank timestamps.");
421
422 spin_lock_irqsave(&dev->vblank_time_lock, flags);
423
424 drm_update_vblank_count(dev, pipe, false);
425 vblank = drm_vblank_count(dev, pipe);
426
427 spin_unlock_irqrestore(&dev->vblank_time_lock, flags);
428
429 return vblank;
430}
431EXPORT_SYMBOL(drm_crtc_accurate_vblank_count);
432
433static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
434{
435 if (drm_core_check_feature(dev, DRIVER_MODESET)) {
436 struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
437
438 if (drm_WARN_ON(dev, !crtc))
439 return;
440
441 if (crtc->funcs->disable_vblank)
442 crtc->funcs->disable_vblank(crtc);
443 }
444}
445
446/*
447 * Disable vblank irq's on crtc, make sure that last vblank count
448 * of hardware and corresponding consistent software vblank counter
449 * are preserved, even if there are any spurious vblank irq's after
450 * disable.
451 */
452void drm_vblank_disable_and_save(struct drm_device *dev, unsigned int pipe)
453{
454 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
455 unsigned long irqflags;
456
457 assert_spin_locked(&dev->vbl_lock);
458
459 /* Prevent vblank irq processing while disabling vblank irqs,
460 * so no updates of timestamps or count can happen after we've
461 * disabled. Needed to prevent races in case of delayed irq's.
462 */
463 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
464
465 /*
466 * Update vblank count and disable vblank interrupts only if the
467 * interrupts were enabled. This avoids calling the ->disable_vblank()
468 * operation in atomic context with the hardware potentially runtime
469 * suspended.
470 */
471 if (!vblank->enabled)
472 goto out;
473
474 /*
475 * Update the count and timestamp to maintain the
476 * appearance that the counter has been ticking all along until
477 * this time. This makes the count account for the entire time
478 * between drm_crtc_vblank_on() and drm_crtc_vblank_off().
479 */
480 drm_update_vblank_count(dev, pipe, false);
481 __disable_vblank(dev, pipe);
482 vblank->enabled = false;
483
484out:
485 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
486}
487
488static void vblank_disable_fn(struct timer_list *t)
489{
490 struct drm_vblank_crtc *vblank = from_timer(vblank, t, disable_timer);
491 struct drm_device *dev = vblank->dev;
492 unsigned int pipe = vblank->pipe;
493 unsigned long irqflags;
494
495 spin_lock_irqsave(&dev->vbl_lock, irqflags);
496 if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
497 drm_dbg_core(dev, "disabling vblank on crtc %u\n", pipe);
498 drm_vblank_disable_and_save(dev, pipe);
499 }
500 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
501}
502
503static void drm_vblank_init_release(struct drm_device *dev, void *ptr)
504{
505 struct drm_vblank_crtc *vblank = ptr;
506
507 drm_WARN_ON(dev, READ_ONCE(vblank->enabled) &&
508 drm_core_check_feature(dev, DRIVER_MODESET));
509
510 drm_vblank_destroy_worker(vblank);
511 del_timer_sync(&vblank->disable_timer);
512}
513
514/**
515 * drm_vblank_init - initialize vblank support
516 * @dev: DRM device
517 * @num_crtcs: number of CRTCs supported by @dev
518 *
519 * This function initializes vblank support for @num_crtcs display pipelines.
520 * Cleanup is handled automatically through a cleanup function added with
521 * drmm_add_action_or_reset().
522 *
523 * Returns:
524 * Zero on success or a negative error code on failure.
525 */
526int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
527{
528 int ret;
529 unsigned int i;
530
531 spin_lock_init(&dev->vbl_lock);
532 spin_lock_init(&dev->vblank_time_lock);
533
534 dev->vblank = drmm_kcalloc(dev, num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
535 if (!dev->vblank)
536 return -ENOMEM;
537
538 dev->num_crtcs = num_crtcs;
539
540 for (i = 0; i < num_crtcs; i++) {
541 struct drm_vblank_crtc *vblank = &dev->vblank[i];
542
543 vblank->dev = dev;
544 vblank->pipe = i;
545 init_waitqueue_head(&vblank->queue);
546 timer_setup(&vblank->disable_timer, vblank_disable_fn, 0);
547 seqlock_init(&vblank->seqlock);
548
549 ret = drmm_add_action_or_reset(dev, drm_vblank_init_release,
550 vblank);
551 if (ret)
552 return ret;
553
554 ret = drm_vblank_worker_init(vblank);
555 if (ret)
556 return ret;
557 }
558
559 return 0;
560}
561EXPORT_SYMBOL(drm_vblank_init);
562
563/**
564 * drm_dev_has_vblank - test if vblanking has been initialized for
565 * a device
566 * @dev: the device
567 *
568 * Drivers may call this function to test if vblank support is
569 * initialized for a device. For most hardware this means that vblanking
570 * can also be enabled.
571 *
572 * Atomic helpers use this function to initialize
573 * &drm_crtc_state.no_vblank. See also drm_atomic_helper_check_modeset().
574 *
575 * Returns:
576 * True if vblanking has been initialized for the given device, false
577 * otherwise.
578 */
579bool drm_dev_has_vblank(const struct drm_device *dev)
580{
581 return dev->num_crtcs != 0;
582}
583EXPORT_SYMBOL(drm_dev_has_vblank);
584
585/**
586 * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC
587 * @crtc: which CRTC's vblank waitqueue to retrieve
588 *
589 * This function returns a pointer to the vblank waitqueue for the CRTC.
590 * Drivers can use this to implement vblank waits using wait_event() and related
591 * functions.
592 */
593wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc)
594{
595 return &crtc->dev->vblank[drm_crtc_index(crtc)].queue;
596}
597EXPORT_SYMBOL(drm_crtc_vblank_waitqueue);
598
599
600/**
601 * drm_calc_timestamping_constants - calculate vblank timestamp constants
602 * @crtc: drm_crtc whose timestamp constants should be updated.
603 * @mode: display mode containing the scanout timings
604 *
605 * Calculate and store various constants which are later needed by vblank and
606 * swap-completion timestamping, e.g, by
607 * drm_crtc_vblank_helper_get_vblank_timestamp(). They are derived from
608 * CRTC's true scanout timing, so they take things like panel scaling or
609 * other adjustments into account.
610 */
611void drm_calc_timestamping_constants(struct drm_crtc *crtc,
612 const struct drm_display_mode *mode)
613{
614 struct drm_device *dev = crtc->dev;
615 unsigned int pipe = drm_crtc_index(crtc);
616 struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc);
617 int linedur_ns = 0, framedur_ns = 0;
618 int dotclock = mode->crtc_clock;
619
620 if (!drm_dev_has_vblank(dev))
621 return;
622
623 if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
624 return;
625
626 /* Valid dotclock? */
627 if (dotclock > 0) {
628 int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
629
630 /*
631 * Convert scanline length in pixels and video
632 * dot clock to line duration and frame duration
633 * in nanoseconds:
634 */
635 linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
636 framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
637
638 /*
639 * Fields of interlaced scanout modes are only half a frame duration.
640 */
641 if (mode->flags & DRM_MODE_FLAG_INTERLACE)
642 framedur_ns /= 2;
643 } else {
644 drm_err(dev, "crtc %u: Can't calculate constants, dotclock = 0!\n",
645 crtc->base.id);
646 }
647
648 vblank->linedur_ns = linedur_ns;
649 vblank->framedur_ns = framedur_ns;
650 drm_mode_copy(&vblank->hwmode, mode);
651
652 drm_dbg_core(dev,
653 "crtc %u: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
654 crtc->base.id, mode->crtc_htotal,
655 mode->crtc_vtotal, mode->crtc_vdisplay);
656 drm_dbg_core(dev, "crtc %u: clock %d kHz framedur %d linedur %d\n",
657 crtc->base.id, dotclock, framedur_ns, linedur_ns);
658}
659EXPORT_SYMBOL(drm_calc_timestamping_constants);
660
661/**
662 * drm_crtc_vblank_helper_get_vblank_timestamp_internal - precise vblank
663 * timestamp helper
664 * @crtc: CRTC whose vblank timestamp to retrieve
665 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
666 * On return contains true maximum error of timestamp
667 * @vblank_time: Pointer to time which should receive the timestamp
668 * @in_vblank_irq:
669 * True when called from drm_crtc_handle_vblank(). Some drivers
670 * need to apply some workarounds for gpu-specific vblank irq quirks
671 * if flag is set.
672 * @get_scanout_position:
673 * Callback function to retrieve the scanout position. See
674 * @struct drm_crtc_helper_funcs.get_scanout_position.
675 *
676 * Implements calculation of exact vblank timestamps from given drm_display_mode
677 * timings and current video scanout position of a CRTC.
678 *
679 * The current implementation only handles standard video modes. For double scan
680 * and interlaced modes the driver is supposed to adjust the hardware mode
681 * (taken from &drm_crtc_state.adjusted mode for atomic modeset drivers) to
682 * match the scanout position reported.
683 *
684 * Note that atomic drivers must call drm_calc_timestamping_constants() before
685 * enabling a CRTC. The atomic helpers already take care of that in
686 * drm_atomic_helper_calc_timestamping_constants().
687 *
688 * Returns:
689 * Returns true on success, and false on failure, i.e. when no accurate
690 * timestamp could be acquired.
691 */
692bool
693drm_crtc_vblank_helper_get_vblank_timestamp_internal(
694 struct drm_crtc *crtc, int *max_error, ktime_t *vblank_time,
695 bool in_vblank_irq,
696 drm_vblank_get_scanout_position_func get_scanout_position)
697{
698 struct drm_device *dev = crtc->dev;
699 unsigned int pipe = crtc->index;
700 struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
701 struct timespec64 ts_etime, ts_vblank_time;
702 ktime_t stime, etime;
703 bool vbl_status;
704 const struct drm_display_mode *mode;
705 int vpos, hpos, i;
706 int delta_ns, duration_ns;
707
708 if (pipe >= dev->num_crtcs) {
709 drm_err(dev, "Invalid crtc %u\n", pipe);
710 return false;
711 }
712
713 /* Scanout position query not supported? Should not happen. */
714 if (!get_scanout_position) {
715 drm_err(dev, "Called from CRTC w/o get_scanout_position()!?\n");
716 return false;
717 }
718
719 if (drm_drv_uses_atomic_modeset(dev))
720 mode = &vblank->hwmode;
721 else
722 mode = &crtc->hwmode;
723
724 /* If mode timing undefined, just return as no-op:
725 * Happens during initial modesetting of a crtc.
726 */
727 if (mode->crtc_clock == 0) {
728 drm_dbg_core(dev, "crtc %u: Noop due to uninitialized mode.\n",
729 pipe);
730 drm_WARN_ON_ONCE(dev, drm_drv_uses_atomic_modeset(dev));
731 return false;
732 }
733
734 /* Get current scanout position with system timestamp.
735 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
736 * if single query takes longer than max_error nanoseconds.
737 *
738 * This guarantees a tight bound on maximum error if
739 * code gets preempted or delayed for some reason.
740 */
741 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
742 /*
743 * Get vertical and horizontal scanout position vpos, hpos,
744 * and bounding timestamps stime, etime, pre/post query.
745 */
746 vbl_status = get_scanout_position(crtc, in_vblank_irq,
747 &vpos, &hpos,
748 &stime, &etime,
749 mode);
750
751 /* Return as no-op if scanout query unsupported or failed. */
752 if (!vbl_status) {
753 drm_dbg_core(dev,
754 "crtc %u : scanoutpos query failed.\n",
755 pipe);
756 return false;
757 }
758
759 /* Compute uncertainty in timestamp of scanout position query. */
760 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
761
762 /* Accept result with < max_error nsecs timing uncertainty. */
763 if (duration_ns <= *max_error)
764 break;
765 }
766
767 /* Noisy system timing? */
768 if (i == DRM_TIMESTAMP_MAXRETRIES) {
769 drm_dbg_core(dev,
770 "crtc %u: Noisy timestamp %d us > %d us [%d reps].\n",
771 pipe, duration_ns / 1000, *max_error / 1000, i);
772 }
773
774 /* Return upper bound of timestamp precision error. */
775 *max_error = duration_ns;
776
777 /* Convert scanout position into elapsed time at raw_time query
778 * since start of scanout at first display scanline. delta_ns
779 * can be negative if start of scanout hasn't happened yet.
780 */
781 delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos),
782 mode->crtc_clock);
783
784 /* Subtract time delta from raw timestamp to get final
785 * vblank_time timestamp for end of vblank.
786 */
787 *vblank_time = ktime_sub_ns(etime, delta_ns);
788
789 if (!drm_debug_enabled(DRM_UT_VBL))
790 return true;
791
792 ts_etime = ktime_to_timespec64(etime);
793 ts_vblank_time = ktime_to_timespec64(*vblank_time);
794
795 drm_dbg_vbl(dev,
796 "crtc %u : v p(%d,%d)@ %lld.%06ld -> %lld.%06ld [e %d us, %d rep]\n",
797 pipe, hpos, vpos,
798 (u64)ts_etime.tv_sec, ts_etime.tv_nsec / 1000,
799 (u64)ts_vblank_time.tv_sec, ts_vblank_time.tv_nsec / 1000,
800 duration_ns / 1000, i);
801
802 return true;
803}
804EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp_internal);
805
806/**
807 * drm_crtc_vblank_helper_get_vblank_timestamp - precise vblank timestamp
808 * helper
809 * @crtc: CRTC whose vblank timestamp to retrieve
810 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
811 * On return contains true maximum error of timestamp
812 * @vblank_time: Pointer to time which should receive the timestamp
813 * @in_vblank_irq:
814 * True when called from drm_crtc_handle_vblank(). Some drivers
815 * need to apply some workarounds for gpu-specific vblank irq quirks
816 * if flag is set.
817 *
818 * Implements calculation of exact vblank timestamps from given drm_display_mode
819 * timings and current video scanout position of a CRTC. This can be directly
820 * used as the &drm_crtc_funcs.get_vblank_timestamp implementation of a kms
821 * driver if &drm_crtc_helper_funcs.get_scanout_position is implemented.
822 *
823 * The current implementation only handles standard video modes. For double scan
824 * and interlaced modes the driver is supposed to adjust the hardware mode
825 * (taken from &drm_crtc_state.adjusted mode for atomic modeset drivers) to
826 * match the scanout position reported.
827 *
828 * Note that atomic drivers must call drm_calc_timestamping_constants() before
829 * enabling a CRTC. The atomic helpers already take care of that in
830 * drm_atomic_helper_calc_timestamping_constants().
831 *
832 * Returns:
833 * Returns true on success, and false on failure, i.e. when no accurate
834 * timestamp could be acquired.
835 */
836bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
837 int *max_error,
838 ktime_t *vblank_time,
839 bool in_vblank_irq)
840{
841 return drm_crtc_vblank_helper_get_vblank_timestamp_internal(
842 crtc, max_error, vblank_time, in_vblank_irq,
843 crtc->helper_private->get_scanout_position);
844}
845EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp);
846
847/**
848 * drm_crtc_get_last_vbltimestamp - retrieve raw timestamp for the most
849 * recent vblank interval
850 * @crtc: CRTC whose vblank timestamp to retrieve
851 * @tvblank: Pointer to target time which should receive the timestamp
852 * @in_vblank_irq:
853 * True when called from drm_crtc_handle_vblank(). Some drivers
854 * need to apply some workarounds for gpu-specific vblank irq quirks
855 * if flag is set.
856 *
857 * Fetches the system timestamp corresponding to the time of the most recent
858 * vblank interval on specified CRTC. May call into kms-driver to
859 * compute the timestamp with a high-precision GPU specific method.
860 *
861 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
862 * call, i.e., it isn't very precisely locked to the true vblank.
863 *
864 * Returns:
865 * True if timestamp is considered to be very precise, false otherwise.
866 */
867static bool
868drm_crtc_get_last_vbltimestamp(struct drm_crtc *crtc, ktime_t *tvblank,
869 bool in_vblank_irq)
870{
871 bool ret = false;
872
873 /* Define requested maximum error on timestamps (nanoseconds). */
874 int max_error = (int) drm_timestamp_precision * 1000;
875
876 /* Query driver if possible and precision timestamping enabled. */
877 if (crtc && crtc->funcs->get_vblank_timestamp && max_error > 0) {
878 ret = crtc->funcs->get_vblank_timestamp(crtc, &max_error,
879 tvblank, in_vblank_irq);
880 }
881
882 /* GPU high precision timestamp query unsupported or failed.
883 * Return current monotonic/gettimeofday timestamp as best estimate.
884 */
885 if (!ret)
886 *tvblank = ktime_get();
887
888 return ret;
889}
890
891static bool
892drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
893 ktime_t *tvblank, bool in_vblank_irq)
894{
895 struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
896
897 return drm_crtc_get_last_vbltimestamp(crtc, tvblank, in_vblank_irq);
898}
899
900/**
901 * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
902 * @crtc: which counter to retrieve
903 *
904 * Fetches the "cooked" vblank count value that represents the number of
905 * vblank events since the system was booted, including lost events due to
906 * modesetting activity. Note that this timer isn't correct against a racing
907 * vblank interrupt (since it only reports the software vblank counter), see
908 * drm_crtc_accurate_vblank_count() for such use-cases.
909 *
910 * Note that for a given vblank counter value drm_crtc_handle_vblank()
911 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
912 * provide a barrier: Any writes done before calling
913 * drm_crtc_handle_vblank() will be visible to callers of the later
914 * functions, if the vblank count is the same or a later one.
915 *
916 * See also &drm_vblank_crtc.count.
917 *
918 * Returns:
919 * The software vblank counter.
920 */
921u64 drm_crtc_vblank_count(struct drm_crtc *crtc)
922{
923 return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
924}
925EXPORT_SYMBOL(drm_crtc_vblank_count);
926
927/**
928 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value and the
929 * system timestamp corresponding to that vblank counter value.
930 * @dev: DRM device
931 * @pipe: index of CRTC whose counter to retrieve
932 * @vblanktime: Pointer to ktime_t to receive the vblank timestamp.
933 *
934 * Fetches the "cooked" vblank count value that represents the number of
935 * vblank events since the system was booted, including lost events due to
936 * modesetting activity. Returns corresponding system timestamp of the time
937 * of the vblank interval that corresponds to the current vblank counter value.
938 *
939 * This is the legacy version of drm_crtc_vblank_count_and_time().
940 */
941static u64 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
942 ktime_t *vblanktime)
943{
944 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
945 u64 vblank_count;
946 unsigned int seq;
947
948 if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) {
949 *vblanktime = 0;
950 return 0;
951 }
952
953 do {
954 seq = read_seqbegin(&vblank->seqlock);
955 vblank_count = atomic64_read(&vblank->count);
956 *vblanktime = vblank->time;
957 } while (read_seqretry(&vblank->seqlock, seq));
958
959 return vblank_count;
960}
961
962/**
963 * drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value
964 * and the system timestamp corresponding to that vblank counter value
965 * @crtc: which counter to retrieve
966 * @vblanktime: Pointer to time to receive the vblank timestamp.
967 *
968 * Fetches the "cooked" vblank count value that represents the number of
969 * vblank events since the system was booted, including lost events due to
970 * modesetting activity. Returns corresponding system timestamp of the time
971 * of the vblank interval that corresponds to the current vblank counter value.
972 *
973 * Note that for a given vblank counter value drm_crtc_handle_vblank()
974 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
975 * provide a barrier: Any writes done before calling
976 * drm_crtc_handle_vblank() will be visible to callers of the later
977 * functions, if the vblank count is the same or a later one.
978 *
979 * See also &drm_vblank_crtc.count.
980 */
981u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
982 ktime_t *vblanktime)
983{
984 return drm_vblank_count_and_time(crtc->dev, drm_crtc_index(crtc),
985 vblanktime);
986}
987EXPORT_SYMBOL(drm_crtc_vblank_count_and_time);
988
989/**
990 * drm_crtc_next_vblank_start - calculate the time of the next vblank
991 * @crtc: the crtc for which to calculate next vblank time
992 * @vblanktime: pointer to time to receive the next vblank timestamp.
993 *
994 * Calculate the expected time of the start of the next vblank period,
995 * based on time of previous vblank and frame duration
996 */
997int drm_crtc_next_vblank_start(struct drm_crtc *crtc, ktime_t *vblanktime)
998{
999 struct drm_vblank_crtc *vblank;
1000 struct drm_display_mode *mode;
1001 u64 vblank_start;
1002
1003 if (!drm_dev_has_vblank(crtc->dev))
1004 return -EINVAL;
1005
1006 vblank = drm_crtc_vblank_crtc(crtc);
1007 mode = &vblank->hwmode;
1008
1009 if (!vblank->framedur_ns || !vblank->linedur_ns)
1010 return -EINVAL;
1011
1012 if (!drm_crtc_get_last_vbltimestamp(crtc, vblanktime, false))
1013 return -EINVAL;
1014
1015 vblank_start = DIV_ROUND_DOWN_ULL(
1016 (u64)vblank->framedur_ns * mode->crtc_vblank_start,
1017 mode->crtc_vtotal);
1018 *vblanktime = ktime_add(*vblanktime, ns_to_ktime(vblank_start));
1019
1020 return 0;
1021}
1022EXPORT_SYMBOL(drm_crtc_next_vblank_start);
1023
1024static void send_vblank_event(struct drm_device *dev,
1025 struct drm_pending_vblank_event *e,
1026 u64 seq, ktime_t now)
1027{
1028 struct timespec64 tv;
1029
1030 switch (e->event.base.type) {
1031 case DRM_EVENT_VBLANK:
1032 case DRM_EVENT_FLIP_COMPLETE:
1033 tv = ktime_to_timespec64(now);
1034 e->event.vbl.sequence = seq;
1035 /*
1036 * e->event is a user space structure, with hardcoded unsigned
1037 * 32-bit seconds/microseconds. This is safe as we always use
1038 * monotonic timestamps since linux-4.15
1039 */
1040 e->event.vbl.tv_sec = tv.tv_sec;
1041 e->event.vbl.tv_usec = tv.tv_nsec / 1000;
1042 break;
1043 case DRM_EVENT_CRTC_SEQUENCE:
1044 if (seq)
1045 e->event.seq.sequence = seq;
1046 e->event.seq.time_ns = ktime_to_ns(now);
1047 break;
1048 }
1049 trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe, seq);
1050 /*
1051 * Use the same timestamp for any associated fence signal to avoid
1052 * mismatch in timestamps for vsync & fence events triggered by the
1053 * same HW event. Frameworks like SurfaceFlinger in Android expects the
1054 * retire-fence timestamp to match exactly with HW vsync as it uses it
1055 * for its software vsync modeling.
1056 */
1057 drm_send_event_timestamp_locked(dev, &e->base, now);
1058}
1059
1060/**
1061 * drm_crtc_arm_vblank_event - arm vblank event after pageflip
1062 * @crtc: the source CRTC of the vblank event
1063 * @e: the event to send
1064 *
1065 * A lot of drivers need to generate vblank events for the very next vblank
1066 * interrupt. For example when the page flip interrupt happens when the page
1067 * flip gets armed, but not when it actually executes within the next vblank
1068 * period. This helper function implements exactly the required vblank arming
1069 * behaviour.
1070 *
1071 * NOTE: Drivers using this to send out the &drm_crtc_state.event as part of an
1072 * atomic commit must ensure that the next vblank happens at exactly the same
1073 * time as the atomic commit is committed to the hardware. This function itself
1074 * does **not** protect against the next vblank interrupt racing with either this
1075 * function call or the atomic commit operation. A possible sequence could be:
1076 *
1077 * 1. Driver commits new hardware state into vblank-synchronized registers.
1078 * 2. A vblank happens, committing the hardware state. Also the corresponding
1079 * vblank interrupt is fired off and fully processed by the interrupt
1080 * handler.
1081 * 3. The atomic commit operation proceeds to call drm_crtc_arm_vblank_event().
1082 * 4. The event is only send out for the next vblank, which is wrong.
1083 *
1084 * An equivalent race can happen when the driver calls
1085 * drm_crtc_arm_vblank_event() before writing out the new hardware state.
1086 *
1087 * The only way to make this work safely is to prevent the vblank from firing
1088 * (and the hardware from committing anything else) until the entire atomic
1089 * commit sequence has run to completion. If the hardware does not have such a
1090 * feature (e.g. using a "go" bit), then it is unsafe to use this functions.
1091 * Instead drivers need to manually send out the event from their interrupt
1092 * handler by calling drm_crtc_send_vblank_event() and make sure that there's no
1093 * possible race with the hardware committing the atomic update.
1094 *
1095 * Caller must hold a vblank reference for the event @e acquired by a
1096 * drm_crtc_vblank_get(), which will be dropped when the next vblank arrives.
1097 */
1098void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
1099 struct drm_pending_vblank_event *e)
1100{
1101 struct drm_device *dev = crtc->dev;
1102 unsigned int pipe = drm_crtc_index(crtc);
1103
1104 assert_spin_locked(&dev->event_lock);
1105
1106 e->pipe = pipe;
1107 e->sequence = drm_crtc_accurate_vblank_count(crtc) + 1;
1108 list_add_tail(&e->base.link, &dev->vblank_event_list);
1109}
1110EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
1111
1112/**
1113 * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
1114 * @crtc: the source CRTC of the vblank event
1115 * @e: the event to send
1116 *
1117 * Updates sequence # and timestamp on event for the most recently processed
1118 * vblank, and sends it to userspace. Caller must hold event lock.
1119 *
1120 * See drm_crtc_arm_vblank_event() for a helper which can be used in certain
1121 * situation, especially to send out events for atomic commit operations.
1122 */
1123void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
1124 struct drm_pending_vblank_event *e)
1125{
1126 struct drm_device *dev = crtc->dev;
1127 u64 seq;
1128 unsigned int pipe = drm_crtc_index(crtc);
1129 ktime_t now;
1130
1131 if (drm_dev_has_vblank(dev)) {
1132 seq = drm_vblank_count_and_time(dev, pipe, &now);
1133 } else {
1134 seq = 0;
1135
1136 now = ktime_get();
1137 }
1138 e->pipe = pipe;
1139 send_vblank_event(dev, e, seq, now);
1140}
1141EXPORT_SYMBOL(drm_crtc_send_vblank_event);
1142
1143static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
1144{
1145 if (drm_core_check_feature(dev, DRIVER_MODESET)) {
1146 struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
1147
1148 if (drm_WARN_ON(dev, !crtc))
1149 return 0;
1150
1151 if (crtc->funcs->enable_vblank)
1152 return crtc->funcs->enable_vblank(crtc);
1153 }
1154
1155 return -EINVAL;
1156}
1157
1158static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
1159{
1160 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
1161 int ret = 0;
1162
1163 assert_spin_locked(&dev->vbl_lock);
1164
1165 spin_lock(&dev->vblank_time_lock);
1166
1167 if (!vblank->enabled) {
1168 /*
1169 * Enable vblank irqs under vblank_time_lock protection.
1170 * All vblank count & timestamp updates are held off
1171 * until we are done reinitializing master counter and
1172 * timestamps. Filtercode in drm_handle_vblank() will
1173 * prevent double-accounting of same vblank interval.
1174 */
1175 ret = __enable_vblank(dev, pipe);
1176 drm_dbg_core(dev, "enabling vblank on crtc %u, ret: %d\n",
1177 pipe, ret);
1178 if (ret) {
1179 atomic_dec(&vblank->refcount);
1180 } else {
1181 drm_update_vblank_count(dev, pipe, 0);
1182 /* drm_update_vblank_count() includes a wmb so we just
1183 * need to ensure that the compiler emits the write
1184 * to mark the vblank as enabled after the call
1185 * to drm_update_vblank_count().
1186 */
1187 WRITE_ONCE(vblank->enabled, true);
1188 }
1189 }
1190
1191 spin_unlock(&dev->vblank_time_lock);
1192
1193 return ret;
1194}
1195
1196int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
1197{
1198 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
1199 unsigned long irqflags;
1200 int ret = 0;
1201
1202 if (!drm_dev_has_vblank(dev))
1203 return -EINVAL;
1204
1205 if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1206 return -EINVAL;
1207
1208 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1209 /* Going from 0->1 means we have to enable interrupts again */
1210 if (atomic_add_return(1, &vblank->refcount) == 1) {
1211 ret = drm_vblank_enable(dev, pipe);
1212 } else {
1213 if (!vblank->enabled) {
1214 atomic_dec(&vblank->refcount);
1215 ret = -EINVAL;
1216 }
1217 }
1218 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1219
1220 return ret;
1221}
1222
1223/**
1224 * drm_crtc_vblank_get - get a reference count on vblank events
1225 * @crtc: which CRTC to own
1226 *
1227 * Acquire a reference count on vblank events to avoid having them disabled
1228 * while in use.
1229 *
1230 * Returns:
1231 * Zero on success or a negative error code on failure.
1232 */
1233int drm_crtc_vblank_get(struct drm_crtc *crtc)
1234{
1235 return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
1236}
1237EXPORT_SYMBOL(drm_crtc_vblank_get);
1238
1239void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
1240{
1241 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
1242 int vblank_offdelay = vblank->config.offdelay_ms;
1243
1244 if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1245 return;
1246
1247 if (drm_WARN_ON(dev, atomic_read(&vblank->refcount) == 0))
1248 return;
1249
1250 /* Last user schedules interrupt disable */
1251 if (atomic_dec_and_test(&vblank->refcount)) {
1252 if (!vblank_offdelay)
1253 return;
1254 else if (vblank_offdelay < 0)
1255 vblank_disable_fn(&vblank->disable_timer);
1256 else if (!vblank->config.disable_immediate)
1257 mod_timer(&vblank->disable_timer,
1258 jiffies + ((vblank_offdelay * HZ) / 1000));
1259 }
1260}
1261
1262/**
1263 * drm_crtc_vblank_put - give up ownership of vblank events
1264 * @crtc: which counter to give up
1265 *
1266 * Release ownership of a given vblank counter, turning off interrupts
1267 * if possible. Disable interrupts after &drm_vblank_crtc_config.offdelay_ms
1268 * milliseconds.
1269 */
1270void drm_crtc_vblank_put(struct drm_crtc *crtc)
1271{
1272 drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
1273}
1274EXPORT_SYMBOL(drm_crtc_vblank_put);
1275
1276/**
1277 * drm_wait_one_vblank - wait for one vblank
1278 * @dev: DRM device
1279 * @pipe: CRTC index
1280 *
1281 * This waits for one vblank to pass on @pipe, using the irq driver interfaces.
1282 * It is a failure to call this when the vblank irq for @pipe is disabled, e.g.
1283 * due to lack of driver support or because the crtc is off.
1284 *
1285 * This is the legacy version of drm_crtc_wait_one_vblank().
1286 */
1287void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe)
1288{
1289 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
1290 int ret;
1291 u64 last;
1292
1293 if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1294 return;
1295
1296 ret = drm_vblank_get(dev, pipe);
1297 if (drm_WARN(dev, ret, "vblank not available on crtc %i, ret=%i\n",
1298 pipe, ret))
1299 return;
1300
1301 last = drm_vblank_count(dev, pipe);
1302
1303 ret = wait_event_timeout(vblank->queue,
1304 last != drm_vblank_count(dev, pipe),
1305 msecs_to_jiffies(100));
1306
1307 drm_WARN(dev, ret == 0, "vblank wait timed out on crtc %i\n", pipe);
1308
1309 drm_vblank_put(dev, pipe);
1310}
1311EXPORT_SYMBOL(drm_wait_one_vblank);
1312
1313/**
1314 * drm_crtc_wait_one_vblank - wait for one vblank
1315 * @crtc: DRM crtc
1316 *
1317 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
1318 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
1319 * due to lack of driver support or because the crtc is off.
1320 */
1321void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
1322{
1323 drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
1324}
1325EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
1326
1327/**
1328 * drm_crtc_vblank_off - disable vblank events on a CRTC
1329 * @crtc: CRTC in question
1330 *
1331 * Drivers can use this function to shut down the vblank interrupt handling when
1332 * disabling a crtc. This function ensures that the latest vblank frame count is
1333 * stored so that drm_vblank_on can restore it again.
1334 *
1335 * Drivers must use this function when the hardware vblank counter can get
1336 * reset, e.g. when suspending or disabling the @crtc in general.
1337 */
1338void drm_crtc_vblank_off(struct drm_crtc *crtc)
1339{
1340 struct drm_device *dev = crtc->dev;
1341 unsigned int pipe = drm_crtc_index(crtc);
1342 struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc);
1343 struct drm_pending_vblank_event *e, *t;
1344 ktime_t now;
1345 u64 seq;
1346
1347 if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1348 return;
1349
1350 /*
1351 * Grab event_lock early to prevent vblank work from being scheduled
1352 * while we're in the middle of shutting down vblank interrupts
1353 */
1354 spin_lock_irq(&dev->event_lock);
1355
1356 spin_lock(&dev->vbl_lock);
1357 drm_dbg_vbl(dev, "crtc %d, vblank enabled %d, inmodeset %d\n",
1358 pipe, vblank->enabled, vblank->inmodeset);
1359
1360 /* Avoid redundant vblank disables without previous
1361 * drm_crtc_vblank_on(). */
1362 if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset)
1363 drm_vblank_disable_and_save(dev, pipe);
1364
1365 wake_up(&vblank->queue);
1366
1367 /*
1368 * Prevent subsequent drm_vblank_get() from re-enabling
1369 * the vblank interrupt by bumping the refcount.
1370 */
1371 if (!vblank->inmodeset) {
1372 atomic_inc(&vblank->refcount);
1373 vblank->inmodeset = 1;
1374 }
1375 spin_unlock(&dev->vbl_lock);
1376
1377 /* Send any queued vblank events, lest the natives grow disquiet */
1378 seq = drm_vblank_count_and_time(dev, pipe, &now);
1379
1380 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1381 if (e->pipe != pipe)
1382 continue;
1383 drm_dbg_core(dev, "Sending premature vblank event on disable: "
1384 "wanted %llu, current %llu\n",
1385 e->sequence, seq);
1386 list_del(&e->base.link);
1387 drm_vblank_put(dev, pipe);
1388 send_vblank_event(dev, e, seq, now);
1389 }
1390
1391 /* Cancel any leftover pending vblank work */
1392 drm_vblank_cancel_pending_works(vblank);
1393
1394 spin_unlock_irq(&dev->event_lock);
1395
1396 /* Will be reset by the modeset helpers when re-enabling the crtc by
1397 * calling drm_calc_timestamping_constants(). */
1398 vblank->hwmode.crtc_clock = 0;
1399
1400 /* Wait for any vblank work that's still executing to finish */
1401 drm_vblank_flush_worker(vblank);
1402}
1403EXPORT_SYMBOL(drm_crtc_vblank_off);
1404
1405/**
1406 * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
1407 * @crtc: CRTC in question
1408 *
1409 * Drivers can use this function to reset the vblank state to off at load time.
1410 * Drivers should use this together with the drm_crtc_vblank_off() and
1411 * drm_crtc_vblank_on() functions. The difference compared to
1412 * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
1413 * and hence doesn't need to call any driver hooks.
1414 *
1415 * This is useful for recovering driver state e.g. on driver load, or on resume.
1416 */
1417void drm_crtc_vblank_reset(struct drm_crtc *crtc)
1418{
1419 struct drm_device *dev = crtc->dev;
1420 struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc);
1421
1422 spin_lock_irq(&dev->vbl_lock);
1423 /*
1424 * Prevent subsequent drm_vblank_get() from enabling the vblank
1425 * interrupt by bumping the refcount.
1426 */
1427 if (!vblank->inmodeset) {
1428 atomic_inc(&vblank->refcount);
1429 vblank->inmodeset = 1;
1430 }
1431 spin_unlock_irq(&dev->vbl_lock);
1432
1433 drm_WARN_ON(dev, !list_empty(&dev->vblank_event_list));
1434 drm_WARN_ON(dev, !list_empty(&vblank->pending_work));
1435}
1436EXPORT_SYMBOL(drm_crtc_vblank_reset);
1437
1438/**
1439 * drm_crtc_set_max_vblank_count - configure the hw max vblank counter value
1440 * @crtc: CRTC in question
1441 * @max_vblank_count: max hardware vblank counter value
1442 *
1443 * Update the maximum hardware vblank counter value for @crtc
1444 * at runtime. Useful for hardware where the operation of the
1445 * hardware vblank counter depends on the currently active
1446 * display configuration.
1447 *
1448 * For example, if the hardware vblank counter does not work
1449 * when a specific connector is active the maximum can be set
1450 * to zero. And when that specific connector isn't active the
1451 * maximum can again be set to the appropriate non-zero value.
1452 *
1453 * If used, must be called before drm_vblank_on().
1454 */
1455void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
1456 u32 max_vblank_count)
1457{
1458 struct drm_device *dev = crtc->dev;
1459 struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc);
1460
1461 drm_WARN_ON(dev, dev->max_vblank_count);
1462 drm_WARN_ON(dev, !READ_ONCE(vblank->inmodeset));
1463
1464 vblank->max_vblank_count = max_vblank_count;
1465}
1466EXPORT_SYMBOL(drm_crtc_set_max_vblank_count);
1467
1468/**
1469 * drm_crtc_vblank_on_config - enable vblank events on a CRTC with custom
1470 * configuration options
1471 * @crtc: CRTC in question
1472 * @config: Vblank configuration value
1473 *
1474 * See drm_crtc_vblank_on(). In addition, this function allows you to provide a
1475 * custom vblank configuration for a given CRTC.
1476 *
1477 * Note that @config is copied, the pointer does not need to stay valid beyond
1478 * this function call. For details of the parameters see
1479 * struct drm_vblank_crtc_config.
1480 */
1481void drm_crtc_vblank_on_config(struct drm_crtc *crtc,
1482 const struct drm_vblank_crtc_config *config)
1483{
1484 struct drm_device *dev = crtc->dev;
1485 unsigned int pipe = drm_crtc_index(crtc);
1486 struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc);
1487
1488 if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1489 return;
1490
1491 spin_lock_irq(&dev->vbl_lock);
1492 drm_dbg_vbl(dev, "crtc %d, vblank enabled %d, inmodeset %d\n",
1493 pipe, vblank->enabled, vblank->inmodeset);
1494
1495 vblank->config = *config;
1496
1497 /* Drop our private "prevent drm_vblank_get" refcount */
1498 if (vblank->inmodeset) {
1499 atomic_dec(&vblank->refcount);
1500 vblank->inmodeset = 0;
1501 }
1502
1503 drm_reset_vblank_timestamp(dev, pipe);
1504
1505 /*
1506 * re-enable interrupts if there are users left, or the
1507 * user wishes vblank interrupts to be enabled all the time.
1508 */
1509 if (atomic_read(&vblank->refcount) != 0 || !vblank->config.offdelay_ms)
1510 drm_WARN_ON(dev, drm_vblank_enable(dev, pipe));
1511 spin_unlock_irq(&dev->vbl_lock);
1512}
1513EXPORT_SYMBOL(drm_crtc_vblank_on_config);
1514
1515/**
1516 * drm_crtc_vblank_on - enable vblank events on a CRTC
1517 * @crtc: CRTC in question
1518 *
1519 * This functions restores the vblank interrupt state captured with
1520 * drm_crtc_vblank_off() again and is generally called when enabling @crtc. Note
1521 * that calls to drm_crtc_vblank_on() and drm_crtc_vblank_off() can be
1522 * unbalanced and so can also be unconditionally called in driver load code to
1523 * reflect the current hardware state of the crtc.
1524 *
1525 * Note that unlike in drm_crtc_vblank_on_config(), default values are used.
1526 */
1527void drm_crtc_vblank_on(struct drm_crtc *crtc)
1528{
1529 const struct drm_vblank_crtc_config config = {
1530 .offdelay_ms = drm_vblank_offdelay,
1531 .disable_immediate = crtc->dev->vblank_disable_immediate
1532 };
1533
1534 drm_crtc_vblank_on_config(crtc, &config);
1535}
1536EXPORT_SYMBOL(drm_crtc_vblank_on);
1537
1538static void drm_vblank_restore(struct drm_device *dev, unsigned int pipe)
1539{
1540 ktime_t t_vblank;
1541 struct drm_vblank_crtc *vblank;
1542 int framedur_ns;
1543 u64 diff_ns;
1544 u32 cur_vblank, diff = 1;
1545 int count = DRM_TIMESTAMP_MAXRETRIES;
1546 u32 max_vblank_count = drm_max_vblank_count(dev, pipe);
1547
1548 if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1549 return;
1550
1551 assert_spin_locked(&dev->vbl_lock);
1552 assert_spin_locked(&dev->vblank_time_lock);
1553
1554 vblank = drm_vblank_crtc(dev, pipe);
1555 drm_WARN_ONCE(dev,
1556 drm_debug_enabled(DRM_UT_VBL) && !vblank->framedur_ns,
1557 "Cannot compute missed vblanks without frame duration\n");
1558 framedur_ns = vblank->framedur_ns;
1559
1560 do {
1561 cur_vblank = __get_vblank_counter(dev, pipe);
1562 drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
1563 } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
1564
1565 diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time));
1566 if (framedur_ns)
1567 diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
1568
1569
1570 drm_dbg_vbl(dev,
1571 "missed %d vblanks in %lld ns, frame duration=%d ns, hw_diff=%d\n",
1572 diff, diff_ns, framedur_ns, cur_vblank - vblank->last);
1573 vblank->last = (cur_vblank - diff) & max_vblank_count;
1574}
1575
1576/**
1577 * drm_crtc_vblank_restore - estimate missed vblanks and update vblank count.
1578 * @crtc: CRTC in question
1579 *
1580 * Power manamement features can cause frame counter resets between vblank
1581 * disable and enable. Drivers can use this function in their
1582 * &drm_crtc_funcs.enable_vblank implementation to estimate missed vblanks since
1583 * the last &drm_crtc_funcs.disable_vblank using timestamps and update the
1584 * vblank counter.
1585 *
1586 * Note that drivers must have race-free high-precision timestamping support,
1587 * i.e. &drm_crtc_funcs.get_vblank_timestamp must be hooked up and
1588 * &drm_vblank_crtc_config.disable_immediate must be set to indicate the
1589 * time-stamping functions are race-free against vblank hardware counter
1590 * increments.
1591 */
1592void drm_crtc_vblank_restore(struct drm_crtc *crtc)
1593{
1594 struct drm_device *dev = crtc->dev;
1595 unsigned int pipe = drm_crtc_index(crtc);
1596 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
1597
1598 drm_WARN_ON_ONCE(dev, !crtc->funcs->get_vblank_timestamp);
1599 drm_WARN_ON_ONCE(dev, vblank->inmodeset);
1600 drm_WARN_ON_ONCE(dev, !vblank->config.disable_immediate);
1601
1602 drm_vblank_restore(dev, pipe);
1603}
1604EXPORT_SYMBOL(drm_crtc_vblank_restore);
1605
1606static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
1607 u64 req_seq,
1608 union drm_wait_vblank *vblwait,
1609 struct drm_file *file_priv)
1610{
1611 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
1612 struct drm_pending_vblank_event *e;
1613 ktime_t now;
1614 u64 seq;
1615 int ret;
1616
1617 e = kzalloc(sizeof(*e), GFP_KERNEL);
1618 if (e == NULL) {
1619 ret = -ENOMEM;
1620 goto err_put;
1621 }
1622
1623 e->pipe = pipe;
1624 e->event.base.type = DRM_EVENT_VBLANK;
1625 e->event.base.length = sizeof(e->event.vbl);
1626 e->event.vbl.user_data = vblwait->request.signal;
1627 e->event.vbl.crtc_id = 0;
1628 if (drm_core_check_feature(dev, DRIVER_MODESET)) {
1629 struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
1630
1631 if (crtc)
1632 e->event.vbl.crtc_id = crtc->base.id;
1633 }
1634
1635 spin_lock_irq(&dev->event_lock);
1636
1637 /*
1638 * drm_crtc_vblank_off() might have been called after we called
1639 * drm_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
1640 * vblank disable, so no need for further locking. The reference from
1641 * drm_vblank_get() protects against vblank disable from another source.
1642 */
1643 if (!READ_ONCE(vblank->enabled)) {
1644 ret = -EINVAL;
1645 goto err_unlock;
1646 }
1647
1648 ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
1649 &e->event.base);
1650
1651 if (ret)
1652 goto err_unlock;
1653
1654 seq = drm_vblank_count_and_time(dev, pipe, &now);
1655
1656 drm_dbg_core(dev, "event on vblank count %llu, current %llu, crtc %u\n",
1657 req_seq, seq, pipe);
1658
1659 trace_drm_vblank_event_queued(file_priv, pipe, req_seq);
1660
1661 e->sequence = req_seq;
1662 if (drm_vblank_passed(seq, req_seq)) {
1663 drm_vblank_put(dev, pipe);
1664 send_vblank_event(dev, e, seq, now);
1665 vblwait->reply.sequence = seq;
1666 } else {
1667 /* drm_handle_vblank_events will call drm_vblank_put */
1668 list_add_tail(&e->base.link, &dev->vblank_event_list);
1669 vblwait->reply.sequence = req_seq;
1670 }
1671
1672 spin_unlock_irq(&dev->event_lock);
1673
1674 return 0;
1675
1676err_unlock:
1677 spin_unlock_irq(&dev->event_lock);
1678 kfree(e);
1679err_put:
1680 drm_vblank_put(dev, pipe);
1681 return ret;
1682}
1683
1684static bool drm_wait_vblank_is_query(union drm_wait_vblank *vblwait)
1685{
1686 if (vblwait->request.sequence)
1687 return false;
1688
1689 return _DRM_VBLANK_RELATIVE ==
1690 (vblwait->request.type & (_DRM_VBLANK_TYPES_MASK |
1691 _DRM_VBLANK_EVENT |
1692 _DRM_VBLANK_NEXTONMISS));
1693}
1694
1695/*
1696 * Widen a 32-bit param to 64-bits.
1697 *
1698 * \param narrow 32-bit value (missing upper 32 bits)
1699 * \param near 64-bit value that should be 'close' to near
1700 *
1701 * This function returns a 64-bit value using the lower 32-bits from
1702 * 'narrow' and constructing the upper 32-bits so that the result is
1703 * as close as possible to 'near'.
1704 */
1705
1706static u64 widen_32_to_64(u32 narrow, u64 near)
1707{
1708 return near + (s32) (narrow - near);
1709}
1710
1711static void drm_wait_vblank_reply(struct drm_device *dev, unsigned int pipe,
1712 struct drm_wait_vblank_reply *reply)
1713{
1714 ktime_t now;
1715 struct timespec64 ts;
1716
1717 /*
1718 * drm_wait_vblank_reply is a UAPI structure that uses 'long'
1719 * to store the seconds. This is safe as we always use monotonic
1720 * timestamps since linux-4.15.
1721 */
1722 reply->sequence = drm_vblank_count_and_time(dev, pipe, &now);
1723 ts = ktime_to_timespec64(now);
1724 reply->tval_sec = (u32)ts.tv_sec;
1725 reply->tval_usec = ts.tv_nsec / 1000;
1726}
1727
1728static bool drm_wait_vblank_supported(struct drm_device *dev)
1729{
1730 return drm_dev_has_vblank(dev);
1731}
1732
1733int drm_wait_vblank_ioctl(struct drm_device *dev, void *data,
1734 struct drm_file *file_priv)
1735{
1736 struct drm_crtc *crtc;
1737 struct drm_vblank_crtc *vblank;
1738 union drm_wait_vblank *vblwait = data;
1739 int ret;
1740 u64 req_seq, seq;
1741 unsigned int pipe_index;
1742 unsigned int flags, pipe, high_pipe;
1743
1744 if (!drm_wait_vblank_supported(dev))
1745 return -EOPNOTSUPP;
1746
1747 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1748 return -EINVAL;
1749
1750 if (vblwait->request.type &
1751 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1752 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1753 drm_dbg_core(dev,
1754 "Unsupported type value 0x%x, supported mask 0x%x\n",
1755 vblwait->request.type,
1756 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1757 _DRM_VBLANK_HIGH_CRTC_MASK));
1758 return -EINVAL;
1759 }
1760
1761 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1762 high_pipe = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1763 if (high_pipe)
1764 pipe_index = high_pipe >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1765 else
1766 pipe_index = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1767
1768 /* Convert lease-relative crtc index into global crtc index */
1769 if (drm_core_check_feature(dev, DRIVER_MODESET)) {
1770 pipe = 0;
1771 drm_for_each_crtc(crtc, dev) {
1772 if (drm_lease_held(file_priv, crtc->base.id)) {
1773 if (pipe_index == 0)
1774 break;
1775 pipe_index--;
1776 }
1777 pipe++;
1778 }
1779 } else {
1780 pipe = pipe_index;
1781 }
1782
1783 if (pipe >= dev->num_crtcs)
1784 return -EINVAL;
1785
1786 vblank = &dev->vblank[pipe];
1787
1788 /* If the counter is currently enabled and accurate, short-circuit
1789 * queries to return the cached timestamp of the last vblank.
1790 */
1791 if (vblank->config.disable_immediate &&
1792 drm_wait_vblank_is_query(vblwait) &&
1793 READ_ONCE(vblank->enabled)) {
1794 drm_wait_vblank_reply(dev, pipe, &vblwait->reply);
1795 return 0;
1796 }
1797
1798 ret = drm_vblank_get(dev, pipe);
1799 if (ret) {
1800 drm_dbg_core(dev,
1801 "crtc %d failed to acquire vblank counter, %d\n",
1802 pipe, ret);
1803 return ret;
1804 }
1805 seq = drm_vblank_count(dev, pipe);
1806
1807 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1808 case _DRM_VBLANK_RELATIVE:
1809 req_seq = seq + vblwait->request.sequence;
1810 vblwait->request.sequence = req_seq;
1811 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1812 break;
1813 case _DRM_VBLANK_ABSOLUTE:
1814 req_seq = widen_32_to_64(vblwait->request.sequence, seq);
1815 break;
1816 default:
1817 ret = -EINVAL;
1818 goto done;
1819 }
1820
1821 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1822 drm_vblank_passed(seq, req_seq)) {
1823 req_seq = seq + 1;
1824 vblwait->request.type &= ~_DRM_VBLANK_NEXTONMISS;
1825 vblwait->request.sequence = req_seq;
1826 }
1827
1828 if (flags & _DRM_VBLANK_EVENT) {
1829 /* must hold on to the vblank ref until the event fires
1830 * drm_vblank_put will be called asynchronously
1831 */
1832 return drm_queue_vblank_event(dev, pipe, req_seq, vblwait, file_priv);
1833 }
1834
1835 if (req_seq != seq) {
1836 int wait;
1837
1838 drm_dbg_core(dev, "waiting on vblank count %llu, crtc %u\n",
1839 req_seq, pipe);
1840 wait = wait_event_interruptible_timeout(vblank->queue,
1841 drm_vblank_passed(drm_vblank_count(dev, pipe), req_seq) ||
1842 !READ_ONCE(vblank->enabled),
1843 msecs_to_jiffies(3000));
1844
1845 switch (wait) {
1846 case 0:
1847 /* timeout */
1848 ret = -EBUSY;
1849 break;
1850 case -ERESTARTSYS:
1851 /* interrupted by signal */
1852 ret = -EINTR;
1853 break;
1854 default:
1855 ret = 0;
1856 break;
1857 }
1858 }
1859
1860 if (ret != -EINTR) {
1861 drm_wait_vblank_reply(dev, pipe, &vblwait->reply);
1862
1863 drm_dbg_core(dev, "crtc %d returning %u to client\n",
1864 pipe, vblwait->reply.sequence);
1865 } else {
1866 drm_dbg_core(dev, "crtc %d vblank wait interrupted by signal\n",
1867 pipe);
1868 }
1869
1870done:
1871 drm_vblank_put(dev, pipe);
1872 return ret;
1873}
1874
1875static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
1876{
1877 struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
1878 bool high_prec = false;
1879 struct drm_pending_vblank_event *e, *t;
1880 ktime_t now;
1881 u64 seq;
1882
1883 assert_spin_locked(&dev->event_lock);
1884
1885 seq = drm_vblank_count_and_time(dev, pipe, &now);
1886
1887 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1888 if (e->pipe != pipe)
1889 continue;
1890 if (!drm_vblank_passed(seq, e->sequence))
1891 continue;
1892
1893 drm_dbg_core(dev, "vblank event on %llu, current %llu\n",
1894 e->sequence, seq);
1895
1896 list_del(&e->base.link);
1897 drm_vblank_put(dev, pipe);
1898 send_vblank_event(dev, e, seq, now);
1899 }
1900
1901 if (crtc && crtc->funcs->get_vblank_timestamp)
1902 high_prec = true;
1903
1904 trace_drm_vblank_event(pipe, seq, now, high_prec);
1905}
1906
1907/**
1908 * drm_handle_vblank - handle a vblank event
1909 * @dev: DRM device
1910 * @pipe: index of CRTC where this event occurred
1911 *
1912 * Drivers should call this routine in their vblank interrupt handlers to
1913 * update the vblank counter and send any signals that may be pending.
1914 *
1915 * This is the legacy version of drm_crtc_handle_vblank().
1916 */
1917bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
1918{
1919 struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe);
1920 unsigned long irqflags;
1921 bool disable_irq;
1922
1923 if (drm_WARN_ON_ONCE(dev, !drm_dev_has_vblank(dev)))
1924 return false;
1925
1926 if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1927 return false;
1928
1929 spin_lock_irqsave(&dev->event_lock, irqflags);
1930
1931 /* Need timestamp lock to prevent concurrent execution with
1932 * vblank enable/disable, as this would cause inconsistent
1933 * or corrupted timestamps and vblank counts.
1934 */
1935 spin_lock(&dev->vblank_time_lock);
1936
1937 /* Vblank irq handling disabled. Nothing to do. */
1938 if (!vblank->enabled) {
1939 spin_unlock(&dev->vblank_time_lock);
1940 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1941 return false;
1942 }
1943
1944 drm_update_vblank_count(dev, pipe, true);
1945
1946 spin_unlock(&dev->vblank_time_lock);
1947
1948 wake_up(&vblank->queue);
1949
1950 /* With instant-off, we defer disabling the interrupt until after
1951 * we finish processing the following vblank after all events have
1952 * been signaled. The disable has to be last (after
1953 * drm_handle_vblank_events) so that the timestamp is always accurate.
1954 */
1955 disable_irq = (vblank->config.disable_immediate &&
1956 vblank->config.offdelay_ms > 0 &&
1957 !atomic_read(&vblank->refcount));
1958
1959 drm_handle_vblank_events(dev, pipe);
1960 drm_handle_vblank_works(vblank);
1961
1962 spin_unlock_irqrestore(&dev->event_lock, irqflags);
1963
1964 if (disable_irq)
1965 vblank_disable_fn(&vblank->disable_timer);
1966
1967 return true;
1968}
1969EXPORT_SYMBOL(drm_handle_vblank);
1970
1971/**
1972 * drm_crtc_handle_vblank - handle a vblank event
1973 * @crtc: where this event occurred
1974 *
1975 * Drivers should call this routine in their vblank interrupt handlers to
1976 * update the vblank counter and send any signals that may be pending.
1977 *
1978 * This is the native KMS version of drm_handle_vblank().
1979 *
1980 * Note that for a given vblank counter value drm_crtc_handle_vblank()
1981 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
1982 * provide a barrier: Any writes done before calling
1983 * drm_crtc_handle_vblank() will be visible to callers of the later
1984 * functions, if the vblank count is the same or a later one.
1985 *
1986 * See also &drm_vblank_crtc.count.
1987 *
1988 * Returns:
1989 * True if the event was successfully handled, false on failure.
1990 */
1991bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
1992{
1993 return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
1994}
1995EXPORT_SYMBOL(drm_crtc_handle_vblank);
1996
1997/*
1998 * Get crtc VBLANK count.
1999 *
2000 * \param dev DRM device
2001 * \param data user argument, pointing to a drm_crtc_get_sequence structure.
2002 * \param file_priv drm file private for the user's open file descriptor
2003 */
2004
2005int drm_crtc_get_sequence_ioctl(struct drm_device *dev, void *data,
2006 struct drm_file *file_priv)
2007{
2008 struct drm_crtc *crtc;
2009 struct drm_vblank_crtc *vblank;
2010 int pipe;
2011 struct drm_crtc_get_sequence *get_seq = data;
2012 ktime_t now;
2013 bool vblank_enabled;
2014 int ret;
2015
2016 if (!drm_core_check_feature(dev, DRIVER_MODESET))
2017 return -EOPNOTSUPP;
2018
2019 if (!drm_dev_has_vblank(dev))
2020 return -EOPNOTSUPP;
2021
2022 crtc = drm_crtc_find(dev, file_priv, get_seq->crtc_id);
2023 if (!crtc)
2024 return -ENOENT;
2025
2026 pipe = drm_crtc_index(crtc);
2027
2028 vblank = drm_crtc_vblank_crtc(crtc);
2029 vblank_enabled = READ_ONCE(vblank->config.disable_immediate) &&
2030 READ_ONCE(vblank->enabled);
2031
2032 if (!vblank_enabled) {
2033 ret = drm_crtc_vblank_get(crtc);
2034 if (ret) {
2035 drm_dbg_core(dev,
2036 "crtc %d failed to acquire vblank counter, %d\n",
2037 pipe, ret);
2038 return ret;
2039 }
2040 }
2041 drm_modeset_lock(&crtc->mutex, NULL);
2042 if (crtc->state)
2043 get_seq->active = crtc->state->enable;
2044 else
2045 get_seq->active = crtc->enabled;
2046 drm_modeset_unlock(&crtc->mutex);
2047 get_seq->sequence = drm_vblank_count_and_time(dev, pipe, &now);
2048 get_seq->sequence_ns = ktime_to_ns(now);
2049 if (!vblank_enabled)
2050 drm_crtc_vblank_put(crtc);
2051 return 0;
2052}
2053
2054/*
2055 * Queue a event for VBLANK sequence
2056 *
2057 * \param dev DRM device
2058 * \param data user argument, pointing to a drm_crtc_queue_sequence structure.
2059 * \param file_priv drm file private for the user's open file descriptor
2060 */
2061
2062int drm_crtc_queue_sequence_ioctl(struct drm_device *dev, void *data,
2063 struct drm_file *file_priv)
2064{
2065 struct drm_crtc *crtc;
2066 struct drm_vblank_crtc *vblank;
2067 int pipe;
2068 struct drm_crtc_queue_sequence *queue_seq = data;
2069 ktime_t now;
2070 struct drm_pending_vblank_event *e;
2071 u32 flags;
2072 u64 seq;
2073 u64 req_seq;
2074 int ret;
2075
2076 if (!drm_core_check_feature(dev, DRIVER_MODESET))
2077 return -EOPNOTSUPP;
2078
2079 if (!drm_dev_has_vblank(dev))
2080 return -EOPNOTSUPP;
2081
2082 crtc = drm_crtc_find(dev, file_priv, queue_seq->crtc_id);
2083 if (!crtc)
2084 return -ENOENT;
2085
2086 flags = queue_seq->flags;
2087 /* Check valid flag bits */
2088 if (flags & ~(DRM_CRTC_SEQUENCE_RELATIVE|
2089 DRM_CRTC_SEQUENCE_NEXT_ON_MISS))
2090 return -EINVAL;
2091
2092 pipe = drm_crtc_index(crtc);
2093
2094 vblank = drm_crtc_vblank_crtc(crtc);
2095
2096 e = kzalloc(sizeof(*e), GFP_KERNEL);
2097 if (e == NULL)
2098 return -ENOMEM;
2099
2100 ret = drm_crtc_vblank_get(crtc);
2101 if (ret) {
2102 drm_dbg_core(dev,
2103 "crtc %d failed to acquire vblank counter, %d\n",
2104 pipe, ret);
2105 goto err_free;
2106 }
2107
2108 seq = drm_vblank_count_and_time(dev, pipe, &now);
2109 req_seq = queue_seq->sequence;
2110
2111 if (flags & DRM_CRTC_SEQUENCE_RELATIVE)
2112 req_seq += seq;
2113
2114 if ((flags & DRM_CRTC_SEQUENCE_NEXT_ON_MISS) && drm_vblank_passed(seq, req_seq))
2115 req_seq = seq + 1;
2116
2117 e->pipe = pipe;
2118 e->event.base.type = DRM_EVENT_CRTC_SEQUENCE;
2119 e->event.base.length = sizeof(e->event.seq);
2120 e->event.seq.user_data = queue_seq->user_data;
2121
2122 spin_lock_irq(&dev->event_lock);
2123
2124 /*
2125 * drm_crtc_vblank_off() might have been called after we called
2126 * drm_crtc_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
2127 * vblank disable, so no need for further locking. The reference from
2128 * drm_crtc_vblank_get() protects against vblank disable from another source.
2129 */
2130 if (!READ_ONCE(vblank->enabled)) {
2131 ret = -EINVAL;
2132 goto err_unlock;
2133 }
2134
2135 ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
2136 &e->event.base);
2137
2138 if (ret)
2139 goto err_unlock;
2140
2141 e->sequence = req_seq;
2142
2143 if (drm_vblank_passed(seq, req_seq)) {
2144 drm_crtc_vblank_put(crtc);
2145 send_vblank_event(dev, e, seq, now);
2146 queue_seq->sequence = seq;
2147 } else {
2148 /* drm_handle_vblank_events will call drm_vblank_put */
2149 list_add_tail(&e->base.link, &dev->vblank_event_list);
2150 queue_seq->sequence = req_seq;
2151 }
2152
2153 spin_unlock_irq(&dev->event_lock);
2154 return 0;
2155
2156err_unlock:
2157 spin_unlock_irq(&dev->event_lock);
2158 drm_crtc_vblank_put(crtc);
2159err_free:
2160 kfree(e);
2161 return ret;
2162}
2163