drm: Remove infrastructure for supporting i915's vblank swapping.
[safe/jmp/linux-2.6] / drivers / gpu / drm / drm_irq.c
1 /**
2  * \file drm_irq.c
3  * IRQ support
4  *
5  * \author Rickard E. (Rik) Faith <faith@valinux.com>
6  * \author Gareth Hughes <gareth@valinux.com>
7  */
8
9 /*
10  * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
11  *
12  * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
13  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14  * All Rights Reserved.
15  *
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:
22  *
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.
26  *
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.
34  */
35
36 #include "drmP.h"
37
38 #include <linux/interrupt.h>    /* For task queue support */
39
40 /**
41  * Get interrupt from bus id.
42  *
43  * \param inode device inode.
44  * \param file_priv DRM file private.
45  * \param cmd command.
46  * \param arg user argument, pointing to a drm_irq_busid structure.
47  * \return zero on success or a negative number on failure.
48  *
49  * Finds the PCI device with the specified bus id and gets its IRQ number.
50  * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
51  * to that of the device that this DRM instance attached to.
52  */
53 int drm_irq_by_busid(struct drm_device *dev, void *data,
54                      struct drm_file *file_priv)
55 {
56         struct drm_irq_busid *p = data;
57
58         if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
59                 return -EINVAL;
60
61         if ((p->busnum >> 8) != drm_get_pci_domain(dev) ||
62             (p->busnum & 0xff) != dev->pdev->bus->number ||
63             p->devnum != PCI_SLOT(dev->pdev->devfn) || p->funcnum != PCI_FUNC(dev->pdev->devfn))
64                 return -EINVAL;
65
66         p->irq = dev->pdev->irq;
67
68         DRM_DEBUG("%d:%d:%d => IRQ %d\n", p->busnum, p->devnum, p->funcnum,
69                   p->irq);
70
71         return 0;
72 }
73
74 static void vblank_disable_fn(unsigned long arg)
75 {
76         struct drm_device *dev = (struct drm_device *)arg;
77         unsigned long irqflags;
78         int i;
79
80         if (!dev->vblank_disable_allowed)
81                 return;
82
83         for (i = 0; i < dev->num_crtcs; i++) {
84                 spin_lock_irqsave(&dev->vbl_lock, irqflags);
85                 if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
86                     dev->vblank_enabled[i]) {
87                         DRM_DEBUG("disabling vblank on crtc %d\n", i);
88                         dev->last_vblank[i] =
89                                 dev->driver->get_vblank_counter(dev, i);
90                         dev->driver->disable_vblank(dev, i);
91                         dev->vblank_enabled[i] = 0;
92                 }
93                 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
94         }
95 }
96
97 static void drm_vblank_cleanup(struct drm_device *dev)
98 {
99         /* Bail if the driver didn't call drm_vblank_init() */
100         if (dev->num_crtcs == 0)
101                 return;
102
103         del_timer(&dev->vblank_disable_timer);
104
105         vblank_disable_fn((unsigned long)dev);
106
107         drm_free(dev->vbl_queue, sizeof(*dev->vbl_queue) * dev->num_crtcs,
108                  DRM_MEM_DRIVER);
109         drm_free(dev->vbl_sigs, sizeof(*dev->vbl_sigs) * dev->num_crtcs,
110                  DRM_MEM_DRIVER);
111         drm_free(dev->_vblank_count, sizeof(*dev->_vblank_count) *
112                  dev->num_crtcs, DRM_MEM_DRIVER);
113         drm_free(dev->vblank_refcount, sizeof(*dev->vblank_refcount) *
114                  dev->num_crtcs, DRM_MEM_DRIVER);
115         drm_free(dev->vblank_enabled, sizeof(*dev->vblank_enabled) *
116                  dev->num_crtcs, DRM_MEM_DRIVER);
117         drm_free(dev->last_vblank, sizeof(*dev->last_vblank) * dev->num_crtcs,
118                  DRM_MEM_DRIVER);
119         drm_free(dev->vblank_inmodeset, sizeof(*dev->vblank_inmodeset) *
120                  dev->num_crtcs, DRM_MEM_DRIVER);
121
122         dev->num_crtcs = 0;
123 }
124
125 int drm_vblank_init(struct drm_device *dev, int num_crtcs)
126 {
127         int i, ret = -ENOMEM;
128
129         setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
130                     (unsigned long)dev);
131         spin_lock_init(&dev->vbl_lock);
132         atomic_set(&dev->vbl_signal_pending, 0);
133         dev->num_crtcs = num_crtcs;
134
135         dev->vbl_queue = drm_alloc(sizeof(wait_queue_head_t) * num_crtcs,
136                                    DRM_MEM_DRIVER);
137         if (!dev->vbl_queue)
138                 goto err;
139
140         dev->vbl_sigs = drm_alloc(sizeof(struct list_head) * num_crtcs,
141                                   DRM_MEM_DRIVER);
142         if (!dev->vbl_sigs)
143                 goto err;
144
145         dev->_vblank_count = drm_alloc(sizeof(atomic_t) * num_crtcs,
146                                       DRM_MEM_DRIVER);
147         if (!dev->_vblank_count)
148                 goto err;
149
150         dev->vblank_refcount = drm_alloc(sizeof(atomic_t) * num_crtcs,
151                                          DRM_MEM_DRIVER);
152         if (!dev->vblank_refcount)
153                 goto err;
154
155         dev->vblank_enabled = drm_calloc(num_crtcs, sizeof(int),
156                                          DRM_MEM_DRIVER);
157         if (!dev->vblank_enabled)
158                 goto err;
159
160         dev->last_vblank = drm_calloc(num_crtcs, sizeof(u32), DRM_MEM_DRIVER);
161         if (!dev->last_vblank)
162                 goto err;
163
164         dev->vblank_inmodeset = drm_calloc(num_crtcs, sizeof(int),
165                                          DRM_MEM_DRIVER);
166         if (!dev->vblank_inmodeset)
167                 goto err;
168
169         /* Zero per-crtc vblank stuff */
170         for (i = 0; i < num_crtcs; i++) {
171                 init_waitqueue_head(&dev->vbl_queue[i]);
172                 INIT_LIST_HEAD(&dev->vbl_sigs[i]);
173                 atomic_set(&dev->_vblank_count[i], 0);
174                 atomic_set(&dev->vblank_refcount[i], 0);
175         }
176
177         dev->vblank_disable_allowed = 0;
178
179         return 0;
180
181 err:
182         drm_vblank_cleanup(dev);
183         return ret;
184 }
185 EXPORT_SYMBOL(drm_vblank_init);
186
187 /**
188  * Install IRQ handler.
189  *
190  * \param dev DRM device.
191  *
192  * Initializes the IRQ related data. Installs the handler, calling the driver
193  * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
194  * before and after the installation.
195  */
196 int drm_irq_install(struct drm_device *dev)
197 {
198         int ret = 0;
199         unsigned long sh_flags = 0;
200
201         if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
202                 return -EINVAL;
203
204         if (dev->pdev->irq == 0)
205                 return -EINVAL;
206
207         mutex_lock(&dev->struct_mutex);
208
209         /* Driver must have been initialized */
210         if (!dev->dev_private) {
211                 mutex_unlock(&dev->struct_mutex);
212                 return -EINVAL;
213         }
214
215         if (dev->irq_enabled) {
216                 mutex_unlock(&dev->struct_mutex);
217                 return -EBUSY;
218         }
219         dev->irq_enabled = 1;
220         mutex_unlock(&dev->struct_mutex);
221
222         DRM_DEBUG("irq=%d\n", dev->pdev->irq);
223
224         /* Before installing handler */
225         dev->driver->irq_preinstall(dev);
226
227         /* Install handler */
228         if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
229                 sh_flags = IRQF_SHARED;
230
231         ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
232                           sh_flags, dev->devname, dev);
233
234         if (ret < 0) {
235                 mutex_lock(&dev->struct_mutex);
236                 dev->irq_enabled = 0;
237                 mutex_unlock(&dev->struct_mutex);
238                 return ret;
239         }
240
241         /* After installing handler */
242         ret = dev->driver->irq_postinstall(dev);
243         if (ret < 0) {
244                 mutex_lock(&dev->struct_mutex);
245                 dev->irq_enabled = 0;
246                 mutex_unlock(&dev->struct_mutex);
247         }
248
249         return ret;
250 }
251 EXPORT_SYMBOL(drm_irq_install);
252
253 /**
254  * Uninstall the IRQ handler.
255  *
256  * \param dev DRM device.
257  *
258  * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq.
259  */
260 int drm_irq_uninstall(struct drm_device * dev)
261 {
262         int irq_enabled;
263
264         if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
265                 return -EINVAL;
266
267         mutex_lock(&dev->struct_mutex);
268         irq_enabled = dev->irq_enabled;
269         dev->irq_enabled = 0;
270         mutex_unlock(&dev->struct_mutex);
271
272         if (!irq_enabled)
273                 return -EINVAL;
274
275         DRM_DEBUG("irq=%d\n", dev->pdev->irq);
276
277         dev->driver->irq_uninstall(dev);
278
279         free_irq(dev->pdev->irq, dev);
280
281         drm_vblank_cleanup(dev);
282
283         return 0;
284 }
285 EXPORT_SYMBOL(drm_irq_uninstall);
286
287 /**
288  * IRQ control ioctl.
289  *
290  * \param inode device inode.
291  * \param file_priv DRM file private.
292  * \param cmd command.
293  * \param arg user argument, pointing to a drm_control structure.
294  * \return zero on success or a negative number on failure.
295  *
296  * Calls irq_install() or irq_uninstall() according to \p arg.
297  */
298 int drm_control(struct drm_device *dev, void *data,
299                 struct drm_file *file_priv)
300 {
301         struct drm_control *ctl = data;
302
303         /* if we haven't irq we fallback for compatibility reasons - this used to be a separate function in drm_dma.h */
304
305
306         switch (ctl->func) {
307         case DRM_INST_HANDLER:
308                 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
309                         return 0;
310                 if (dev->if_version < DRM_IF_VERSION(1, 2) &&
311                     ctl->irq != dev->pdev->irq)
312                         return -EINVAL;
313                 return drm_irq_install(dev);
314         case DRM_UNINST_HANDLER:
315                 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
316                         return 0;
317                 return drm_irq_uninstall(dev);
318         default:
319                 return -EINVAL;
320         }
321 }
322
323 /**
324  * drm_vblank_count - retrieve "cooked" vblank counter value
325  * @dev: DRM device
326  * @crtc: which counter to retrieve
327  *
328  * Fetches the "cooked" vblank count value that represents the number of
329  * vblank events since the system was booted, including lost events due to
330  * modesetting activity.
331  */
332 u32 drm_vblank_count(struct drm_device *dev, int crtc)
333 {
334         return atomic_read(&dev->_vblank_count[crtc]);
335 }
336 EXPORT_SYMBOL(drm_vblank_count);
337
338 /**
339  * drm_update_vblank_count - update the master vblank counter
340  * @dev: DRM device
341  * @crtc: counter to update
342  *
343  * Call back into the driver to update the appropriate vblank counter
344  * (specified by @crtc).  Deal with wraparound, if it occurred, and
345  * update the last read value so we can deal with wraparound on the next
346  * call if necessary.
347  *
348  * Only necessary when going from off->on, to account for frames we
349  * didn't get an interrupt for.
350  *
351  * Note: caller must hold dev->vbl_lock since this reads & writes
352  * device vblank fields.
353  */
354 static void drm_update_vblank_count(struct drm_device *dev, int crtc)
355 {
356         u32 cur_vblank, diff;
357
358         /*
359          * Interrupts were disabled prior to this call, so deal with counter
360          * wrap if needed.
361          * NOTE!  It's possible we lost a full dev->max_vblank_count events
362          * here if the register is small or we had vblank interrupts off for
363          * a long time.
364          */
365         cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
366         diff = cur_vblank - dev->last_vblank[crtc];
367         if (cur_vblank < dev->last_vblank[crtc]) {
368                 diff += dev->max_vblank_count;
369
370                 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
371                           crtc, dev->last_vblank[crtc], cur_vblank, diff);
372         }
373
374         DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
375                   crtc, diff);
376
377         atomic_add(diff, &dev->_vblank_count[crtc]);
378 }
379
380 /**
381  * drm_vblank_get - get a reference count on vblank events
382  * @dev: DRM device
383  * @crtc: which CRTC to own
384  *
385  * Acquire a reference count on vblank events to avoid having them disabled
386  * while in use.
387  *
388  * RETURNS
389  * Zero on success, nonzero on failure.
390  */
391 int drm_vblank_get(struct drm_device *dev, int crtc)
392 {
393         unsigned long irqflags;
394         int ret = 0;
395
396         spin_lock_irqsave(&dev->vbl_lock, irqflags);
397         /* Going from 0->1 means we have to enable interrupts again */
398         if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1 &&
399             !dev->vblank_enabled[crtc]) {
400                 ret = dev->driver->enable_vblank(dev, crtc);
401                 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
402                 if (ret)
403                         atomic_dec(&dev->vblank_refcount[crtc]);
404                 else {
405                         dev->vblank_enabled[crtc] = 1;
406                         drm_update_vblank_count(dev, crtc);
407                 }
408         }
409         spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
410
411         return ret;
412 }
413 EXPORT_SYMBOL(drm_vblank_get);
414
415 /**
416  * drm_vblank_put - give up ownership of vblank events
417  * @dev: DRM device
418  * @crtc: which counter to give up
419  *
420  * Release ownership of a given vblank counter, turning off interrupts
421  * if possible.
422  */
423 void drm_vblank_put(struct drm_device *dev, int crtc)
424 {
425         /* Last user schedules interrupt disable */
426         if (atomic_dec_and_test(&dev->vblank_refcount[crtc]))
427                 mod_timer(&dev->vblank_disable_timer, jiffies + 5*DRM_HZ);
428 }
429 EXPORT_SYMBOL(drm_vblank_put);
430
431 /**
432  * drm_modeset_ctl - handle vblank event counter changes across mode switch
433  * @DRM_IOCTL_ARGS: standard ioctl arguments
434  *
435  * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
436  * ioctls around modesetting so that any lost vblank events are accounted for.
437  *
438  * Generally the counter will reset across mode sets.  If interrupts are
439  * enabled around this call, we don't have to do anything since the counter
440  * will have already been incremented.
441  */
442 int drm_modeset_ctl(struct drm_device *dev, void *data,
443                     struct drm_file *file_priv)
444 {
445         struct drm_modeset_ctl *modeset = data;
446         unsigned long irqflags;
447         int crtc, ret = 0;
448
449         /* If drm_vblank_init() hasn't been called yet, just no-op */
450         if (!dev->num_crtcs)
451                 goto out;
452
453         crtc = modeset->crtc;
454         if (crtc >= dev->num_crtcs) {
455                 ret = -EINVAL;
456                 goto out;
457         }
458
459         /*
460          * To avoid all the problems that might happen if interrupts
461          * were enabled/disabled around or between these calls, we just
462          * have the kernel take a reference on the CRTC (just once though
463          * to avoid corrupting the count if multiple, mismatch calls occur),
464          * so that interrupts remain enabled in the interim.
465          */
466         switch (modeset->cmd) {
467         case _DRM_PRE_MODESET:
468                 if (!dev->vblank_inmodeset[crtc]) {
469                         dev->vblank_inmodeset[crtc] = 1;
470                         drm_vblank_get(dev, crtc);
471                 }
472                 break;
473         case _DRM_POST_MODESET:
474                 if (dev->vblank_inmodeset[crtc]) {
475                         spin_lock_irqsave(&dev->vbl_lock, irqflags);
476                         dev->vblank_disable_allowed = 1;
477                         dev->vblank_inmodeset[crtc] = 0;
478                         spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
479                         drm_vblank_put(dev, crtc);
480                 }
481                 break;
482         default:
483                 ret = -EINVAL;
484                 break;
485         }
486
487 out:
488         return ret;
489 }
490
491 /**
492  * Wait for VBLANK.
493  *
494  * \param inode device inode.
495  * \param file_priv DRM file private.
496  * \param cmd command.
497  * \param data user argument, pointing to a drm_wait_vblank structure.
498  * \return zero on success or a negative number on failure.
499  *
500  * Verifies the IRQ is installed.
501  *
502  * If a signal is requested checks if this task has already scheduled the same signal
503  * for the same vblank sequence number - nothing to be done in
504  * that case. If the number of tasks waiting for the interrupt exceeds 100 the
505  * function fails. Otherwise adds a new entry to drm_device::vbl_sigs for this
506  * task.
507  *
508  * If a signal is not requested, then calls vblank_wait().
509  */
510 int drm_wait_vblank(struct drm_device *dev, void *data,
511                     struct drm_file *file_priv)
512 {
513         union drm_wait_vblank *vblwait = data;
514         int ret = 0;
515         unsigned int flags, seq, crtc;
516
517         if ((!dev->pdev->irq) || (!dev->irq_enabled))
518                 return -EINVAL;
519
520         if (vblwait->request.type &
521             ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK)) {
522                 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
523                           vblwait->request.type,
524                           (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK));
525                 return -EINVAL;
526         }
527
528         flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
529         crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
530
531         if (crtc >= dev->num_crtcs)
532                 return -EINVAL;
533
534         ret = drm_vblank_get(dev, crtc);
535         if (ret) {
536                 DRM_ERROR("failed to acquire vblank counter, %d\n", ret);
537                 return ret;
538         }
539         seq = drm_vblank_count(dev, crtc);
540
541         switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
542         case _DRM_VBLANK_RELATIVE:
543                 vblwait->request.sequence += seq;
544                 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
545         case _DRM_VBLANK_ABSOLUTE:
546                 break;
547         default:
548                 ret = -EINVAL;
549                 goto done;
550         }
551
552         if ((flags & _DRM_VBLANK_NEXTONMISS) &&
553             (seq - vblwait->request.sequence) <= (1<<23)) {
554                 vblwait->request.sequence = seq + 1;
555         }
556
557         if (flags & _DRM_VBLANK_SIGNAL) {
558                 unsigned long irqflags;
559                 struct list_head *vbl_sigs = &dev->vbl_sigs[crtc];
560                 struct drm_vbl_sig *vbl_sig;
561
562                 spin_lock_irqsave(&dev->vbl_lock, irqflags);
563
564                 /* Check if this task has already scheduled the same signal
565                  * for the same vblank sequence number; nothing to be done in
566                  * that case
567                  */
568                 list_for_each_entry(vbl_sig, vbl_sigs, head) {
569                         if (vbl_sig->sequence == vblwait->request.sequence
570                             && vbl_sig->info.si_signo ==
571                             vblwait->request.signal
572                             && vbl_sig->task == current) {
573                                 spin_unlock_irqrestore(&dev->vbl_lock,
574                                                        irqflags);
575                                 vblwait->reply.sequence = seq;
576                                 goto done;
577                         }
578                 }
579
580                 if (atomic_read(&dev->vbl_signal_pending) >= 100) {
581                         spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
582                         ret = -EBUSY;
583                         goto done;
584                 }
585
586                 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
587
588                 vbl_sig = drm_calloc(1, sizeof(struct drm_vbl_sig),
589                                      DRM_MEM_DRIVER);
590                 if (!vbl_sig) {
591                         ret = -ENOMEM;
592                         goto done;
593                 }
594
595                 /* Get a refcount on the vblank, which will be released by
596                  * drm_vbl_send_signals().
597                  */
598                 ret = drm_vblank_get(dev, crtc);
599                 if (ret) {
600                         drm_free(vbl_sig, sizeof(struct drm_vbl_sig),
601                                  DRM_MEM_DRIVER);
602                         goto done;
603                 }
604
605                 atomic_inc(&dev->vbl_signal_pending);
606
607                 vbl_sig->sequence = vblwait->request.sequence;
608                 vbl_sig->info.si_signo = vblwait->request.signal;
609                 vbl_sig->task = current;
610
611                 spin_lock_irqsave(&dev->vbl_lock, irqflags);
612
613                 list_add_tail(&vbl_sig->head, vbl_sigs);
614
615                 spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
616
617                 vblwait->reply.sequence = seq;
618         } else {
619                 DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
620                           vblwait->request.sequence, crtc);
621                 DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
622                             ((drm_vblank_count(dev, crtc)
623                               - vblwait->request.sequence) <= (1 << 23)));
624
625                 if (ret != -EINTR) {
626                         struct timeval now;
627
628                         do_gettimeofday(&now);
629
630                         vblwait->reply.tval_sec = now.tv_sec;
631                         vblwait->reply.tval_usec = now.tv_usec;
632                         vblwait->reply.sequence = drm_vblank_count(dev, crtc);
633                         DRM_DEBUG("returning %d to client\n",
634                                   vblwait->reply.sequence);
635                 } else {
636                         DRM_DEBUG("vblank wait interrupted by signal\n");
637                 }
638         }
639
640 done:
641         drm_vblank_put(dev, crtc);
642         return ret;
643 }
644
645 /**
646  * Send the VBLANK signals.
647  *
648  * \param dev DRM device.
649  * \param crtc CRTC where the vblank event occurred
650  *
651  * Sends a signal for each task in drm_device::vbl_sigs and empties the list.
652  *
653  * If a signal is not requested, then calls vblank_wait().
654  */
655 static void drm_vbl_send_signals(struct drm_device *dev, int crtc)
656 {
657         struct drm_vbl_sig *vbl_sig, *tmp;
658         struct list_head *vbl_sigs;
659         unsigned int vbl_seq;
660         unsigned long flags;
661
662         spin_lock_irqsave(&dev->vbl_lock, flags);
663
664         vbl_sigs = &dev->vbl_sigs[crtc];
665         vbl_seq = drm_vblank_count(dev, crtc);
666
667         list_for_each_entry_safe(vbl_sig, tmp, vbl_sigs, head) {
668             if ((vbl_seq - vbl_sig->sequence) <= (1 << 23)) {
669                 vbl_sig->info.si_code = vbl_seq;
670                 send_sig_info(vbl_sig->info.si_signo,
671                               &vbl_sig->info, vbl_sig->task);
672
673                 list_del(&vbl_sig->head);
674
675                 drm_free(vbl_sig, sizeof(*vbl_sig),
676                          DRM_MEM_DRIVER);
677                 atomic_dec(&dev->vbl_signal_pending);
678                 drm_vblank_put(dev, crtc);
679             }
680         }
681
682         spin_unlock_irqrestore(&dev->vbl_lock, flags);
683 }
684
685 /**
686  * drm_handle_vblank - handle a vblank event
687  * @dev: DRM device
688  * @crtc: where this event occurred
689  *
690  * Drivers should call this routine in their vblank interrupt handlers to
691  * update the vblank counter and send any signals that may be pending.
692  */
693 void drm_handle_vblank(struct drm_device *dev, int crtc)
694 {
695         atomic_inc(&dev->_vblank_count[crtc]);
696         DRM_WAKEUP(&dev->vbl_queue[crtc]);
697         drm_vbl_send_signals(dev, crtc);
698 }
699 EXPORT_SYMBOL(drm_handle_vblank);