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 #include "drm_trace.h" 38 39 #include <linux/interrupt.h> /* For task queue support */ 40 #include <linux/slab.h> 41 42 #include <linux/vgaarb.h> 43 44 /* Access macro for slots in vblank timestamp ringbuffer. */ 45 #define vblanktimestamp(dev, crtc, count) ( \ 46 (dev)->_vblank_time[(crtc) * DRM_VBLANKTIME_RBSIZE + \ 47 ((count) % DRM_VBLANKTIME_RBSIZE)]) 48 49 /* Retry timestamp calculation up to 3 times to satisfy 50 * drm_timestamp_precision before giving up. 51 */ 52 #define DRM_TIMESTAMP_MAXRETRIES 3 53 54 /* Threshold in nanoseconds for detection of redundant 55 * vblank irq in drm_handle_vblank(). 1 msec should be ok. 56 */ 57 #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000 58 59 /** 60 * Get interrupt from bus id. 61 * 62 * \param inode device inode. 63 * \param file_priv DRM file private. 64 * \param cmd command. 65 * \param arg user argument, pointing to a drm_irq_busid structure. 66 * \return zero on success or a negative number on failure. 67 * 68 * Finds the PCI device with the specified bus id and gets its IRQ number. 69 * This IOCTL is deprecated, and will now return EINVAL for any busid not equal 70 * to that of the device that this DRM instance attached to. 71 */ 72 int drm_irq_by_busid(struct drm_device *dev, void *data, 73 struct drm_file *file_priv) 74 { 75 struct drm_irq_busid *p = data; 76 77 if (drm_core_check_feature(dev, DRIVER_USE_PLATFORM_DEVICE)) 78 return -EINVAL; 79 80 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 81 return -EINVAL; 82 83 if ((p->busnum >> 8) != drm_get_pci_domain(dev) || 84 (p->busnum & 0xff) != dev->pdev->bus->number || 85 p->devnum != PCI_SLOT(dev->pdev->devfn) || p->funcnum != PCI_FUNC(dev->pdev->devfn)) 86 return -EINVAL; 87 88 p->irq = dev->pdev->irq; 89 90 DRM_DEBUG("%d:%d:%d => IRQ %d\n", p->busnum, p->devnum, p->funcnum, 91 p->irq); 92 93 return 0; 94 } 95 96 /* 97 * Clear vblank timestamp buffer for a crtc. 98 */ 99 static void clear_vblank_timestamps(struct drm_device *dev, int crtc) 100 { 101 memset(&dev->_vblank_time[crtc * DRM_VBLANKTIME_RBSIZE], 0, 102 DRM_VBLANKTIME_RBSIZE * sizeof(struct timeval)); 103 } 104 105 /* 106 * Disable vblank irq's on crtc, make sure that last vblank count 107 * of hardware and corresponding consistent software vblank counter 108 * are preserved, even if there are any spurious vblank irq's after 109 * disable. 110 */ 111 static void vblank_disable_and_save(struct drm_device *dev, int crtc) 112 { 113 unsigned long irqflags; 114 u32 vblcount; 115 s64 diff_ns; 116 int vblrc; 117 struct timeval tvblank; 118 119 /* Prevent vblank irq processing while disabling vblank irqs, 120 * so no updates of timestamps or count can happen after we've 121 * disabled. Needed to prevent races in case of delayed irq's. 122 * Disable preemption, so vblank_time_lock is held as short as 123 * possible, even under a kernel with PREEMPT_RT patches. 124 */ 125 preempt_disable(); 126 spin_lock_irqsave(&dev->vblank_time_lock, irqflags); 127 128 dev->driver->disable_vblank(dev, crtc); 129 dev->vblank_enabled[crtc] = 0; 130 131 /* No further vblank irq's will be processed after 132 * this point. Get current hardware vblank count and 133 * vblank timestamp, repeat until they are consistent. 134 * 135 * FIXME: There is still a race condition here and in 136 * drm_update_vblank_count() which can cause off-by-one 137 * reinitialization of software vblank counter. If gpu 138 * vblank counter doesn't increment exactly at the leading 139 * edge of a vblank interval, then we can lose 1 count if 140 * we happen to execute between start of vblank and the 141 * delayed gpu counter increment. 142 */ 143 do { 144 dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc); 145 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0); 146 } while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc)); 147 148 /* Compute time difference to stored timestamp of last vblank 149 * as updated by last invocation of drm_handle_vblank() in vblank irq. 150 */ 151 vblcount = atomic_read(&dev->_vblank_count[crtc]); 152 diff_ns = timeval_to_ns(&tvblank) - 153 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); 154 155 /* If there is at least 1 msec difference between the last stored 156 * timestamp and tvblank, then we are currently executing our 157 * disable inside a new vblank interval, the tvblank timestamp 158 * corresponds to this new vblank interval and the irq handler 159 * for this vblank didn't run yet and won't run due to our disable. 160 * Therefore we need to do the job of drm_handle_vblank() and 161 * increment the vblank counter by one to account for this vblank. 162 * 163 * Skip this step if there isn't any high precision timestamp 164 * available. In that case we can't account for this and just 165 * hope for the best. 166 */ 167 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) { 168 atomic_inc(&dev->_vblank_count[crtc]); 169 smp_mb__after_atomic_inc(); 170 } 171 172 /* Invalidate all timestamps while vblank irq's are off. */ 173 clear_vblank_timestamps(dev, crtc); 174 175 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); 176 preempt_enable(); 177 } 178 179 static void vblank_disable_fn(unsigned long arg) 180 { 181 struct drm_device *dev = (struct drm_device *)arg; 182 unsigned long irqflags; 183 int i; 184 185 if (!dev->vblank_disable_allowed) 186 return; 187 188 for (i = 0; i < dev->num_crtcs; i++) { 189 spin_lock_irqsave(&dev->vbl_lock, irqflags); 190 if (atomic_read(&dev->vblank_refcount[i]) == 0 && 191 dev->vblank_enabled[i]) { 192 DRM_DEBUG("disabling vblank on crtc %d\n", i); 193 vblank_disable_and_save(dev, i); 194 } 195 spin_unlock_irqrestore(&dev->vbl_lock, irqflags); 196 } 197 } 198 199 void drm_vblank_cleanup(struct drm_device *dev) 200 { 201 /* Bail if the driver didn't call drm_vblank_init() */ 202 if (dev->num_crtcs == 0) 203 return; 204 205 del_timer(&dev->vblank_disable_timer); 206 207 vblank_disable_fn((unsigned long)dev); 208 209 kfree(dev->vbl_queue); 210 kfree(dev->_vblank_count); 211 kfree(dev->vblank_refcount); 212 kfree(dev->vblank_enabled); 213 kfree(dev->last_vblank); 214 kfree(dev->last_vblank_wait); 215 kfree(dev->vblank_inmodeset); 216 kfree(dev->_vblank_time); 217 218 dev->num_crtcs = 0; 219 } 220 EXPORT_SYMBOL(drm_vblank_cleanup); 221 222 int drm_vblank_init(struct drm_device *dev, int num_crtcs) 223 { 224 int i, ret = -ENOMEM; 225 226 setup_timer(&dev->vblank_disable_timer, vblank_disable_fn, 227 (unsigned long)dev); 228 spin_lock_init(&dev->vbl_lock); 229 spin_lock_init(&dev->vblank_time_lock); 230 231 dev->num_crtcs = num_crtcs; 232 233 dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs, 234 GFP_KERNEL); 235 if (!dev->vbl_queue) 236 goto err; 237 238 dev->_vblank_count = kmalloc(sizeof(atomic_t) * num_crtcs, GFP_KERNEL); 239 if (!dev->_vblank_count) 240 goto err; 241 242 dev->vblank_refcount = kmalloc(sizeof(atomic_t) * num_crtcs, 243 GFP_KERNEL); 244 if (!dev->vblank_refcount) 245 goto err; 246 247 dev->vblank_enabled = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL); 248 if (!dev->vblank_enabled) 249 goto err; 250 251 dev->last_vblank = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL); 252 if (!dev->last_vblank) 253 goto err; 254 255 dev->last_vblank_wait = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL); 256 if (!dev->last_vblank_wait) 257 goto err; 258 259 dev->vblank_inmodeset = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL); 260 if (!dev->vblank_inmodeset) 261 goto err; 262 263 dev->_vblank_time = kcalloc(num_crtcs * DRM_VBLANKTIME_RBSIZE, 264 sizeof(struct timeval), GFP_KERNEL); 265 if (!dev->_vblank_time) 266 goto err; 267 268 DRM_INFO("Supports vblank timestamp caching Rev 1 (10.10.2010).\n"); 269 270 /* Driver specific high-precision vblank timestamping supported? */ 271 if (dev->driver->get_vblank_timestamp) 272 DRM_INFO("Driver supports precise vblank timestamp query.\n"); 273 else 274 DRM_INFO("No driver support for vblank timestamp query.\n"); 275 276 /* Zero per-crtc vblank stuff */ 277 for (i = 0; i < num_crtcs; i++) { 278 init_waitqueue_head(&dev->vbl_queue[i]); 279 atomic_set(&dev->_vblank_count[i], 0); 280 atomic_set(&dev->vblank_refcount[i], 0); 281 } 282 283 dev->vblank_disable_allowed = 0; 284 return 0; 285 286 err: 287 drm_vblank_cleanup(dev); 288 return ret; 289 } 290 EXPORT_SYMBOL(drm_vblank_init); 291 292 static void drm_irq_vgaarb_nokms(void *cookie, bool state) 293 { 294 struct drm_device *dev = cookie; 295 296 if (dev->driver->vgaarb_irq) { 297 dev->driver->vgaarb_irq(dev, state); 298 return; 299 } 300 301 if (!dev->irq_enabled) 302 return; 303 304 if (state) 305 dev->driver->irq_uninstall(dev); 306 else { 307 dev->driver->irq_preinstall(dev); 308 dev->driver->irq_postinstall(dev); 309 } 310 } 311 312 /** 313 * Install IRQ handler. 314 * 315 * \param dev DRM device. 316 * 317 * Initializes the IRQ related data. Installs the handler, calling the driver 318 * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions 319 * before and after the installation. 320 */ 321 int drm_irq_install(struct drm_device *dev) 322 { 323 int ret = 0; 324 unsigned long sh_flags = 0; 325 char *irqname; 326 327 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 328 return -EINVAL; 329 330 if (drm_dev_to_irq(dev) == 0) 331 return -EINVAL; 332 333 mutex_lock(&dev->struct_mutex); 334 335 /* Driver must have been initialized */ 336 if (!dev->dev_private) { 337 mutex_unlock(&dev->struct_mutex); 338 return -EINVAL; 339 } 340 341 if (dev->irq_enabled) { 342 mutex_unlock(&dev->struct_mutex); 343 return -EBUSY; 344 } 345 dev->irq_enabled = 1; 346 mutex_unlock(&dev->struct_mutex); 347 348 DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev)); 349 350 /* Before installing handler */ 351 dev->driver->irq_preinstall(dev); 352 353 /* Install handler */ 354 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED)) 355 sh_flags = IRQF_SHARED; 356 357 if (dev->devname) 358 irqname = dev->devname; 359 else 360 irqname = dev->driver->name; 361 362 ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler, 363 sh_flags, irqname, dev); 364 365 if (ret < 0) { 366 mutex_lock(&dev->struct_mutex); 367 dev->irq_enabled = 0; 368 mutex_unlock(&dev->struct_mutex); 369 return ret; 370 } 371 372 if (!drm_core_check_feature(dev, DRIVER_MODESET)) 373 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL); 374 375 /* After installing handler */ 376 ret = dev->driver->irq_postinstall(dev); 377 if (ret < 0) { 378 mutex_lock(&dev->struct_mutex); 379 dev->irq_enabled = 0; 380 mutex_unlock(&dev->struct_mutex); 381 } 382 383 return ret; 384 } 385 EXPORT_SYMBOL(drm_irq_install); 386 387 /** 388 * Uninstall the IRQ handler. 389 * 390 * \param dev DRM device. 391 * 392 * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq. 393 */ 394 int drm_irq_uninstall(struct drm_device *dev) 395 { 396 unsigned long irqflags; 397 int irq_enabled, i; 398 399 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 400 return -EINVAL; 401 402 mutex_lock(&dev->struct_mutex); 403 irq_enabled = dev->irq_enabled; 404 dev->irq_enabled = 0; 405 mutex_unlock(&dev->struct_mutex); 406 407 /* 408 * Wake up any waiters so they don't hang. 409 */ 410 spin_lock_irqsave(&dev->vbl_lock, irqflags); 411 for (i = 0; i < dev->num_crtcs; i++) { 412 DRM_WAKEUP(&dev->vbl_queue[i]); 413 dev->vblank_enabled[i] = 0; 414 dev->last_vblank[i] = dev->driver->get_vblank_counter(dev, i); 415 } 416 spin_unlock_irqrestore(&dev->vbl_lock, irqflags); 417 418 if (!irq_enabled) 419 return -EINVAL; 420 421 DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev)); 422 423 if (!drm_core_check_feature(dev, DRIVER_MODESET)) 424 vga_client_register(dev->pdev, NULL, NULL, NULL); 425 426 dev->driver->irq_uninstall(dev); 427 428 free_irq(drm_dev_to_irq(dev), dev); 429 430 return 0; 431 } 432 EXPORT_SYMBOL(drm_irq_uninstall); 433 434 /** 435 * IRQ control ioctl. 436 * 437 * \param inode device inode. 438 * \param file_priv DRM file private. 439 * \param cmd command. 440 * \param arg user argument, pointing to a drm_control structure. 441 * \return zero on success or a negative number on failure. 442 * 443 * Calls irq_install() or irq_uninstall() according to \p arg. 444 */ 445 int drm_control(struct drm_device *dev, void *data, 446 struct drm_file *file_priv) 447 { 448 struct drm_control *ctl = data; 449 450 /* if we haven't irq we fallback for compatibility reasons - 451 * this used to be a separate function in drm_dma.h 452 */ 453 454 455 switch (ctl->func) { 456 case DRM_INST_HANDLER: 457 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 458 return 0; 459 if (drm_core_check_feature(dev, DRIVER_MODESET)) 460 return 0; 461 if (dev->if_version < DRM_IF_VERSION(1, 2) && 462 ctl->irq != drm_dev_to_irq(dev)) 463 return -EINVAL; 464 return drm_irq_install(dev); 465 case DRM_UNINST_HANDLER: 466 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 467 return 0; 468 if (drm_core_check_feature(dev, DRIVER_MODESET)) 469 return 0; 470 return drm_irq_uninstall(dev); 471 default: 472 return -EINVAL; 473 } 474 } 475 476 /** 477 * drm_calc_timestamping_constants - Calculate and 478 * store various constants which are later needed by 479 * vblank and swap-completion timestamping, e.g, by 480 * drm_calc_vbltimestamp_from_scanoutpos(). 481 * They are derived from crtc's true scanout timing, 482 * so they take things like panel scaling or other 483 * adjustments into account. 484 * 485 * @crtc drm_crtc whose timestamp constants should be updated. 486 * 487 */ 488 void drm_calc_timestamping_constants(struct drm_crtc *crtc) 489 { 490 s64 linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0; 491 u64 dotclock; 492 493 /* Dot clock in Hz: */ 494 dotclock = (u64) crtc->hwmode.clock * 1000; 495 496 /* Fields of interlaced scanout modes are only halve a frame duration. 497 * Double the dotclock to get halve the frame-/line-/pixelduration. 498 */ 499 if (crtc->hwmode.flags & DRM_MODE_FLAG_INTERLACE) 500 dotclock *= 2; 501 502 /* Valid dotclock? */ 503 if (dotclock > 0) { 504 /* Convert scanline length in pixels and video dot clock to 505 * line duration, frame duration and pixel duration in 506 * nanoseconds: 507 */ 508 pixeldur_ns = (s64) div64_u64(1000000000, dotclock); 509 linedur_ns = (s64) div64_u64(((u64) crtc->hwmode.crtc_htotal * 510 1000000000), dotclock); 511 framedur_ns = (s64) crtc->hwmode.crtc_vtotal * linedur_ns; 512 } else 513 DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n", 514 crtc->base.id); 515 516 crtc->pixeldur_ns = pixeldur_ns; 517 crtc->linedur_ns = linedur_ns; 518 crtc->framedur_ns = framedur_ns; 519 520 DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n", 521 crtc->base.id, crtc->hwmode.crtc_htotal, 522 crtc->hwmode.crtc_vtotal, crtc->hwmode.crtc_vdisplay); 523 DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n", 524 crtc->base.id, (int) dotclock/1000, (int) framedur_ns, 525 (int) linedur_ns, (int) pixeldur_ns); 526 } 527 EXPORT_SYMBOL(drm_calc_timestamping_constants); 528 529 /** 530 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms 531 * drivers. Implements calculation of exact vblank timestamps from 532 * given drm_display_mode timings and current video scanout position 533 * of a crtc. This can be called from within get_vblank_timestamp() 534 * implementation of a kms driver to implement the actual timestamping. 535 * 536 * Should return timestamps conforming to the OML_sync_control OpenML 537 * extension specification. The timestamp corresponds to the end of 538 * the vblank interval, aka start of scanout of topmost-leftmost display 539 * pixel in the following video frame. 540 * 541 * Requires support for optional dev->driver->get_scanout_position() 542 * in kms driver, plus a bit of setup code to provide a drm_display_mode 543 * that corresponds to the true scanout timing. 544 * 545 * The current implementation only handles standard video modes. It 546 * returns as no operation if a doublescan or interlaced video mode is 547 * active. Higher level code is expected to handle this. 548 * 549 * @dev: DRM device. 550 * @crtc: Which crtc's vblank timestamp to retrieve. 551 * @max_error: Desired maximum allowable error in timestamps (nanosecs). 552 * On return contains true maximum error of timestamp. 553 * @vblank_time: Pointer to struct timeval which should receive the timestamp. 554 * @flags: Flags to pass to driver: 555 * 0 = Default. 556 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. 557 * @refcrtc: drm_crtc* of crtc which defines scanout timing. 558 * 559 * Returns negative value on error, failure or if not supported in current 560 * video mode: 561 * 562 * -EINVAL - Invalid crtc. 563 * -EAGAIN - Temporary unavailable, e.g., called before initial modeset. 564 * -ENOTSUPP - Function not supported in current display mode. 565 * -EIO - Failed, e.g., due to failed scanout position query. 566 * 567 * Returns or'ed positive status flags on success: 568 * 569 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping. 570 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval. 571 * 572 */ 573 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, 574 int *max_error, 575 struct timeval *vblank_time, 576 unsigned flags, 577 struct drm_crtc *refcrtc) 578 { 579 struct timeval stime, raw_time; 580 struct drm_display_mode *mode; 581 int vbl_status, vtotal, vdisplay; 582 int vpos, hpos, i; 583 s64 framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns; 584 bool invbl; 585 586 if (crtc < 0 || crtc >= dev->num_crtcs) { 587 DRM_ERROR("Invalid crtc %d\n", crtc); 588 return -EINVAL; 589 } 590 591 /* Scanout position query not supported? Should not happen. */ 592 if (!dev->driver->get_scanout_position) { 593 DRM_ERROR("Called from driver w/o get_scanout_position()!?\n"); 594 return -EIO; 595 } 596 597 mode = &refcrtc->hwmode; 598 vtotal = mode->crtc_vtotal; 599 vdisplay = mode->crtc_vdisplay; 600 601 /* Durations of frames, lines, pixels in nanoseconds. */ 602 framedur_ns = refcrtc->framedur_ns; 603 linedur_ns = refcrtc->linedur_ns; 604 pixeldur_ns = refcrtc->pixeldur_ns; 605 606 /* If mode timing undefined, just return as no-op: 607 * Happens during initial modesetting of a crtc. 608 */ 609 if (vtotal <= 0 || vdisplay <= 0 || framedur_ns == 0) { 610 DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc); 611 return -EAGAIN; 612 } 613 614 /* Get current scanout position with system timestamp. 615 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times 616 * if single query takes longer than max_error nanoseconds. 617 * 618 * This guarantees a tight bound on maximum error if 619 * code gets preempted or delayed for some reason. 620 */ 621 for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) { 622 /* Disable preemption to make it very likely to 623 * succeed in the first iteration even on PREEMPT_RT kernel. 624 */ 625 preempt_disable(); 626 627 /* Get system timestamp before query. */ 628 do_gettimeofday(&stime); 629 630 /* Get vertical and horizontal scanout pos. vpos, hpos. */ 631 vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos); 632 633 /* Get system timestamp after query. */ 634 do_gettimeofday(&raw_time); 635 636 preempt_enable(); 637 638 /* Return as no-op if scanout query unsupported or failed. */ 639 if (!(vbl_status & DRM_SCANOUTPOS_VALID)) { 640 DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n", 641 crtc, vbl_status); 642 return -EIO; 643 } 644 645 duration_ns = timeval_to_ns(&raw_time) - timeval_to_ns(&stime); 646 647 /* Accept result with < max_error nsecs timing uncertainty. */ 648 if (duration_ns <= (s64) *max_error) 649 break; 650 } 651 652 /* Noisy system timing? */ 653 if (i == DRM_TIMESTAMP_MAXRETRIES) { 654 DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n", 655 crtc, (int) duration_ns/1000, *max_error/1000, i); 656 } 657 658 /* Return upper bound of timestamp precision error. */ 659 *max_error = (int) duration_ns; 660 661 /* Check if in vblank area: 662 * vpos is >=0 in video scanout area, but negative 663 * within vblank area, counting down the number of lines until 664 * start of scanout. 665 */ 666 invbl = vbl_status & DRM_SCANOUTPOS_INVBL; 667 668 /* Convert scanout position into elapsed time at raw_time query 669 * since start of scanout at first display scanline. delta_ns 670 * can be negative if start of scanout hasn't happened yet. 671 */ 672 delta_ns = (s64) vpos * linedur_ns + (s64) hpos * pixeldur_ns; 673 674 /* Is vpos outside nominal vblank area, but less than 675 * 1/100 of a frame height away from start of vblank? 676 * If so, assume this isn't a massively delayed vblank 677 * interrupt, but a vblank interrupt that fired a few 678 * microseconds before true start of vblank. Compensate 679 * by adding a full frame duration to the final timestamp. 680 * Happens, e.g., on ATI R500, R600. 681 * 682 * We only do this if DRM_CALLED_FROM_VBLIRQ. 683 */ 684 if ((flags & DRM_CALLED_FROM_VBLIRQ) && !invbl && 685 ((vdisplay - vpos) < vtotal / 100)) { 686 delta_ns = delta_ns - framedur_ns; 687 688 /* Signal this correction as "applied". */ 689 vbl_status |= 0x8; 690 } 691 692 /* Subtract time delta from raw timestamp to get final 693 * vblank_time timestamp for end of vblank. 694 */ 695 *vblank_time = ns_to_timeval(timeval_to_ns(&raw_time) - delta_ns); 696 697 DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %d.%d -> %d.%d [e %d us, %d rep]\n", 698 crtc, (int) vbl_status, hpos, vpos, raw_time.tv_sec, 699 raw_time.tv_usec, vblank_time->tv_sec, vblank_time->tv_usec, 700 (int) duration_ns/1000, i); 701 702 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD; 703 if (invbl) 704 vbl_status |= DRM_VBLANKTIME_INVBL; 705 706 return vbl_status; 707 } 708 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos); 709 710 /** 711 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent 712 * vblank interval. 713 * 714 * @dev: DRM device 715 * @crtc: which crtc's vblank timestamp to retrieve 716 * @tvblank: Pointer to target struct timeval which should receive the timestamp 717 * @flags: Flags to pass to driver: 718 * 0 = Default. 719 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. 720 * 721 * Fetches the system timestamp corresponding to the time of the most recent 722 * vblank interval on specified crtc. May call into kms-driver to 723 * compute the timestamp with a high-precision GPU specific method. 724 * 725 * Returns zero if timestamp originates from uncorrected do_gettimeofday() 726 * call, i.e., it isn't very precisely locked to the true vblank. 727 * 728 * Returns non-zero if timestamp is considered to be very precise. 729 */ 730 u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc, 731 struct timeval *tvblank, unsigned flags) 732 { 733 int ret = 0; 734 735 /* Define requested maximum error on timestamps (nanoseconds). */ 736 int max_error = (int) drm_timestamp_precision * 1000; 737 738 /* Query driver if possible and precision timestamping enabled. */ 739 if (dev->driver->get_vblank_timestamp && (max_error > 0)) { 740 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error, 741 tvblank, flags); 742 if (ret > 0) 743 return (u32) ret; 744 } 745 746 /* GPU high precision timestamp query unsupported or failed. 747 * Return gettimeofday timestamp as best estimate. 748 */ 749 do_gettimeofday(tvblank); 750 751 return 0; 752 } 753 EXPORT_SYMBOL(drm_get_last_vbltimestamp); 754 755 /** 756 * drm_vblank_count - retrieve "cooked" vblank counter value 757 * @dev: DRM device 758 * @crtc: which counter to retrieve 759 * 760 * Fetches the "cooked" vblank count value that represents the number of 761 * vblank events since the system was booted, including lost events due to 762 * modesetting activity. 763 */ 764 u32 drm_vblank_count(struct drm_device *dev, int crtc) 765 { 766 return atomic_read(&dev->_vblank_count[crtc]); 767 } 768 EXPORT_SYMBOL(drm_vblank_count); 769 770 /** 771 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value 772 * and the system timestamp corresponding to that vblank counter value. 773 * 774 * @dev: DRM device 775 * @crtc: which counter to retrieve 776 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp. 777 * 778 * Fetches the "cooked" vblank count value that represents the number of 779 * vblank events since the system was booted, including lost events due to 780 * modesetting activity. Returns corresponding system timestamp of the time 781 * of the vblank interval that corresponds to the current value vblank counter 782 * value. 783 */ 784 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc, 785 struct timeval *vblanktime) 786 { 787 u32 cur_vblank; 788 789 /* Read timestamp from slot of _vblank_time ringbuffer 790 * that corresponds to current vblank count. Retry if 791 * count has incremented during readout. This works like 792 * a seqlock. 793 */ 794 do { 795 cur_vblank = atomic_read(&dev->_vblank_count[crtc]); 796 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank); 797 smp_rmb(); 798 } while (cur_vblank != atomic_read(&dev->_vblank_count[crtc])); 799 800 return cur_vblank; 801 } 802 EXPORT_SYMBOL(drm_vblank_count_and_time); 803 804 /** 805 * drm_update_vblank_count - update the master vblank counter 806 * @dev: DRM device 807 * @crtc: counter to update 808 * 809 * Call back into the driver to update the appropriate vblank counter 810 * (specified by @crtc). Deal with wraparound, if it occurred, and 811 * update the last read value so we can deal with wraparound on the next 812 * call if necessary. 813 * 814 * Only necessary when going from off->on, to account for frames we 815 * didn't get an interrupt for. 816 * 817 * Note: caller must hold dev->vbl_lock since this reads & writes 818 * device vblank fields. 819 */ 820 static void drm_update_vblank_count(struct drm_device *dev, int crtc) 821 { 822 u32 cur_vblank, diff, tslot, rc; 823 struct timeval t_vblank; 824 825 /* 826 * Interrupts were disabled prior to this call, so deal with counter 827 * wrap if needed. 828 * NOTE! It's possible we lost a full dev->max_vblank_count events 829 * here if the register is small or we had vblank interrupts off for 830 * a long time. 831 * 832 * We repeat the hardware vblank counter & timestamp query until 833 * we get consistent results. This to prevent races between gpu 834 * updating its hardware counter while we are retrieving the 835 * corresponding vblank timestamp. 836 */ 837 do { 838 cur_vblank = dev->driver->get_vblank_counter(dev, crtc); 839 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0); 840 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc)); 841 842 /* Deal with counter wrap */ 843 diff = cur_vblank - dev->last_vblank[crtc]; 844 if (cur_vblank < dev->last_vblank[crtc]) { 845 diff += dev->max_vblank_count; 846 847 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n", 848 crtc, dev->last_vblank[crtc], cur_vblank, diff); 849 } 850 851 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n", 852 crtc, diff); 853 854 /* Reinitialize corresponding vblank timestamp if high-precision query 855 * available. Skip this step if query unsupported or failed. Will 856 * reinitialize delayed at next vblank interrupt in that case. 857 */ 858 if (rc) { 859 tslot = atomic_read(&dev->_vblank_count[crtc]) + diff; 860 vblanktimestamp(dev, crtc, tslot) = t_vblank; 861 } 862 863 smp_mb__before_atomic_inc(); 864 atomic_add(diff, &dev->_vblank_count[crtc]); 865 smp_mb__after_atomic_inc(); 866 } 867 868 /** 869 * drm_vblank_get - get a reference count on vblank events 870 * @dev: DRM device 871 * @crtc: which CRTC to own 872 * 873 * Acquire a reference count on vblank events to avoid having them disabled 874 * while in use. 875 * 876 * RETURNS 877 * Zero on success, nonzero on failure. 878 */ 879 int drm_vblank_get(struct drm_device *dev, int crtc) 880 { 881 unsigned long irqflags, irqflags2; 882 int ret = 0; 883 884 spin_lock_irqsave(&dev->vbl_lock, irqflags); 885 /* Going from 0->1 means we have to enable interrupts again */ 886 if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) { 887 /* Disable preemption while holding vblank_time_lock. Do 888 * it explicitely to guard against PREEMPT_RT kernel. 889 */ 890 preempt_disable(); 891 spin_lock_irqsave(&dev->vblank_time_lock, irqflags2); 892 if (!dev->vblank_enabled[crtc]) { 893 /* Enable vblank irqs under vblank_time_lock protection. 894 * All vblank count & timestamp updates are held off 895 * until we are done reinitializing master counter and 896 * timestamps. Filtercode in drm_handle_vblank() will 897 * prevent double-accounting of same vblank interval. 898 */ 899 ret = dev->driver->enable_vblank(dev, crtc); 900 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", 901 crtc, ret); 902 if (ret) 903 atomic_dec(&dev->vblank_refcount[crtc]); 904 else { 905 dev->vblank_enabled[crtc] = 1; 906 drm_update_vblank_count(dev, crtc); 907 } 908 } 909 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2); 910 preempt_enable(); 911 } else { 912 if (!dev->vblank_enabled[crtc]) { 913 atomic_dec(&dev->vblank_refcount[crtc]); 914 ret = -EINVAL; 915 } 916 } 917 spin_unlock_irqrestore(&dev->vbl_lock, irqflags); 918 919 return ret; 920 } 921 EXPORT_SYMBOL(drm_vblank_get); 922 923 /** 924 * drm_vblank_put - give up ownership of vblank events 925 * @dev: DRM device 926 * @crtc: which counter to give up 927 * 928 * Release ownership of a given vblank counter, turning off interrupts 929 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds. 930 */ 931 void drm_vblank_put(struct drm_device *dev, int crtc) 932 { 933 BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0); 934 935 /* Last user schedules interrupt disable */ 936 if (atomic_dec_and_test(&dev->vblank_refcount[crtc]) && 937 (drm_vblank_offdelay > 0)) 938 mod_timer(&dev->vblank_disable_timer, 939 jiffies + ((drm_vblank_offdelay * DRM_HZ)/1000)); 940 } 941 EXPORT_SYMBOL(drm_vblank_put); 942 943 void drm_vblank_off(struct drm_device *dev, int crtc) 944 { 945 unsigned long irqflags; 946 947 spin_lock_irqsave(&dev->vbl_lock, irqflags); 948 vblank_disable_and_save(dev, crtc); 949 DRM_WAKEUP(&dev->vbl_queue[crtc]); 950 spin_unlock_irqrestore(&dev->vbl_lock, irqflags); 951 } 952 EXPORT_SYMBOL(drm_vblank_off); 953 954 /** 955 * drm_vblank_pre_modeset - account for vblanks across mode sets 956 * @dev: DRM device 957 * @crtc: CRTC in question 958 * @post: post or pre mode set? 959 * 960 * Account for vblank events across mode setting events, which will likely 961 * reset the hardware frame counter. 962 */ 963 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) 964 { 965 /* vblank is not initialized (IRQ not installed ?) */ 966 if (!dev->num_crtcs) 967 return; 968 /* 969 * To avoid all the problems that might happen if interrupts 970 * were enabled/disabled around or between these calls, we just 971 * have the kernel take a reference on the CRTC (just once though 972 * to avoid corrupting the count if multiple, mismatch calls occur), 973 * so that interrupts remain enabled in the interim. 974 */ 975 if (!dev->vblank_inmodeset[crtc]) { 976 dev->vblank_inmodeset[crtc] = 0x1; 977 if (drm_vblank_get(dev, crtc) == 0) 978 dev->vblank_inmodeset[crtc] |= 0x2; 979 } 980 } 981 EXPORT_SYMBOL(drm_vblank_pre_modeset); 982 983 void drm_vblank_post_modeset(struct drm_device *dev, int crtc) 984 { 985 unsigned long irqflags; 986 987 if (dev->vblank_inmodeset[crtc]) { 988 spin_lock_irqsave(&dev->vbl_lock, irqflags); 989 dev->vblank_disable_allowed = 1; 990 spin_unlock_irqrestore(&dev->vbl_lock, irqflags); 991 992 if (dev->vblank_inmodeset[crtc] & 0x2) 993 drm_vblank_put(dev, crtc); 994 995 dev->vblank_inmodeset[crtc] = 0; 996 } 997 } 998 EXPORT_SYMBOL(drm_vblank_post_modeset); 999 1000 /** 1001 * drm_modeset_ctl - handle vblank event counter changes across mode switch 1002 * @DRM_IOCTL_ARGS: standard ioctl arguments 1003 * 1004 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET 1005 * ioctls around modesetting so that any lost vblank events are accounted for. 1006 * 1007 * Generally the counter will reset across mode sets. If interrupts are 1008 * enabled around this call, we don't have to do anything since the counter 1009 * will have already been incremented. 1010 */ 1011 int drm_modeset_ctl(struct drm_device *dev, void *data, 1012 struct drm_file *file_priv) 1013 { 1014 struct drm_modeset_ctl *modeset = data; 1015 int ret = 0; 1016 unsigned int crtc; 1017 1018 /* If drm_vblank_init() hasn't been called yet, just no-op */ 1019 if (!dev->num_crtcs) 1020 goto out; 1021 1022 crtc = modeset->crtc; 1023 if (crtc >= dev->num_crtcs) { 1024 ret = -EINVAL; 1025 goto out; 1026 } 1027 1028 switch (modeset->cmd) { 1029 case _DRM_PRE_MODESET: 1030 drm_vblank_pre_modeset(dev, crtc); 1031 break; 1032 case _DRM_POST_MODESET: 1033 drm_vblank_post_modeset(dev, crtc); 1034 break; 1035 default: 1036 ret = -EINVAL; 1037 break; 1038 } 1039 1040 out: 1041 return ret; 1042 } 1043 1044 static int drm_queue_vblank_event(struct drm_device *dev, int pipe, 1045 union drm_wait_vblank *vblwait, 1046 struct drm_file *file_priv) 1047 { 1048 struct drm_pending_vblank_event *e; 1049 struct timeval now; 1050 unsigned long flags; 1051 unsigned int seq; 1052 int ret; 1053 1054 e = kzalloc(sizeof *e, GFP_KERNEL); 1055 if (e == NULL) { 1056 ret = -ENOMEM; 1057 goto err_put; 1058 } 1059 1060 e->pipe = pipe; 1061 e->base.pid = current->pid; 1062 e->event.base.type = DRM_EVENT_VBLANK; 1063 e->event.base.length = sizeof e->event; 1064 e->event.user_data = vblwait->request.signal; 1065 e->base.event = &e->event.base; 1066 e->base.file_priv = file_priv; 1067 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree; 1068 1069 spin_lock_irqsave(&dev->event_lock, flags); 1070 1071 if (file_priv->event_space < sizeof e->event) { 1072 ret = -EBUSY; 1073 goto err_unlock; 1074 } 1075 1076 file_priv->event_space -= sizeof e->event; 1077 seq = drm_vblank_count_and_time(dev, pipe, &now); 1078 1079 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) && 1080 (seq - vblwait->request.sequence) <= (1 << 23)) { 1081 vblwait->request.sequence = seq + 1; 1082 vblwait->reply.sequence = vblwait->request.sequence; 1083 } 1084 1085 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n", 1086 vblwait->request.sequence, seq, pipe); 1087 1088 trace_drm_vblank_event_queued(current->pid, pipe, 1089 vblwait->request.sequence); 1090 1091 e->event.sequence = vblwait->request.sequence; 1092 if ((seq - vblwait->request.sequence) <= (1 << 23)) { 1093 e->event.sequence = seq; 1094 e->event.tv_sec = now.tv_sec; 1095 e->event.tv_usec = now.tv_usec; 1096 drm_vblank_put(dev, pipe); 1097 list_add_tail(&e->base.link, &e->base.file_priv->event_list); 1098 wake_up_interruptible(&e->base.file_priv->event_wait); 1099 vblwait->reply.sequence = seq; 1100 trace_drm_vblank_event_delivered(current->pid, pipe, 1101 vblwait->request.sequence); 1102 } else { 1103 list_add_tail(&e->base.link, &dev->vblank_event_list); 1104 vblwait->reply.sequence = vblwait->request.sequence; 1105 } 1106 1107 spin_unlock_irqrestore(&dev->event_lock, flags); 1108 1109 return 0; 1110 1111 err_unlock: 1112 spin_unlock_irqrestore(&dev->event_lock, flags); 1113 kfree(e); 1114 err_put: 1115 drm_vblank_put(dev, pipe); 1116 return ret; 1117 } 1118 1119 /** 1120 * Wait for VBLANK. 1121 * 1122 * \param inode device inode. 1123 * \param file_priv DRM file private. 1124 * \param cmd command. 1125 * \param data user argument, pointing to a drm_wait_vblank structure. 1126 * \return zero on success or a negative number on failure. 1127 * 1128 * This function enables the vblank interrupt on the pipe requested, then 1129 * sleeps waiting for the requested sequence number to occur, and drops 1130 * the vblank interrupt refcount afterwards. (vblank irq disable follows that 1131 * after a timeout with no further vblank waits scheduled). 1132 */ 1133 int drm_wait_vblank(struct drm_device *dev, void *data, 1134 struct drm_file *file_priv) 1135 { 1136 union drm_wait_vblank *vblwait = data; 1137 int ret = 0; 1138 unsigned int flags, seq, crtc; 1139 1140 if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled)) 1141 return -EINVAL; 1142 1143 if (vblwait->request.type & _DRM_VBLANK_SIGNAL) 1144 return -EINVAL; 1145 1146 if (vblwait->request.type & 1147 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK)) { 1148 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n", 1149 vblwait->request.type, 1150 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK)); 1151 return -EINVAL; 1152 } 1153 1154 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK; 1155 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0; 1156 1157 if (crtc >= dev->num_crtcs) 1158 return -EINVAL; 1159 1160 ret = drm_vblank_get(dev, crtc); 1161 if (ret) { 1162 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret); 1163 return ret; 1164 } 1165 seq = drm_vblank_count(dev, crtc); 1166 1167 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) { 1168 case _DRM_VBLANK_RELATIVE: 1169 vblwait->request.sequence += seq; 1170 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE; 1171 case _DRM_VBLANK_ABSOLUTE: 1172 break; 1173 default: 1174 ret = -EINVAL; 1175 goto done; 1176 } 1177 1178 if (flags & _DRM_VBLANK_EVENT) 1179 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv); 1180 1181 if ((flags & _DRM_VBLANK_NEXTONMISS) && 1182 (seq - vblwait->request.sequence) <= (1<<23)) { 1183 vblwait->request.sequence = seq + 1; 1184 } 1185 1186 DRM_DEBUG("waiting on vblank count %d, crtc %d\n", 1187 vblwait->request.sequence, crtc); 1188 dev->last_vblank_wait[crtc] = vblwait->request.sequence; 1189 DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ, 1190 (((drm_vblank_count(dev, crtc) - 1191 vblwait->request.sequence) <= (1 << 23)) || 1192 !dev->irq_enabled)); 1193 1194 if (ret != -EINTR) { 1195 struct timeval now; 1196 1197 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now); 1198 vblwait->reply.tval_sec = now.tv_sec; 1199 vblwait->reply.tval_usec = now.tv_usec; 1200 1201 DRM_DEBUG("returning %d to client\n", 1202 vblwait->reply.sequence); 1203 } else { 1204 DRM_DEBUG("vblank wait interrupted by signal\n"); 1205 } 1206 1207 done: 1208 drm_vblank_put(dev, crtc); 1209 return ret; 1210 } 1211 1212 void drm_handle_vblank_events(struct drm_device *dev, int crtc) 1213 { 1214 struct drm_pending_vblank_event *e, *t; 1215 struct timeval now; 1216 unsigned long flags; 1217 unsigned int seq; 1218 1219 seq = drm_vblank_count_and_time(dev, crtc, &now); 1220 1221 spin_lock_irqsave(&dev->event_lock, flags); 1222 1223 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { 1224 if (e->pipe != crtc) 1225 continue; 1226 if ((seq - e->event.sequence) > (1<<23)) 1227 continue; 1228 1229 DRM_DEBUG("vblank event on %d, current %d\n", 1230 e->event.sequence, seq); 1231 1232 e->event.sequence = seq; 1233 e->event.tv_sec = now.tv_sec; 1234 e->event.tv_usec = now.tv_usec; 1235 drm_vblank_put(dev, e->pipe); 1236 list_move_tail(&e->base.link, &e->base.file_priv->event_list); 1237 wake_up_interruptible(&e->base.file_priv->event_wait); 1238 trace_drm_vblank_event_delivered(e->base.pid, e->pipe, 1239 e->event.sequence); 1240 } 1241 1242 spin_unlock_irqrestore(&dev->event_lock, flags); 1243 1244 trace_drm_vblank_event(crtc, seq); 1245 } 1246 1247 /** 1248 * drm_handle_vblank - handle a vblank event 1249 * @dev: DRM device 1250 * @crtc: where this event occurred 1251 * 1252 * Drivers should call this routine in their vblank interrupt handlers to 1253 * update the vblank counter and send any signals that may be pending. 1254 */ 1255 bool drm_handle_vblank(struct drm_device *dev, int crtc) 1256 { 1257 u32 vblcount; 1258 s64 diff_ns; 1259 struct timeval tvblank; 1260 unsigned long irqflags; 1261 1262 if (!dev->num_crtcs) 1263 return false; 1264 1265 /* Need timestamp lock to prevent concurrent execution with 1266 * vblank enable/disable, as this would cause inconsistent 1267 * or corrupted timestamps and vblank counts. 1268 */ 1269 spin_lock_irqsave(&dev->vblank_time_lock, irqflags); 1270 1271 /* Vblank irq handling disabled. Nothing to do. */ 1272 if (!dev->vblank_enabled[crtc]) { 1273 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); 1274 return false; 1275 } 1276 1277 /* Fetch corresponding timestamp for this vblank interval from 1278 * driver and store it in proper slot of timestamp ringbuffer. 1279 */ 1280 1281 /* Get current timestamp and count. */ 1282 vblcount = atomic_read(&dev->_vblank_count[crtc]); 1283 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ); 1284 1285 /* Compute time difference to timestamp of last vblank */ 1286 diff_ns = timeval_to_ns(&tvblank) - 1287 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); 1288 1289 /* Update vblank timestamp and count if at least 1290 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds 1291 * difference between last stored timestamp and current 1292 * timestamp. A smaller difference means basically 1293 * identical timestamps. Happens if this vblank has 1294 * been already processed and this is a redundant call, 1295 * e.g., due to spurious vblank interrupts. We need to 1296 * ignore those for accounting. 1297 */ 1298 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) { 1299 /* Store new timestamp in ringbuffer. */ 1300 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank; 1301 1302 /* Increment cooked vblank count. This also atomically commits 1303 * the timestamp computed above. 1304 */ 1305 smp_mb__before_atomic_inc(); 1306 atomic_inc(&dev->_vblank_count[crtc]); 1307 smp_mb__after_atomic_inc(); 1308 } else { 1309 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n", 1310 crtc, (int) diff_ns); 1311 } 1312 1313 DRM_WAKEUP(&dev->vbl_queue[crtc]); 1314 drm_handle_vblank_events(dev, crtc); 1315 1316 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); 1317 return true; 1318 } 1319 EXPORT_SYMBOL(drm_handle_vblank); 1320