drivers/gpu/drm/i915/display/intel_hotplug.c

   1 /*
   2  * Copyright © 2015 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #include <linux/kernel.h>
  25
  26 #include "i915_drv.h"
  27 #include "i915_irq.h"
  28 #include "intel_display_types.h"
  29 #include "intel_hotplug.h"
  30 #include "intel_hotplug_irq.h"
  31
  32 /**
  33  * DOC: Hotplug
  34  *
  35  * Simply put, hotplug occurs when a display is connected to or disconnected
  36  * from the system. However, there may be adapters and docking stations and
  37  * Display Port short pulses and MST devices involved, complicating matters.
  38  *
  39  * Hotplug in i915 is handled in many different levels of abstraction.
  40  *
  41  * The platform dependent interrupt handling code in i915_irq.c enables,
  42  * disables, and does preliminary handling of the interrupts. The interrupt
  43  * handlers gather the hotplug detect (HPD) information from relevant registers
  44  * into a platform independent mask of hotplug pins that have fired.
  45  *
  46  * The platform independent interrupt handler intel_hpd_irq_handler() in
  47  * intel_hotplug.c does hotplug irq storm detection and mitigation, and passes
  48  * further processing to appropriate bottom halves (Display Port specific and
  49  * regular hotplug).
  50  *
  51  * The Display Port work function i915_digport_work_func() calls into
  52  * intel_dp_hpd_pulse() via hooks, which handles DP short pulses and DP MST long
  53  * pulses, with failures and non-MST long pulses triggering regular hotplug
  54  * processing on the connector.
  55  *
  56  * The regular hotplug work function i915_hotplug_work_func() calls connector
  57  * detect hooks, and, if connector status changes, triggers sending of hotplug
  58  * uevent to userspace via drm_kms_helper_hotplug_event().
  59  *
  60  * Finally, the userspace is responsible for triggering a modeset upon receiving
  61  * the hotplug uevent, disabling or enabling the crtc as needed.
  62  *
  63  * The hotplug interrupt storm detection and mitigation code keeps track of the
  64  * number of interrupts per hotplug pin per a period of time, and if the number
  65  * of interrupts exceeds a certain threshold, the interrupt is disabled for a
  66  * while before being re-enabled. The intention is to mitigate issues raising
  67  * from broken hardware triggering massive amounts of interrupts and grinding
  68  * the system to a halt.
  69  *
  70  * Current implementation expects that hotplug interrupt storm will not be
  71  * seen when display port sink is connected, hence on platforms whose DP
  72  * callback is handled by i915_digport_work_func reenabling of hpd is not
  73  * performed (it was never expected to be disabled in the first place ;) )
  74  * this is specific to DP sinks handled by this routine and any other display
  75  * such as HDMI or DVI enabled on the same port will have proper logic since
  76  * it will use i915_hotplug_work_func where this logic is handled.
  77  */
  78
  79 /**
  80  * intel_hpd_pin_default - return default pin associated with certain port.
  81  * @dev_priv: private driver data pointer
  82  * @port: the hpd port to get associated pin
  83  *
  84  * It is only valid and used by digital port encoder.
  85  *
  86  * Return pin that is associatade with @port.
  87  */
  88 enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
  89                                    enum port port)
  90 {
  91         return HPD_PORT_A + port - PORT_A;
  92 }
  93
  94 /* Threshold == 5 for long IRQs, 50 for short */
  95 #define HPD_STORM_DEFAULT_THRESHOLD     50
  96
  97 #define HPD_STORM_DETECT_PERIOD         1000
  98 #define HPD_STORM_REENABLE_DELAY        (2 * 60 * 1000)
  99 #define HPD_RETRY_DELAY                 1000
 100
 101 static enum hpd_pin
 102 intel_connector_hpd_pin(struct intel_connector *connector)
 103 {
 104         struct intel_encoder *encoder = intel_attached_encoder(connector);
 105
 106         /*
 107          * MST connectors get their encoder attached dynamically
 108          * so need to make sure we have an encoder here. But since
 109          * MST encoders have their hpd_pin set to HPD_NONE we don't
 110          * have to special case them beyond that.
 111          */
 112         return encoder ? encoder->hpd_pin : HPD_NONE;
 113 }
 114
 115 /**
 116  * intel_hpd_irq_storm_detect - gather stats and detect HPD IRQ storm on a pin
 117  * @dev_priv: private driver data pointer
 118  * @pin: the pin to gather stats on
 119  * @long_hpd: whether the HPD IRQ was long or short
 120  *
 121  * Gather stats about HPD IRQs from the specified @pin, and detect IRQ
 122  * storms. Only the pin specific stats and state are changed, the caller is
 123  * responsible for further action.
 124  *
 125  * The number of IRQs that are allowed within @HPD_STORM_DETECT_PERIOD is
 126  * stored in @dev_priv->display.hotplug.hpd_storm_threshold which defaults to
 127  * @HPD_STORM_DEFAULT_THRESHOLD. Long IRQs count as +10 to this threshold, and
 128  * short IRQs count as +1. If this threshold is exceeded, it's considered an
 129  * IRQ storm and the IRQ state is set to @HPD_MARK_DISABLED.
 130  *
 131  * By default, most systems will only count long IRQs towards
 132  * &dev_priv->display.hotplug.hpd_storm_threshold. However, some older systems also
 133  * suffer from short IRQ storms and must also track these. Because short IRQ
 134  * storms are naturally caused by sideband interactions with DP MST devices,
 135  * short IRQ detection is only enabled for systems without DP MST support.
 136  * Systems which are new enough to support DP MST are far less likely to
 137  * suffer from IRQ storms at all, so this is fine.
 138  *
 139  * The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
 140  * and should only be adjusted for automated hotplug testing.
 141  *
 142  * Return true if an IRQ storm was detected on @pin.
 143  */
 144 static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
 145                                        enum hpd_pin pin, bool long_hpd)
 146 {
 147         struct intel_hotplug *hpd = &dev_priv->display.hotplug;
 148         unsigned long start = hpd->stats[pin].last_jiffies;
 149         unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
 150         const int increment = long_hpd ? 10 : 1;
 151         const int threshold = hpd->hpd_storm_threshold;
 152         bool storm = false;
 153
 154         if (!threshold ||
 155             (!long_hpd && !dev_priv->display.hotplug.hpd_short_storm_enabled))
 156                 return false;
 157
 158         if (!time_in_range(jiffies, start, end)) {
 159                 hpd->stats[pin].last_jiffies = jiffies;
 160                 hpd->stats[pin].count = 0;
 161         }
 162
 163         hpd->stats[pin].count += increment;
 164         if (hpd->stats[pin].count > threshold) {
 165                 hpd->stats[pin].state = HPD_MARK_DISABLED;
 166                 drm_dbg_kms(&dev_priv->drm,
 167                             "HPD interrupt storm detected on PIN %d\n", pin);
 168                 storm = true;
 169         } else {
 170                 drm_dbg_kms(&dev_priv->drm,
 171                             "Received HPD interrupt on PIN %d - cnt: %d\n",
 172                               pin,
 173                               hpd->stats[pin].count);
 174         }
 175
 176         return storm;
 177 }
 178
 179 static void
 180 intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
 181 {
 182         struct drm_connector_list_iter conn_iter;
 183         struct intel_connector *connector;
 184         bool hpd_disabled = false;
 185
 186         lockdep_assert_held(&dev_priv->irq_lock);
 187
 188         drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
 189         for_each_intel_connector_iter(connector, &conn_iter) {
 190                 enum hpd_pin pin;
 191
 192                 if (connector->base.polled != DRM_CONNECTOR_POLL_HPD)
 193                         continue;
 194
 195                 pin = intel_connector_hpd_pin(connector);
 196                 if (pin == HPD_NONE ||
 197                     dev_priv->display.hotplug.stats[pin].state != HPD_MARK_DISABLED)
 198                         continue;
 199
 200                 drm_info(&dev_priv->drm,
 201                          "HPD interrupt storm detected on connector %s: "
 202                          "switching from hotplug detection to polling\n",
 203                          connector->base.name);
 204
 205                 dev_priv->display.hotplug.stats[pin].state = HPD_DISABLED;
 206                 connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
 207                         DRM_CONNECTOR_POLL_DISCONNECT;
 208                 hpd_disabled = true;
 209         }
 210         drm_connector_list_iter_end(&conn_iter);
 211
 212         /* Enable polling and queue hotplug re-enabling. */
 213         if (hpd_disabled) {
 214                 drm_kms_helper_poll_enable(&dev_priv->drm);
 215                 mod_delayed_work(system_wq, &dev_priv->display.hotplug.reenable_work,
 216                                  msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 217         }
 218 }
 219
 220 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 221 {
 222         struct drm_i915_private *dev_priv =
 223                 container_of(work, typeof(*dev_priv),
 224                              display.hotplug.reenable_work.work);
 225         struct drm_connector_list_iter conn_iter;
 226         struct intel_connector *connector;
 227         intel_wakeref_t wakeref;
 228         enum hpd_pin pin;
 229
 230         wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
 231
 232         spin_lock_irq(&dev_priv->irq_lock);
 233
 234         drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
 235         for_each_intel_connector_iter(connector, &conn_iter) {
 236                 pin = intel_connector_hpd_pin(connector);
 237                 if (pin == HPD_NONE ||
 238                     dev_priv->display.hotplug.stats[pin].state != HPD_DISABLED)
 239                         continue;
 240
 241                 if (connector->base.polled != connector->polled)
 242                         drm_dbg(&dev_priv->drm,
 243                                 "Reenabling HPD on connector %s\n",
 244                                 connector->base.name);
 245                 connector->base.polled = connector->polled;
 246         }
 247         drm_connector_list_iter_end(&conn_iter);
 248
 249         for_each_hpd_pin(pin) {
 250                 if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED)
 251                         dev_priv->display.hotplug.stats[pin].state = HPD_ENABLED;
 252         }
 253
 254         intel_hpd_irq_setup(dev_priv);
 255
 256         spin_unlock_irq(&dev_priv->irq_lock);
 257
 258         intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
 259 }
 260
 261 enum intel_hotplug_state
 262 intel_encoder_hotplug(struct intel_encoder *encoder,
 263                       struct intel_connector *connector)
 264 {
 265         struct drm_device *dev = connector->base.dev;
 266         enum drm_connector_status old_status;
 267         u64 old_epoch_counter;
 268         bool ret = false;
 269
 270         drm_WARN_ON(dev, !mutex_is_locked(&dev->mode_config.mutex));
 271         old_status = connector->base.status;
 272         old_epoch_counter = connector->base.epoch_counter;
 273
 274         connector->base.status =
 275                 drm_helper_probe_detect(&connector->base, NULL, false);
 276
 277         if (old_epoch_counter != connector->base.epoch_counter)
 278                 ret = true;
 279
 280         if (ret) {
 281                 drm_dbg_kms(dev, "[CONNECTOR:%d:%s] status updated from %s to %s (epoch counter %llu->%llu)\n",
 282                             connector->base.base.id,
 283                             connector->base.name,
 284                             drm_get_connector_status_name(old_status),
 285                             drm_get_connector_status_name(connector->base.status),
 286                             old_epoch_counter,
 287                             connector->base.epoch_counter);
 288                 return INTEL_HOTPLUG_CHANGED;
 289         }
 290         return INTEL_HOTPLUG_UNCHANGED;
 291 }
 292
 293 static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
 294 {
 295         return intel_encoder_is_dig_port(encoder) &&
 296                 enc_to_dig_port(encoder)->hpd_pulse != NULL;
 297 }
 298
 299 static void i915_digport_work_func(struct work_struct *work)
 300 {
 301         struct drm_i915_private *dev_priv =
 302                 container_of(work, struct drm_i915_private, display.hotplug.dig_port_work);
 303         u32 long_port_mask, short_port_mask;
 304         struct intel_encoder *encoder;
 305         u32 old_bits = 0;
 306
 307         spin_lock_irq(&dev_priv->irq_lock);
 308         long_port_mask = dev_priv->display.hotplug.long_port_mask;
 309         dev_priv->display.hotplug.long_port_mask = 0;
 310         short_port_mask = dev_priv->display.hotplug.short_port_mask;
 311         dev_priv->display.hotplug.short_port_mask = 0;
 312         spin_unlock_irq(&dev_priv->irq_lock);
 313
 314         for_each_intel_encoder(&dev_priv->drm, encoder) {
 315                 struct intel_digital_port *dig_port;
 316                 enum port port = encoder->port;
 317                 bool long_hpd, short_hpd;
 318                 enum irqreturn ret;
 319
 320                 if (!intel_encoder_has_hpd_pulse(encoder))
 321                         continue;
 322
 323                 long_hpd = long_port_mask & BIT(port);
 324                 short_hpd = short_port_mask & BIT(port);
 325
 326                 if (!long_hpd && !short_hpd)
 327                         continue;
 328
 329                 dig_port = enc_to_dig_port(encoder);
 330
 331                 ret = dig_port->hpd_pulse(dig_port, long_hpd);
 332                 if (ret == IRQ_NONE) {
 333                         /* fall back to old school hpd */
 334                         old_bits |= BIT(encoder->hpd_pin);
 335                 }
 336         }
 337
 338         if (old_bits) {
 339                 spin_lock_irq(&dev_priv->irq_lock);
 340                 dev_priv->display.hotplug.event_bits |= old_bits;
 341                 spin_unlock_irq(&dev_priv->irq_lock);
 342                 queue_delayed_work(system_wq, &dev_priv->display.hotplug.hotplug_work, 0);
 343         }
 344 }
 345
 346 /**
 347  * intel_hpd_trigger_irq - trigger an hpd irq event for a port
 348  * @dig_port: digital port
 349  *
 350  * Trigger an HPD interrupt event for the given port, emulating a short pulse
 351  * generated by the sink, and schedule the dig port work to handle it.
 352  */
 353 void intel_hpd_trigger_irq(struct intel_digital_port *dig_port)
 354 {
 355         struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
 356
 357         spin_lock_irq(&i915->irq_lock);
 358         i915->display.hotplug.short_port_mask |= BIT(dig_port->base.port);
 359         spin_unlock_irq(&i915->irq_lock);
 360
 361         queue_work(i915->display.hotplug.dp_wq, &i915->display.hotplug.dig_port_work);
 362 }
 363
 364 /*
 365  * Handle hotplug events outside the interrupt handler proper.
 366  */
 367 static void i915_hotplug_work_func(struct work_struct *work)
 368 {
 369         struct drm_i915_private *dev_priv =
 370                 container_of(work, struct drm_i915_private,
 371                              display.hotplug.hotplug_work.work);
 372         struct drm_connector_list_iter conn_iter;
 373         struct intel_connector *connector;
 374         u32 changed = 0, retry = 0;
 375         u32 hpd_event_bits;
 376         u32 hpd_retry_bits;
 377
 378         mutex_lock(&dev_priv->drm.mode_config.mutex);
 379         drm_dbg_kms(&dev_priv->drm, "running encoder hotplug functions\n");
 380
 381         spin_lock_irq(&dev_priv->irq_lock);
 382
 383         hpd_event_bits = dev_priv->display.hotplug.event_bits;
 384         dev_priv->display.hotplug.event_bits = 0;
 385         hpd_retry_bits = dev_priv->display.hotplug.retry_bits;
 386         dev_priv->display.hotplug.retry_bits = 0;
 387
 388         /* Enable polling for connectors which had HPD IRQ storms */
 389         intel_hpd_irq_storm_switch_to_polling(dev_priv);
 390
 391         spin_unlock_irq(&dev_priv->irq_lock);
 392
 393         /* Skip calling encode hotplug handlers if ignore long HPD set*/
 394         if (dev_priv->display.hotplug.ignore_long_hpd) {
 395                 drm_dbg_kms(&dev_priv->drm, "Ignore HPD flag on - skip encoder hotplug handlers\n");
 396                 mutex_unlock(&dev_priv->drm.mode_config.mutex);
 397                 return;
 398         }
 399
 400         drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
 401         for_each_intel_connector_iter(connector, &conn_iter) {
 402                 enum hpd_pin pin;
 403                 u32 hpd_bit;
 404
 405                 pin = intel_connector_hpd_pin(connector);
 406                 if (pin == HPD_NONE)
 407                         continue;
 408
 409                 hpd_bit = BIT(pin);
 410                 if ((hpd_event_bits | hpd_retry_bits) & hpd_bit) {
 411                         struct intel_encoder *encoder =
 412                                 intel_attached_encoder(connector);
 413
 414                         if (hpd_event_bits & hpd_bit)
 415                                 connector->hotplug_retries = 0;
 416                         else
 417                                 connector->hotplug_retries++;
 418
 419                         drm_dbg_kms(&dev_priv->drm,
 420                                     "Connector %s (pin %i) received hotplug event. (retry %d)\n",
 421                                     connector->base.name, pin,
 422                                     connector->hotplug_retries);
 423
 424                         switch (encoder->hotplug(encoder, connector)) {
 425                         case INTEL_HOTPLUG_UNCHANGED:
 426                                 break;
 427                         case INTEL_HOTPLUG_CHANGED:
 428                                 changed |= hpd_bit;
 429                                 break;
 430                         case INTEL_HOTPLUG_RETRY:
 431                                 retry |= hpd_bit;
 432                                 break;
 433                         }
 434                 }
 435         }
 436         drm_connector_list_iter_end(&conn_iter);
 437         mutex_unlock(&dev_priv->drm.mode_config.mutex);
 438
 439         if (changed)
 440                 drm_kms_helper_hotplug_event(&dev_priv->drm);
 441
 442         /* Remove shared HPD pins that have changed */
 443         retry &= ~changed;
 444         if (retry) {
 445                 spin_lock_irq(&dev_priv->irq_lock);
 446                 dev_priv->display.hotplug.retry_bits |= retry;
 447                 spin_unlock_irq(&dev_priv->irq_lock);
 448
 449                 mod_delayed_work(system_wq, &dev_priv->display.hotplug.hotplug_work,
 450                                  msecs_to_jiffies(HPD_RETRY_DELAY));
 451         }
 452 }
 453
 454
 455 /**
 456  * intel_hpd_irq_handler - main hotplug irq handler
 457  * @dev_priv: drm_i915_private
 458  * @pin_mask: a mask of hpd pins that have triggered the irq
 459  * @long_mask: a mask of hpd pins that may be long hpd pulses
 460  *
 461  * This is the main hotplug irq handler for all platforms. The platform specific
 462  * irq handlers call the platform specific hotplug irq handlers, which read and
 463  * decode the appropriate registers into bitmasks about hpd pins that have
 464  * triggered (@pin_mask), and which of those pins may be long pulses
 465  * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
 466  * is not a digital port.
 467  *
 468  * Here, we do hotplug irq storm detection and mitigation, and pass further
 469  * processing to appropriate bottom halves.
 470  */
 471 void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 472                            u32 pin_mask, u32 long_mask)
 473 {
 474         struct intel_encoder *encoder;
 475         bool storm_detected = false;
 476         bool queue_dig = false, queue_hp = false;
 477         u32 long_hpd_pulse_mask = 0;
 478         u32 short_hpd_pulse_mask = 0;
 479         enum hpd_pin pin;
 480
 481         if (!pin_mask)
 482                 return;
 483
 484         spin_lock(&dev_priv->irq_lock);
 485
 486         /*
 487          * Determine whether ->hpd_pulse() exists for each pin, and
 488          * whether we have a short or a long pulse. This is needed
 489          * as each pin may have up to two encoders (HDMI and DP) and
 490          * only the one of them (DP) will have ->hpd_pulse().
 491          */
 492         for_each_intel_encoder(&dev_priv->drm, encoder) {
 493                 enum port port = encoder->port;
 494                 bool long_hpd;
 495
 496                 pin = encoder->hpd_pin;
 497                 if (!(BIT(pin) & pin_mask))
 498                         continue;
 499
 500                 if (!intel_encoder_has_hpd_pulse(encoder))
 501                         continue;
 502
 503                 long_hpd = long_mask & BIT(pin);
 504
 505                 drm_dbg(&dev_priv->drm,
 506                         "digital hpd on [ENCODER:%d:%s] - %s\n",
 507                         encoder->base.base.id, encoder->base.name,
 508                         long_hpd ? "long" : "short");
 509                 queue_dig = true;
 510
 511                 if (long_hpd) {
 512                         long_hpd_pulse_mask |= BIT(pin);
 513                         dev_priv->display.hotplug.long_port_mask |= BIT(port);
 514                 } else {
 515                         short_hpd_pulse_mask |= BIT(pin);
 516                         dev_priv->display.hotplug.short_port_mask |= BIT(port);
 517                 }
 518         }
 519
 520         /* Now process each pin just once */
 521         for_each_hpd_pin(pin) {
 522                 bool long_hpd;
 523
 524                 if (!(BIT(pin) & pin_mask))
 525                         continue;
 526
 527                 if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED) {
 528                         /*
 529                          * On GMCH platforms the interrupt mask bits only
 530                          * prevent irq generation, not the setting of the
 531                          * hotplug bits itself. So only WARN about unexpected
 532                          * interrupts on saner platforms.
 533                          */
 534                         drm_WARN_ONCE(&dev_priv->drm, !HAS_GMCH(dev_priv),
 535                                       "Received HPD interrupt on pin %d although disabled\n",
 536                                       pin);
 537                         continue;
 538                 }
 539
 540                 if (dev_priv->display.hotplug.stats[pin].state != HPD_ENABLED)
 541                         continue;
 542
 543                 /*
 544                  * Delegate to ->hpd_pulse() if one of the encoders for this
 545                  * pin has it, otherwise let the hotplug_work deal with this
 546                  * pin directly.
 547                  */
 548                 if (((short_hpd_pulse_mask | long_hpd_pulse_mask) & BIT(pin))) {
 549                         long_hpd = long_hpd_pulse_mask & BIT(pin);
 550                 } else {
 551                         dev_priv->display.hotplug.event_bits |= BIT(pin);
 552                         long_hpd = true;
 553                         queue_hp = true;
 554                 }
 555
 556                 if (intel_hpd_irq_storm_detect(dev_priv, pin, long_hpd)) {
 557                         dev_priv->display.hotplug.event_bits &= ~BIT(pin);
 558                         storm_detected = true;
 559                         queue_hp = true;
 560                 }
 561         }
 562
 563         /*
 564          * Disable any IRQs that storms were detected on. Polling enablement
 565          * happens later in our hotplug work.
 566          */
 567         if (storm_detected)
 568                 intel_hpd_irq_setup(dev_priv);
 569         spin_unlock(&dev_priv->irq_lock);
 570
 571         /*
 572          * Our hotplug handler can grab modeset locks (by calling down into the
 573          * fb helpers). Hence it must not be run on our own dev-priv->wq work
 574          * queue for otherwise the flush_work in the pageflip code will
 575          * deadlock.
 576          */
 577         if (queue_dig)
 578                 queue_work(dev_priv->display.hotplug.dp_wq, &dev_priv->display.hotplug.dig_port_work);
 579         if (queue_hp)
 580                 queue_delayed_work(system_wq, &dev_priv->display.hotplug.hotplug_work, 0);
 581 }
 582
 583 /**
 584  * intel_hpd_init - initializes and enables hpd support
 585  * @dev_priv: i915 device instance
 586  *
 587  * This function enables the hotplug support. It requires that interrupts have
 588  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
 589  * poll request can run concurrently to other code, so locking rules must be
 590  * obeyed.
 591  *
 592  * This is a separate step from interrupt enabling to simplify the locking rules
 593  * in the driver load and resume code.
 594  *
 595  * Also see: intel_hpd_poll_enable() and intel_hpd_poll_disable().
 596  */
 597 void intel_hpd_init(struct drm_i915_private *dev_priv)
 598 {
 599         int i;
 600
 601         if (!HAS_DISPLAY(dev_priv))
 602                 return;
 603
 604         for_each_hpd_pin(i) {
 605                 dev_priv->display.hotplug.stats[i].count = 0;
 606                 dev_priv->display.hotplug.stats[i].state = HPD_ENABLED;
 607         }
 608
 609         /*
 610          * Interrupt setup is already guaranteed to be single-threaded, this is
 611          * just to make the assert_spin_locked checks happy.
 612          */
 613         spin_lock_irq(&dev_priv->irq_lock);
 614         intel_hpd_irq_setup(dev_priv);
 615         spin_unlock_irq(&dev_priv->irq_lock);
 616 }
 617
 618 static void i915_hpd_poll_init_work(struct work_struct *work)
 619 {
 620         struct drm_i915_private *dev_priv =
 621                 container_of(work, struct drm_i915_private,
 622                              display.hotplug.poll_init_work);
 623         struct drm_connector_list_iter conn_iter;
 624         struct intel_connector *connector;
 625         bool enabled;
 626
 627         mutex_lock(&dev_priv->drm.mode_config.mutex);
 628
 629         enabled = READ_ONCE(dev_priv->display.hotplug.poll_enabled);
 630
 631         drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
 632         for_each_intel_connector_iter(connector, &conn_iter) {
 633                 enum hpd_pin pin;
 634
 635                 pin = intel_connector_hpd_pin(connector);
 636                 if (pin == HPD_NONE)
 637                         continue;
 638
 639                 connector->base.polled = connector->polled;
 640
 641                 if (enabled && connector->base.polled == DRM_CONNECTOR_POLL_HPD)
 642                         connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
 643                                 DRM_CONNECTOR_POLL_DISCONNECT;
 644         }
 645         drm_connector_list_iter_end(&conn_iter);
 646
 647         if (enabled)
 648                 drm_kms_helper_poll_enable(&dev_priv->drm);
 649
 650         mutex_unlock(&dev_priv->drm.mode_config.mutex);
 651
 652         /*
 653          * We might have missed any hotplugs that happened while we were
 654          * in the middle of disabling polling
 655          */
 656         if (!enabled)
 657                 drm_helper_hpd_irq_event(&dev_priv->drm);
 658 }
 659
 660 /**
 661  * intel_hpd_poll_enable - enable polling for connectors with hpd
 662  * @dev_priv: i915 device instance
 663  *
 664  * This function enables polling for all connectors which support HPD.
 665  * Under certain conditions HPD may not be functional. On most Intel GPUs,
 666  * this happens when we enter runtime suspend.
 667  * On Valleyview and Cherryview systems, this also happens when we shut off all
 668  * of the powerwells.
 669  *
 670  * Since this function can get called in contexts where we're already holding
 671  * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
 672  * worker.
 673  *
 674  * Also see: intel_hpd_init() and intel_hpd_poll_disable().
 675  */
 676 void intel_hpd_poll_enable(struct drm_i915_private *dev_priv)
 677 {
 678         if (!HAS_DISPLAY(dev_priv) ||
 679             !INTEL_DISPLAY_ENABLED(dev_priv))
 680                 return;
 681
 682         WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, true);
 683
 684         /*
 685          * We might already be holding dev->mode_config.mutex, so do this in a
 686          * seperate worker
 687          * As well, there's no issue if we race here since we always reschedule
 688          * this worker anyway
 689          */
 690         schedule_work(&dev_priv->display.hotplug.poll_init_work);
 691 }
 692
 693 /**
 694  * intel_hpd_poll_disable - disable polling for connectors with hpd
 695  * @dev_priv: i915 device instance
 696  *
 697  * This function disables polling for all connectors which support HPD.
 698  * Under certain conditions HPD may not be functional. On most Intel GPUs,
 699  * this happens when we enter runtime suspend.
 700  * On Valleyview and Cherryview systems, this also happens when we shut off all
 701  * of the powerwells.
 702  *
 703  * Since this function can get called in contexts where we're already holding
 704  * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
 705  * worker.
 706  *
 707  * Also used during driver init to initialize connector->polled
 708  * appropriately for all connectors.
 709  *
 710  * Also see: intel_hpd_init() and intel_hpd_poll_enable().
 711  */
 712 void intel_hpd_poll_disable(struct drm_i915_private *dev_priv)
 713 {
 714         if (!HAS_DISPLAY(dev_priv))
 715                 return;
 716
 717         WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, false);
 718         schedule_work(&dev_priv->display.hotplug.poll_init_work);
 719 }
 720
 721 void intel_hpd_init_early(struct drm_i915_private *i915)
 722 {
 723         INIT_DELAYED_WORK(&i915->display.hotplug.hotplug_work,
 724                           i915_hotplug_work_func);
 725         INIT_WORK(&i915->display.hotplug.dig_port_work, i915_digport_work_func);
 726         INIT_WORK(&i915->display.hotplug.poll_init_work, i915_hpd_poll_init_work);
 727         INIT_DELAYED_WORK(&i915->display.hotplug.reenable_work,
 728                           intel_hpd_irq_storm_reenable_work);
 729
 730         i915->display.hotplug.hpd_storm_threshold = HPD_STORM_DEFAULT_THRESHOLD;
 731         /* If we have MST support, we want to avoid doing short HPD IRQ storm
 732          * detection, as short HPD storms will occur as a natural part of
 733          * sideband messaging with MST.
 734          * On older platforms however, IRQ storms can occur with both long and
 735          * short pulses, as seen on some G4x systems.
 736          */
 737         i915->display.hotplug.hpd_short_storm_enabled = !HAS_DP_MST(i915);
 738 }
 739
 740 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 741 {
 742         if (!HAS_DISPLAY(dev_priv))
 743                 return;
 744
 745         spin_lock_irq(&dev_priv->irq_lock);
 746
 747         dev_priv->display.hotplug.long_port_mask = 0;
 748         dev_priv->display.hotplug.short_port_mask = 0;
 749         dev_priv->display.hotplug.event_bits = 0;
 750         dev_priv->display.hotplug.retry_bits = 0;
 751
 752         spin_unlock_irq(&dev_priv->irq_lock);
 753
 754         cancel_work_sync(&dev_priv->display.hotplug.dig_port_work);
 755         cancel_delayed_work_sync(&dev_priv->display.hotplug.hotplug_work);
 756         cancel_work_sync(&dev_priv->display.hotplug.poll_init_work);
 757         cancel_delayed_work_sync(&dev_priv->display.hotplug.reenable_work);
 758 }
 759
 760 bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 761 {
 762         bool ret = false;
 763
 764         if (pin == HPD_NONE)
 765                 return false;
 766
 767         spin_lock_irq(&dev_priv->irq_lock);
 768         if (dev_priv->display.hotplug.stats[pin].state == HPD_ENABLED) {
 769                 dev_priv->display.hotplug.stats[pin].state = HPD_DISABLED;
 770                 ret = true;
 771         }
 772         spin_unlock_irq(&dev_priv->irq_lock);
 773
 774         return ret;
 775 }
 776
 777 void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 778 {
 779         if (pin == HPD_NONE)
 780                 return;
 781
 782         spin_lock_irq(&dev_priv->irq_lock);
 783         dev_priv->display.hotplug.stats[pin].state = HPD_ENABLED;
 784         spin_unlock_irq(&dev_priv->irq_lock);
 785 }
 786
 787 static int i915_hpd_storm_ctl_show(struct seq_file *m, void *data)
 788 {
 789         struct drm_i915_private *dev_priv = m->private;
 790         struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
 791
 792         /* Synchronize with everything first in case there's been an HPD
 793          * storm, but we haven't finished handling it in the kernel yet
 794          */
 795         intel_synchronize_irq(dev_priv);
 796         flush_work(&dev_priv->display.hotplug.dig_port_work);
 797         flush_delayed_work(&dev_priv->display.hotplug.hotplug_work);
 798
 799         seq_printf(m, "Threshold: %d\n", hotplug->hpd_storm_threshold);
 800         seq_printf(m, "Detected: %s\n",
 801                    str_yes_no(delayed_work_pending(&hotplug->reenable_work)));
 802
 803         return 0;
 804 }
 805
 806 static ssize_t i915_hpd_storm_ctl_write(struct file *file,
 807                                         const char __user *ubuf, size_t len,
 808                                         loff_t *offp)
 809 {
 810         struct seq_file *m = file->private_data;
 811         struct drm_i915_private *dev_priv = m->private;
 812         struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
 813         unsigned int new_threshold;
 814         int i;
 815         char *newline;
 816         char tmp[16];
 817
 818         if (len >= sizeof(tmp))
 819                 return -EINVAL;
 820
 821         if (copy_from_user(tmp, ubuf, len))
 822                 return -EFAULT;
 823
 824         tmp[len] = '\0';
 825
 826         /* Strip newline, if any */
 827         newline = strchr(tmp, '\n');
 828         if (newline)
 829                 *newline = '\0';
 830
 831         if (strcmp(tmp, "reset") == 0)
 832                 new_threshold = HPD_STORM_DEFAULT_THRESHOLD;
 833         else if (kstrtouint(tmp, 10, &new_threshold) != 0)
 834                 return -EINVAL;
 835
 836         if (new_threshold > 0)
 837                 drm_dbg_kms(&dev_priv->drm,
 838                             "Setting HPD storm detection threshold to %d\n",
 839                             new_threshold);
 840         else
 841                 drm_dbg_kms(&dev_priv->drm, "Disabling HPD storm detection\n");
 842
 843         spin_lock_irq(&dev_priv->irq_lock);
 844         hotplug->hpd_storm_threshold = new_threshold;
 845         /* Reset the HPD storm stats so we don't accidentally trigger a storm */
 846         for_each_hpd_pin(i)
 847                 hotplug->stats[i].count = 0;
 848         spin_unlock_irq(&dev_priv->irq_lock);
 849
 850         /* Re-enable hpd immediately if we were in an irq storm */
 851         flush_delayed_work(&dev_priv->display.hotplug.reenable_work);
 852
 853         return len;
 854 }
 855
 856 static int i915_hpd_storm_ctl_open(struct inode *inode, struct file *file)
 857 {
 858         return single_open(file, i915_hpd_storm_ctl_show, inode->i_private);
 859 }
 860
 861 static const struct file_operations i915_hpd_storm_ctl_fops = {
 862         .owner = THIS_MODULE,
 863         .open = i915_hpd_storm_ctl_open,
 864         .read = seq_read,
 865         .llseek = seq_lseek,
 866         .release = single_release,
 867         .write = i915_hpd_storm_ctl_write
 868 };
 869
 870 static int i915_hpd_short_storm_ctl_show(struct seq_file *m, void *data)
 871 {
 872         struct drm_i915_private *dev_priv = m->private;
 873
 874         seq_printf(m, "Enabled: %s\n",
 875                    str_yes_no(dev_priv->display.hotplug.hpd_short_storm_enabled));
 876
 877         return 0;
 878 }
 879
 880 static int
 881 i915_hpd_short_storm_ctl_open(struct inode *inode, struct file *file)
 882 {
 883         return single_open(file, i915_hpd_short_storm_ctl_show,
 884                            inode->i_private);
 885 }
 886
 887 static ssize_t i915_hpd_short_storm_ctl_write(struct file *file,
 888                                               const char __user *ubuf,
 889                                               size_t len, loff_t *offp)
 890 {
 891         struct seq_file *m = file->private_data;
 892         struct drm_i915_private *dev_priv = m->private;
 893         struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
 894         char *newline;
 895         char tmp[16];
 896         int i;
 897         bool new_state;
 898
 899         if (len >= sizeof(tmp))
 900                 return -EINVAL;
 901
 902         if (copy_from_user(tmp, ubuf, len))
 903                 return -EFAULT;
 904
 905         tmp[len] = '\0';
 906
 907         /* Strip newline, if any */
 908         newline = strchr(tmp, '\n');
 909         if (newline)
 910                 *newline = '\0';
 911
 912         /* Reset to the "default" state for this system */
 913         if (strcmp(tmp, "reset") == 0)
 914                 new_state = !HAS_DP_MST(dev_priv);
 915         else if (kstrtobool(tmp, &new_state) != 0)
 916                 return -EINVAL;
 917
 918         drm_dbg_kms(&dev_priv->drm, "%sabling HPD short storm detection\n",
 919                     new_state ? "En" : "Dis");
 920
 921         spin_lock_irq(&dev_priv->irq_lock);
 922         hotplug->hpd_short_storm_enabled = new_state;
 923         /* Reset the HPD storm stats so we don't accidentally trigger a storm */
 924         for_each_hpd_pin(i)
 925                 hotplug->stats[i].count = 0;
 926         spin_unlock_irq(&dev_priv->irq_lock);
 927
 928         /* Re-enable hpd immediately if we were in an irq storm */
 929         flush_delayed_work(&dev_priv->display.hotplug.reenable_work);
 930
 931         return len;
 932 }
 933
 934 static const struct file_operations i915_hpd_short_storm_ctl_fops = {
 935         .owner = THIS_MODULE,
 936         .open = i915_hpd_short_storm_ctl_open,
 937         .read = seq_read,
 938         .llseek = seq_lseek,
 939         .release = single_release,
 940         .write = i915_hpd_short_storm_ctl_write,
 941 };
 942
 943 void intel_hpd_debugfs_register(struct drm_i915_private *i915)
 944 {
 945         struct drm_minor *minor = i915->drm.primary;
 946
 947         debugfs_create_file("i915_hpd_storm_ctl", 0644, minor->debugfs_root,
 948                             i915, &i915_hpd_storm_ctl_fops);
 949         debugfs_create_file("i915_hpd_short_storm_ctl", 0644, minor->debugfs_root,
 950                             i915, &i915_hpd_short_storm_ctl_fops);
 951         debugfs_create_bool("i915_ignore_long_hpd", 0644, minor->debugfs_root,
 952                             &i915->display.hotplug.ignore_long_hpd);
 953 }