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 "intel_display_types.h"
  28 #include "intel_hotplug.h"
  29
  30 /**
  31  * DOC: Hotplug
  32  *
  33  * Simply put, hotplug occurs when a display is connected to or disconnected
  34  * from the system. However, there may be adapters and docking stations and
  35  * Display Port short pulses and MST devices involved, complicating matters.
  36  *
  37  * Hotplug in i915 is handled in many different levels of abstraction.
  38  *
  39  * The platform dependent interrupt handling code in i915_irq.c enables,
  40  * disables, and does preliminary handling of the interrupts. The interrupt
  41  * handlers gather the hotplug detect (HPD) information from relevant registers
  42  * into a platform independent mask of hotplug pins that have fired.
  43  *
  44  * The platform independent interrupt handler intel_hpd_irq_handler() in
  45  * intel_hotplug.c does hotplug irq storm detection and mitigation, and passes
  46  * further processing to appropriate bottom halves (Display Port specific and
  47  * regular hotplug).
  48  *
  49  * The Display Port work function i915_digport_work_func() calls into
  50  * intel_dp_hpd_pulse() via hooks, which handles DP short pulses and DP MST long
  51  * pulses, with failures and non-MST long pulses triggering regular hotplug
  52  * processing on the connector.
  53  *
  54  * The regular hotplug work function i915_hotplug_work_func() calls connector
  55  * detect hooks, and, if connector status changes, triggers sending of hotplug
  56  * uevent to userspace via drm_kms_helper_hotplug_event().
  57  *
  58  * Finally, the userspace is responsible for triggering a modeset upon receiving
  59  * the hotplug uevent, disabling or enabling the crtc as needed.
  60  *
  61  * The hotplug interrupt storm detection and mitigation code keeps track of the
  62  * number of interrupts per hotplug pin per a period of time, and if the number
  63  * of interrupts exceeds a certain threshold, the interrupt is disabled for a
  64  * while before being re-enabled. The intention is to mitigate issues raising
  65  * from broken hardware triggering massive amounts of interrupts and grinding
  66  * the system to a halt.
  67  *
  68  * Current implementation expects that hotplug interrupt storm will not be
  69  * seen when display port sink is connected, hence on platforms whose DP
  70  * callback is handled by i915_digport_work_func reenabling of hpd is not
  71  * performed (it was never expected to be disabled in the first place ;) )
  72  * this is specific to DP sinks handled by this routine and any other display
  73  * such as HDMI or DVI enabled on the same port will have proper logic since
  74  * it will use i915_hotplug_work_func where this logic is handled.
  75  */
  76
  77 /**
  78  * intel_hpd_pin_default - return default pin associated with certain port.
  79  * @dev_priv: private driver data pointer
  80  * @port: the hpd port to get associated pin
  81  *
  82  * It is only valid and used by digital port encoder.
  83  *
  84  * Return pin that is associatade with @port.
  85  */
  86 enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
  87                                    enum port port)
  88 {
  89         return HPD_PORT_A + port - PORT_A;
  90 }
  91
  92 #define HPD_STORM_DETECT_PERIOD         1000
  93 #define HPD_STORM_REENABLE_DELAY        (2 * 60 * 1000)
  94 #define HPD_RETRY_DELAY                 1000
  95
  96 static enum hpd_pin
  97 intel_connector_hpd_pin(struct intel_connector *connector)
  98 {
  99         struct intel_encoder *encoder = intel_attached_encoder(connector);
 100
 101         /*
 102          * MST connectors get their encoder attached dynamically
 103          * so need to make sure we have an encoder here. But since
 104          * MST encoders have their hpd_pin set to HPD_NONE we don't
 105          * have to special case them beyond that.
 106          */
 107         return encoder ? encoder->hpd_pin : HPD_NONE;
 108 }
 109
 110 /**
 111  * intel_hpd_irq_storm_detect - gather stats and detect HPD IRQ storm on a pin
 112  * @dev_priv: private driver data pointer
 113  * @pin: the pin to gather stats on
 114  * @long_hpd: whether the HPD IRQ was long or short
 115  *
 116  * Gather stats about HPD IRQs from the specified @pin, and detect IRQ
 117  * storms. Only the pin specific stats and state are changed, the caller is
 118  * responsible for further action.
 119  *
 120  * The number of IRQs that are allowed within @HPD_STORM_DETECT_PERIOD is
 121  * stored in @dev_priv->hotplug.hpd_storm_threshold which defaults to
 122  * @HPD_STORM_DEFAULT_THRESHOLD. Long IRQs count as +10 to this threshold, and
 123  * short IRQs count as +1. If this threshold is exceeded, it's considered an
 124  * IRQ storm and the IRQ state is set to @HPD_MARK_DISABLED.
 125  *
 126  * By default, most systems will only count long IRQs towards
 127  * &dev_priv->hotplug.hpd_storm_threshold. However, some older systems also
 128  * suffer from short IRQ storms and must also track these. Because short IRQ
 129  * storms are naturally caused by sideband interactions with DP MST devices,
 130  * short IRQ detection is only enabled for systems without DP MST support.
 131  * Systems which are new enough to support DP MST are far less likely to
 132  * suffer from IRQ storms at all, so this is fine.
 133  *
 134  * The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
 135  * and should only be adjusted for automated hotplug testing.
 136  *
 137  * Return true if an IRQ storm was detected on @pin.
 138  */
 139 static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
 140                                        enum hpd_pin pin, bool long_hpd)
 141 {
 142         struct i915_hotplug *hpd = &dev_priv->hotplug;
 143         unsigned long start = hpd->stats[pin].last_jiffies;
 144         unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
 145         const int increment = long_hpd ? 10 : 1;
 146         const int threshold = hpd->hpd_storm_threshold;
 147         bool storm = false;
 148
 149         if (!threshold ||
 150             (!long_hpd && !dev_priv->hotplug.hpd_short_storm_enabled))
 151                 return false;
 152
 153         if (!time_in_range(jiffies, start, end)) {
 154                 hpd->stats[pin].last_jiffies = jiffies;
 155                 hpd->stats[pin].count = 0;
 156         }
 157
 158         hpd->stats[pin].count += increment;
 159         if (hpd->stats[pin].count > threshold) {
 160                 hpd->stats[pin].state = HPD_MARK_DISABLED;
 161                 drm_dbg_kms(&dev_priv->drm,
 162                             "HPD interrupt storm detected on PIN %d\n", pin);
 163                 storm = true;
 164         } else {
 165                 drm_dbg_kms(&dev_priv->drm,
 166                             "Received HPD interrupt on PIN %d - cnt: %d\n",
 167                               pin,
 168                               hpd->stats[pin].count);
 169         }
 170
 171         return storm;
 172 }
 173
 174 static void
 175 intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
 176 {
 177         struct drm_device *dev = &dev_priv->drm;
 178         struct drm_connector_list_iter conn_iter;
 179         struct intel_connector *connector;
 180         bool hpd_disabled = false;
 181
 182         lockdep_assert_held(&dev_priv->irq_lock);
 183
 184         drm_connector_list_iter_begin(dev, &conn_iter);
 185         for_each_intel_connector_iter(connector, &conn_iter) {
 186                 enum hpd_pin pin;
 187
 188                 if (connector->base.polled != DRM_CONNECTOR_POLL_HPD)
 189                         continue;
 190
 191                 pin = intel_connector_hpd_pin(connector);
 192                 if (pin == HPD_NONE ||
 193                     dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
 194                         continue;
 195
 196                 drm_info(&dev_priv->drm,
 197                          "HPD interrupt storm detected on connector %s: "
 198                          "switching from hotplug detection to polling\n",
 199                          connector->base.name);
 200
 201                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 202                 connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
 203                         DRM_CONNECTOR_POLL_DISCONNECT;
 204                 hpd_disabled = true;
 205         }
 206         drm_connector_list_iter_end(&conn_iter);
 207
 208         /* Enable polling and queue hotplug re-enabling. */
 209         if (hpd_disabled) {
 210                 drm_kms_helper_poll_enable(dev);
 211                 mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
 212                                  msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 213         }
 214 }
 215
 216 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 217 {
 218         struct drm_i915_private *dev_priv =
 219                 container_of(work, typeof(*dev_priv),
 220                              hotplug.reenable_work.work);
 221         struct drm_device *dev = &dev_priv->drm;
 222         struct drm_connector_list_iter conn_iter;
 223         struct intel_connector *connector;
 224         intel_wakeref_t wakeref;
 225         enum hpd_pin pin;
 226
 227         wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
 228
 229         spin_lock_irq(&dev_priv->irq_lock);
 230
 231         drm_connector_list_iter_begin(dev, &conn_iter);
 232         for_each_intel_connector_iter(connector, &conn_iter) {
 233                 pin = intel_connector_hpd_pin(connector);
 234                 if (pin == HPD_NONE ||
 235                     dev_priv->hotplug.stats[pin].state != HPD_DISABLED)
 236                         continue;
 237
 238                 if (connector->base.polled != connector->polled)
 239                         drm_dbg(&dev_priv->drm,
 240                                 "Reenabling HPD on connector %s\n",
 241                                 connector->base.name);
 242                 connector->base.polled = connector->polled;
 243         }
 244         drm_connector_list_iter_end(&conn_iter);
 245
 246         for_each_hpd_pin(pin) {
 247                 if (dev_priv->hotplug.stats[pin].state == HPD_DISABLED)
 248                         dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
 249         }
 250
 251         if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup)
 252                 dev_priv->display.hpd_irq_setup(dev_priv);
 253
 254         spin_unlock_irq(&dev_priv->irq_lock);
 255
 256         intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
 257 }
 258
 259 enum intel_hotplug_state
 260 intel_encoder_hotplug(struct intel_encoder *encoder,
 261                       struct intel_connector *connector)
 262 {
 263         struct drm_device *dev = connector->base.dev;
 264         enum drm_connector_status old_status;
 265         u64 old_epoch_counter;
 266         bool ret = false;
 267
 268         drm_WARN_ON(dev, !mutex_is_locked(&dev->mode_config.mutex));
 269         old_status = connector->base.status;
 270         old_epoch_counter = connector->base.epoch_counter;
 271
 272         connector->base.status =
 273                 drm_helper_probe_detect(&connector->base, NULL, false);
 274
 275         if (old_epoch_counter != connector->base.epoch_counter)
 276                 ret = true;
 277
 278         if (ret) {
 279                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s (epoch counter %llu->%llu)\n",
 280                               connector->base.base.id,
 281                               connector->base.name,
 282                               drm_get_connector_status_name(old_status),
 283                               drm_get_connector_status_name(connector->base.status),
 284                               old_epoch_counter,
 285                               connector->base.epoch_counter);
 286                 return INTEL_HOTPLUG_CHANGED;
 287         }
 288         return INTEL_HOTPLUG_UNCHANGED;
 289 }
 290
 291 static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
 292 {
 293         return intel_encoder_is_dig_port(encoder) &&
 294                 enc_to_dig_port(encoder)->hpd_pulse != NULL;
 295 }
 296
 297 static void i915_digport_work_func(struct work_struct *work)
 298 {
 299         struct drm_i915_private *dev_priv =
 300                 container_of(work, struct drm_i915_private, hotplug.dig_port_work);
 301         u32 long_port_mask, short_port_mask;
 302         struct intel_encoder *encoder;
 303         u32 old_bits = 0;
 304
 305         spin_lock_irq(&dev_priv->irq_lock);
 306         long_port_mask = dev_priv->hotplug.long_port_mask;
 307         dev_priv->hotplug.long_port_mask = 0;
 308         short_port_mask = dev_priv->hotplug.short_port_mask;
 309         dev_priv->hotplug.short_port_mask = 0;
 310         spin_unlock_irq(&dev_priv->irq_lock);
 311
 312         for_each_intel_encoder(&dev_priv->drm, encoder) {
 313                 struct intel_digital_port *dig_port;
 314                 enum port port = encoder->port;
 315                 bool long_hpd, short_hpd;
 316                 enum irqreturn ret;
 317
 318                 if (!intel_encoder_has_hpd_pulse(encoder))
 319                         continue;
 320
 321                 long_hpd = long_port_mask & BIT(port);
 322                 short_hpd = short_port_mask & BIT(port);
 323
 324                 if (!long_hpd && !short_hpd)
 325                         continue;
 326
 327                 dig_port = enc_to_dig_port(encoder);
 328
 329                 ret = dig_port->hpd_pulse(dig_port, long_hpd);
 330                 if (ret == IRQ_NONE) {
 331                         /* fall back to old school hpd */
 332                         old_bits |= BIT(encoder->hpd_pin);
 333                 }
 334         }
 335
 336         if (old_bits) {
 337                 spin_lock_irq(&dev_priv->irq_lock);
 338                 dev_priv->hotplug.event_bits |= old_bits;
 339                 spin_unlock_irq(&dev_priv->irq_lock);
 340                 queue_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work, 0);
 341         }
 342 }
 343
 344 /**
 345  * intel_hpd_trigger_irq - trigger an hpd irq event for a port
 346  * @dig_port: digital port
 347  *
 348  * Trigger an HPD interrupt event for the given port, emulating a short pulse
 349  * generated by the sink, and schedule the dig port work to handle it.
 350  */
 351 void intel_hpd_trigger_irq(struct intel_digital_port *dig_port)
 352 {
 353         struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
 354
 355         spin_lock_irq(&i915->irq_lock);
 356         i915->hotplug.short_port_mask |= BIT(dig_port->base.port);
 357         spin_unlock_irq(&i915->irq_lock);
 358
 359         queue_work(i915->hotplug.dp_wq, &i915->hotplug.dig_port_work);
 360 }
 361
 362 /*
 363  * Handle hotplug events outside the interrupt handler proper.
 364  */
 365 static void i915_hotplug_work_func(struct work_struct *work)
 366 {
 367         struct drm_i915_private *dev_priv =
 368                 container_of(work, struct drm_i915_private,
 369                              hotplug.hotplug_work.work);
 370         struct drm_device *dev = &dev_priv->drm;
 371         struct drm_connector_list_iter conn_iter;
 372         struct intel_connector *connector;
 373         u32 changed = 0, retry = 0;
 374         u32 hpd_event_bits;
 375         u32 hpd_retry_bits;
 376
 377         mutex_lock(&dev->mode_config.mutex);
 378         drm_dbg_kms(&dev_priv->drm, "running encoder hotplug functions\n");
 379
 380         spin_lock_irq(&dev_priv->irq_lock);
 381
 382         hpd_event_bits = dev_priv->hotplug.event_bits;
 383         dev_priv->hotplug.event_bits = 0;
 384         hpd_retry_bits = dev_priv->hotplug.retry_bits;
 385         dev_priv->hotplug.retry_bits = 0;
 386
 387         /* Enable polling for connectors which had HPD IRQ storms */
 388         intel_hpd_irq_storm_switch_to_polling(dev_priv);
 389
 390         spin_unlock_irq(&dev_priv->irq_lock);
 391
 392         drm_connector_list_iter_begin(dev, &conn_iter);
 393         for_each_intel_connector_iter(connector, &conn_iter) {
 394                 enum hpd_pin pin;
 395                 u32 hpd_bit;
 396
 397                 pin = intel_connector_hpd_pin(connector);
 398                 if (pin == HPD_NONE)
 399                         continue;
 400
 401                 hpd_bit = BIT(pin);
 402                 if ((hpd_event_bits | hpd_retry_bits) & hpd_bit) {
 403                         struct intel_encoder *encoder =
 404                                 intel_attached_encoder(connector);
 405
 406                         if (hpd_event_bits & hpd_bit)
 407                                 connector->hotplug_retries = 0;
 408                         else
 409                                 connector->hotplug_retries++;
 410
 411                         drm_dbg_kms(&dev_priv->drm,
 412                                     "Connector %s (pin %i) received hotplug event. (retry %d)\n",
 413                                     connector->base.name, pin,
 414                                     connector->hotplug_retries);
 415
 416                         switch (encoder->hotplug(encoder, connector)) {
 417                         case INTEL_HOTPLUG_UNCHANGED:
 418                                 break;
 419                         case INTEL_HOTPLUG_CHANGED:
 420                                 changed |= hpd_bit;
 421                                 break;
 422                         case INTEL_HOTPLUG_RETRY:
 423                                 retry |= hpd_bit;
 424                                 break;
 425                         }
 426                 }
 427         }
 428         drm_connector_list_iter_end(&conn_iter);
 429         mutex_unlock(&dev->mode_config.mutex);
 430
 431         if (changed)
 432                 drm_kms_helper_hotplug_event(dev);
 433
 434         /* Remove shared HPD pins that have changed */
 435         retry &= ~changed;
 436         if (retry) {
 437                 spin_lock_irq(&dev_priv->irq_lock);
 438                 dev_priv->hotplug.retry_bits |= retry;
 439                 spin_unlock_irq(&dev_priv->irq_lock);
 440
 441                 mod_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work,
 442                                  msecs_to_jiffies(HPD_RETRY_DELAY));
 443         }
 444 }
 445
 446
 447 /**
 448  * intel_hpd_irq_handler - main hotplug irq handler
 449  * @dev_priv: drm_i915_private
 450  * @pin_mask: a mask of hpd pins that have triggered the irq
 451  * @long_mask: a mask of hpd pins that may be long hpd pulses
 452  *
 453  * This is the main hotplug irq handler for all platforms. The platform specific
 454  * irq handlers call the platform specific hotplug irq handlers, which read and
 455  * decode the appropriate registers into bitmasks about hpd pins that have
 456  * triggered (@pin_mask), and which of those pins may be long pulses
 457  * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
 458  * is not a digital port.
 459  *
 460  * Here, we do hotplug irq storm detection and mitigation, and pass further
 461  * processing to appropriate bottom halves.
 462  */
 463 void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 464                            u32 pin_mask, u32 long_mask)
 465 {
 466         struct intel_encoder *encoder;
 467         bool storm_detected = false;
 468         bool queue_dig = false, queue_hp = false;
 469         u32 long_hpd_pulse_mask = 0;
 470         u32 short_hpd_pulse_mask = 0;
 471         enum hpd_pin pin;
 472
 473         if (!pin_mask)
 474                 return;
 475
 476         spin_lock(&dev_priv->irq_lock);
 477
 478         /*
 479          * Determine whether ->hpd_pulse() exists for each pin, and
 480          * whether we have a short or a long pulse. This is needed
 481          * as each pin may have up to two encoders (HDMI and DP) and
 482          * only the one of them (DP) will have ->hpd_pulse().
 483          */
 484         for_each_intel_encoder(&dev_priv->drm, encoder) {
 485                 enum port port = encoder->port;
 486                 bool long_hpd;
 487
 488                 pin = encoder->hpd_pin;
 489                 if (!(BIT(pin) & pin_mask))
 490                         continue;
 491
 492                 if (!intel_encoder_has_hpd_pulse(encoder))
 493                         continue;
 494
 495                 long_hpd = long_mask & BIT(pin);
 496
 497                 drm_dbg(&dev_priv->drm,
 498                         "digital hpd on [ENCODER:%d:%s] - %s\n",
 499                         encoder->base.base.id, encoder->base.name,
 500                         long_hpd ? "long" : "short");
 501                 queue_dig = true;
 502
 503                 if (long_hpd) {
 504                         long_hpd_pulse_mask |= BIT(pin);
 505                         dev_priv->hotplug.long_port_mask |= BIT(port);
 506                 } else {
 507                         short_hpd_pulse_mask |= BIT(pin);
 508                         dev_priv->hotplug.short_port_mask |= BIT(port);
 509                 }
 510         }
 511
 512         /* Now process each pin just once */
 513         for_each_hpd_pin(pin) {
 514                 bool long_hpd;
 515
 516                 if (!(BIT(pin) & pin_mask))
 517                         continue;
 518
 519                 if (dev_priv->hotplug.stats[pin].state == HPD_DISABLED) {
 520                         /*
 521                          * On GMCH platforms the interrupt mask bits only
 522                          * prevent irq generation, not the setting of the
 523                          * hotplug bits itself. So only WARN about unexpected
 524                          * interrupts on saner platforms.
 525                          */
 526                         drm_WARN_ONCE(&dev_priv->drm, !HAS_GMCH(dev_priv),
 527                                       "Received HPD interrupt on pin %d although disabled\n",
 528                                       pin);
 529                         continue;
 530                 }
 531
 532                 if (dev_priv->hotplug.stats[pin].state != HPD_ENABLED)
 533                         continue;
 534
 535                 /*
 536                  * Delegate to ->hpd_pulse() if one of the encoders for this
 537                  * pin has it, otherwise let the hotplug_work deal with this
 538                  * pin directly.
 539                  */
 540                 if (((short_hpd_pulse_mask | long_hpd_pulse_mask) & BIT(pin))) {
 541                         long_hpd = long_hpd_pulse_mask & BIT(pin);
 542                 } else {
 543                         dev_priv->hotplug.event_bits |= BIT(pin);
 544                         long_hpd = true;
 545                         queue_hp = true;
 546                 }
 547
 548                 if (intel_hpd_irq_storm_detect(dev_priv, pin, long_hpd)) {
 549                         dev_priv->hotplug.event_bits &= ~BIT(pin);
 550                         storm_detected = true;
 551                         queue_hp = true;
 552                 }
 553         }
 554
 555         /*
 556          * Disable any IRQs that storms were detected on. Polling enablement
 557          * happens later in our hotplug work.
 558          */
 559         if (storm_detected && dev_priv->display_irqs_enabled)
 560                 dev_priv->display.hpd_irq_setup(dev_priv);
 561         spin_unlock(&dev_priv->irq_lock);
 562
 563         /*
 564          * Our hotplug handler can grab modeset locks (by calling down into the
 565          * fb helpers). Hence it must not be run on our own dev-priv->wq work
 566          * queue for otherwise the flush_work in the pageflip code will
 567          * deadlock.
 568          */
 569         if (queue_dig)
 570                 queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
 571         if (queue_hp)
 572                 queue_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work, 0);
 573 }
 574
 575 /**
 576  * intel_hpd_init - initializes and enables hpd support
 577  * @dev_priv: i915 device instance
 578  *
 579  * This function enables the hotplug support. It requires that interrupts have
 580  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
 581  * poll request can run concurrently to other code, so locking rules must be
 582  * obeyed.
 583  *
 584  * This is a separate step from interrupt enabling to simplify the locking rules
 585  * in the driver load and resume code.
 586  *
 587  * Also see: intel_hpd_poll_init(), which enables connector polling
 588  */
 589 void intel_hpd_init(struct drm_i915_private *dev_priv)
 590 {
 591         int i;
 592
 593         for_each_hpd_pin(i) {
 594                 dev_priv->hotplug.stats[i].count = 0;
 595                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 596         }
 597
 598         WRITE_ONCE(dev_priv->hotplug.poll_enabled, false);
 599         schedule_work(&dev_priv->hotplug.poll_init_work);
 600
 601         /*
 602          * Interrupt setup is already guaranteed to be single-threaded, this is
 603          * just to make the assert_spin_locked checks happy.
 604          */
 605         if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup) {
 606                 spin_lock_irq(&dev_priv->irq_lock);
 607                 if (dev_priv->display_irqs_enabled)
 608                         dev_priv->display.hpd_irq_setup(dev_priv);
 609                 spin_unlock_irq(&dev_priv->irq_lock);
 610         }
 611 }
 612
 613 static void i915_hpd_poll_init_work(struct work_struct *work)
 614 {
 615         struct drm_i915_private *dev_priv =
 616                 container_of(work, struct drm_i915_private,
 617                              hotplug.poll_init_work);
 618         struct drm_device *dev = &dev_priv->drm;
 619         struct drm_connector_list_iter conn_iter;
 620         struct intel_connector *connector;
 621         bool enabled;
 622
 623         mutex_lock(&dev->mode_config.mutex);
 624
 625         enabled = READ_ONCE(dev_priv->hotplug.poll_enabled);
 626
 627         drm_connector_list_iter_begin(dev, &conn_iter);
 628         for_each_intel_connector_iter(connector, &conn_iter) {
 629                 enum hpd_pin pin;
 630
 631                 pin = intel_connector_hpd_pin(connector);
 632                 if (pin == HPD_NONE)
 633                         continue;
 634
 635                 connector->base.polled = connector->polled;
 636
 637                 if (enabled && connector->base.polled == DRM_CONNECTOR_POLL_HPD)
 638                         connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
 639                                 DRM_CONNECTOR_POLL_DISCONNECT;
 640         }
 641         drm_connector_list_iter_end(&conn_iter);
 642
 643         if (enabled)
 644                 drm_kms_helper_poll_enable(dev);
 645
 646         mutex_unlock(&dev->mode_config.mutex);
 647
 648         /*
 649          * We might have missed any hotplugs that happened while we were
 650          * in the middle of disabling polling
 651          */
 652         if (!enabled)
 653                 drm_helper_hpd_irq_event(dev);
 654 }
 655
 656 /**
 657  * intel_hpd_poll_init - enables/disables polling for connectors with hpd
 658  * @dev_priv: i915 device instance
 659  *
 660  * This function enables polling for all connectors, regardless of whether or
 661  * not they support hotplug detection. Under certain conditions HPD may not be
 662  * functional. On most Intel GPUs, this happens when we enter runtime suspend.
 663  * On Valleyview and Cherryview systems, this also happens when we shut off all
 664  * of the powerwells.
 665  *
 666  * Since this function can get called in contexts where we're already holding
 667  * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
 668  * worker.
 669  *
 670  * Also see: intel_hpd_init(), which restores hpd handling.
 671  */
 672 void intel_hpd_poll_init(struct drm_i915_private *dev_priv)
 673 {
 674         WRITE_ONCE(dev_priv->hotplug.poll_enabled, true);
 675
 676         /*
 677          * We might already be holding dev->mode_config.mutex, so do this in a
 678          * seperate worker
 679          * As well, there's no issue if we race here since we always reschedule
 680          * this worker anyway
 681          */
 682         schedule_work(&dev_priv->hotplug.poll_init_work);
 683 }
 684
 685 void intel_hpd_init_work(struct drm_i915_private *dev_priv)
 686 {
 687         INIT_DELAYED_WORK(&dev_priv->hotplug.hotplug_work,
 688                           i915_hotplug_work_func);
 689         INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
 690         INIT_WORK(&dev_priv->hotplug.poll_init_work, i915_hpd_poll_init_work);
 691         INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
 692                           intel_hpd_irq_storm_reenable_work);
 693 }
 694
 695 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 696 {
 697         spin_lock_irq(&dev_priv->irq_lock);
 698
 699         dev_priv->hotplug.long_port_mask = 0;
 700         dev_priv->hotplug.short_port_mask = 0;
 701         dev_priv->hotplug.event_bits = 0;
 702         dev_priv->hotplug.retry_bits = 0;
 703
 704         spin_unlock_irq(&dev_priv->irq_lock);
 705
 706         cancel_work_sync(&dev_priv->hotplug.dig_port_work);
 707         cancel_delayed_work_sync(&dev_priv->hotplug.hotplug_work);
 708         cancel_work_sync(&dev_priv->hotplug.poll_init_work);
 709         cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 710 }
 711
 712 bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 713 {
 714         bool ret = false;
 715
 716         if (pin == HPD_NONE)
 717                 return false;
 718
 719         spin_lock_irq(&dev_priv->irq_lock);
 720         if (dev_priv->hotplug.stats[pin].state == HPD_ENABLED) {
 721                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 722                 ret = true;
 723         }
 724         spin_unlock_irq(&dev_priv->irq_lock);
 725
 726         return ret;
 727 }
 728
 729 void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 730 {
 731         if (pin == HPD_NONE)
 732                 return;
 733
 734         spin_lock_irq(&dev_priv->irq_lock);
 735         dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
 736         spin_unlock_irq(&dev_priv->irq_lock);
 737 }