5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
6 * \author Gareth Hughes <gareth@valinux.com>
10 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
12 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14 * All Rights Reserved.
16 * Permission is hereby granted, free of charge, to any person obtaining a
17 * copy of this software and associated documentation files (the "Software"),
18 * to deal in the Software without restriction, including without limitation
19 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
20 * and/or sell copies of the Software, and to permit persons to whom the
21 * Software is furnished to do so, subject to the following conditions:
23 * The above copyright notice and this permission notice (including the next
24 * paragraph) shall be included in all copies or substantial portions of the
27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
28 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
30 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
33 * OTHER DEALINGS IN THE SOFTWARE.
37 #include "drm_trace.h"
39 #include <linux/interrupt.h> /* For task queue support */
40 #include <linux/slab.h>
42 #include <linux/vgaarb.h>
43 #include <linux/export.h>
45 /* Access macro for slots in vblank timestamp ringbuffer. */
46 #define vblanktimestamp(dev, crtc, count) \
47 ((dev)->vblank[crtc].time[(count) % DRM_VBLANKTIME_RBSIZE])
49 /* Retry timestamp calculation up to 3 times to satisfy
50 * drm_timestamp_precision before giving up.
52 #define DRM_TIMESTAMP_MAXRETRIES 3
54 /* Threshold in nanoseconds for detection of redundant
55 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
57 #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
60 * Clear vblank timestamp buffer for a crtc.
62 static void clear_vblank_timestamps(struct drm_device
*dev
, int crtc
)
64 memset(dev
->vblank
[crtc
].time
, 0, sizeof(dev
->vblank
[crtc
].time
));
68 * Disable vblank irq's on crtc, make sure that last vblank count
69 * of hardware and corresponding consistent software vblank counter
70 * are preserved, even if there are any spurious vblank irq's after
73 static void vblank_disable_and_save(struct drm_device
*dev
, int crtc
)
75 unsigned long irqflags
;
79 struct timeval tvblank
;
80 int count
= DRM_TIMESTAMP_MAXRETRIES
;
82 /* Prevent vblank irq processing while disabling vblank irqs,
83 * so no updates of timestamps or count can happen after we've
84 * disabled. Needed to prevent races in case of delayed irq's.
86 spin_lock_irqsave(&dev
->vblank_time_lock
, irqflags
);
88 dev
->driver
->disable_vblank(dev
, crtc
);
89 dev
->vblank
[crtc
].enabled
= false;
91 /* No further vblank irq's will be processed after
92 * this point. Get current hardware vblank count and
93 * vblank timestamp, repeat until they are consistent.
95 * FIXME: There is still a race condition here and in
96 * drm_update_vblank_count() which can cause off-by-one
97 * reinitialization of software vblank counter. If gpu
98 * vblank counter doesn't increment exactly at the leading
99 * edge of a vblank interval, then we can lose 1 count if
100 * we happen to execute between start of vblank and the
101 * delayed gpu counter increment.
104 dev
->vblank
[crtc
].last
= dev
->driver
->get_vblank_counter(dev
, crtc
);
105 vblrc
= drm_get_last_vbltimestamp(dev
, crtc
, &tvblank
, 0);
106 } while (dev
->vblank
[crtc
].last
!= dev
->driver
->get_vblank_counter(dev
, crtc
) && (--count
) && vblrc
);
111 /* Compute time difference to stored timestamp of last vblank
112 * as updated by last invocation of drm_handle_vblank() in vblank irq.
114 vblcount
= atomic_read(&dev
->vblank
[crtc
].count
);
115 diff_ns
= timeval_to_ns(&tvblank
) -
116 timeval_to_ns(&vblanktimestamp(dev
, crtc
, vblcount
));
118 /* If there is at least 1 msec difference between the last stored
119 * timestamp and tvblank, then we are currently executing our
120 * disable inside a new vblank interval, the tvblank timestamp
121 * corresponds to this new vblank interval and the irq handler
122 * for this vblank didn't run yet and won't run due to our disable.
123 * Therefore we need to do the job of drm_handle_vblank() and
124 * increment the vblank counter by one to account for this vblank.
126 * Skip this step if there isn't any high precision timestamp
127 * available. In that case we can't account for this and just
130 if ((vblrc
> 0) && (abs64(diff_ns
) > 1000000)) {
131 atomic_inc(&dev
->vblank
[crtc
].count
);
132 smp_mb__after_atomic_inc();
135 /* Invalidate all timestamps while vblank irq's are off. */
136 clear_vblank_timestamps(dev
, crtc
);
138 spin_unlock_irqrestore(&dev
->vblank_time_lock
, irqflags
);
141 static void vblank_disable_fn(unsigned long arg
)
143 struct drm_device
*dev
= (struct drm_device
*)arg
;
144 unsigned long irqflags
;
147 if (!dev
->vblank_disable_allowed
)
150 for (i
= 0; i
< dev
->num_crtcs
; i
++) {
151 spin_lock_irqsave(&dev
->vbl_lock
, irqflags
);
152 if (atomic_read(&dev
->vblank
[i
].refcount
) == 0 &&
153 dev
->vblank
[i
].enabled
) {
154 DRM_DEBUG("disabling vblank on crtc %d\n", i
);
155 vblank_disable_and_save(dev
, i
);
157 spin_unlock_irqrestore(&dev
->vbl_lock
, irqflags
);
161 void drm_vblank_cleanup(struct drm_device
*dev
)
163 /* Bail if the driver didn't call drm_vblank_init() */
164 if (dev
->num_crtcs
== 0)
167 del_timer_sync(&dev
->vblank_disable_timer
);
169 vblank_disable_fn((unsigned long)dev
);
175 EXPORT_SYMBOL(drm_vblank_cleanup
);
177 int drm_vblank_init(struct drm_device
*dev
, int num_crtcs
)
179 int i
, ret
= -ENOMEM
;
181 setup_timer(&dev
->vblank_disable_timer
, vblank_disable_fn
,
183 spin_lock_init(&dev
->vbl_lock
);
184 spin_lock_init(&dev
->vblank_time_lock
);
186 dev
->num_crtcs
= num_crtcs
;
188 dev
->vblank
= kcalloc(num_crtcs
, sizeof(*dev
->vblank
), GFP_KERNEL
);
192 for (i
= 0; i
< num_crtcs
; i
++)
193 init_waitqueue_head(&dev
->vblank
[i
].queue
);
195 DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
197 /* Driver specific high-precision vblank timestamping supported? */
198 if (dev
->driver
->get_vblank_timestamp
)
199 DRM_INFO("Driver supports precise vblank timestamp query.\n");
201 DRM_INFO("No driver support for vblank timestamp query.\n");
203 dev
->vblank_disable_allowed
= false;
208 drm_vblank_cleanup(dev
);
211 EXPORT_SYMBOL(drm_vblank_init
);
213 static void drm_irq_vgaarb_nokms(void *cookie
, bool state
)
215 struct drm_device
*dev
= cookie
;
217 if (dev
->driver
->vgaarb_irq
) {
218 dev
->driver
->vgaarb_irq(dev
, state
);
222 if (!dev
->irq_enabled
)
226 if (dev
->driver
->irq_uninstall
)
227 dev
->driver
->irq_uninstall(dev
);
229 if (dev
->driver
->irq_preinstall
)
230 dev
->driver
->irq_preinstall(dev
);
231 if (dev
->driver
->irq_postinstall
)
232 dev
->driver
->irq_postinstall(dev
);
236 static inline int drm_dev_to_irq(struct drm_device
*dev
)
238 return dev
->driver
->bus
->get_irq(dev
);
242 * Install IRQ handler.
244 * \param dev DRM device.
246 * Initializes the IRQ related data. Installs the handler, calling the driver
247 * \c irq_preinstall() and \c irq_postinstall() functions
248 * before and after the installation.
250 int drm_irq_install(struct drm_device
*dev
)
253 unsigned long sh_flags
= 0;
256 irq
= drm_dev_to_irq(dev
);
258 if (!drm_core_check_feature(dev
, DRIVER_HAVE_IRQ
))
264 /* Driver must have been initialized */
265 if (!dev
->dev_private
)
268 if (dev
->irq_enabled
)
270 dev
->irq_enabled
= true;
272 DRM_DEBUG("irq=%d\n", irq
);
274 /* Before installing handler */
275 if (dev
->driver
->irq_preinstall
)
276 dev
->driver
->irq_preinstall(dev
);
278 /* Install handler */
279 if (drm_core_check_feature(dev
, DRIVER_IRQ_SHARED
))
280 sh_flags
= IRQF_SHARED
;
283 irqname
= dev
->devname
;
285 irqname
= dev
->driver
->name
;
287 ret
= request_irq(irq
, dev
->driver
->irq_handler
,
288 sh_flags
, irqname
, dev
);
291 dev
->irq_enabled
= false;
295 if (!drm_core_check_feature(dev
, DRIVER_MODESET
))
296 vga_client_register(dev
->pdev
, (void *)dev
, drm_irq_vgaarb_nokms
, NULL
);
298 /* After installing handler */
299 if (dev
->driver
->irq_postinstall
)
300 ret
= dev
->driver
->irq_postinstall(dev
);
303 dev
->irq_enabled
= false;
304 if (!drm_core_check_feature(dev
, DRIVER_MODESET
))
305 vga_client_register(dev
->pdev
, NULL
, NULL
, NULL
);
313 EXPORT_SYMBOL(drm_irq_install
);
316 * Uninstall the IRQ handler.
318 * \param dev DRM device.
320 * Calls the driver's \c irq_uninstall() function, and stops the irq.
322 int drm_irq_uninstall(struct drm_device
*dev
)
324 unsigned long irqflags
;
328 if (!drm_core_check_feature(dev
, DRIVER_HAVE_IRQ
))
331 irq_enabled
= dev
->irq_enabled
;
332 dev
->irq_enabled
= false;
335 * Wake up any waiters so they don't hang.
337 if (dev
->num_crtcs
) {
338 spin_lock_irqsave(&dev
->vbl_lock
, irqflags
);
339 for (i
= 0; i
< dev
->num_crtcs
; i
++) {
340 wake_up(&dev
->vblank
[i
].queue
);
341 dev
->vblank
[i
].enabled
= false;
342 dev
->vblank
[i
].last
=
343 dev
->driver
->get_vblank_counter(dev
, i
);
345 spin_unlock_irqrestore(&dev
->vbl_lock
, irqflags
);
351 DRM_DEBUG("irq=%d\n", dev
->irq
);
353 if (!drm_core_check_feature(dev
, DRIVER_MODESET
))
354 vga_client_register(dev
->pdev
, NULL
, NULL
, NULL
);
356 if (dev
->driver
->irq_uninstall
)
357 dev
->driver
->irq_uninstall(dev
);
359 free_irq(dev
->irq
, dev
);
363 EXPORT_SYMBOL(drm_irq_uninstall
);
368 * \param inode device inode.
369 * \param file_priv DRM file private.
370 * \param cmd command.
371 * \param arg user argument, pointing to a drm_control structure.
372 * \return zero on success or a negative number on failure.
374 * Calls irq_install() or irq_uninstall() according to \p arg.
376 int drm_control(struct drm_device
*dev
, void *data
,
377 struct drm_file
*file_priv
)
379 struct drm_control
*ctl
= data
;
382 /* if we haven't irq we fallback for compatibility reasons -
383 * this used to be a separate function in drm_dma.h
386 if (!drm_core_check_feature(dev
, DRIVER_HAVE_IRQ
))
388 if (drm_core_check_feature(dev
, DRIVER_MODESET
))
390 /* UMS was only ever support on pci devices. */
391 if (WARN_ON(!dev
->pdev
))
395 case DRM_INST_HANDLER
:
396 irq
= dev
->pdev
->irq
;
398 if (dev
->if_version
< DRM_IF_VERSION(1, 2) &&
401 mutex_lock(&dev
->struct_mutex
);
402 ret
= drm_irq_install(dev
);
403 mutex_unlock(&dev
->struct_mutex
);
406 case DRM_UNINST_HANDLER
:
407 mutex_lock(&dev
->struct_mutex
);
408 ret
= drm_irq_uninstall(dev
);
409 mutex_unlock(&dev
->struct_mutex
);
418 * drm_calc_timestamping_constants - Calculate vblank timestamp constants
420 * @crtc drm_crtc whose timestamp constants should be updated.
421 * @mode display mode containing the scanout timings
423 * Calculate and store various constants which are later
424 * needed by vblank and swap-completion timestamping, e.g,
425 * by drm_calc_vbltimestamp_from_scanoutpos(). They are
426 * derived from crtc's true scanout timing, so they take
427 * things like panel scaling or other adjustments into account.
429 void drm_calc_timestamping_constants(struct drm_crtc
*crtc
,
430 const struct drm_display_mode
*mode
)
432 int linedur_ns
= 0, pixeldur_ns
= 0, framedur_ns
= 0;
433 int dotclock
= mode
->crtc_clock
;
435 /* Valid dotclock? */
437 int frame_size
= mode
->crtc_htotal
* mode
->crtc_vtotal
;
440 * Convert scanline length in pixels and video
441 * dot clock to line duration, frame duration
442 * and pixel duration in nanoseconds:
444 pixeldur_ns
= 1000000 / dotclock
;
445 linedur_ns
= div_u64((u64
) mode
->crtc_htotal
* 1000000, dotclock
);
446 framedur_ns
= div_u64((u64
) frame_size
* 1000000, dotclock
);
449 * Fields of interlaced scanout modes are only half a frame duration.
451 if (mode
->flags
& DRM_MODE_FLAG_INTERLACE
)
454 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
457 crtc
->pixeldur_ns
= pixeldur_ns
;
458 crtc
->linedur_ns
= linedur_ns
;
459 crtc
->framedur_ns
= framedur_ns
;
461 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
462 crtc
->base
.id
, mode
->crtc_htotal
,
463 mode
->crtc_vtotal
, mode
->crtc_vdisplay
);
464 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
465 crtc
->base
.id
, dotclock
, framedur_ns
,
466 linedur_ns
, pixeldur_ns
);
468 EXPORT_SYMBOL(drm_calc_timestamping_constants
);
471 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
472 * drivers. Implements calculation of exact vblank timestamps from
473 * given drm_display_mode timings and current video scanout position
474 * of a crtc. This can be called from within get_vblank_timestamp()
475 * implementation of a kms driver to implement the actual timestamping.
477 * Should return timestamps conforming to the OML_sync_control OpenML
478 * extension specification. The timestamp corresponds to the end of
479 * the vblank interval, aka start of scanout of topmost-leftmost display
480 * pixel in the following video frame.
482 * Requires support for optional dev->driver->get_scanout_position()
483 * in kms driver, plus a bit of setup code to provide a drm_display_mode
484 * that corresponds to the true scanout timing.
486 * The current implementation only handles standard video modes. It
487 * returns as no operation if a doublescan or interlaced video mode is
488 * active. Higher level code is expected to handle this.
491 * @crtc: Which crtc's vblank timestamp to retrieve.
492 * @max_error: Desired maximum allowable error in timestamps (nanosecs).
493 * On return contains true maximum error of timestamp.
494 * @vblank_time: Pointer to struct timeval which should receive the timestamp.
495 * @flags: Flags to pass to driver:
497 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
498 * @refcrtc: drm_crtc* of crtc which defines scanout timing.
499 * @mode: mode which defines the scanout timings
501 * Returns negative value on error, failure or if not supported in current
504 * -EINVAL - Invalid crtc.
505 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
506 * -ENOTSUPP - Function not supported in current display mode.
507 * -EIO - Failed, e.g., due to failed scanout position query.
509 * Returns or'ed positive status flags on success:
511 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
512 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
515 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device
*dev
, int crtc
,
517 struct timeval
*vblank_time
,
519 const struct drm_crtc
*refcrtc
,
520 const struct drm_display_mode
*mode
)
522 ktime_t stime
, etime
, mono_time_offset
;
523 struct timeval tv_etime
;
526 int framedur_ns
, linedur_ns
, pixeldur_ns
, delta_ns
, duration_ns
;
529 if (crtc
< 0 || crtc
>= dev
->num_crtcs
) {
530 DRM_ERROR("Invalid crtc %d\n", crtc
);
534 /* Scanout position query not supported? Should not happen. */
535 if (!dev
->driver
->get_scanout_position
) {
536 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
540 /* Durations of frames, lines, pixels in nanoseconds. */
541 framedur_ns
= refcrtc
->framedur_ns
;
542 linedur_ns
= refcrtc
->linedur_ns
;
543 pixeldur_ns
= refcrtc
->pixeldur_ns
;
545 /* If mode timing undefined, just return as no-op:
546 * Happens during initial modesetting of a crtc.
548 if (framedur_ns
== 0) {
549 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc
);
553 /* Get current scanout position with system timestamp.
554 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
555 * if single query takes longer than max_error nanoseconds.
557 * This guarantees a tight bound on maximum error if
558 * code gets preempted or delayed for some reason.
560 for (i
= 0; i
< DRM_TIMESTAMP_MAXRETRIES
; i
++) {
562 * Get vertical and horizontal scanout position vpos, hpos,
563 * and bounding timestamps stime, etime, pre/post query.
565 vbl_status
= dev
->driver
->get_scanout_position(dev
, crtc
, flags
, &vpos
,
566 &hpos
, &stime
, &etime
);
569 * Get correction for CLOCK_MONOTONIC -> CLOCK_REALTIME if
570 * CLOCK_REALTIME is requested.
572 if (!drm_timestamp_monotonic
)
573 mono_time_offset
= ktime_get_monotonic_offset();
575 /* Return as no-op if scanout query unsupported or failed. */
576 if (!(vbl_status
& DRM_SCANOUTPOS_VALID
)) {
577 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
582 /* Compute uncertainty in timestamp of scanout position query. */
583 duration_ns
= ktime_to_ns(etime
) - ktime_to_ns(stime
);
585 /* Accept result with < max_error nsecs timing uncertainty. */
586 if (duration_ns
<= *max_error
)
590 /* Noisy system timing? */
591 if (i
== DRM_TIMESTAMP_MAXRETRIES
) {
592 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
593 crtc
, duration_ns
/1000, *max_error
/1000, i
);
596 /* Return upper bound of timestamp precision error. */
597 *max_error
= duration_ns
;
599 /* Check if in vblank area:
600 * vpos is >=0 in video scanout area, but negative
601 * within vblank area, counting down the number of lines until
604 invbl
= vbl_status
& DRM_SCANOUTPOS_INVBL
;
606 /* Convert scanout position into elapsed time at raw_time query
607 * since start of scanout at first display scanline. delta_ns
608 * can be negative if start of scanout hasn't happened yet.
610 delta_ns
= vpos
* linedur_ns
+ hpos
* pixeldur_ns
;
612 if (!drm_timestamp_monotonic
)
613 etime
= ktime_sub(etime
, mono_time_offset
);
615 /* save this only for debugging purposes */
616 tv_etime
= ktime_to_timeval(etime
);
617 /* Subtract time delta from raw timestamp to get final
618 * vblank_time timestamp for end of vblank.
621 etime
= ktime_add_ns(etime
, -delta_ns
);
623 etime
= ktime_sub_ns(etime
, delta_ns
);
624 *vblank_time
= ktime_to_timeval(etime
);
626 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
627 crtc
, (int)vbl_status
, hpos
, vpos
,
628 (long)tv_etime
.tv_sec
, (long)tv_etime
.tv_usec
,
629 (long)vblank_time
->tv_sec
, (long)vblank_time
->tv_usec
,
630 duration_ns
/1000, i
);
632 vbl_status
= DRM_VBLANKTIME_SCANOUTPOS_METHOD
;
634 vbl_status
|= DRM_VBLANKTIME_INVBL
;
638 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos
);
640 static struct timeval
get_drm_timestamp(void)
645 if (!drm_timestamp_monotonic
)
646 now
= ktime_sub(now
, ktime_get_monotonic_offset());
648 return ktime_to_timeval(now
);
652 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
656 * @crtc: which crtc's vblank timestamp to retrieve
657 * @tvblank: Pointer to target struct timeval which should receive the timestamp
658 * @flags: Flags to pass to driver:
660 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
662 * Fetches the system timestamp corresponding to the time of the most recent
663 * vblank interval on specified crtc. May call into kms-driver to
664 * compute the timestamp with a high-precision GPU specific method.
666 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
667 * call, i.e., it isn't very precisely locked to the true vblank.
669 * Returns non-zero if timestamp is considered to be very precise.
671 u32
drm_get_last_vbltimestamp(struct drm_device
*dev
, int crtc
,
672 struct timeval
*tvblank
, unsigned flags
)
676 /* Define requested maximum error on timestamps (nanoseconds). */
677 int max_error
= (int) drm_timestamp_precision
* 1000;
679 /* Query driver if possible and precision timestamping enabled. */
680 if (dev
->driver
->get_vblank_timestamp
&& (max_error
> 0)) {
681 ret
= dev
->driver
->get_vblank_timestamp(dev
, crtc
, &max_error
,
687 /* GPU high precision timestamp query unsupported or failed.
688 * Return current monotonic/gettimeofday timestamp as best estimate.
690 *tvblank
= get_drm_timestamp();
694 EXPORT_SYMBOL(drm_get_last_vbltimestamp
);
697 * drm_vblank_count - retrieve "cooked" vblank counter value
699 * @crtc: which counter to retrieve
701 * Fetches the "cooked" vblank count value that represents the number of
702 * vblank events since the system was booted, including lost events due to
703 * modesetting activity.
705 u32
drm_vblank_count(struct drm_device
*dev
, int crtc
)
707 return atomic_read(&dev
->vblank
[crtc
].count
);
709 EXPORT_SYMBOL(drm_vblank_count
);
712 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
713 * and the system timestamp corresponding to that vblank counter value.
716 * @crtc: which counter to retrieve
717 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
719 * Fetches the "cooked" vblank count value that represents the number of
720 * vblank events since the system was booted, including lost events due to
721 * modesetting activity. Returns corresponding system timestamp of the time
722 * of the vblank interval that corresponds to the current value vblank counter
725 u32
drm_vblank_count_and_time(struct drm_device
*dev
, int crtc
,
726 struct timeval
*vblanktime
)
730 /* Read timestamp from slot of _vblank_time ringbuffer
731 * that corresponds to current vblank count. Retry if
732 * count has incremented during readout. This works like
736 cur_vblank
= atomic_read(&dev
->vblank
[crtc
].count
);
737 *vblanktime
= vblanktimestamp(dev
, crtc
, cur_vblank
);
739 } while (cur_vblank
!= atomic_read(&dev
->vblank
[crtc
].count
));
743 EXPORT_SYMBOL(drm_vblank_count_and_time
);
745 static void send_vblank_event(struct drm_device
*dev
,
746 struct drm_pending_vblank_event
*e
,
747 unsigned long seq
, struct timeval
*now
)
749 WARN_ON_SMP(!spin_is_locked(&dev
->event_lock
));
750 e
->event
.sequence
= seq
;
751 e
->event
.tv_sec
= now
->tv_sec
;
752 e
->event
.tv_usec
= now
->tv_usec
;
754 list_add_tail(&e
->base
.link
,
755 &e
->base
.file_priv
->event_list
);
756 wake_up_interruptible(&e
->base
.file_priv
->event_wait
);
757 trace_drm_vblank_event_delivered(e
->base
.pid
, e
->pipe
,
762 * drm_send_vblank_event - helper to send vblank event after pageflip
764 * @crtc: CRTC in question
765 * @e: the event to send
767 * Updates sequence # and timestamp on event, and sends it to userspace.
768 * Caller must hold event lock.
770 void drm_send_vblank_event(struct drm_device
*dev
, int crtc
,
771 struct drm_pending_vblank_event
*e
)
776 seq
= drm_vblank_count_and_time(dev
, crtc
, &now
);
780 now
= get_drm_timestamp();
783 send_vblank_event(dev
, e
, seq
, &now
);
785 EXPORT_SYMBOL(drm_send_vblank_event
);
788 * drm_update_vblank_count - update the master vblank counter
790 * @crtc: counter to update
792 * Call back into the driver to update the appropriate vblank counter
793 * (specified by @crtc). Deal with wraparound, if it occurred, and
794 * update the last read value so we can deal with wraparound on the next
797 * Only necessary when going from off->on, to account for frames we
798 * didn't get an interrupt for.
800 * Note: caller must hold dev->vbl_lock since this reads & writes
801 * device vblank fields.
803 static void drm_update_vblank_count(struct drm_device
*dev
, int crtc
)
805 u32 cur_vblank
, diff
, tslot
, rc
;
806 struct timeval t_vblank
;
809 * Interrupts were disabled prior to this call, so deal with counter
811 * NOTE! It's possible we lost a full dev->max_vblank_count events
812 * here if the register is small or we had vblank interrupts off for
815 * We repeat the hardware vblank counter & timestamp query until
816 * we get consistent results. This to prevent races between gpu
817 * updating its hardware counter while we are retrieving the
818 * corresponding vblank timestamp.
821 cur_vblank
= dev
->driver
->get_vblank_counter(dev
, crtc
);
822 rc
= drm_get_last_vbltimestamp(dev
, crtc
, &t_vblank
, 0);
823 } while (cur_vblank
!= dev
->driver
->get_vblank_counter(dev
, crtc
));
825 /* Deal with counter wrap */
826 diff
= cur_vblank
- dev
->vblank
[crtc
].last
;
827 if (cur_vblank
< dev
->vblank
[crtc
].last
) {
828 diff
+= dev
->max_vblank_count
;
830 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
831 crtc
, dev
->vblank
[crtc
].last
, cur_vblank
, diff
);
834 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
837 /* Reinitialize corresponding vblank timestamp if high-precision query
838 * available. Skip this step if query unsupported or failed. Will
839 * reinitialize delayed at next vblank interrupt in that case.
842 tslot
= atomic_read(&dev
->vblank
[crtc
].count
) + diff
;
843 vblanktimestamp(dev
, crtc
, tslot
) = t_vblank
;
846 smp_mb__before_atomic_inc();
847 atomic_add(diff
, &dev
->vblank
[crtc
].count
);
848 smp_mb__after_atomic_inc();
852 * drm_vblank_get - get a reference count on vblank events
854 * @crtc: which CRTC to own
856 * Acquire a reference count on vblank events to avoid having them disabled
860 * Zero on success, nonzero on failure.
862 int drm_vblank_get(struct drm_device
*dev
, int crtc
)
864 unsigned long irqflags
, irqflags2
;
867 spin_lock_irqsave(&dev
->vbl_lock
, irqflags
);
868 /* Going from 0->1 means we have to enable interrupts again */
869 if (atomic_add_return(1, &dev
->vblank
[crtc
].refcount
) == 1) {
870 spin_lock_irqsave(&dev
->vblank_time_lock
, irqflags2
);
871 if (!dev
->vblank
[crtc
].enabled
) {
872 /* Enable vblank irqs under vblank_time_lock protection.
873 * All vblank count & timestamp updates are held off
874 * until we are done reinitializing master counter and
875 * timestamps. Filtercode in drm_handle_vblank() will
876 * prevent double-accounting of same vblank interval.
878 ret
= dev
->driver
->enable_vblank(dev
, crtc
);
879 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n",
882 atomic_dec(&dev
->vblank
[crtc
].refcount
);
884 dev
->vblank
[crtc
].enabled
= true;
885 drm_update_vblank_count(dev
, crtc
);
888 spin_unlock_irqrestore(&dev
->vblank_time_lock
, irqflags2
);
890 if (!dev
->vblank
[crtc
].enabled
) {
891 atomic_dec(&dev
->vblank
[crtc
].refcount
);
895 spin_unlock_irqrestore(&dev
->vbl_lock
, irqflags
);
899 EXPORT_SYMBOL(drm_vblank_get
);
902 * drm_vblank_put - give up ownership of vblank events
904 * @crtc: which counter to give up
906 * Release ownership of a given vblank counter, turning off interrupts
907 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
909 void drm_vblank_put(struct drm_device
*dev
, int crtc
)
911 BUG_ON(atomic_read(&dev
->vblank
[crtc
].refcount
) == 0);
913 /* Last user schedules interrupt disable */
914 if (atomic_dec_and_test(&dev
->vblank
[crtc
].refcount
) &&
915 (drm_vblank_offdelay
> 0))
916 mod_timer(&dev
->vblank_disable_timer
,
917 jiffies
+ ((drm_vblank_offdelay
* HZ
)/1000));
919 EXPORT_SYMBOL(drm_vblank_put
);
922 * drm_vblank_off - disable vblank events on a CRTC
924 * @crtc: CRTC in question
926 * Caller must hold event lock.
928 void drm_vblank_off(struct drm_device
*dev
, int crtc
)
930 struct drm_pending_vblank_event
*e
, *t
;
932 unsigned long irqflags
;
935 spin_lock_irqsave(&dev
->vbl_lock
, irqflags
);
936 vblank_disable_and_save(dev
, crtc
);
937 wake_up(&dev
->vblank
[crtc
].queue
);
939 /* Send any queued vblank events, lest the natives grow disquiet */
940 seq
= drm_vblank_count_and_time(dev
, crtc
, &now
);
942 spin_lock(&dev
->event_lock
);
943 list_for_each_entry_safe(e
, t
, &dev
->vblank_event_list
, base
.link
) {
946 DRM_DEBUG("Sending premature vblank event on disable: \
947 wanted %d, current %d\n",
948 e
->event
.sequence
, seq
);
949 list_del(&e
->base
.link
);
950 drm_vblank_put(dev
, e
->pipe
);
951 send_vblank_event(dev
, e
, seq
, &now
);
953 spin_unlock(&dev
->event_lock
);
955 spin_unlock_irqrestore(&dev
->vbl_lock
, irqflags
);
957 EXPORT_SYMBOL(drm_vblank_off
);
960 * drm_vblank_pre_modeset - account for vblanks across mode sets
962 * @crtc: CRTC in question
964 * Account for vblank events across mode setting events, which will likely
965 * reset the hardware frame counter.
967 void drm_vblank_pre_modeset(struct drm_device
*dev
, int crtc
)
969 /* vblank is not initialized (IRQ not installed ?), or has been freed */
973 * To avoid all the problems that might happen if interrupts
974 * were enabled/disabled around or between these calls, we just
975 * have the kernel take a reference on the CRTC (just once though
976 * to avoid corrupting the count if multiple, mismatch calls occur),
977 * so that interrupts remain enabled in the interim.
979 if (!dev
->vblank
[crtc
].inmodeset
) {
980 dev
->vblank
[crtc
].inmodeset
= 0x1;
981 if (drm_vblank_get(dev
, crtc
) == 0)
982 dev
->vblank
[crtc
].inmodeset
|= 0x2;
985 EXPORT_SYMBOL(drm_vblank_pre_modeset
);
987 void drm_vblank_post_modeset(struct drm_device
*dev
, int crtc
)
989 unsigned long irqflags
;
991 /* vblank is not initialized (IRQ not installed ?), or has been freed */
995 if (dev
->vblank
[crtc
].inmodeset
) {
996 spin_lock_irqsave(&dev
->vbl_lock
, irqflags
);
997 dev
->vblank_disable_allowed
= true;
998 spin_unlock_irqrestore(&dev
->vbl_lock
, irqflags
);
1000 if (dev
->vblank
[crtc
].inmodeset
& 0x2)
1001 drm_vblank_put(dev
, crtc
);
1003 dev
->vblank
[crtc
].inmodeset
= 0;
1006 EXPORT_SYMBOL(drm_vblank_post_modeset
);
1009 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1010 * @DRM_IOCTL_ARGS: standard ioctl arguments
1012 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1013 * ioctls around modesetting so that any lost vblank events are accounted for.
1015 * Generally the counter will reset across mode sets. If interrupts are
1016 * enabled around this call, we don't have to do anything since the counter
1017 * will have already been incremented.
1019 int drm_modeset_ctl(struct drm_device
*dev
, void *data
,
1020 struct drm_file
*file_priv
)
1022 struct drm_modeset_ctl
*modeset
= data
;
1025 /* If drm_vblank_init() hasn't been called yet, just no-op */
1026 if (!dev
->num_crtcs
)
1029 /* KMS drivers handle this internally */
1030 if (drm_core_check_feature(dev
, DRIVER_MODESET
))
1033 crtc
= modeset
->crtc
;
1034 if (crtc
>= dev
->num_crtcs
)
1037 switch (modeset
->cmd
) {
1038 case _DRM_PRE_MODESET
:
1039 drm_vblank_pre_modeset(dev
, crtc
);
1041 case _DRM_POST_MODESET
:
1042 drm_vblank_post_modeset(dev
, crtc
);
1051 static int drm_queue_vblank_event(struct drm_device
*dev
, int pipe
,
1052 union drm_wait_vblank
*vblwait
,
1053 struct drm_file
*file_priv
)
1055 struct drm_pending_vblank_event
*e
;
1057 unsigned long flags
;
1061 e
= kzalloc(sizeof *e
, GFP_KERNEL
);
1068 e
->base
.pid
= current
->pid
;
1069 e
->event
.base
.type
= DRM_EVENT_VBLANK
;
1070 e
->event
.base
.length
= sizeof e
->event
;
1071 e
->event
.user_data
= vblwait
->request
.signal
;
1072 e
->base
.event
= &e
->event
.base
;
1073 e
->base
.file_priv
= file_priv
;
1074 e
->base
.destroy
= (void (*) (struct drm_pending_event
*)) kfree
;
1076 spin_lock_irqsave(&dev
->event_lock
, flags
);
1078 if (file_priv
->event_space
< sizeof e
->event
) {
1083 file_priv
->event_space
-= sizeof e
->event
;
1084 seq
= drm_vblank_count_and_time(dev
, pipe
, &now
);
1086 if ((vblwait
->request
.type
& _DRM_VBLANK_NEXTONMISS
) &&
1087 (seq
- vblwait
->request
.sequence
) <= (1 << 23)) {
1088 vblwait
->request
.sequence
= seq
+ 1;
1089 vblwait
->reply
.sequence
= vblwait
->request
.sequence
;
1092 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1093 vblwait
->request
.sequence
, seq
, pipe
);
1095 trace_drm_vblank_event_queued(current
->pid
, pipe
,
1096 vblwait
->request
.sequence
);
1098 e
->event
.sequence
= vblwait
->request
.sequence
;
1099 if ((seq
- vblwait
->request
.sequence
) <= (1 << 23)) {
1100 drm_vblank_put(dev
, pipe
);
1101 send_vblank_event(dev
, e
, seq
, &now
);
1102 vblwait
->reply
.sequence
= seq
;
1104 /* drm_handle_vblank_events will call drm_vblank_put */
1105 list_add_tail(&e
->base
.link
, &dev
->vblank_event_list
);
1106 vblwait
->reply
.sequence
= vblwait
->request
.sequence
;
1109 spin_unlock_irqrestore(&dev
->event_lock
, flags
);
1114 spin_unlock_irqrestore(&dev
->event_lock
, flags
);
1117 drm_vblank_put(dev
, pipe
);
1124 * \param inode device inode.
1125 * \param file_priv DRM file private.
1126 * \param cmd command.
1127 * \param data user argument, pointing to a drm_wait_vblank structure.
1128 * \return zero on success or a negative number on failure.
1130 * This function enables the vblank interrupt on the pipe requested, then
1131 * sleeps waiting for the requested sequence number to occur, and drops
1132 * the vblank interrupt refcount afterwards. (vblank irq disable follows that
1133 * after a timeout with no further vblank waits scheduled).
1135 int drm_wait_vblank(struct drm_device
*dev
, void *data
,
1136 struct drm_file
*file_priv
)
1138 union drm_wait_vblank
*vblwait
= data
;
1140 unsigned int flags
, seq
, crtc
, high_crtc
;
1142 if (!dev
->irq_enabled
)
1145 if (vblwait
->request
.type
& _DRM_VBLANK_SIGNAL
)
1148 if (vblwait
->request
.type
&
1149 ~(_DRM_VBLANK_TYPES_MASK
| _DRM_VBLANK_FLAGS_MASK
|
1150 _DRM_VBLANK_HIGH_CRTC_MASK
)) {
1151 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1152 vblwait
->request
.type
,
1153 (_DRM_VBLANK_TYPES_MASK
| _DRM_VBLANK_FLAGS_MASK
|
1154 _DRM_VBLANK_HIGH_CRTC_MASK
));
1158 flags
= vblwait
->request
.type
& _DRM_VBLANK_FLAGS_MASK
;
1159 high_crtc
= (vblwait
->request
.type
& _DRM_VBLANK_HIGH_CRTC_MASK
);
1161 crtc
= high_crtc
>> _DRM_VBLANK_HIGH_CRTC_SHIFT
;
1163 crtc
= flags
& _DRM_VBLANK_SECONDARY
? 1 : 0;
1164 if (crtc
>= dev
->num_crtcs
)
1167 ret
= drm_vblank_get(dev
, crtc
);
1169 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret
);
1172 seq
= drm_vblank_count(dev
, crtc
);
1174 switch (vblwait
->request
.type
& _DRM_VBLANK_TYPES_MASK
) {
1175 case _DRM_VBLANK_RELATIVE
:
1176 vblwait
->request
.sequence
+= seq
;
1177 vblwait
->request
.type
&= ~_DRM_VBLANK_RELATIVE
;
1178 case _DRM_VBLANK_ABSOLUTE
:
1185 if (flags
& _DRM_VBLANK_EVENT
) {
1186 /* must hold on to the vblank ref until the event fires
1187 * drm_vblank_put will be called asynchronously
1189 return drm_queue_vblank_event(dev
, crtc
, vblwait
, file_priv
);
1192 if ((flags
& _DRM_VBLANK_NEXTONMISS
) &&
1193 (seq
- vblwait
->request
.sequence
) <= (1<<23)) {
1194 vblwait
->request
.sequence
= seq
+ 1;
1197 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1198 vblwait
->request
.sequence
, crtc
);
1199 dev
->vblank
[crtc
].last_wait
= vblwait
->request
.sequence
;
1200 DRM_WAIT_ON(ret
, dev
->vblank
[crtc
].queue
, 3 * HZ
,
1201 (((drm_vblank_count(dev
, crtc
) -
1202 vblwait
->request
.sequence
) <= (1 << 23)) ||
1203 !dev
->irq_enabled
));
1205 if (ret
!= -EINTR
) {
1208 vblwait
->reply
.sequence
= drm_vblank_count_and_time(dev
, crtc
, &now
);
1209 vblwait
->reply
.tval_sec
= now
.tv_sec
;
1210 vblwait
->reply
.tval_usec
= now
.tv_usec
;
1212 DRM_DEBUG("returning %d to client\n",
1213 vblwait
->reply
.sequence
);
1215 DRM_DEBUG("vblank wait interrupted by signal\n");
1219 drm_vblank_put(dev
, crtc
);
1223 static void drm_handle_vblank_events(struct drm_device
*dev
, int crtc
)
1225 struct drm_pending_vblank_event
*e
, *t
;
1227 unsigned long flags
;
1230 seq
= drm_vblank_count_and_time(dev
, crtc
, &now
);
1232 spin_lock_irqsave(&dev
->event_lock
, flags
);
1234 list_for_each_entry_safe(e
, t
, &dev
->vblank_event_list
, base
.link
) {
1235 if (e
->pipe
!= crtc
)
1237 if ((seq
- e
->event
.sequence
) > (1<<23))
1240 DRM_DEBUG("vblank event on %d, current %d\n",
1241 e
->event
.sequence
, seq
);
1243 list_del(&e
->base
.link
);
1244 drm_vblank_put(dev
, e
->pipe
);
1245 send_vblank_event(dev
, e
, seq
, &now
);
1248 spin_unlock_irqrestore(&dev
->event_lock
, flags
);
1250 trace_drm_vblank_event(crtc
, seq
);
1254 * drm_handle_vblank - handle a vblank event
1256 * @crtc: where this event occurred
1258 * Drivers should call this routine in their vblank interrupt handlers to
1259 * update the vblank counter and send any signals that may be pending.
1261 bool drm_handle_vblank(struct drm_device
*dev
, int crtc
)
1265 struct timeval tvblank
;
1266 unsigned long irqflags
;
1268 if (!dev
->num_crtcs
)
1271 /* Need timestamp lock to prevent concurrent execution with
1272 * vblank enable/disable, as this would cause inconsistent
1273 * or corrupted timestamps and vblank counts.
1275 spin_lock_irqsave(&dev
->vblank_time_lock
, irqflags
);
1277 /* Vblank irq handling disabled. Nothing to do. */
1278 if (!dev
->vblank
[crtc
].enabled
) {
1279 spin_unlock_irqrestore(&dev
->vblank_time_lock
, irqflags
);
1283 /* Fetch corresponding timestamp for this vblank interval from
1284 * driver and store it in proper slot of timestamp ringbuffer.
1287 /* Get current timestamp and count. */
1288 vblcount
= atomic_read(&dev
->vblank
[crtc
].count
);
1289 drm_get_last_vbltimestamp(dev
, crtc
, &tvblank
, DRM_CALLED_FROM_VBLIRQ
);
1291 /* Compute time difference to timestamp of last vblank */
1292 diff_ns
= timeval_to_ns(&tvblank
) -
1293 timeval_to_ns(&vblanktimestamp(dev
, crtc
, vblcount
));
1295 /* Update vblank timestamp and count if at least
1296 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1297 * difference between last stored timestamp and current
1298 * timestamp. A smaller difference means basically
1299 * identical timestamps. Happens if this vblank has
1300 * been already processed and this is a redundant call,
1301 * e.g., due to spurious vblank interrupts. We need to
1302 * ignore those for accounting.
1304 if (abs64(diff_ns
) > DRM_REDUNDANT_VBLIRQ_THRESH_NS
) {
1305 /* Store new timestamp in ringbuffer. */
1306 vblanktimestamp(dev
, crtc
, vblcount
+ 1) = tvblank
;
1308 /* Increment cooked vblank count. This also atomically commits
1309 * the timestamp computed above.
1311 smp_mb__before_atomic_inc();
1312 atomic_inc(&dev
->vblank
[crtc
].count
);
1313 smp_mb__after_atomic_inc();
1315 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1316 crtc
, (int) diff_ns
);
1319 wake_up(&dev
->vblank
[crtc
].queue
);
1320 drm_handle_vblank_events(dev
, crtc
);
1322 spin_unlock_irqrestore(&dev
->vblank_time_lock
, irqflags
);
1325 EXPORT_SYMBOL(drm_handle_vblank
);