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 (!dev->driver->bus->irq_by_busid) 78 return -EINVAL; 79 80 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 81 return -EINVAL; 82 83 return dev->driver->bus->irq_by_busid(dev, p); 84 } 85 86 /* 87 * Clear vblank timestamp buffer for a crtc. 88 */ 89 static void clear_vblank_timestamps(struct drm_device *dev, int crtc) 90 { 91 memset(&dev->_vblank_time[crtc * DRM_VBLANKTIME_RBSIZE], 0, 92 DRM_VBLANKTIME_RBSIZE * sizeof(struct timeval)); 93 } 94 95 /* 96 * Disable vblank irq's on crtc, make sure that last vblank count 97 * of hardware and corresponding consistent software vblank counter 98 * are preserved, even if there are any spurious vblank irq's after 99 * disable. 100 */ 101 static void vblank_disable_and_save(struct drm_device *dev, int crtc) 102 { 103 unsigned long irqflags; 104 u32 vblcount; 105 s64 diff_ns; 106 int vblrc; 107 struct timeval tvblank; 108 109 /* Prevent vblank irq processing while disabling vblank irqs, 110 * so no updates of timestamps or count can happen after we've 111 * disabled. Needed to prevent races in case of delayed irq's. 112 * Disable preemption, so vblank_time_lock is held as short as 113 * possible, even under a kernel with PREEMPT_RT patches. 114 */ 115 preempt_disable(); 116 spin_lock_irqsave(&dev->vblank_time_lock, irqflags); 117 118 dev->driver->disable_vblank(dev, crtc); 119 dev->vblank_enabled[crtc] = 0; 120 121 /* No further vblank irq's will be processed after 122 * this point. Get current hardware vblank count and 123 * vblank timestamp, repeat until they are consistent. 124 * 125 * FIXME: There is still a race condition here and in 126 * drm_update_vblank_count() which can cause off-by-one 127 * reinitialization of software vblank counter. If gpu 128 * vblank counter doesn't increment exactly at the leading 129 * edge of a vblank interval, then we can lose 1 count if 130 * we happen to execute between start of vblank and the 131 * delayed gpu counter increment. 132 */ 133 do { 134 dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc); 135 vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0); 136 } while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc)); 137 138 /* Compute time difference to stored timestamp of last vblank 139 * as updated by last invocation of drm_handle_vblank() in vblank irq. 140 */ 141 vblcount = atomic_read(&dev->_vblank_count[crtc]); 142 diff_ns = timeval_to_ns(&tvblank) - 143 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); 144 145 /* If there is at least 1 msec difference between the last stored 146 * timestamp and tvblank, then we are currently executing our 147 * disable inside a new vblank interval, the tvblank timestamp 148 * corresponds to this new vblank interval and the irq handler 149 * for this vblank didn't run yet and won't run due to our disable. 150 * Therefore we need to do the job of drm_handle_vblank() and 151 * increment the vblank counter by one to account for this vblank. 152 * 153 * Skip this step if there isn't any high precision timestamp 154 * available. In that case we can't account for this and just 155 * hope for the best. 156 */ 157 if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) { 158 atomic_inc(&dev->_vblank_count[crtc]); 159 smp_mb__after_atomic_inc(); 160 } 161 162 /* Invalidate all timestamps while vblank irq's are off. */ 163 clear_vblank_timestamps(dev, crtc); 164 165 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); 166 preempt_enable(); 167 } 168 169 static void vblank_disable_fn(unsigned long arg) 170 { 171 struct drm_device *dev = (struct drm_device *)arg; 172 unsigned long irqflags; 173 int i; 174 175 if (!dev->vblank_disable_allowed) 176 return; 177 178 for (i = 0; i < dev->num_crtcs; i++) { 179 spin_lock_irqsave(&dev->vbl_lock, irqflags); 180 if (atomic_read(&dev->vblank_refcount[i]) == 0 && 181 dev->vblank_enabled[i]) { 182 DRM_DEBUG("disabling vblank on crtc %d\n", i); 183 vblank_disable_and_save(dev, i); 184 } 185 spin_unlock_irqrestore(&dev->vbl_lock, irqflags); 186 } 187 } 188 189 void drm_vblank_cleanup(struct drm_device *dev) 190 { 191 /* Bail if the driver didn't call drm_vblank_init() */ 192 if (dev->num_crtcs == 0) 193 return; 194 195 del_timer(&dev->vblank_disable_timer); 196 197 vblank_disable_fn((unsigned long)dev); 198 199 kfree(dev->vbl_queue); 200 kfree(dev->_vblank_count); 201 kfree(dev->vblank_refcount); 202 kfree(dev->vblank_enabled); 203 kfree(dev->last_vblank); 204 kfree(dev->last_vblank_wait); 205 kfree(dev->vblank_inmodeset); 206 kfree(dev->_vblank_time); 207 208 dev->num_crtcs = 0; 209 } 210 EXPORT_SYMBOL(drm_vblank_cleanup); 211 212 int drm_vblank_init(struct drm_device *dev, int num_crtcs) 213 { 214 int i, ret = -ENOMEM; 215 216 setup_timer(&dev->vblank_disable_timer, vblank_disable_fn, 217 (unsigned long)dev); 218 spin_lock_init(&dev->vbl_lock); 219 spin_lock_init(&dev->vblank_time_lock); 220 221 dev->num_crtcs = num_crtcs; 222 223 dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs, 224 GFP_KERNEL); 225 if (!dev->vbl_queue) 226 goto err; 227 228 dev->_vblank_count = kmalloc(sizeof(atomic_t) * num_crtcs, GFP_KERNEL); 229 if (!dev->_vblank_count) 230 goto err; 231 232 dev->vblank_refcount = kmalloc(sizeof(atomic_t) * num_crtcs, 233 GFP_KERNEL); 234 if (!dev->vblank_refcount) 235 goto err; 236 237 dev->vblank_enabled = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL); 238 if (!dev->vblank_enabled) 239 goto err; 240 241 dev->last_vblank = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL); 242 if (!dev->last_vblank) 243 goto err; 244 245 dev->last_vblank_wait = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL); 246 if (!dev->last_vblank_wait) 247 goto err; 248 249 dev->vblank_inmodeset = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL); 250 if (!dev->vblank_inmodeset) 251 goto err; 252 253 dev->_vblank_time = kcalloc(num_crtcs * DRM_VBLANKTIME_RBSIZE, 254 sizeof(struct timeval), GFP_KERNEL); 255 if (!dev->_vblank_time) 256 goto err; 257 258 DRM_INFO("Supports vblank timestamp caching Rev 1 (10.10.2010).\n"); 259 260 /* Driver specific high-precision vblank timestamping supported? */ 261 if (dev->driver->get_vblank_timestamp) 262 DRM_INFO("Driver supports precise vblank timestamp query.\n"); 263 else 264 DRM_INFO("No driver support for vblank timestamp query.\n"); 265 266 /* Zero per-crtc vblank stuff */ 267 for (i = 0; i < num_crtcs; i++) { 268 init_waitqueue_head(&dev->vbl_queue[i]); 269 atomic_set(&dev->_vblank_count[i], 0); 270 atomic_set(&dev->vblank_refcount[i], 0); 271 } 272 273 dev->vblank_disable_allowed = 0; 274 return 0; 275 276 err: 277 drm_vblank_cleanup(dev); 278 return ret; 279 } 280 EXPORT_SYMBOL(drm_vblank_init); 281 282 static void drm_irq_vgaarb_nokms(void *cookie, bool state) 283 { 284 struct drm_device *dev = cookie; 285 286 if (dev->driver->vgaarb_irq) { 287 dev->driver->vgaarb_irq(dev, state); 288 return; 289 } 290 291 if (!dev->irq_enabled) 292 return; 293 294 if (state) { 295 if (dev->driver->irq_uninstall) 296 dev->driver->irq_uninstall(dev); 297 } else { 298 if (dev->driver->irq_preinstall) 299 dev->driver->irq_preinstall(dev); 300 if (dev->driver->irq_postinstall) 301 dev->driver->irq_postinstall(dev); 302 } 303 } 304 305 /** 306 * Install IRQ handler. 307 * 308 * \param dev DRM device. 309 * 310 * Initializes the IRQ related data. Installs the handler, calling the driver 311 * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions 312 * before and after the installation. 313 */ 314 int drm_irq_install(struct drm_device *dev) 315 { 316 int ret = 0; 317 unsigned long sh_flags = 0; 318 char *irqname; 319 320 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 321 return -EINVAL; 322 323 if (drm_dev_to_irq(dev) == 0) 324 return -EINVAL; 325 326 mutex_lock(&dev->struct_mutex); 327 328 /* Driver must have been initialized */ 329 if (!dev->dev_private) { 330 mutex_unlock(&dev->struct_mutex); 331 return -EINVAL; 332 } 333 334 if (dev->irq_enabled) { 335 mutex_unlock(&dev->struct_mutex); 336 return -EBUSY; 337 } 338 dev->irq_enabled = 1; 339 mutex_unlock(&dev->struct_mutex); 340 341 DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev)); 342 343 /* Before installing handler */ 344 if (dev->driver->irq_preinstall) 345 dev->driver->irq_preinstall(dev); 346 347 /* Install handler */ 348 if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED)) 349 sh_flags = IRQF_SHARED; 350 351 if (dev->devname) 352 irqname = dev->devname; 353 else 354 irqname = dev->driver->name; 355 356 ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler, 357 sh_flags, irqname, dev); 358 359 if (ret < 0) { 360 mutex_lock(&dev->struct_mutex); 361 dev->irq_enabled = 0; 362 mutex_unlock(&dev->struct_mutex); 363 return ret; 364 } 365 366 if (!drm_core_check_feature(dev, DRIVER_MODESET)) 367 vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL); 368 369 /* After installing handler */ 370 if (dev->driver->irq_postinstall) 371 ret = dev->driver->irq_postinstall(dev); 372 373 if (ret < 0) { 374 mutex_lock(&dev->struct_mutex); 375 dev->irq_enabled = 0; 376 mutex_unlock(&dev->struct_mutex); 377 if (!drm_core_check_feature(dev, DRIVER_MODESET)) 378 vga_client_register(dev->pdev, NULL, NULL, NULL); 379 free_irq(drm_dev_to_irq(dev), dev); 380 } 381 382 return ret; 383 } 384 EXPORT_SYMBOL(drm_irq_install); 385 386 /** 387 * Uninstall the IRQ handler. 388 * 389 * \param dev DRM device. 390 * 391 * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq. 392 */ 393 int drm_irq_uninstall(struct drm_device *dev) 394 { 395 unsigned long irqflags; 396 int irq_enabled, i; 397 398 if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) 399 return -EINVAL; 400 401 mutex_lock(&dev->struct_mutex); 402 irq_enabled = dev->irq_enabled; 403 dev->irq_enabled = 0; 404 mutex_unlock(&dev->struct_mutex); 405 406 /* 407 * Wake up any waiters so they don't hang. 408 */ 409 spin_lock_irqsave(&dev->vbl_lock, irqflags); 410 for (i = 0; i < dev->num_crtcs; i++) { 411 DRM_WAKEUP(&dev->vbl_queue[i]); 412 dev->vblank_enabled[i] = 0; 413 dev->last_vblank[i] = dev->driver->get_vblank_counter(dev, i); 414 } 415 spin_unlock_irqrestore(&dev->vbl_lock, irqflags); 416 417 if (!irq_enabled) 418 return -EINVAL; 419 420 DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev)); 421 422 if (!drm_core_check_feature(dev, DRIVER_MODESET)) 423 vga_client_register(dev->pdev, NULL, NULL, NULL); 424 425 if (dev->driver->irq_uninstall) 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)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n", 698 crtc, (int)vbl_status, hpos, vpos, 699 (long)raw_time.tv_sec, (long)raw_time.tv_usec, 700 (long)vblank_time->tv_sec, (long)vblank_time->tv_usec, 701 (int)duration_ns/1000, i); 702 703 vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD; 704 if (invbl) 705 vbl_status |= DRM_VBLANKTIME_INVBL; 706 707 return vbl_status; 708 } 709 EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos); 710 711 /** 712 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent 713 * vblank interval. 714 * 715 * @dev: DRM device 716 * @crtc: which crtc's vblank timestamp to retrieve 717 * @tvblank: Pointer to target struct timeval which should receive the timestamp 718 * @flags: Flags to pass to driver: 719 * 0 = Default. 720 * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. 721 * 722 * Fetches the system timestamp corresponding to the time of the most recent 723 * vblank interval on specified crtc. May call into kms-driver to 724 * compute the timestamp with a high-precision GPU specific method. 725 * 726 * Returns zero if timestamp originates from uncorrected do_gettimeofday() 727 * call, i.e., it isn't very precisely locked to the true vblank. 728 * 729 * Returns non-zero if timestamp is considered to be very precise. 730 */ 731 u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc, 732 struct timeval *tvblank, unsigned flags) 733 { 734 int ret = 0; 735 736 /* Define requested maximum error on timestamps (nanoseconds). */ 737 int max_error = (int) drm_timestamp_precision * 1000; 738 739 /* Query driver if possible and precision timestamping enabled. */ 740 if (dev->driver->get_vblank_timestamp && (max_error > 0)) { 741 ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error, 742 tvblank, flags); 743 if (ret > 0) 744 return (u32) ret; 745 } 746 747 /* GPU high precision timestamp query unsupported or failed. 748 * Return gettimeofday timestamp as best estimate. 749 */ 750 do_gettimeofday(tvblank); 751 752 return 0; 753 } 754 EXPORT_SYMBOL(drm_get_last_vbltimestamp); 755 756 /** 757 * drm_vblank_count - retrieve "cooked" vblank counter value 758 * @dev: DRM device 759 * @crtc: which counter to retrieve 760 * 761 * Fetches the "cooked" vblank count value that represents the number of 762 * vblank events since the system was booted, including lost events due to 763 * modesetting activity. 764 */ 765 u32 drm_vblank_count(struct drm_device *dev, int crtc) 766 { 767 return atomic_read(&dev->_vblank_count[crtc]); 768 } 769 EXPORT_SYMBOL(drm_vblank_count); 770 771 /** 772 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value 773 * and the system timestamp corresponding to that vblank counter value. 774 * 775 * @dev: DRM device 776 * @crtc: which counter to retrieve 777 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp. 778 * 779 * Fetches the "cooked" vblank count value that represents the number of 780 * vblank events since the system was booted, including lost events due to 781 * modesetting activity. Returns corresponding system timestamp of the time 782 * of the vblank interval that corresponds to the current value vblank counter 783 * value. 784 */ 785 u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc, 786 struct timeval *vblanktime) 787 { 788 u32 cur_vblank; 789 790 /* Read timestamp from slot of _vblank_time ringbuffer 791 * that corresponds to current vblank count. Retry if 792 * count has incremented during readout. This works like 793 * a seqlock. 794 */ 795 do { 796 cur_vblank = atomic_read(&dev->_vblank_count[crtc]); 797 *vblanktime = vblanktimestamp(dev, crtc, cur_vblank); 798 smp_rmb(); 799 } while (cur_vblank != atomic_read(&dev->_vblank_count[crtc])); 800 801 return cur_vblank; 802 } 803 EXPORT_SYMBOL(drm_vblank_count_and_time); 804 805 /** 806 * drm_update_vblank_count - update the master vblank counter 807 * @dev: DRM device 808 * @crtc: counter to update 809 * 810 * Call back into the driver to update the appropriate vblank counter 811 * (specified by @crtc). Deal with wraparound, if it occurred, and 812 * update the last read value so we can deal with wraparound on the next 813 * call if necessary. 814 * 815 * Only necessary when going from off->on, to account for frames we 816 * didn't get an interrupt for. 817 * 818 * Note: caller must hold dev->vbl_lock since this reads & writes 819 * device vblank fields. 820 */ 821 static void drm_update_vblank_count(struct drm_device *dev, int crtc) 822 { 823 u32 cur_vblank, diff, tslot, rc; 824 struct timeval t_vblank; 825 826 /* 827 * Interrupts were disabled prior to this call, so deal with counter 828 * wrap if needed. 829 * NOTE! It's possible we lost a full dev->max_vblank_count events 830 * here if the register is small or we had vblank interrupts off for 831 * a long time. 832 * 833 * We repeat the hardware vblank counter & timestamp query until 834 * we get consistent results. This to prevent races between gpu 835 * updating its hardware counter while we are retrieving the 836 * corresponding vblank timestamp. 837 */ 838 do { 839 cur_vblank = dev->driver->get_vblank_counter(dev, crtc); 840 rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0); 841 } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc)); 842 843 /* Deal with counter wrap */ 844 diff = cur_vblank - dev->last_vblank[crtc]; 845 if (cur_vblank < dev->last_vblank[crtc]) { 846 diff += dev->max_vblank_count; 847 848 DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n", 849 crtc, dev->last_vblank[crtc], cur_vblank, diff); 850 } 851 852 DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n", 853 crtc, diff); 854 855 /* Reinitialize corresponding vblank timestamp if high-precision query 856 * available. Skip this step if query unsupported or failed. Will 857 * reinitialize delayed at next vblank interrupt in that case. 858 */ 859 if (rc) { 860 tslot = atomic_read(&dev->_vblank_count[crtc]) + diff; 861 vblanktimestamp(dev, crtc, tslot) = t_vblank; 862 } 863 864 smp_mb__before_atomic_inc(); 865 atomic_add(diff, &dev->_vblank_count[crtc]); 866 smp_mb__after_atomic_inc(); 867 } 868 869 /** 870 * drm_vblank_get - get a reference count on vblank events 871 * @dev: DRM device 872 * @crtc: which CRTC to own 873 * 874 * Acquire a reference count on vblank events to avoid having them disabled 875 * while in use. 876 * 877 * RETURNS 878 * Zero on success, nonzero on failure. 879 */ 880 int drm_vblank_get(struct drm_device *dev, int crtc) 881 { 882 unsigned long irqflags, irqflags2; 883 int ret = 0; 884 885 spin_lock_irqsave(&dev->vbl_lock, irqflags); 886 /* Going from 0->1 means we have to enable interrupts again */ 887 if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) { 888 /* Disable preemption while holding vblank_time_lock. Do 889 * it explicitely to guard against PREEMPT_RT kernel. 890 */ 891 preempt_disable(); 892 spin_lock_irqsave(&dev->vblank_time_lock, irqflags2); 893 if (!dev->vblank_enabled[crtc]) { 894 /* Enable vblank irqs under vblank_time_lock protection. 895 * All vblank count & timestamp updates are held off 896 * until we are done reinitializing master counter and 897 * timestamps. Filtercode in drm_handle_vblank() will 898 * prevent double-accounting of same vblank interval. 899 */ 900 ret = dev->driver->enable_vblank(dev, crtc); 901 DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", 902 crtc, ret); 903 if (ret) 904 atomic_dec(&dev->vblank_refcount[crtc]); 905 else { 906 dev->vblank_enabled[crtc] = 1; 907 drm_update_vblank_count(dev, crtc); 908 } 909 } 910 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2); 911 preempt_enable(); 912 } else { 913 if (!dev->vblank_enabled[crtc]) { 914 atomic_dec(&dev->vblank_refcount[crtc]); 915 ret = -EINVAL; 916 } 917 } 918 spin_unlock_irqrestore(&dev->vbl_lock, irqflags); 919 920 return ret; 921 } 922 EXPORT_SYMBOL(drm_vblank_get); 923 924 /** 925 * drm_vblank_put - give up ownership of vblank events 926 * @dev: DRM device 927 * @crtc: which counter to give up 928 * 929 * Release ownership of a given vblank counter, turning off interrupts 930 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds. 931 */ 932 void drm_vblank_put(struct drm_device *dev, int crtc) 933 { 934 BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0); 935 936 /* Last user schedules interrupt disable */ 937 if (atomic_dec_and_test(&dev->vblank_refcount[crtc]) && 938 (drm_vblank_offdelay > 0)) 939 mod_timer(&dev->vblank_disable_timer, 940 jiffies + ((drm_vblank_offdelay * DRM_HZ)/1000)); 941 } 942 EXPORT_SYMBOL(drm_vblank_put); 943 944 void drm_vblank_off(struct drm_device *dev, int crtc) 945 { 946 struct drm_pending_vblank_event *e, *t; 947 struct timeval now; 948 unsigned long irqflags; 949 unsigned int seq; 950 951 spin_lock_irqsave(&dev->vbl_lock, irqflags); 952 vblank_disable_and_save(dev, crtc); 953 DRM_WAKEUP(&dev->vbl_queue[crtc]); 954 955 /* Send any queued vblank events, lest the natives grow disquiet */ 956 seq = drm_vblank_count_and_time(dev, crtc, &now); 957 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { 958 if (e->pipe != crtc) 959 continue; 960 DRM_DEBUG("Sending premature vblank event on disable: \ 961 wanted %d, current %d\n", 962 e->event.sequence, seq); 963 964 e->event.sequence = seq; 965 e->event.tv_sec = now.tv_sec; 966 e->event.tv_usec = now.tv_usec; 967 drm_vblank_put(dev, e->pipe); 968 list_move_tail(&e->base.link, &e->base.file_priv->event_list); 969 wake_up_interruptible(&e->base.file_priv->event_wait); 970 trace_drm_vblank_event_delivered(e->base.pid, e->pipe, 971 e->event.sequence); 972 } 973 974 spin_unlock_irqrestore(&dev->vbl_lock, irqflags); 975 } 976 EXPORT_SYMBOL(drm_vblank_off); 977 978 /** 979 * drm_vblank_pre_modeset - account for vblanks across mode sets 980 * @dev: DRM device 981 * @crtc: CRTC in question 982 * @post: post or pre mode set? 983 * 984 * Account for vblank events across mode setting events, which will likely 985 * reset the hardware frame counter. 986 */ 987 void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) 988 { 989 /* vblank is not initialized (IRQ not installed ?) */ 990 if (!dev->num_crtcs) 991 return; 992 /* 993 * To avoid all the problems that might happen if interrupts 994 * were enabled/disabled around or between these calls, we just 995 * have the kernel take a reference on the CRTC (just once though 996 * to avoid corrupting the count if multiple, mismatch calls occur), 997 * so that interrupts remain enabled in the interim. 998 */ 999 if (!dev->vblank_inmodeset[crtc]) { 1000 dev->vblank_inmodeset[crtc] = 0x1; 1001 if (drm_vblank_get(dev, crtc) == 0) 1002 dev->vblank_inmodeset[crtc] |= 0x2; 1003 } 1004 } 1005 EXPORT_SYMBOL(drm_vblank_pre_modeset); 1006 1007 void drm_vblank_post_modeset(struct drm_device *dev, int crtc) 1008 { 1009 unsigned long irqflags; 1010 1011 if (dev->vblank_inmodeset[crtc]) { 1012 spin_lock_irqsave(&dev->vbl_lock, irqflags); 1013 dev->vblank_disable_allowed = 1; 1014 spin_unlock_irqrestore(&dev->vbl_lock, irqflags); 1015 1016 if (dev->vblank_inmodeset[crtc] & 0x2) 1017 drm_vblank_put(dev, crtc); 1018 1019 dev->vblank_inmodeset[crtc] = 0; 1020 } 1021 } 1022 EXPORT_SYMBOL(drm_vblank_post_modeset); 1023 1024 /** 1025 * drm_modeset_ctl - handle vblank event counter changes across mode switch 1026 * @DRM_IOCTL_ARGS: standard ioctl arguments 1027 * 1028 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET 1029 * ioctls around modesetting so that any lost vblank events are accounted for. 1030 * 1031 * Generally the counter will reset across mode sets. If interrupts are 1032 * enabled around this call, we don't have to do anything since the counter 1033 * will have already been incremented. 1034 */ 1035 int drm_modeset_ctl(struct drm_device *dev, void *data, 1036 struct drm_file *file_priv) 1037 { 1038 struct drm_modeset_ctl *modeset = data; 1039 int ret = 0; 1040 unsigned int crtc; 1041 1042 /* If drm_vblank_init() hasn't been called yet, just no-op */ 1043 if (!dev->num_crtcs) 1044 goto out; 1045 1046 crtc = modeset->crtc; 1047 if (crtc >= dev->num_crtcs) { 1048 ret = -EINVAL; 1049 goto out; 1050 } 1051 1052 switch (modeset->cmd) { 1053 case _DRM_PRE_MODESET: 1054 drm_vblank_pre_modeset(dev, crtc); 1055 break; 1056 case _DRM_POST_MODESET: 1057 drm_vblank_post_modeset(dev, crtc); 1058 break; 1059 default: 1060 ret = -EINVAL; 1061 break; 1062 } 1063 1064 out: 1065 return ret; 1066 } 1067 1068 static int drm_queue_vblank_event(struct drm_device *dev, int pipe, 1069 union drm_wait_vblank *vblwait, 1070 struct drm_file *file_priv) 1071 { 1072 struct drm_pending_vblank_event *e; 1073 struct timeval now; 1074 unsigned long flags; 1075 unsigned int seq; 1076 int ret; 1077 1078 e = kzalloc(sizeof *e, GFP_KERNEL); 1079 if (e == NULL) { 1080 ret = -ENOMEM; 1081 goto err_put; 1082 } 1083 1084 e->pipe = pipe; 1085 e->base.pid = current->pid; 1086 e->event.base.type = DRM_EVENT_VBLANK; 1087 e->event.base.length = sizeof e->event; 1088 e->event.user_data = vblwait->request.signal; 1089 e->base.event = &e->event.base; 1090 e->base.file_priv = file_priv; 1091 e->base.destroy = (void (*) (struct drm_pending_event *)) kfree; 1092 1093 spin_lock_irqsave(&dev->event_lock, flags); 1094 1095 if (file_priv->event_space < sizeof e->event) { 1096 ret = -EBUSY; 1097 goto err_unlock; 1098 } 1099 1100 file_priv->event_space -= sizeof e->event; 1101 seq = drm_vblank_count_and_time(dev, pipe, &now); 1102 1103 if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) && 1104 (seq - vblwait->request.sequence) <= (1 << 23)) { 1105 vblwait->request.sequence = seq + 1; 1106 vblwait->reply.sequence = vblwait->request.sequence; 1107 } 1108 1109 DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n", 1110 vblwait->request.sequence, seq, pipe); 1111 1112 trace_drm_vblank_event_queued(current->pid, pipe, 1113 vblwait->request.sequence); 1114 1115 e->event.sequence = vblwait->request.sequence; 1116 if ((seq - vblwait->request.sequence) <= (1 << 23)) { 1117 e->event.sequence = seq; 1118 e->event.tv_sec = now.tv_sec; 1119 e->event.tv_usec = now.tv_usec; 1120 drm_vblank_put(dev, pipe); 1121 list_add_tail(&e->base.link, &e->base.file_priv->event_list); 1122 wake_up_interruptible(&e->base.file_priv->event_wait); 1123 vblwait->reply.sequence = seq; 1124 trace_drm_vblank_event_delivered(current->pid, pipe, 1125 vblwait->request.sequence); 1126 } else { 1127 list_add_tail(&e->base.link, &dev->vblank_event_list); 1128 vblwait->reply.sequence = vblwait->request.sequence; 1129 } 1130 1131 spin_unlock_irqrestore(&dev->event_lock, flags); 1132 1133 return 0; 1134 1135 err_unlock: 1136 spin_unlock_irqrestore(&dev->event_lock, flags); 1137 kfree(e); 1138 err_put: 1139 drm_vblank_put(dev, pipe); 1140 return ret; 1141 } 1142 1143 /** 1144 * Wait for VBLANK. 1145 * 1146 * \param inode device inode. 1147 * \param file_priv DRM file private. 1148 * \param cmd command. 1149 * \param data user argument, pointing to a drm_wait_vblank structure. 1150 * \return zero on success or a negative number on failure. 1151 * 1152 * This function enables the vblank interrupt on the pipe requested, then 1153 * sleeps waiting for the requested sequence number to occur, and drops 1154 * the vblank interrupt refcount afterwards. (vblank irq disable follows that 1155 * after a timeout with no further vblank waits scheduled). 1156 */ 1157 int drm_wait_vblank(struct drm_device *dev, void *data, 1158 struct drm_file *file_priv) 1159 { 1160 union drm_wait_vblank *vblwait = data; 1161 int ret = 0; 1162 unsigned int flags, seq, crtc, high_crtc; 1163 1164 if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled)) 1165 return -EINVAL; 1166 1167 if (vblwait->request.type & _DRM_VBLANK_SIGNAL) 1168 return -EINVAL; 1169 1170 if (vblwait->request.type & 1171 ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | 1172 _DRM_VBLANK_HIGH_CRTC_MASK)) { 1173 DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n", 1174 vblwait->request.type, 1175 (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | 1176 _DRM_VBLANK_HIGH_CRTC_MASK)); 1177 return -EINVAL; 1178 } 1179 1180 flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK; 1181 high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK); 1182 if (high_crtc) 1183 crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT; 1184 else 1185 crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0; 1186 if (crtc >= dev->num_crtcs) 1187 return -EINVAL; 1188 1189 ret = drm_vblank_get(dev, crtc); 1190 if (ret) { 1191 DRM_DEBUG("failed to acquire vblank counter, %d\n", ret); 1192 return ret; 1193 } 1194 seq = drm_vblank_count(dev, crtc); 1195 1196 switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) { 1197 case _DRM_VBLANK_RELATIVE: 1198 vblwait->request.sequence += seq; 1199 vblwait->request.type &= ~_DRM_VBLANK_RELATIVE; 1200 case _DRM_VBLANK_ABSOLUTE: 1201 break; 1202 default: 1203 ret = -EINVAL; 1204 goto done; 1205 } 1206 1207 if (flags & _DRM_VBLANK_EVENT) 1208 return drm_queue_vblank_event(dev, crtc, vblwait, file_priv); 1209 1210 if ((flags & _DRM_VBLANK_NEXTONMISS) && 1211 (seq - vblwait->request.sequence) <= (1<<23)) { 1212 vblwait->request.sequence = seq + 1; 1213 } 1214 1215 DRM_DEBUG("waiting on vblank count %d, crtc %d\n", 1216 vblwait->request.sequence, crtc); 1217 dev->last_vblank_wait[crtc] = vblwait->request.sequence; 1218 DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ, 1219 (((drm_vblank_count(dev, crtc) - 1220 vblwait->request.sequence) <= (1 << 23)) || 1221 !dev->irq_enabled)); 1222 1223 if (ret != -EINTR) { 1224 struct timeval now; 1225 1226 vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now); 1227 vblwait->reply.tval_sec = now.tv_sec; 1228 vblwait->reply.tval_usec = now.tv_usec; 1229 1230 DRM_DEBUG("returning %d to client\n", 1231 vblwait->reply.sequence); 1232 } else { 1233 DRM_DEBUG("vblank wait interrupted by signal\n"); 1234 } 1235 1236 done: 1237 drm_vblank_put(dev, crtc); 1238 return ret; 1239 } 1240 1241 void drm_handle_vblank_events(struct drm_device *dev, int crtc) 1242 { 1243 struct drm_pending_vblank_event *e, *t; 1244 struct timeval now; 1245 unsigned long flags; 1246 unsigned int seq; 1247 1248 seq = drm_vblank_count_and_time(dev, crtc, &now); 1249 1250 spin_lock_irqsave(&dev->event_lock, flags); 1251 1252 list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { 1253 if (e->pipe != crtc) 1254 continue; 1255 if ((seq - e->event.sequence) > (1<<23)) 1256 continue; 1257 1258 DRM_DEBUG("vblank event on %d, current %d\n", 1259 e->event.sequence, seq); 1260 1261 e->event.sequence = seq; 1262 e->event.tv_sec = now.tv_sec; 1263 e->event.tv_usec = now.tv_usec; 1264 drm_vblank_put(dev, e->pipe); 1265 list_move_tail(&e->base.link, &e->base.file_priv->event_list); 1266 wake_up_interruptible(&e->base.file_priv->event_wait); 1267 trace_drm_vblank_event_delivered(e->base.pid, e->pipe, 1268 e->event.sequence); 1269 } 1270 1271 spin_unlock_irqrestore(&dev->event_lock, flags); 1272 1273 trace_drm_vblank_event(crtc, seq); 1274 } 1275 1276 /** 1277 * drm_handle_vblank - handle a vblank event 1278 * @dev: DRM device 1279 * @crtc: where this event occurred 1280 * 1281 * Drivers should call this routine in their vblank interrupt handlers to 1282 * update the vblank counter and send any signals that may be pending. 1283 */ 1284 bool drm_handle_vblank(struct drm_device *dev, int crtc) 1285 { 1286 u32 vblcount; 1287 s64 diff_ns; 1288 struct timeval tvblank; 1289 unsigned long irqflags; 1290 1291 if (!dev->num_crtcs) 1292 return false; 1293 1294 /* Need timestamp lock to prevent concurrent execution with 1295 * vblank enable/disable, as this would cause inconsistent 1296 * or corrupted timestamps and vblank counts. 1297 */ 1298 spin_lock_irqsave(&dev->vblank_time_lock, irqflags); 1299 1300 /* Vblank irq handling disabled. Nothing to do. */ 1301 if (!dev->vblank_enabled[crtc]) { 1302 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); 1303 return false; 1304 } 1305 1306 /* Fetch corresponding timestamp for this vblank interval from 1307 * driver and store it in proper slot of timestamp ringbuffer. 1308 */ 1309 1310 /* Get current timestamp and count. */ 1311 vblcount = atomic_read(&dev->_vblank_count[crtc]); 1312 drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ); 1313 1314 /* Compute time difference to timestamp of last vblank */ 1315 diff_ns = timeval_to_ns(&tvblank) - 1316 timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); 1317 1318 /* Update vblank timestamp and count if at least 1319 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds 1320 * difference between last stored timestamp and current 1321 * timestamp. A smaller difference means basically 1322 * identical timestamps. Happens if this vblank has 1323 * been already processed and this is a redundant call, 1324 * e.g., due to spurious vblank interrupts. We need to 1325 * ignore those for accounting. 1326 */ 1327 if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) { 1328 /* Store new timestamp in ringbuffer. */ 1329 vblanktimestamp(dev, crtc, vblcount + 1) = tvblank; 1330 1331 /* Increment cooked vblank count. This also atomically commits 1332 * the timestamp computed above. 1333 */ 1334 smp_mb__before_atomic_inc(); 1335 atomic_inc(&dev->_vblank_count[crtc]); 1336 smp_mb__after_atomic_inc(); 1337 } else { 1338 DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n", 1339 crtc, (int) diff_ns); 1340 } 1341 1342 DRM_WAKEUP(&dev->vbl_queue[crtc]); 1343 drm_handle_vblank_events(dev, crtc); 1344 1345 spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); 1346 return true; 1347 } 1348 EXPORT_SYMBOL(drm_handle_vblank); 1349