x86/xen: resume timer irqs early
[linux/fpc-iii.git] / drivers / gpu / drm / drm_irq.c
blobf92da0a32f0d30d02fe8afeb09f5272a16b8a060
1 /**
2 * \file drm_irq.c
3 * IRQ support
5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
6 * \author Gareth Hughes <gareth@valinux.com>
7 */
9 /*
10 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
12 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14 * All Rights Reserved.
16 * Permission is hereby granted, free of charge, to any person obtaining a
17 * copy of this software and associated documentation files (the "Software"),
18 * to deal in the Software without restriction, including without limitation
19 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
20 * and/or sell copies of the Software, and to permit persons to whom the
21 * Software is furnished to do so, subject to the following conditions:
23 * The above copyright notice and this permission notice (including the next
24 * paragraph) shall be included in all copies or substantial portions of the
25 * Software.
27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
28 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
30 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
33 * OTHER DEALINGS IN THE SOFTWARE.
36 #include <drm/drmP.h>
37 #include "drm_trace.h"
39 #include <linux/interrupt.h> /* For task queue support */
40 #include <linux/slab.h>
42 #include <linux/vgaarb.h>
43 #include <linux/export.h>
45 /* Access macro for slots in vblank timestamp ringbuffer. */
46 #define vblanktimestamp(dev, crtc, count) ( \
47 (dev)->_vblank_time[(crtc) * DRM_VBLANKTIME_RBSIZE + \
48 ((count) % DRM_VBLANKTIME_RBSIZE)])
50 /* Retry timestamp calculation up to 3 times to satisfy
51 * drm_timestamp_precision before giving up.
53 #define DRM_TIMESTAMP_MAXRETRIES 3
55 /* Threshold in nanoseconds for detection of redundant
56 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
58 #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
60 /**
61 * Get interrupt from bus id.
63 * \param inode device inode.
64 * \param file_priv DRM file private.
65 * \param cmd command.
66 * \param arg user argument, pointing to a drm_irq_busid structure.
67 * \return zero on success or a negative number on failure.
69 * Finds the PCI device with the specified bus id and gets its IRQ number.
70 * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
71 * to that of the device that this DRM instance attached to.
73 int drm_irq_by_busid(struct drm_device *dev, void *data,
74 struct drm_file *file_priv)
76 struct drm_irq_busid *p = data;
78 if (!dev->driver->bus->irq_by_busid)
79 return -EINVAL;
81 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
82 return -EINVAL;
84 return dev->driver->bus->irq_by_busid(dev, p);
88 * Clear vblank timestamp buffer for a crtc.
90 static void clear_vblank_timestamps(struct drm_device *dev, int crtc)
92 memset(&dev->_vblank_time[crtc * DRM_VBLANKTIME_RBSIZE], 0,
93 DRM_VBLANKTIME_RBSIZE * sizeof(struct timeval));
97 * Disable vblank irq's on crtc, make sure that last vblank count
98 * of hardware and corresponding consistent software vblank counter
99 * are preserved, even if there are any spurious vblank irq's after
100 * disable.
102 static void vblank_disable_and_save(struct drm_device *dev, int crtc)
104 unsigned long irqflags;
105 u32 vblcount;
106 s64 diff_ns;
107 int vblrc;
108 struct timeval tvblank;
109 int count = DRM_TIMESTAMP_MAXRETRIES;
111 /* Prevent vblank irq processing while disabling vblank irqs,
112 * so no updates of timestamps or count can happen after we've
113 * disabled. Needed to prevent races in case of delayed irq's.
115 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
117 dev->driver->disable_vblank(dev, crtc);
118 dev->vblank_enabled[crtc] = 0;
120 /* No further vblank irq's will be processed after
121 * this point. Get current hardware vblank count and
122 * vblank timestamp, repeat until they are consistent.
124 * FIXME: There is still a race condition here and in
125 * drm_update_vblank_count() which can cause off-by-one
126 * reinitialization of software vblank counter. If gpu
127 * vblank counter doesn't increment exactly at the leading
128 * edge of a vblank interval, then we can lose 1 count if
129 * we happen to execute between start of vblank and the
130 * delayed gpu counter increment.
132 do {
133 dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc);
134 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
135 } while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
137 if (!count)
138 vblrc = 0;
140 /* Compute time difference to stored timestamp of last vblank
141 * as updated by last invocation of drm_handle_vblank() in vblank irq.
143 vblcount = atomic_read(&dev->_vblank_count[crtc]);
144 diff_ns = timeval_to_ns(&tvblank) -
145 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
147 /* If there is at least 1 msec difference between the last stored
148 * timestamp and tvblank, then we are currently executing our
149 * disable inside a new vblank interval, the tvblank timestamp
150 * corresponds to this new vblank interval and the irq handler
151 * for this vblank didn't run yet and won't run due to our disable.
152 * Therefore we need to do the job of drm_handle_vblank() and
153 * increment the vblank counter by one to account for this vblank.
155 * Skip this step if there isn't any high precision timestamp
156 * available. In that case we can't account for this and just
157 * hope for the best.
159 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
160 atomic_inc(&dev->_vblank_count[crtc]);
161 smp_mb__after_atomic_inc();
164 /* Invalidate all timestamps while vblank irq's are off. */
165 clear_vblank_timestamps(dev, crtc);
167 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
170 static void vblank_disable_fn(unsigned long arg)
172 struct drm_device *dev = (struct drm_device *)arg;
173 unsigned long irqflags;
174 int i;
176 if (!dev->vblank_disable_allowed)
177 return;
179 for (i = 0; i < dev->num_crtcs; i++) {
180 spin_lock_irqsave(&dev->vbl_lock, irqflags);
181 if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
182 dev->vblank_enabled[i]) {
183 DRM_DEBUG("disabling vblank on crtc %d\n", i);
184 vblank_disable_and_save(dev, i);
186 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
190 void drm_vblank_cleanup(struct drm_device *dev)
192 /* Bail if the driver didn't call drm_vblank_init() */
193 if (dev->num_crtcs == 0)
194 return;
196 del_timer_sync(&dev->vblank_disable_timer);
198 vblank_disable_fn((unsigned long)dev);
200 kfree(dev->vbl_queue);
201 kfree(dev->_vblank_count);
202 kfree(dev->vblank_refcount);
203 kfree(dev->vblank_enabled);
204 kfree(dev->last_vblank);
205 kfree(dev->last_vblank_wait);
206 kfree(dev->vblank_inmodeset);
207 kfree(dev->_vblank_time);
209 dev->num_crtcs = 0;
211 EXPORT_SYMBOL(drm_vblank_cleanup);
213 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
215 int i, ret = -ENOMEM;
217 setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
218 (unsigned long)dev);
219 spin_lock_init(&dev->vbl_lock);
220 spin_lock_init(&dev->vblank_time_lock);
222 dev->num_crtcs = num_crtcs;
224 dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs,
225 GFP_KERNEL);
226 if (!dev->vbl_queue)
227 goto err;
229 dev->_vblank_count = kmalloc(sizeof(atomic_t) * num_crtcs, GFP_KERNEL);
230 if (!dev->_vblank_count)
231 goto err;
233 dev->vblank_refcount = kmalloc(sizeof(atomic_t) * num_crtcs,
234 GFP_KERNEL);
235 if (!dev->vblank_refcount)
236 goto err;
238 dev->vblank_enabled = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
239 if (!dev->vblank_enabled)
240 goto err;
242 dev->last_vblank = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
243 if (!dev->last_vblank)
244 goto err;
246 dev->last_vblank_wait = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
247 if (!dev->last_vblank_wait)
248 goto err;
250 dev->vblank_inmodeset = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
251 if (!dev->vblank_inmodeset)
252 goto err;
254 dev->_vblank_time = kcalloc(num_crtcs * DRM_VBLANKTIME_RBSIZE,
255 sizeof(struct timeval), GFP_KERNEL);
256 if (!dev->_vblank_time)
257 goto err;
259 DRM_INFO("Supports vblank timestamp caching Rev 1 (10.10.2010).\n");
261 /* Driver specific high-precision vblank timestamping supported? */
262 if (dev->driver->get_vblank_timestamp)
263 DRM_INFO("Driver supports precise vblank timestamp query.\n");
264 else
265 DRM_INFO("No driver support for vblank timestamp query.\n");
267 /* Zero per-crtc vblank stuff */
268 for (i = 0; i < num_crtcs; i++) {
269 init_waitqueue_head(&dev->vbl_queue[i]);
270 atomic_set(&dev->_vblank_count[i], 0);
271 atomic_set(&dev->vblank_refcount[i], 0);
274 dev->vblank_disable_allowed = 0;
275 return 0;
277 err:
278 drm_vblank_cleanup(dev);
279 return ret;
281 EXPORT_SYMBOL(drm_vblank_init);
283 static void drm_irq_vgaarb_nokms(void *cookie, bool state)
285 struct drm_device *dev = cookie;
287 if (dev->driver->vgaarb_irq) {
288 dev->driver->vgaarb_irq(dev, state);
289 return;
292 if (!dev->irq_enabled)
293 return;
295 if (state) {
296 if (dev->driver->irq_uninstall)
297 dev->driver->irq_uninstall(dev);
298 } else {
299 if (dev->driver->irq_preinstall)
300 dev->driver->irq_preinstall(dev);
301 if (dev->driver->irq_postinstall)
302 dev->driver->irq_postinstall(dev);
307 * Install IRQ handler.
309 * \param dev DRM device.
311 * Initializes the IRQ related data. Installs the handler, calling the driver
312 * \c irq_preinstall() and \c irq_postinstall() functions
313 * before and after the installation.
315 int drm_irq_install(struct drm_device *dev)
317 int ret;
318 unsigned long sh_flags = 0;
319 char *irqname;
321 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
322 return -EINVAL;
324 if (drm_dev_to_irq(dev) == 0)
325 return -EINVAL;
327 mutex_lock(&dev->struct_mutex);
329 /* Driver must have been initialized */
330 if (!dev->dev_private) {
331 mutex_unlock(&dev->struct_mutex);
332 return -EINVAL;
335 if (dev->irq_enabled) {
336 mutex_unlock(&dev->struct_mutex);
337 return -EBUSY;
339 dev->irq_enabled = 1;
340 mutex_unlock(&dev->struct_mutex);
342 DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
344 /* Before installing handler */
345 if (dev->driver->irq_preinstall)
346 dev->driver->irq_preinstall(dev);
348 /* Install handler */
349 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
350 sh_flags = IRQF_SHARED;
352 if (dev->devname)
353 irqname = dev->devname;
354 else
355 irqname = dev->driver->name;
357 ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
358 sh_flags, irqname, dev);
360 if (ret < 0) {
361 mutex_lock(&dev->struct_mutex);
362 dev->irq_enabled = 0;
363 mutex_unlock(&dev->struct_mutex);
364 return ret;
367 if (!drm_core_check_feature(dev, DRIVER_MODESET))
368 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
370 /* After installing handler */
371 if (dev->driver->irq_postinstall)
372 ret = dev->driver->irq_postinstall(dev);
374 if (ret < 0) {
375 mutex_lock(&dev->struct_mutex);
376 dev->irq_enabled = 0;
377 mutex_unlock(&dev->struct_mutex);
378 if (!drm_core_check_feature(dev, DRIVER_MODESET))
379 vga_client_register(dev->pdev, NULL, NULL, NULL);
380 free_irq(drm_dev_to_irq(dev), dev);
383 return ret;
385 EXPORT_SYMBOL(drm_irq_install);
388 * Uninstall the IRQ handler.
390 * \param dev DRM device.
392 * Calls the driver's \c irq_uninstall() function, and stops the irq.
394 int drm_irq_uninstall(struct drm_device *dev)
396 unsigned long irqflags;
397 int irq_enabled, i;
399 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
400 return -EINVAL;
402 mutex_lock(&dev->struct_mutex);
403 irq_enabled = dev->irq_enabled;
404 dev->irq_enabled = 0;
405 mutex_unlock(&dev->struct_mutex);
408 * Wake up any waiters so they don't hang.
410 if (dev->num_crtcs) {
411 spin_lock_irqsave(&dev->vbl_lock, irqflags);
412 for (i = 0; i < dev->num_crtcs; i++) {
413 DRM_WAKEUP(&dev->vbl_queue[i]);
414 dev->vblank_enabled[i] = 0;
415 dev->last_vblank[i] =
416 dev->driver->get_vblank_counter(dev, i);
418 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
421 if (!irq_enabled)
422 return -EINVAL;
424 DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
426 if (!drm_core_check_feature(dev, DRIVER_MODESET))
427 vga_client_register(dev->pdev, NULL, NULL, NULL);
429 if (dev->driver->irq_uninstall)
430 dev->driver->irq_uninstall(dev);
432 free_irq(drm_dev_to_irq(dev), dev);
434 return 0;
436 EXPORT_SYMBOL(drm_irq_uninstall);
439 * IRQ control ioctl.
441 * \param inode device inode.
442 * \param file_priv DRM file private.
443 * \param cmd command.
444 * \param arg user argument, pointing to a drm_control structure.
445 * \return zero on success or a negative number on failure.
447 * Calls irq_install() or irq_uninstall() according to \p arg.
449 int drm_control(struct drm_device *dev, void *data,
450 struct drm_file *file_priv)
452 struct drm_control *ctl = data;
454 /* if we haven't irq we fallback for compatibility reasons -
455 * this used to be a separate function in drm_dma.h
459 switch (ctl->func) {
460 case DRM_INST_HANDLER:
461 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
462 return 0;
463 if (drm_core_check_feature(dev, DRIVER_MODESET))
464 return 0;
465 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
466 ctl->irq != drm_dev_to_irq(dev))
467 return -EINVAL;
468 return drm_irq_install(dev);
469 case DRM_UNINST_HANDLER:
470 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
471 return 0;
472 if (drm_core_check_feature(dev, DRIVER_MODESET))
473 return 0;
474 return drm_irq_uninstall(dev);
475 default:
476 return -EINVAL;
481 * drm_calc_timestamping_constants - Calculate and
482 * store various constants which are later needed by
483 * vblank and swap-completion timestamping, e.g, by
484 * drm_calc_vbltimestamp_from_scanoutpos().
485 * They are derived from crtc's true scanout timing,
486 * so they take things like panel scaling or other
487 * adjustments into account.
489 * @crtc drm_crtc whose timestamp constants should be updated.
492 void drm_calc_timestamping_constants(struct drm_crtc *crtc)
494 s64 linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
495 u64 dotclock;
497 /* Dot clock in Hz: */
498 dotclock = (u64) crtc->hwmode.clock * 1000;
500 /* Fields of interlaced scanout modes are only halve a frame duration.
501 * Double the dotclock to get halve the frame-/line-/pixelduration.
503 if (crtc->hwmode.flags & DRM_MODE_FLAG_INTERLACE)
504 dotclock *= 2;
506 /* Valid dotclock? */
507 if (dotclock > 0) {
508 int frame_size;
509 /* Convert scanline length in pixels and video dot clock to
510 * line duration, frame duration and pixel duration in
511 * nanoseconds:
513 pixeldur_ns = (s64) div64_u64(1000000000, dotclock);
514 linedur_ns = (s64) div64_u64(((u64) crtc->hwmode.crtc_htotal *
515 1000000000), dotclock);
516 frame_size = crtc->hwmode.crtc_htotal *
517 crtc->hwmode.crtc_vtotal;
518 framedur_ns = (s64) div64_u64((u64) frame_size * 1000000000,
519 dotclock);
520 } else
521 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
522 crtc->base.id);
524 crtc->pixeldur_ns = pixeldur_ns;
525 crtc->linedur_ns = linedur_ns;
526 crtc->framedur_ns = framedur_ns;
528 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
529 crtc->base.id, crtc->hwmode.crtc_htotal,
530 crtc->hwmode.crtc_vtotal, crtc->hwmode.crtc_vdisplay);
531 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
532 crtc->base.id, (int) dotclock/1000, (int) framedur_ns,
533 (int) linedur_ns, (int) pixeldur_ns);
535 EXPORT_SYMBOL(drm_calc_timestamping_constants);
538 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
539 * drivers. Implements calculation of exact vblank timestamps from
540 * given drm_display_mode timings and current video scanout position
541 * of a crtc. This can be called from within get_vblank_timestamp()
542 * implementation of a kms driver to implement the actual timestamping.
544 * Should return timestamps conforming to the OML_sync_control OpenML
545 * extension specification. The timestamp corresponds to the end of
546 * the vblank interval, aka start of scanout of topmost-leftmost display
547 * pixel in the following video frame.
549 * Requires support for optional dev->driver->get_scanout_position()
550 * in kms driver, plus a bit of setup code to provide a drm_display_mode
551 * that corresponds to the true scanout timing.
553 * The current implementation only handles standard video modes. It
554 * returns as no operation if a doublescan or interlaced video mode is
555 * active. Higher level code is expected to handle this.
557 * @dev: DRM device.
558 * @crtc: Which crtc's vblank timestamp to retrieve.
559 * @max_error: Desired maximum allowable error in timestamps (nanosecs).
560 * On return contains true maximum error of timestamp.
561 * @vblank_time: Pointer to struct timeval which should receive the timestamp.
562 * @flags: Flags to pass to driver:
563 * 0 = Default.
564 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
565 * @refcrtc: drm_crtc* of crtc which defines scanout timing.
567 * Returns negative value on error, failure or if not supported in current
568 * video mode:
570 * -EINVAL - Invalid crtc.
571 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
572 * -ENOTSUPP - Function not supported in current display mode.
573 * -EIO - Failed, e.g., due to failed scanout position query.
575 * Returns or'ed positive status flags on success:
577 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
578 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
581 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
582 int *max_error,
583 struct timeval *vblank_time,
584 unsigned flags,
585 struct drm_crtc *refcrtc)
587 ktime_t stime, etime, mono_time_offset;
588 struct timeval tv_etime;
589 struct drm_display_mode *mode;
590 int vbl_status, vtotal, vdisplay;
591 int vpos, hpos, i;
592 s64 framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
593 bool invbl;
595 if (crtc < 0 || crtc >= dev->num_crtcs) {
596 DRM_ERROR("Invalid crtc %d\n", crtc);
597 return -EINVAL;
600 /* Scanout position query not supported? Should not happen. */
601 if (!dev->driver->get_scanout_position) {
602 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
603 return -EIO;
606 mode = &refcrtc->hwmode;
607 vtotal = mode->crtc_vtotal;
608 vdisplay = mode->crtc_vdisplay;
610 /* Durations of frames, lines, pixels in nanoseconds. */
611 framedur_ns = refcrtc->framedur_ns;
612 linedur_ns = refcrtc->linedur_ns;
613 pixeldur_ns = refcrtc->pixeldur_ns;
615 /* If mode timing undefined, just return as no-op:
616 * Happens during initial modesetting of a crtc.
618 if (vtotal <= 0 || vdisplay <= 0 || framedur_ns == 0) {
619 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
620 return -EAGAIN;
623 /* Get current scanout position with system timestamp.
624 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
625 * if single query takes longer than max_error nanoseconds.
627 * This guarantees a tight bound on maximum error if
628 * code gets preempted or delayed for some reason.
630 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
631 /* Disable preemption to make it very likely to
632 * succeed in the first iteration even on PREEMPT_RT kernel.
634 preempt_disable();
636 /* Get system timestamp before query. */
637 stime = ktime_get();
639 /* Get vertical and horizontal scanout pos. vpos, hpos. */
640 vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos);
642 /* Get system timestamp after query. */
643 etime = ktime_get();
644 if (!drm_timestamp_monotonic)
645 mono_time_offset = ktime_get_monotonic_offset();
647 preempt_enable();
649 /* Return as no-op if scanout query unsupported or failed. */
650 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
651 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
652 crtc, vbl_status);
653 return -EIO;
656 duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
658 /* Accept result with < max_error nsecs timing uncertainty. */
659 if (duration_ns <= (s64) *max_error)
660 break;
663 /* Noisy system timing? */
664 if (i == DRM_TIMESTAMP_MAXRETRIES) {
665 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
666 crtc, (int) duration_ns/1000, *max_error/1000, i);
669 /* Return upper bound of timestamp precision error. */
670 *max_error = (int) duration_ns;
672 /* Check if in vblank area:
673 * vpos is >=0 in video scanout area, but negative
674 * within vblank area, counting down the number of lines until
675 * start of scanout.
677 invbl = vbl_status & DRM_SCANOUTPOS_INVBL;
679 /* Convert scanout position into elapsed time at raw_time query
680 * since start of scanout at first display scanline. delta_ns
681 * can be negative if start of scanout hasn't happened yet.
683 delta_ns = (s64) vpos * linedur_ns + (s64) hpos * pixeldur_ns;
685 /* Is vpos outside nominal vblank area, but less than
686 * 1/100 of a frame height away from start of vblank?
687 * If so, assume this isn't a massively delayed vblank
688 * interrupt, but a vblank interrupt that fired a few
689 * microseconds before true start of vblank. Compensate
690 * by adding a full frame duration to the final timestamp.
691 * Happens, e.g., on ATI R500, R600.
693 * We only do this if DRM_CALLED_FROM_VBLIRQ.
695 if ((flags & DRM_CALLED_FROM_VBLIRQ) && !invbl &&
696 ((vdisplay - vpos) < vtotal / 100)) {
697 delta_ns = delta_ns - framedur_ns;
699 /* Signal this correction as "applied". */
700 vbl_status |= 0x8;
703 if (!drm_timestamp_monotonic)
704 etime = ktime_sub(etime, mono_time_offset);
706 /* save this only for debugging purposes */
707 tv_etime = ktime_to_timeval(etime);
708 /* Subtract time delta from raw timestamp to get final
709 * vblank_time timestamp for end of vblank.
711 if (delta_ns < 0)
712 etime = ktime_add_ns(etime, -delta_ns);
713 else
714 etime = ktime_sub_ns(etime, delta_ns);
715 *vblank_time = ktime_to_timeval(etime);
717 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
718 crtc, (int)vbl_status, hpos, vpos,
719 (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
720 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
721 (int)duration_ns/1000, i);
723 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
724 if (invbl)
725 vbl_status |= DRM_VBLANKTIME_INVBL;
727 return vbl_status;
729 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
731 static struct timeval get_drm_timestamp(void)
733 ktime_t now;
735 now = ktime_get();
736 if (!drm_timestamp_monotonic)
737 now = ktime_sub(now, ktime_get_monotonic_offset());
739 return ktime_to_timeval(now);
743 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
744 * vblank interval.
746 * @dev: DRM device
747 * @crtc: which crtc's vblank timestamp to retrieve
748 * @tvblank: Pointer to target struct timeval which should receive the timestamp
749 * @flags: Flags to pass to driver:
750 * 0 = Default.
751 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
753 * Fetches the system timestamp corresponding to the time of the most recent
754 * vblank interval on specified crtc. May call into kms-driver to
755 * compute the timestamp with a high-precision GPU specific method.
757 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
758 * call, i.e., it isn't very precisely locked to the true vblank.
760 * Returns non-zero if timestamp is considered to be very precise.
762 u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
763 struct timeval *tvblank, unsigned flags)
765 int ret;
767 /* Define requested maximum error on timestamps (nanoseconds). */
768 int max_error = (int) drm_timestamp_precision * 1000;
770 /* Query driver if possible and precision timestamping enabled. */
771 if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
772 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
773 tvblank, flags);
774 if (ret > 0)
775 return (u32) ret;
778 /* GPU high precision timestamp query unsupported or failed.
779 * Return current monotonic/gettimeofday timestamp as best estimate.
781 *tvblank = get_drm_timestamp();
783 return 0;
785 EXPORT_SYMBOL(drm_get_last_vbltimestamp);
788 * drm_vblank_count - retrieve "cooked" vblank counter value
789 * @dev: DRM device
790 * @crtc: which counter to retrieve
792 * Fetches the "cooked" vblank count value that represents the number of
793 * vblank events since the system was booted, including lost events due to
794 * modesetting activity.
796 u32 drm_vblank_count(struct drm_device *dev, int crtc)
798 return atomic_read(&dev->_vblank_count[crtc]);
800 EXPORT_SYMBOL(drm_vblank_count);
803 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
804 * and the system timestamp corresponding to that vblank counter value.
806 * @dev: DRM device
807 * @crtc: which counter to retrieve
808 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
810 * Fetches the "cooked" vblank count value that represents the number of
811 * vblank events since the system was booted, including lost events due to
812 * modesetting activity. Returns corresponding system timestamp of the time
813 * of the vblank interval that corresponds to the current value vblank counter
814 * value.
816 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
817 struct timeval *vblanktime)
819 u32 cur_vblank;
821 /* Read timestamp from slot of _vblank_time ringbuffer
822 * that corresponds to current vblank count. Retry if
823 * count has incremented during readout. This works like
824 * a seqlock.
826 do {
827 cur_vblank = atomic_read(&dev->_vblank_count[crtc]);
828 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
829 smp_rmb();
830 } while (cur_vblank != atomic_read(&dev->_vblank_count[crtc]));
832 return cur_vblank;
834 EXPORT_SYMBOL(drm_vblank_count_and_time);
836 static void send_vblank_event(struct drm_device *dev,
837 struct drm_pending_vblank_event *e,
838 unsigned long seq, struct timeval *now)
840 WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
841 e->event.sequence = seq;
842 e->event.tv_sec = now->tv_sec;
843 e->event.tv_usec = now->tv_usec;
845 list_add_tail(&e->base.link,
846 &e->base.file_priv->event_list);
847 wake_up_interruptible(&e->base.file_priv->event_wait);
848 trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
849 e->event.sequence);
853 * drm_send_vblank_event - helper to send vblank event after pageflip
854 * @dev: DRM device
855 * @crtc: CRTC in question
856 * @e: the event to send
858 * Updates sequence # and timestamp on event, and sends it to userspace.
859 * Caller must hold event lock.
861 void drm_send_vblank_event(struct drm_device *dev, int crtc,
862 struct drm_pending_vblank_event *e)
864 struct timeval now;
865 unsigned int seq;
866 if (crtc >= 0) {
867 seq = drm_vblank_count_and_time(dev, crtc, &now);
868 } else {
869 seq = 0;
871 now = get_drm_timestamp();
873 e->pipe = crtc;
874 send_vblank_event(dev, e, seq, &now);
876 EXPORT_SYMBOL(drm_send_vblank_event);
879 * drm_update_vblank_count - update the master vblank counter
880 * @dev: DRM device
881 * @crtc: counter to update
883 * Call back into the driver to update the appropriate vblank counter
884 * (specified by @crtc). Deal with wraparound, if it occurred, and
885 * update the last read value so we can deal with wraparound on the next
886 * call if necessary.
888 * Only necessary when going from off->on, to account for frames we
889 * didn't get an interrupt for.
891 * Note: caller must hold dev->vbl_lock since this reads & writes
892 * device vblank fields.
894 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
896 u32 cur_vblank, diff, tslot, rc;
897 struct timeval t_vblank;
900 * Interrupts were disabled prior to this call, so deal with counter
901 * wrap if needed.
902 * NOTE! It's possible we lost a full dev->max_vblank_count events
903 * here if the register is small or we had vblank interrupts off for
904 * a long time.
906 * We repeat the hardware vblank counter & timestamp query until
907 * we get consistent results. This to prevent races between gpu
908 * updating its hardware counter while we are retrieving the
909 * corresponding vblank timestamp.
911 do {
912 cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
913 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
914 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
916 /* Deal with counter wrap */
917 diff = cur_vblank - dev->last_vblank[crtc];
918 if (cur_vblank < dev->last_vblank[crtc]) {
919 diff += dev->max_vblank_count;
921 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
922 crtc, dev->last_vblank[crtc], cur_vblank, diff);
925 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
926 crtc, diff);
928 /* Reinitialize corresponding vblank timestamp if high-precision query
929 * available. Skip this step if query unsupported or failed. Will
930 * reinitialize delayed at next vblank interrupt in that case.
932 if (rc) {
933 tslot = atomic_read(&dev->_vblank_count[crtc]) + diff;
934 vblanktimestamp(dev, crtc, tslot) = t_vblank;
937 smp_mb__before_atomic_inc();
938 atomic_add(diff, &dev->_vblank_count[crtc]);
939 smp_mb__after_atomic_inc();
943 * drm_vblank_get - get a reference count on vblank events
944 * @dev: DRM device
945 * @crtc: which CRTC to own
947 * Acquire a reference count on vblank events to avoid having them disabled
948 * while in use.
950 * RETURNS
951 * Zero on success, nonzero on failure.
953 int drm_vblank_get(struct drm_device *dev, int crtc)
955 unsigned long irqflags, irqflags2;
956 int ret = 0;
958 spin_lock_irqsave(&dev->vbl_lock, irqflags);
959 /* Going from 0->1 means we have to enable interrupts again */
960 if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) {
961 spin_lock_irqsave(&dev->vblank_time_lock, irqflags2);
962 if (!dev->vblank_enabled[crtc]) {
963 /* Enable vblank irqs under vblank_time_lock protection.
964 * All vblank count & timestamp updates are held off
965 * until we are done reinitializing master counter and
966 * timestamps. Filtercode in drm_handle_vblank() will
967 * prevent double-accounting of same vblank interval.
969 ret = dev->driver->enable_vblank(dev, crtc);
970 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n",
971 crtc, ret);
972 if (ret)
973 atomic_dec(&dev->vblank_refcount[crtc]);
974 else {
975 dev->vblank_enabled[crtc] = 1;
976 drm_update_vblank_count(dev, crtc);
979 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2);
980 } else {
981 if (!dev->vblank_enabled[crtc]) {
982 atomic_dec(&dev->vblank_refcount[crtc]);
983 ret = -EINVAL;
986 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
988 return ret;
990 EXPORT_SYMBOL(drm_vblank_get);
993 * drm_vblank_put - give up ownership of vblank events
994 * @dev: DRM device
995 * @crtc: which counter to give up
997 * Release ownership of a given vblank counter, turning off interrupts
998 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1000 void drm_vblank_put(struct drm_device *dev, int crtc)
1002 BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0);
1004 /* Last user schedules interrupt disable */
1005 if (atomic_dec_and_test(&dev->vblank_refcount[crtc]) &&
1006 (drm_vblank_offdelay > 0))
1007 mod_timer(&dev->vblank_disable_timer,
1008 jiffies + ((drm_vblank_offdelay * DRM_HZ)/1000));
1010 EXPORT_SYMBOL(drm_vblank_put);
1013 * drm_vblank_off - disable vblank events on a CRTC
1014 * @dev: DRM device
1015 * @crtc: CRTC in question
1017 * Caller must hold event lock.
1019 void drm_vblank_off(struct drm_device *dev, int crtc)
1021 struct drm_pending_vblank_event *e, *t;
1022 struct timeval now;
1023 unsigned long irqflags;
1024 unsigned int seq;
1026 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1027 vblank_disable_and_save(dev, crtc);
1028 DRM_WAKEUP(&dev->vbl_queue[crtc]);
1030 /* Send any queued vblank events, lest the natives grow disquiet */
1031 seq = drm_vblank_count_and_time(dev, crtc, &now);
1033 spin_lock(&dev->event_lock);
1034 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1035 if (e->pipe != crtc)
1036 continue;
1037 DRM_DEBUG("Sending premature vblank event on disable: \
1038 wanted %d, current %d\n",
1039 e->event.sequence, seq);
1040 list_del(&e->base.link);
1041 drm_vblank_put(dev, e->pipe);
1042 send_vblank_event(dev, e, seq, &now);
1044 spin_unlock(&dev->event_lock);
1046 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1048 EXPORT_SYMBOL(drm_vblank_off);
1051 * drm_vblank_pre_modeset - account for vblanks across mode sets
1052 * @dev: DRM device
1053 * @crtc: CRTC in question
1055 * Account for vblank events across mode setting events, which will likely
1056 * reset the hardware frame counter.
1058 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
1060 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1061 if (!dev->num_crtcs)
1062 return;
1064 * To avoid all the problems that might happen if interrupts
1065 * were enabled/disabled around or between these calls, we just
1066 * have the kernel take a reference on the CRTC (just once though
1067 * to avoid corrupting the count if multiple, mismatch calls occur),
1068 * so that interrupts remain enabled in the interim.
1070 if (!dev->vblank_inmodeset[crtc]) {
1071 dev->vblank_inmodeset[crtc] = 0x1;
1072 if (drm_vblank_get(dev, crtc) == 0)
1073 dev->vblank_inmodeset[crtc] |= 0x2;
1076 EXPORT_SYMBOL(drm_vblank_pre_modeset);
1078 void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
1080 unsigned long irqflags;
1082 /* vblank is not initialized (IRQ not installed ?), or has been freed */
1083 if (!dev->num_crtcs)
1084 return;
1086 if (dev->vblank_inmodeset[crtc]) {
1087 spin_lock_irqsave(&dev->vbl_lock, irqflags);
1088 dev->vblank_disable_allowed = 1;
1089 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1091 if (dev->vblank_inmodeset[crtc] & 0x2)
1092 drm_vblank_put(dev, crtc);
1094 dev->vblank_inmodeset[crtc] = 0;
1097 EXPORT_SYMBOL(drm_vblank_post_modeset);
1100 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1101 * @DRM_IOCTL_ARGS: standard ioctl arguments
1103 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1104 * ioctls around modesetting so that any lost vblank events are accounted for.
1106 * Generally the counter will reset across mode sets. If interrupts are
1107 * enabled around this call, we don't have to do anything since the counter
1108 * will have already been incremented.
1110 int drm_modeset_ctl(struct drm_device *dev, void *data,
1111 struct drm_file *file_priv)
1113 struct drm_modeset_ctl *modeset = data;
1114 unsigned int crtc;
1116 /* If drm_vblank_init() hasn't been called yet, just no-op */
1117 if (!dev->num_crtcs)
1118 return 0;
1120 /* KMS drivers handle this internally */
1121 if (drm_core_check_feature(dev, DRIVER_MODESET))
1122 return 0;
1124 crtc = modeset->crtc;
1125 if (crtc >= dev->num_crtcs)
1126 return -EINVAL;
1128 switch (modeset->cmd) {
1129 case _DRM_PRE_MODESET:
1130 drm_vblank_pre_modeset(dev, crtc);
1131 break;
1132 case _DRM_POST_MODESET:
1133 drm_vblank_post_modeset(dev, crtc);
1134 break;
1135 default:
1136 return -EINVAL;
1139 return 0;
1142 static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1143 union drm_wait_vblank *vblwait,
1144 struct drm_file *file_priv)
1146 struct drm_pending_vblank_event *e;
1147 struct timeval now;
1148 unsigned long flags;
1149 unsigned int seq;
1150 int ret;
1152 e = kzalloc(sizeof *e, GFP_KERNEL);
1153 if (e == NULL) {
1154 ret = -ENOMEM;
1155 goto err_put;
1158 e->pipe = pipe;
1159 e->base.pid = current->pid;
1160 e->event.base.type = DRM_EVENT_VBLANK;
1161 e->event.base.length = sizeof e->event;
1162 e->event.user_data = vblwait->request.signal;
1163 e->base.event = &e->event.base;
1164 e->base.file_priv = file_priv;
1165 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
1167 spin_lock_irqsave(&dev->event_lock, flags);
1169 if (file_priv->event_space < sizeof e->event) {
1170 ret = -EBUSY;
1171 goto err_unlock;
1174 file_priv->event_space -= sizeof e->event;
1175 seq = drm_vblank_count_and_time(dev, pipe, &now);
1177 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1178 (seq - vblwait->request.sequence) <= (1 << 23)) {
1179 vblwait->request.sequence = seq + 1;
1180 vblwait->reply.sequence = vblwait->request.sequence;
1183 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1184 vblwait->request.sequence, seq, pipe);
1186 trace_drm_vblank_event_queued(current->pid, pipe,
1187 vblwait->request.sequence);
1189 e->event.sequence = vblwait->request.sequence;
1190 if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1191 drm_vblank_put(dev, pipe);
1192 send_vblank_event(dev, e, seq, &now);
1193 vblwait->reply.sequence = seq;
1194 } else {
1195 /* drm_handle_vblank_events will call drm_vblank_put */
1196 list_add_tail(&e->base.link, &dev->vblank_event_list);
1197 vblwait->reply.sequence = vblwait->request.sequence;
1200 spin_unlock_irqrestore(&dev->event_lock, flags);
1202 return 0;
1204 err_unlock:
1205 spin_unlock_irqrestore(&dev->event_lock, flags);
1206 kfree(e);
1207 err_put:
1208 drm_vblank_put(dev, pipe);
1209 return ret;
1213 * Wait for VBLANK.
1215 * \param inode device inode.
1216 * \param file_priv DRM file private.
1217 * \param cmd command.
1218 * \param data user argument, pointing to a drm_wait_vblank structure.
1219 * \return zero on success or a negative number on failure.
1221 * This function enables the vblank interrupt on the pipe requested, then
1222 * sleeps waiting for the requested sequence number to occur, and drops
1223 * the vblank interrupt refcount afterwards. (vblank irq disable follows that
1224 * after a timeout with no further vblank waits scheduled).
1226 int drm_wait_vblank(struct drm_device *dev, void *data,
1227 struct drm_file *file_priv)
1229 union drm_wait_vblank *vblwait = data;
1230 int ret;
1231 unsigned int flags, seq, crtc, high_crtc;
1233 if (drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
1234 if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled))
1235 return -EINVAL;
1237 if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1238 return -EINVAL;
1240 if (vblwait->request.type &
1241 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1242 _DRM_VBLANK_HIGH_CRTC_MASK)) {
1243 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1244 vblwait->request.type,
1245 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1246 _DRM_VBLANK_HIGH_CRTC_MASK));
1247 return -EINVAL;
1250 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1251 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1252 if (high_crtc)
1253 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1254 else
1255 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1256 if (crtc >= dev->num_crtcs)
1257 return -EINVAL;
1259 ret = drm_vblank_get(dev, crtc);
1260 if (ret) {
1261 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1262 return ret;
1264 seq = drm_vblank_count(dev, crtc);
1266 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1267 case _DRM_VBLANK_RELATIVE:
1268 vblwait->request.sequence += seq;
1269 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1270 case _DRM_VBLANK_ABSOLUTE:
1271 break;
1272 default:
1273 ret = -EINVAL;
1274 goto done;
1277 if (flags & _DRM_VBLANK_EVENT) {
1278 /* must hold on to the vblank ref until the event fires
1279 * drm_vblank_put will be called asynchronously
1281 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
1284 if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1285 (seq - vblwait->request.sequence) <= (1<<23)) {
1286 vblwait->request.sequence = seq + 1;
1289 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1290 vblwait->request.sequence, crtc);
1291 dev->last_vblank_wait[crtc] = vblwait->request.sequence;
1292 DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
1293 (((drm_vblank_count(dev, crtc) -
1294 vblwait->request.sequence) <= (1 << 23)) ||
1295 !dev->irq_enabled));
1297 if (ret != -EINTR) {
1298 struct timeval now;
1300 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1301 vblwait->reply.tval_sec = now.tv_sec;
1302 vblwait->reply.tval_usec = now.tv_usec;
1304 DRM_DEBUG("returning %d to client\n",
1305 vblwait->reply.sequence);
1306 } else {
1307 DRM_DEBUG("vblank wait interrupted by signal\n");
1310 done:
1311 drm_vblank_put(dev, crtc);
1312 return ret;
1315 static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1317 struct drm_pending_vblank_event *e, *t;
1318 struct timeval now;
1319 unsigned long flags;
1320 unsigned int seq;
1322 seq = drm_vblank_count_and_time(dev, crtc, &now);
1324 spin_lock_irqsave(&dev->event_lock, flags);
1326 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1327 if (e->pipe != crtc)
1328 continue;
1329 if ((seq - e->event.sequence) > (1<<23))
1330 continue;
1332 DRM_DEBUG("vblank event on %d, current %d\n",
1333 e->event.sequence, seq);
1335 list_del(&e->base.link);
1336 drm_vblank_put(dev, e->pipe);
1337 send_vblank_event(dev, e, seq, &now);
1340 spin_unlock_irqrestore(&dev->event_lock, flags);
1342 trace_drm_vblank_event(crtc, seq);
1346 * drm_handle_vblank - handle a vblank event
1347 * @dev: DRM device
1348 * @crtc: where this event occurred
1350 * Drivers should call this routine in their vblank interrupt handlers to
1351 * update the vblank counter and send any signals that may be pending.
1353 bool drm_handle_vblank(struct drm_device *dev, int crtc)
1355 u32 vblcount;
1356 s64 diff_ns;
1357 struct timeval tvblank;
1358 unsigned long irqflags;
1360 if (!dev->num_crtcs)
1361 return false;
1363 /* Need timestamp lock to prevent concurrent execution with
1364 * vblank enable/disable, as this would cause inconsistent
1365 * or corrupted timestamps and vblank counts.
1367 spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
1369 /* Vblank irq handling disabled. Nothing to do. */
1370 if (!dev->vblank_enabled[crtc]) {
1371 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1372 return false;
1375 /* Fetch corresponding timestamp for this vblank interval from
1376 * driver and store it in proper slot of timestamp ringbuffer.
1379 /* Get current timestamp and count. */
1380 vblcount = atomic_read(&dev->_vblank_count[crtc]);
1381 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1383 /* Compute time difference to timestamp of last vblank */
1384 diff_ns = timeval_to_ns(&tvblank) -
1385 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1387 /* Update vblank timestamp and count if at least
1388 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1389 * difference between last stored timestamp and current
1390 * timestamp. A smaller difference means basically
1391 * identical timestamps. Happens if this vblank has
1392 * been already processed and this is a redundant call,
1393 * e.g., due to spurious vblank interrupts. We need to
1394 * ignore those for accounting.
1396 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1397 /* Store new timestamp in ringbuffer. */
1398 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1400 /* Increment cooked vblank count. This also atomically commits
1401 * the timestamp computed above.
1403 smp_mb__before_atomic_inc();
1404 atomic_inc(&dev->_vblank_count[crtc]);
1405 smp_mb__after_atomic_inc();
1406 } else {
1407 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1408 crtc, (int) diff_ns);
1411 DRM_WAKEUP(&dev->vbl_queue[crtc]);
1412 drm_handle_vblank_events(dev, crtc);
1414 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1415 return true;
1417 EXPORT_SYMBOL(drm_handle_vblank);