1 /*- 2 * Copyright 2003 Eric Anholt 3 * All Rights Reserved. 4 * 5 * Permission is hereby granted, free of charge, to any person obtaining a 6 * copy of this software and associated documentation files (the "Software"), 7 * to deal in the Software without restriction, including without limitation 8 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 9 * and/or sell copies of the Software, and to permit persons to whom the 10 * Software is furnished to do so, subject to the following conditions: 11 * 12 * The above copyright notice and this permission notice (including the next 13 * paragraph) shall be included in all copies or substantial portions of the 14 * Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * ERIC ANHOLT BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER 20 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 22 * 23 * Authors: 24 * Eric Anholt <anholt@FreeBSD.org> 25 * 26 * $FreeBSD: src/sys/dev/drm2/drm_irq.c,v 1.1 2012/05/22 11:07:44 kib Exp $ 27 */ 28 29 /** @file drm_irq.c 30 * Support code for handling setup/teardown of interrupt handlers and 31 * handing interrupt handlers off to the drivers. 32 */ 33 34 #include <linux/export.h> 35 #include <linux/mutex.h> 36 #include <linux/time.h> 37 #include <linux/timer.h> 38 #include <drm/drmP.h> 39 40 /* Access macro for slots in vblank timestamp ringbuffer. */ 41 #define vblanktimestamp(dev, crtc, count) ( \ 42 (dev)->_vblank_time[(crtc) * DRM_VBLANKTIME_RBSIZE + \ 43 ((count) % DRM_VBLANKTIME_RBSIZE)]) 44 45 /* Retry timestamp calculation up to 3 times to satisfy 46 * drm_timestamp_precision before giving up. 47 */ 48 #define DRM_TIMESTAMP_MAXRETRIES 3 49 50 /* Threshold in nanoseconds for detection of redundant 51 * vblank irq in drm_handle_vblank(). 1 msec should be ok. 52 */ 53 #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000 54 55 int drm_irq_by_busid(struct drm_device *dev, void *data, 56 struct drm_file *file_priv) 57 { 58 struct drm_irq_busid *irq = data; 59 60 if ((irq->busnum >> 8) != dev->pci_domain || 61 (irq->busnum & 0xff) != dev->pci_bus || 62 irq->devnum != dev->pci_slot || 63 irq->funcnum != dev->pci_func) 64 return EINVAL; 65 66 irq->irq = dev->irq; 67 68 DRM_DEBUG("%d:%d:%d => IRQ %d\n", 69 irq->busnum, irq->devnum, irq->funcnum, irq->irq); 70 71 return 0; 72 } 73 74 /* 75 * Clear vblank timestamp buffer for a crtc. 76 */ 77 static void clear_vblank_timestamps(struct drm_device *dev, int crtc) 78 { 79 memset(&dev->_vblank_time[crtc * DRM_VBLANKTIME_RBSIZE], 0, 80 DRM_VBLANKTIME_RBSIZE * sizeof(struct timeval)); 81 } 82 83 static int64_t 84 abs64(int64_t x) 85 { 86 87 return (x < 0 ? -x : x); 88 } 89 90 /* 91 * Disable vblank irq's on crtc, make sure that last vblank count 92 * of hardware and corresponding consistent software vblank counter 93 * are preserved, even if there are any spurious vblank irq's after 94 * disable. 95 */ 96 static void vblank_disable_and_save(struct drm_device *dev, int crtc) 97 { 98 u32 vblcount; 99 int64_t diff_ns; 100 int vblrc; 101 struct timeval tvblank; 102 103 /* Prevent vblank irq processing while disabling vblank irqs, 104 * so no updates of timestamps or count can happen after we've 105 * disabled. Needed to prevent races in case of delayed irq's. 106 */ 107 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE); 108 109 dev->driver->disable_vblank(dev, crtc); 110 dev->vblank_enabled[crtc] = 0; 111 112 /* No further vblank irq's will be processed after 113 * this point. Get current hardware vblank count and 114 * vblank timestamp, repeat until they are consistent. 115 * 116 * FIXME: There is still a race condition here and in 117 * drm_update_vblank_count() which can cause off-by-one 118 * reinitialization of software vblank counter. If gpu 119 * vblank counter doesn't increment exactly at the leading 120 * edge of a vblank interval, then we can lose 1 count if 121 * we happen to execute between start of vblank and the 122 * delayed gpu counter increment. 123 */ 124 do { 125 dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc); 126 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0); 127 } while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc)); 128 129 /* Compute time difference to stored timestamp of last vblank 130 * as updated by last invocation of drm_handle_vblank() in vblank irq. 131 */ 132 vblcount = atomic_read(&dev->_vblank_count[crtc]); 133 diff_ns = timeval_to_ns(&tvblank) - 134 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); 135 136 /* If there is at least 1 msec difference between the last stored 137 * timestamp and tvblank, then we are currently executing our 138 * disable inside a new vblank interval, the tvblank timestamp 139 * corresponds to this new vblank interval and the irq handler 140 * for this vblank didn't run yet and won't run due to our disable. 141 * Therefore we need to do the job of drm_handle_vblank() and 142 * increment the vblank counter by one to account for this vblank. 143 * 144 * Skip this step if there isn't any high precision timestamp 145 * available. In that case we can't account for this and just 146 * hope for the best. 147 */ 148 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) { 149 atomic_inc(&dev->_vblank_count[crtc]); 150 } 151 152 /* Invalidate all timestamps while vblank irq's are off. */ 153 clear_vblank_timestamps(dev, crtc); 154 155 lockmgr(&dev->vblank_time_lock, LK_RELEASE); 156 } 157 158 static void vblank_disable_fn(unsigned long arg) 159 { 160 struct drm_device *dev = (struct drm_device *)arg; 161 int i; 162 163 if (!dev->vblank_disable_allowed) 164 return; 165 166 for (i = 0; i < dev->num_crtcs; i++) { 167 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE); 168 if (atomic_read(&dev->vblank_refcount[i]) == 0 && 169 dev->vblank_enabled[i]) { 170 DRM_DEBUG("disabling vblank on crtc %d\n", i); 171 vblank_disable_and_save(dev, i); 172 } 173 lockmgr(&dev->vbl_lock, LK_RELEASE); 174 } 175 } 176 177 void drm_vblank_cleanup(struct drm_device *dev) 178 { 179 /* Bail if the driver didn't call drm_vblank_init() */ 180 if (dev->num_crtcs == 0) 181 return; 182 183 del_timer_sync(&dev->vblank_disable_timer); 184 185 vblank_disable_fn((unsigned long)dev); 186 187 drm_free(dev->_vblank_count, M_DRM); 188 drm_free(dev->vblank_refcount, M_DRM); 189 drm_free(dev->vblank_enabled, M_DRM); 190 drm_free(dev->last_vblank, M_DRM); 191 drm_free(dev->last_vblank_wait, M_DRM); 192 drm_free(dev->vblank_inmodeset, M_DRM); 193 drm_free(dev->_vblank_time, M_DRM); 194 195 dev->num_crtcs = 0; 196 } 197 EXPORT_SYMBOL(drm_vblank_cleanup); 198 199 int drm_vblank_init(struct drm_device *dev, int num_crtcs) 200 { 201 int i; 202 203 setup_timer(&dev->vblank_disable_timer, vblank_disable_fn, 204 (unsigned long)dev); 205 lockinit(&dev->vblank_time_lock, "drmvtl", 0, LK_CANRECURSE); 206 207 dev->num_crtcs = num_crtcs; 208 209 dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs, 210 M_DRM, M_WAITOK); 211 212 dev->_vblank_count = kmalloc(sizeof(atomic_t) * num_crtcs, 213 M_DRM, M_WAITOK); 214 dev->vblank_refcount = kmalloc(sizeof(atomic_t) * num_crtcs, 215 M_DRM, M_WAITOK); 216 dev->vblank_enabled = kmalloc(num_crtcs * sizeof(int), 217 M_DRM, M_WAITOK | M_ZERO); 218 dev->last_vblank = kmalloc(num_crtcs * sizeof(u32), 219 M_DRM, M_WAITOK | M_ZERO); 220 dev->last_vblank_wait = kmalloc(num_crtcs * sizeof(u32), 221 M_DRM, M_WAITOK | M_ZERO); 222 dev->vblank_inmodeset = kmalloc(num_crtcs * sizeof(int), 223 M_DRM, M_WAITOK | M_ZERO); 224 dev->_vblank_time = kmalloc(num_crtcs * DRM_VBLANKTIME_RBSIZE * 225 sizeof(struct timeval), M_DRM, M_WAITOK | M_ZERO); 226 DRM_INFO("Supports vblank timestamp caching Rev 1 (10.10.2010).\n"); 227 228 /* Driver specific high-precision vblank timestamping supported? */ 229 if (dev->driver->get_vblank_timestamp) 230 DRM_INFO("Driver supports precise vblank timestamp query.\n"); 231 else 232 DRM_INFO("No driver support for vblank timestamp query.\n"); 233 234 /* Zero per-crtc vblank stuff */ 235 for (i = 0; i < num_crtcs; i++) { 236 init_waitqueue_head(&dev->vbl_queue[i]); 237 atomic_set(&dev->_vblank_count[i], 0); 238 atomic_set(&dev->vblank_refcount[i], 0); 239 } 240 241 dev->vblank_disable_allowed = 0; 242 return 0; 243 } 244 EXPORT_SYMBOL(drm_vblank_init); 245 246 /** 247 * Install IRQ handler. 248 * 249 * \param dev DRM device. 250 * 251 * Initializes the IRQ related data. Installs the handler, calling the driver 252 * \c irq_preinstall() and \c irq_postinstall() functions 253 * before and after the installation. 254 */ 255 int drm_irq_install(struct drm_device *dev) 256 { 257 int ret; 258 259 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 260 return -EINVAL; 261 262 if (dev->irq == 0) 263 return -EINVAL; 264 265 DRM_LOCK(dev); 266 267 /* Driver must have been initialized */ 268 if (!dev->dev_private) { 269 DRM_UNLOCK(dev); 270 return -EINVAL; 271 } 272 273 if (dev->irq_enabled) { 274 DRM_UNLOCK(dev); 275 return -EBUSY; 276 } 277 dev->irq_enabled = 1; 278 DRM_UNLOCK(dev); 279 280 DRM_DEBUG("irq=%d\n", dev->irq); 281 282 /* Before installing handler */ 283 if (dev->driver->irq_preinstall) 284 dev->driver->irq_preinstall(dev); 285 286 /* Install handler */ 287 ret = bus_setup_intr(dev->dev, dev->irqr, INTR_MPSAFE, 288 dev->driver->irq_handler, dev, &dev->irqh, &dev->irq_lock); 289 290 if (ret != 0) { 291 DRM_LOCK(dev); 292 dev->irq_enabled = 0; 293 DRM_UNLOCK(dev); 294 return ret; 295 } 296 297 /* After installing handler */ 298 if (dev->driver->irq_postinstall) 299 ret = dev->driver->irq_postinstall(dev); 300 301 if (ret < 0) { 302 DRM_LOCK(dev); 303 dev->irq_enabled = 0; 304 DRM_UNLOCK(dev); 305 bus_teardown_intr(dev->dev, dev->irqr, dev->irqh); 306 } 307 308 return ret; 309 } 310 EXPORT_SYMBOL(drm_irq_install); 311 312 /** 313 * Uninstall the IRQ handler. 314 * 315 * \param dev DRM device. 316 * 317 * Calls the driver's \c irq_uninstall() function, and stops the irq. 318 */ 319 int drm_irq_uninstall(struct drm_device *dev) 320 { 321 int irq_enabled, i; 322 323 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 324 return -EINVAL; 325 326 DRM_LOCK(dev); 327 irq_enabled = dev->irq_enabled; 328 dev->irq_enabled = 0; 329 DRM_UNLOCK(dev); 330 331 /* 332 * Wake up any waiters so they don't hang. 333 */ 334 if (dev->num_crtcs) { 335 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE); 336 for (i = 0; i < dev->num_crtcs; i++) { 337 DRM_WAKEUP(&dev->vbl_queue[i]); 338 dev->vblank_enabled[i] = 0; 339 dev->last_vblank[i] = 340 dev->driver->get_vblank_counter(dev, i); 341 } 342 lockmgr(&dev->vbl_lock, LK_RELEASE); 343 } 344 345 if (!irq_enabled) 346 return -EINVAL; 347 348 DRM_DEBUG("irq=%d\n", dev->irq); 349 350 if (dev->driver->irq_uninstall) 351 dev->driver->irq_uninstall(dev); 352 353 bus_teardown_intr(dev->dev, dev->irqr, dev->irqh); 354 355 return 0; 356 } 357 EXPORT_SYMBOL(drm_irq_uninstall); 358 359 /** 360 * IRQ control ioctl. 361 * 362 * \param inode device inode. 363 * \param file_priv DRM file private. 364 * \param cmd command. 365 * \param arg user argument, pointing to a drm_control structure. 366 * \return zero on success or a negative number on failure. 367 * 368 * Calls irq_install() or irq_uninstall() according to \p arg. 369 */ 370 int drm_control(struct drm_device *dev, void *data, 371 struct drm_file *file_priv) 372 { 373 struct drm_control *ctl = data; 374 375 /* if we haven't irq we fallback for compatibility reasons - 376 * this used to be a separate function in drm_dma.h 377 */ 378 379 380 switch (ctl->func) { 381 case DRM_INST_HANDLER: 382 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 383 return 0; 384 if (drm_core_check_feature(dev, DRIVER_MODESET)) 385 return 0; 386 if (dev->if_version < DRM_IF_VERSION(1, 2) && 387 ctl->irq != dev->irq) 388 return -EINVAL; 389 return drm_irq_install(dev); 390 case DRM_UNINST_HANDLER: 391 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 392 return 0; 393 if (drm_core_check_feature(dev, DRIVER_MODESET)) 394 return 0; 395 return drm_irq_uninstall(dev); 396 default: 397 return -EINVAL; 398 } 399 } 400 401 void 402 drm_calc_timestamping_constants(struct drm_crtc *crtc) 403 { 404 int64_t linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0; 405 uint64_t dotclock; 406 407 /* Dot clock in Hz: */ 408 dotclock = (uint64_t) crtc->hwmode.clock * 1000; 409 410 /* Fields of interlaced scanout modes are only halve a frame duration. 411 * Double the dotclock to get halve the frame-/line-/pixelduration. 412 */ 413 if (crtc->hwmode.flags & DRM_MODE_FLAG_INTERLACE) 414 dotclock *= 2; 415 416 /* Valid dotclock? */ 417 if (dotclock > 0) { 418 /* Convert scanline length in pixels and video dot clock to 419 * line duration, frame duration and pixel duration in 420 * nanoseconds: 421 */ 422 pixeldur_ns = (int64_t)1000000000 / dotclock; 423 linedur_ns = ((uint64_t)crtc->hwmode.crtc_htotal * 424 1000000000) / dotclock; 425 framedur_ns = (int64_t)crtc->hwmode.crtc_vtotal * linedur_ns; 426 } else 427 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n", 428 crtc->base.id); 429 430 crtc->pixeldur_ns = pixeldur_ns; 431 crtc->linedur_ns = linedur_ns; 432 crtc->framedur_ns = framedur_ns; 433 434 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n", 435 crtc->base.id, crtc->hwmode.crtc_htotal, 436 crtc->hwmode.crtc_vtotal, crtc->hwmode.crtc_vdisplay); 437 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n", 438 crtc->base.id, (int) dotclock/1000, (int) framedur_ns, 439 (int) linedur_ns, (int) pixeldur_ns); 440 } 441 442 /** 443 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms 444 * drivers. Implements calculation of exact vblank timestamps from 445 * given drm_display_mode timings and current video scanout position 446 * of a crtc. This can be called from within get_vblank_timestamp() 447 * implementation of a kms driver to implement the actual timestamping. 448 * 449 * Should return timestamps conforming to the OML_sync_control OpenML 450 * extension specification. The timestamp corresponds to the end of 451 * the vblank interval, aka start of scanout of topmost-leftmost display 452 * pixel in the following video frame. 453 * 454 * Requires support for optional dev->driver->get_scanout_position() 455 * in kms driver, plus a bit of setup code to provide a drm_display_mode 456 * that corresponds to the true scanout timing. 457 * 458 * The current implementation only handles standard video modes. It 459 * returns as no operation if a doublescan or interlaced video mode is 460 * active. Higher level code is expected to handle this. 461 * 462 * @dev: DRM device. 463 * @crtc: Which crtc's vblank timestamp to retrieve. 464 * @max_error: Desired maximum allowable error in timestamps (nanosecs). 465 * On return contains true maximum error of timestamp. 466 * @vblank_time: Pointer to struct timeval which should receive the timestamp. 467 * @flags: Flags to pass to driver: 468 * 0 = Default. 469 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. 470 * @refcrtc: drm_crtc* of crtc which defines scanout timing. 471 * 472 * Returns negative value on error, failure or if not supported in current 473 * video mode: 474 * 475 * -EINVAL - Invalid crtc. 476 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset. 477 * -ENOTSUPP - Function not supported in current display mode. 478 * -EIO - Failed, e.g., due to failed scanout position query. 479 * 480 * Returns or'ed positive status flags on success: 481 * 482 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping. 483 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval. 484 * 485 */ 486 int 487 drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, 488 int *max_error, struct timeval *vblank_time, unsigned flags, 489 struct drm_crtc *refcrtc) 490 { 491 struct timeval stime, raw_time; 492 struct drm_display_mode *mode; 493 int vbl_status, vtotal, vdisplay; 494 int vpos, hpos, i; 495 int64_t framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns; 496 bool invbl; 497 498 if (crtc < 0 || crtc >= dev->num_crtcs) { 499 DRM_ERROR("Invalid crtc %d\n", crtc); 500 return -EINVAL; 501 } 502 503 /* Scanout position query not supported? Should not happen. */ 504 if (!dev->driver->get_scanout_position) { 505 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n"); 506 return -EIO; 507 } 508 509 mode = &refcrtc->hwmode; 510 vtotal = mode->crtc_vtotal; 511 vdisplay = mode->crtc_vdisplay; 512 513 /* Durations of frames, lines, pixels in nanoseconds. */ 514 framedur_ns = refcrtc->framedur_ns; 515 linedur_ns = refcrtc->linedur_ns; 516 pixeldur_ns = refcrtc->pixeldur_ns; 517 518 /* If mode timing undefined, just return as no-op: 519 * Happens during initial modesetting of a crtc. 520 */ 521 if (vtotal <= 0 || vdisplay <= 0 || framedur_ns == 0) { 522 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc); 523 return -EAGAIN; 524 } 525 526 /* Get current scanout position with system timestamp. 527 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times 528 * if single query takes longer than max_error nanoseconds. 529 * 530 * This guarantees a tight bound on maximum error if 531 * code gets preempted or delayed for some reason. 532 */ 533 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) { 534 /* Disable preemption to make it very likely to 535 * succeed in the first iteration. 536 */ 537 crit_enter(); 538 539 /* Get system timestamp before query. */ 540 getmicrouptime(&stime); 541 542 /* Get vertical and horizontal scanout pos. vpos, hpos. */ 543 vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos); 544 545 /* Get system timestamp after query. */ 546 getmicrouptime(&raw_time); 547 548 crit_exit(); 549 550 /* Return as no-op if scanout query unsupported or failed. */ 551 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) { 552 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n", 553 crtc, vbl_status); 554 return -EIO; 555 } 556 557 duration_ns = timeval_to_ns(&raw_time) - timeval_to_ns(&stime); 558 559 /* Accept result with < max_error nsecs timing uncertainty. */ 560 if (duration_ns <= (int64_t) *max_error) 561 break; 562 } 563 564 /* Noisy system timing? */ 565 if (i == DRM_TIMESTAMP_MAXRETRIES) { 566 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n", 567 crtc, (int) duration_ns/1000, *max_error/1000, i); 568 } 569 570 /* Return upper bound of timestamp precision error. */ 571 *max_error = (int) duration_ns; 572 573 /* Check if in vblank area: 574 * vpos is >=0 in video scanout area, but negative 575 * within vblank area, counting down the number of lines until 576 * start of scanout. 577 */ 578 invbl = vbl_status & DRM_SCANOUTPOS_INVBL; 579 580 /* Convert scanout position into elapsed time at raw_time query 581 * since start of scanout at first display scanline. delta_ns 582 * can be negative if start of scanout hasn't happened yet. 583 */ 584 delta_ns = (int64_t)vpos * linedur_ns + (int64_t)hpos * pixeldur_ns; 585 586 /* Is vpos outside nominal vblank area, but less than 587 * 1/100 of a frame height away from start of vblank? 588 * If so, assume this isn't a massively delayed vblank 589 * interrupt, but a vblank interrupt that fired a few 590 * microseconds before true start of vblank. Compensate 591 * by adding a full frame duration to the final timestamp. 592 * Happens, e.g., on ATI R500, R600. 593 * 594 * We only do this if DRM_CALLED_FROM_VBLIRQ. 595 */ 596 if ((flags & DRM_CALLED_FROM_VBLIRQ) && !invbl && 597 ((vdisplay - vpos) < vtotal / 100)) { 598 delta_ns = delta_ns - framedur_ns; 599 600 /* Signal this correction as "applied". */ 601 vbl_status |= 0x8; 602 } 603 604 /* Subtract time delta from raw timestamp to get final 605 * vblank_time timestamp for end of vblank. 606 */ 607 *vblank_time = ns_to_timeval(timeval_to_ns(&raw_time) - delta_ns); 608 609 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %jd.%jd -> %jd.%jd [e %d us, %d rep]\n", 610 crtc, (int)vbl_status, hpos, vpos, (uintmax_t)raw_time.tv_sec, 611 (uintmax_t)raw_time.tv_usec, (uintmax_t)vblank_time->tv_sec, 612 (uintmax_t)vblank_time->tv_usec, (int)duration_ns/1000, i); 613 614 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD; 615 if (invbl) 616 vbl_status |= DRM_VBLANKTIME_INVBL; 617 618 return vbl_status; 619 } 620 621 static struct timeval get_drm_timestamp(void) 622 { 623 struct timeval now; 624 625 getmicrouptime(&now); 626 627 return now; 628 } 629 630 /** 631 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent 632 * vblank interval. 633 * 634 * @dev: DRM device 635 * @crtc: which crtc's vblank timestamp to retrieve 636 * @tvblank: Pointer to target struct timeval which should receive the timestamp 637 * @flags: Flags to pass to driver: 638 * 0 = Default. 639 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. 640 * 641 * Fetches the system timestamp corresponding to the time of the most recent 642 * vblank interval on specified crtc. May call into kms-driver to 643 * compute the timestamp with a high-precision GPU specific method. 644 * 645 * Returns zero if timestamp originates from uncorrected do_gettimeofday() 646 * call, i.e., it isn't very precisely locked to the true vblank. 647 * 648 * Returns non-zero if timestamp is considered to be very precise. 649 */ 650 u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc, 651 struct timeval *tvblank, unsigned flags) 652 { 653 int ret = 0; 654 655 /* Define requested maximum error on timestamps (nanoseconds). */ 656 int max_error = (int) drm_timestamp_precision * 1000; 657 658 /* Query driver if possible and precision timestamping enabled. */ 659 if (dev->driver->get_vblank_timestamp && (max_error > 0)) { 660 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error, 661 tvblank, flags); 662 if (ret > 0) 663 return (u32) ret; 664 } 665 666 /* GPU high precision timestamp query unsupported or failed. 667 * Return gettimeofday timestamp as best estimate. 668 */ 669 microtime(tvblank); 670 671 return 0; 672 } 673 674 /** 675 * drm_vblank_count - retrieve "cooked" vblank counter value 676 * @dev: DRM device 677 * @crtc: which counter to retrieve 678 * 679 * Fetches the "cooked" vblank count value that represents the number of 680 * vblank events since the system was booted, including lost events due to 681 * modesetting activity. 682 */ 683 u32 drm_vblank_count(struct drm_device *dev, int crtc) 684 { 685 return atomic_read(&dev->_vblank_count[crtc]); 686 } 687 688 /** 689 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value 690 * and the system timestamp corresponding to that vblank counter value. 691 * 692 * @dev: DRM device 693 * @crtc: which counter to retrieve 694 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp. 695 * 696 * Fetches the "cooked" vblank count value that represents the number of 697 * vblank events since the system was booted, including lost events due to 698 * modesetting activity. Returns corresponding system timestamp of the time 699 * of the vblank interval that corresponds to the current value vblank counter 700 * value. 701 */ 702 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc, 703 struct timeval *vblanktime) 704 { 705 u32 cur_vblank; 706 707 /* Read timestamp from slot of _vblank_time ringbuffer 708 * that corresponds to current vblank count. Retry if 709 * count has incremented during readout. This works like 710 * a seqlock. 711 */ 712 do { 713 cur_vblank = atomic_read(&dev->_vblank_count[crtc]); 714 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank); 715 cpu_lfence(); 716 } while (cur_vblank != atomic_read(&dev->_vblank_count[crtc])); 717 718 return cur_vblank; 719 } 720 721 static void send_vblank_event(struct drm_device *dev, 722 struct drm_pending_vblank_event *e, 723 unsigned long seq, struct timeval *now) 724 { 725 KKASSERT(mutex_is_locked(&dev->event_lock)); 726 e->event.sequence = seq; 727 e->event.tv_sec = now->tv_sec; 728 e->event.tv_usec = now->tv_usec; 729 730 list_add_tail(&e->base.link, 731 &e->base.file_priv->event_list); 732 drm_event_wakeup(&e->base); 733 #if 0 734 trace_drm_vblank_event_delivered(e->base.pid, e->pipe, 735 e->event.sequence); 736 #endif 737 } 738 739 /** 740 * drm_send_vblank_event - helper to send vblank event after pageflip 741 * @dev: DRM device 742 * @crtc: CRTC in question 743 * @e: the event to send 744 * 745 * Updates sequence # and timestamp on event, and sends it to userspace. 746 * Caller must hold event lock. 747 */ 748 void drm_send_vblank_event(struct drm_device *dev, int crtc, 749 struct drm_pending_vblank_event *e) 750 { 751 struct timeval now; 752 unsigned int seq; 753 if (crtc >= 0) { 754 seq = drm_vblank_count_and_time(dev, crtc, &now); 755 } else { 756 seq = 0; 757 758 now = get_drm_timestamp(); 759 } 760 e->pipe = crtc; 761 send_vblank_event(dev, e, seq, &now); 762 } 763 EXPORT_SYMBOL(drm_send_vblank_event); 764 765 /** 766 * drm_update_vblank_count - update the master vblank counter 767 * @dev: DRM device 768 * @crtc: counter to update 769 * 770 * Call back into the driver to update the appropriate vblank counter 771 * (specified by @crtc). Deal with wraparound, if it occurred, and 772 * update the last read value so we can deal with wraparound on the next 773 * call if necessary. 774 * 775 * Only necessary when going from off->on, to account for frames we 776 * didn't get an interrupt for. 777 * 778 * Note: caller must hold dev->vbl_lock since this reads & writes 779 * device vblank fields. 780 */ 781 static void drm_update_vblank_count(struct drm_device *dev, int crtc) 782 { 783 u32 cur_vblank, diff, tslot, rc; 784 struct timeval t_vblank; 785 786 /* 787 * Interrupts were disabled prior to this call, so deal with counter 788 * wrap if needed. 789 * NOTE! It's possible we lost a full dev->max_vblank_count events 790 * here if the register is small or we had vblank interrupts off for 791 * a long time. 792 * 793 * We repeat the hardware vblank counter & timestamp query until 794 * we get consistent results. This to prevent races between gpu 795 * updating its hardware counter while we are retrieving the 796 * corresponding vblank timestamp. 797 */ 798 do { 799 cur_vblank = dev->driver->get_vblank_counter(dev, crtc); 800 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0); 801 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc)); 802 803 /* Deal with counter wrap */ 804 diff = cur_vblank - dev->last_vblank[crtc]; 805 if (cur_vblank < dev->last_vblank[crtc]) { 806 diff += dev->max_vblank_count; 807 808 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n", 809 crtc, dev->last_vblank[crtc], cur_vblank, diff); 810 } 811 812 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n", 813 crtc, diff); 814 815 /* Reinitialize corresponding vblank timestamp if high-precision query 816 * available. Skip this step if query unsupported or failed. Will 817 * reinitialize delayed at next vblank interrupt in that case. 818 */ 819 if (rc) { 820 tslot = atomic_read(&dev->_vblank_count[crtc]) + diff; 821 vblanktimestamp(dev, crtc, tslot) = t_vblank; 822 } 823 824 atomic_add(diff, &dev->_vblank_count[crtc]); 825 } 826 827 /** 828 * drm_vblank_get - get a reference count on vblank events 829 * @dev: DRM device 830 * @crtc: which CRTC to own 831 * 832 * Acquire a reference count on vblank events to avoid having them disabled 833 * while in use. 834 * 835 * RETURNS 836 * Zero on success, nonzero on failure. 837 */ 838 int drm_vblank_get(struct drm_device *dev, int crtc) 839 { 840 int ret = 0; 841 842 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE); 843 /* Going from 0->1 means we have to enable interrupts again */ 844 if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) { 845 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE); 846 if (!dev->vblank_enabled[crtc]) { 847 /* Enable vblank irqs under vblank_time_lock protection. 848 * All vblank count & timestamp updates are held off 849 * until we are done reinitializing master counter and 850 * timestamps. Filtercode in drm_handle_vblank() will 851 * prevent double-accounting of same vblank interval. 852 */ 853 ret = -dev->driver->enable_vblank(dev, crtc); 854 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", 855 crtc, ret); 856 if (ret) 857 atomic_dec(&dev->vblank_refcount[crtc]); 858 else { 859 dev->vblank_enabled[crtc] = 1; 860 drm_update_vblank_count(dev, crtc); 861 } 862 } 863 lockmgr(&dev->vblank_time_lock, LK_RELEASE); 864 } else { 865 if (!dev->vblank_enabled[crtc]) { 866 atomic_dec(&dev->vblank_refcount[crtc]); 867 ret = EINVAL; 868 } 869 } 870 lockmgr(&dev->vbl_lock, LK_RELEASE); 871 872 return ret; 873 } 874 875 /** 876 * drm_vblank_put - give up ownership of vblank events 877 * @dev: DRM device 878 * @crtc: which counter to give up 879 * 880 * Release ownership of a given vblank counter, turning off interrupts 881 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds. 882 */ 883 void drm_vblank_put(struct drm_device *dev, int crtc) 884 { 885 BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0); 886 887 /* Last user schedules interrupt disable */ 888 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE); 889 if (atomic_dec_and_test(&dev->vblank_refcount[crtc]) && 890 (drm_vblank_offdelay > 0)) { 891 mod_timer(&dev->vblank_disable_timer, 892 jiffies + ((drm_vblank_offdelay * DRM_HZ)/1000)); 893 } 894 lockmgr(&dev->vblank_time_lock, LK_RELEASE); 895 } 896 EXPORT_SYMBOL(drm_vblank_put); 897 898 void drm_vblank_off(struct drm_device *dev, int crtc) 899 { 900 struct drm_pending_vblank_event *e, *t; 901 struct timeval now; 902 unsigned int seq; 903 904 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE); 905 vblank_disable_and_save(dev, crtc); 906 lockmgr(&dev->event_lock, LK_EXCLUSIVE); 907 wakeup(&dev->_vblank_count[crtc]); 908 909 /* Send any queued vblank events, lest the natives grow disquiet */ 910 seq = drm_vblank_count_and_time(dev, crtc, &now); 911 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { 912 if (e->pipe != crtc) 913 continue; 914 DRM_DEBUG("Sending premature vblank event on disable: \ 915 wanted %d, current %d\n", 916 e->event.sequence, seq); 917 list_del(&e->base.link); 918 drm_vblank_put(dev, e->pipe); 919 send_vblank_event(dev, e, seq, &now); 920 } 921 922 lockmgr(&dev->event_lock, LK_RELEASE); 923 lockmgr(&dev->vbl_lock, LK_RELEASE); 924 } 925 926 /** 927 * drm_vblank_pre_modeset - account for vblanks across mode sets 928 * @dev: DRM device 929 * @crtc: CRTC in question 930 * @post: post or pre mode set? 931 * 932 * Account for vblank events across mode setting events, which will likely 933 * reset the hardware frame counter. 934 */ 935 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) 936 { 937 /* vblank is not initialized (IRQ not installed ?) */ 938 if (!dev->num_crtcs) 939 return; 940 /* 941 * To avoid all the problems that might happen if interrupts 942 * were enabled/disabled around or between these calls, we just 943 * have the kernel take a reference on the CRTC (just once though 944 * to avoid corrupting the count if multiple, mismatch calls occur), 945 * so that interrupts remain enabled in the interim. 946 */ 947 if (!dev->vblank_inmodeset[crtc]) { 948 dev->vblank_inmodeset[crtc] = 0x1; 949 if (drm_vblank_get(dev, crtc) == 0) 950 dev->vblank_inmodeset[crtc] |= 0x2; 951 } 952 } 953 954 void drm_vblank_post_modeset(struct drm_device *dev, int crtc) 955 { 956 957 if (dev->vblank_inmodeset[crtc]) { 958 lockmgr(&dev->vbl_lock, LK_EXCLUSIVE); 959 dev->vblank_disable_allowed = 1; 960 lockmgr(&dev->vbl_lock, LK_RELEASE); 961 962 if (dev->vblank_inmodeset[crtc] & 0x2) 963 drm_vblank_put(dev, crtc); 964 965 dev->vblank_inmodeset[crtc] = 0; 966 } 967 } 968 969 /** 970 * drm_modeset_ctl - handle vblank event counter changes across mode switch 971 * @DRM_IOCTL_ARGS: standard ioctl arguments 972 * 973 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET 974 * ioctls around modesetting so that any lost vblank events are accounted for. 975 * 976 * Generally the counter will reset across mode sets. If interrupts are 977 * enabled around this call, we don't have to do anything since the counter 978 * will have already been incremented. 979 */ 980 int drm_modeset_ctl(struct drm_device *dev, void *data, 981 struct drm_file *file_priv) 982 { 983 struct drm_modeset_ctl *modeset = data; 984 int ret = 0; 985 unsigned int crtc; 986 987 /* If drm_vblank_init() hasn't been called yet, just no-op */ 988 if (!dev->num_crtcs) 989 goto out; 990 991 crtc = modeset->crtc; 992 if (crtc >= dev->num_crtcs) { 993 ret = -EINVAL; 994 goto out; 995 } 996 997 switch (modeset->cmd) { 998 case _DRM_PRE_MODESET: 999 drm_vblank_pre_modeset(dev, crtc); 1000 break; 1001 case _DRM_POST_MODESET: 1002 drm_vblank_post_modeset(dev, crtc); 1003 break; 1004 default: 1005 ret = -EINVAL; 1006 break; 1007 } 1008 1009 out: 1010 return ret; 1011 } 1012 1013 static void 1014 drm_vblank_event_destroy(struct drm_pending_event *e) 1015 { 1016 1017 drm_free(e, M_DRM); 1018 } 1019 1020 static int drm_queue_vblank_event(struct drm_device *dev, int pipe, 1021 union drm_wait_vblank *vblwait, 1022 struct drm_file *file_priv) 1023 { 1024 struct drm_pending_vblank_event *e; 1025 struct timeval now; 1026 unsigned int seq; 1027 int ret; 1028 1029 e = kmalloc(sizeof *e, M_DRM, M_WAITOK | M_ZERO); 1030 1031 e->pipe = pipe; 1032 e->base.pid = curproc->p_pid; 1033 e->event.base.type = DRM_EVENT_VBLANK; 1034 e->event.base.length = sizeof e->event; 1035 e->event.user_data = vblwait->request.signal; 1036 e->base.event = &e->event.base; 1037 e->base.file_priv = file_priv; 1038 e->base.destroy = drm_vblank_event_destroy; 1039 1040 lockmgr(&dev->event_lock, LK_EXCLUSIVE); 1041 1042 if (file_priv->event_space < sizeof e->event) { 1043 ret = EBUSY; 1044 goto err_unlock; 1045 } 1046 1047 file_priv->event_space -= sizeof e->event; 1048 seq = drm_vblank_count_and_time(dev, pipe, &now); 1049 1050 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) && 1051 (seq - vblwait->request.sequence) <= (1 << 23)) { 1052 vblwait->request.sequence = seq + 1; 1053 vblwait->reply.sequence = vblwait->request.sequence; 1054 } 1055 1056 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n", 1057 vblwait->request.sequence, seq, pipe); 1058 1059 e->event.sequence = vblwait->request.sequence; 1060 if ((seq - vblwait->request.sequence) <= (1 << 23)) { 1061 drm_vblank_put(dev, pipe); 1062 send_vblank_event(dev, e, seq, &now); 1063 vblwait->reply.sequence = seq; 1064 } else { 1065 /* drm_handle_vblank_events will call drm_vblank_put */ 1066 list_add_tail(&e->base.link, &dev->vblank_event_list); 1067 vblwait->reply.sequence = vblwait->request.sequence; 1068 } 1069 1070 lockmgr(&dev->event_lock, LK_RELEASE); 1071 1072 return 0; 1073 1074 err_unlock: 1075 lockmgr(&dev->event_lock, LK_RELEASE); 1076 drm_free(e, M_DRM); 1077 drm_vblank_put(dev, pipe); 1078 return ret; 1079 } 1080 1081 /** 1082 * Wait for VBLANK. 1083 * 1084 * \param inode device inode. 1085 * \param file_priv DRM file private. 1086 * \param cmd command. 1087 * \param data user argument, pointing to a drm_wait_vblank structure. 1088 * \return zero on success or a negative number on failure. 1089 * 1090 * This function enables the vblank interrupt on the pipe requested, then 1091 * sleeps waiting for the requested sequence number to occur, and drops 1092 * the vblank interrupt refcount afterwards. (vblank irq disable follows that 1093 * after a timeout with no further vblank waits scheduled). 1094 */ 1095 int drm_wait_vblank(struct drm_device *dev, void *data, 1096 struct drm_file *file_priv) 1097 { 1098 union drm_wait_vblank *vblwait = data; 1099 int ret = 0; 1100 unsigned int flags, seq, crtc, high_crtc; 1101 1102 if (/*(!drm_dev_to_irq(dev)) || */(!dev->irq_enabled)) 1103 return (EINVAL); 1104 1105 if (vblwait->request.type & _DRM_VBLANK_SIGNAL) 1106 return (EINVAL); 1107 1108 if (vblwait->request.type & 1109 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | 1110 _DRM_VBLANK_HIGH_CRTC_MASK)) { 1111 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n", 1112 vblwait->request.type, 1113 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | 1114 _DRM_VBLANK_HIGH_CRTC_MASK)); 1115 return (EINVAL); 1116 } 1117 1118 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK; 1119 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK); 1120 if (high_crtc) 1121 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT; 1122 else 1123 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0; 1124 if (crtc >= dev->num_crtcs) 1125 return (EINVAL); 1126 1127 ret = drm_vblank_get(dev, crtc); 1128 if (ret) { 1129 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret); 1130 return (ret); 1131 } 1132 seq = drm_vblank_count(dev, crtc); 1133 1134 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) { 1135 case _DRM_VBLANK_RELATIVE: 1136 vblwait->request.sequence += seq; 1137 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE; 1138 case _DRM_VBLANK_ABSOLUTE: 1139 break; 1140 default: 1141 ret = (EINVAL); 1142 goto done; 1143 } 1144 1145 if (flags & _DRM_VBLANK_EVENT) { 1146 /* must hold on to the vblank ref until the event fires 1147 * drm_vblank_put will be called asynchronously 1148 */ 1149 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv); 1150 } 1151 1152 if ((flags & _DRM_VBLANK_NEXTONMISS) && 1153 (seq - vblwait->request.sequence) <= (1<<23)) { 1154 vblwait->request.sequence = seq + 1; 1155 } 1156 1157 dev->last_vblank_wait[crtc] = vblwait->request.sequence; 1158 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE); 1159 while (((drm_vblank_count(dev, crtc) - vblwait->request.sequence) > 1160 (1 << 23)) && dev->irq_enabled) { 1161 /* 1162 * The wakeups from the drm_irq_uninstall() and 1163 * drm_vblank_off() may be lost there since vbl_lock 1164 * is not held. Then, the timeout will wake us; the 3 1165 * seconds delay should not be a problem for 1166 * application when crtc is disabled or irq 1167 * uninstalled anyway. 1168 */ 1169 ret = lksleep(&dev->_vblank_count[crtc], &dev->vblank_time_lock, 1170 PCATCH, "drmvbl", 3 * hz); 1171 if (ret != 0) 1172 break; 1173 } 1174 lockmgr(&dev->vblank_time_lock, LK_RELEASE); 1175 if (ret != EINTR) { 1176 struct timeval now; 1177 long reply_seq; 1178 1179 reply_seq = drm_vblank_count_and_time(dev, crtc, &now); 1180 vblwait->reply.sequence = reply_seq; 1181 vblwait->reply.tval_sec = now.tv_sec; 1182 vblwait->reply.tval_usec = now.tv_usec; 1183 } 1184 1185 done: 1186 drm_vblank_put(dev, crtc); 1187 return ret; 1188 } 1189 1190 void drm_handle_vblank_events(struct drm_device *dev, int crtc) 1191 { 1192 struct drm_pending_vblank_event *e, *t; 1193 struct timeval now; 1194 unsigned int seq; 1195 1196 seq = drm_vblank_count_and_time(dev, crtc, &now); 1197 1198 lockmgr(&dev->event_lock, LK_EXCLUSIVE); 1199 1200 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { 1201 if (e->pipe != crtc) 1202 continue; 1203 if ((seq - e->event.sequence) > (1<<23)) 1204 continue; 1205 1206 DRM_DEBUG("vblank event on %d, current %d\n", 1207 e->event.sequence, seq); 1208 1209 list_del(&e->base.link); 1210 drm_vblank_put(dev, e->pipe); 1211 send_vblank_event(dev, e, seq, &now); 1212 } 1213 1214 lockmgr(&dev->event_lock, LK_RELEASE); 1215 } 1216 1217 /** 1218 * drm_handle_vblank - handle a vblank event 1219 * @dev: DRM device 1220 * @crtc: where this event occurred 1221 * 1222 * Drivers should call this routine in their vblank interrupt handlers to 1223 * update the vblank counter and send any signals that may be pending. 1224 */ 1225 bool drm_handle_vblank(struct drm_device *dev, int crtc) 1226 { 1227 u32 vblcount; 1228 int64_t diff_ns; 1229 struct timeval tvblank; 1230 1231 if (!dev->num_crtcs) 1232 return false; 1233 1234 /* Need timestamp lock to prevent concurrent execution with 1235 * vblank enable/disable, as this would cause inconsistent 1236 * or corrupted timestamps and vblank counts. 1237 */ 1238 lockmgr(&dev->vblank_time_lock, LK_EXCLUSIVE); 1239 1240 /* Vblank irq handling disabled. Nothing to do. */ 1241 if (!dev->vblank_enabled[crtc]) { 1242 lockmgr(&dev->vblank_time_lock, LK_RELEASE); 1243 return false; 1244 } 1245 1246 /* Fetch corresponding timestamp for this vblank interval from 1247 * driver and store it in proper slot of timestamp ringbuffer. 1248 */ 1249 1250 /* Get current timestamp and count. */ 1251 vblcount = atomic_read(&dev->_vblank_count[crtc]); 1252 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ); 1253 1254 /* Compute time difference to timestamp of last vblank */ 1255 diff_ns = timeval_to_ns(&tvblank) - 1256 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); 1257 1258 /* Update vblank timestamp and count if at least 1259 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds 1260 * difference between last stored timestamp and current 1261 * timestamp. A smaller difference means basically 1262 * identical timestamps. Happens if this vblank has 1263 * been already processed and this is a redundant call, 1264 * e.g., due to spurious vblank interrupts. We need to 1265 * ignore those for accounting. 1266 */ 1267 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) { 1268 /* Store new timestamp in ringbuffer. */ 1269 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank; 1270 1271 /* Increment cooked vblank count. This also atomically commits 1272 * the timestamp computed above. 1273 */ 1274 atomic_inc(&dev->_vblank_count[crtc]); 1275 } else { 1276 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n", 1277 crtc, (int) diff_ns); 1278 } 1279 1280 wakeup(&dev->_vblank_count[crtc]); 1281 drm_handle_vblank_events(dev, crtc); 1282 1283 lockmgr(&dev->vblank_time_lock, LK_RELEASE); 1284 return true; 1285 } 1286