drivers/gpu/drm/i915/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 <drm/drmP.h>
  27 #include <drm/i915_drm.h>
  28
  29 #include "i915_drv.h"
  30 #include "intel_drv.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 and HDP_NONE if no pin is
  87  * hard associated with that @port.
  88  */
  89 enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
  90                                    enum port port)
  91 {
  92         switch (port) {
  93         case PORT_A:
  94                 return HPD_PORT_A;
  95         case PORT_B:
  96                 return HPD_PORT_B;
  97         case PORT_C:
  98                 return HPD_PORT_C;
  99         case PORT_D:
 100                 return HPD_PORT_D;
 101         case PORT_E:
 102                 return HPD_PORT_E;
 103         case PORT_F:
 104                 if (IS_CNL_WITH_PORT_F(dev_priv))
 105                         return HPD_PORT_E;
 106                 return HPD_PORT_F;
 107         default:
 108                 MISSING_CASE(port);
 109                 return HPD_NONE;
 110         }
 111 }
 112
 113 #define HPD_STORM_DETECT_PERIOD         1000
 114 #define HPD_STORM_REENABLE_DELAY        (2 * 60 * 1000)
 115
 116 /**
 117  * intel_hpd_irq_storm_detect - gather stats and detect HPD irq storm on a pin
 118  * @dev_priv: private driver data pointer
 119  * @pin: the pin to gather stats on
 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->hotplug.hpd_storm_threshold which defaults to
 127  * @HPD_STORM_DEFAULT_THRESHOLD. If this threshold is exceeded, it's
 128  * considered an irq storm and the irq state is set to @HPD_MARK_DISABLED.
 129  *
 130  * The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
 131  * and should only be adjusted for automated hotplug testing.
 132  *
 133  * Return true if an irq storm was detected on @pin.
 134  */
 135 static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
 136                                        enum hpd_pin pin)
 137 {
 138         unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies;
 139         unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
 140         const int threshold = dev_priv->hotplug.hpd_storm_threshold;
 141         bool storm = false;
 142
 143         if (!time_in_range(jiffies, start, end)) {
 144                 dev_priv->hotplug.stats[pin].last_jiffies = jiffies;
 145                 dev_priv->hotplug.stats[pin].count = 0;
 146                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", pin);
 147         } else if (dev_priv->hotplug.stats[pin].count > threshold &&
 148                    threshold) {
 149                 dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED;
 150                 DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);
 151                 storm = true;
 152         } else {
 153                 dev_priv->hotplug.stats[pin].count++;
 154                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,
 155                               dev_priv->hotplug.stats[pin].count);
 156         }
 157
 158         return storm;
 159 }
 160
 161 static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)
 162 {
 163         struct drm_device *dev = &dev_priv->drm;
 164         struct intel_connector *intel_connector;
 165         struct intel_encoder *intel_encoder;
 166         struct drm_connector *connector;
 167         struct drm_connector_list_iter conn_iter;
 168         enum hpd_pin pin;
 169         bool hpd_disabled = false;
 170
 171         lockdep_assert_held(&dev_priv->irq_lock);
 172
 173         drm_connector_list_iter_begin(dev, &conn_iter);
 174         drm_for_each_connector_iter(connector, &conn_iter) {
 175                 if (connector->polled != DRM_CONNECTOR_POLL_HPD)
 176                         continue;
 177
 178                 intel_connector = to_intel_connector(connector);
 179                 intel_encoder = intel_connector->encoder;
 180                 if (!intel_encoder)
 181                         continue;
 182
 183                 pin = intel_encoder->hpd_pin;
 184                 if (pin == HPD_NONE ||
 185                     dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
 186                         continue;
 187
 188                 DRM_INFO("HPD interrupt storm detected on connector %s: "
 189                          "switching from hotplug detection to polling\n",
 190                          connector->name);
 191
 192                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 193                 connector->polled = DRM_CONNECTOR_POLL_CONNECT
 194                         | DRM_CONNECTOR_POLL_DISCONNECT;
 195                 hpd_disabled = true;
 196         }
 197         drm_connector_list_iter_end(&conn_iter);
 198
 199         /* Enable polling and queue hotplug re-enabling. */
 200         if (hpd_disabled) {
 201                 drm_kms_helper_poll_enable(dev);
 202                 mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
 203                                  msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 204         }
 205 }
 206
 207 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 208 {
 209         struct drm_i915_private *dev_priv =
 210                 container_of(work, typeof(*dev_priv),
 211                              hotplug.reenable_work.work);
 212         struct drm_device *dev = &dev_priv->drm;
 213         enum hpd_pin pin;
 214
 215         intel_runtime_pm_get(dev_priv);
 216
 217         spin_lock_irq(&dev_priv->irq_lock);
 218         for_each_hpd_pin(pin) {
 219                 struct drm_connector *connector;
 220                 struct drm_connector_list_iter conn_iter;
 221
 222                 if (dev_priv->hotplug.stats[pin].state != HPD_DISABLED)
 223                         continue;
 224
 225                 dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
 226
 227                 drm_connector_list_iter_begin(dev, &conn_iter);
 228                 drm_for_each_connector_iter(connector, &conn_iter) {
 229                         struct intel_connector *intel_connector = to_intel_connector(connector);
 230
 231                         /* Don't check MST ports, they don't have pins */
 232                         if (!intel_connector->mst_port &&
 233                             intel_connector->encoder->hpd_pin == pin) {
 234                                 if (connector->polled != intel_connector->polled)
 235                                         DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
 236                                                          connector->name);
 237                                 connector->polled = intel_connector->polled;
 238                                 if (!connector->polled)
 239                                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 240                         }
 241                 }
 242                 drm_connector_list_iter_end(&conn_iter);
 243         }
 244         if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup)
 245                 dev_priv->display.hpd_irq_setup(dev_priv);
 246         spin_unlock_irq(&dev_priv->irq_lock);
 247
 248         intel_runtime_pm_put(dev_priv);
 249 }
 250
 251 bool intel_encoder_hotplug(struct intel_encoder *encoder,
 252                            struct intel_connector *connector)
 253 {
 254         struct drm_device *dev = connector->base.dev;
 255         enum drm_connector_status old_status;
 256
 257         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 258         old_status = connector->base.status;
 259
 260         connector->base.status =
 261                 drm_helper_probe_detect(&connector->base, NULL, false);
 262
 263         if (old_status == connector->base.status)
 264                 return false;
 265
 266         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 267                       connector->base.base.id,
 268                       connector->base.name,
 269                       drm_get_connector_status_name(old_status),
 270                       drm_get_connector_status_name(connector->base.status));
 271
 272         return true;
 273 }
 274
 275 static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
 276 {
 277         return intel_encoder_is_dig_port(encoder) &&
 278                 enc_to_dig_port(&encoder->base)->hpd_pulse != NULL;
 279 }
 280
 281 static void i915_digport_work_func(struct work_struct *work)
 282 {
 283         struct drm_i915_private *dev_priv =
 284                 container_of(work, struct drm_i915_private, hotplug.dig_port_work);
 285         u32 long_port_mask, short_port_mask;
 286         struct intel_encoder *encoder;
 287         u32 old_bits = 0;
 288
 289         spin_lock_irq(&dev_priv->irq_lock);
 290         long_port_mask = dev_priv->hotplug.long_port_mask;
 291         dev_priv->hotplug.long_port_mask = 0;
 292         short_port_mask = dev_priv->hotplug.short_port_mask;
 293         dev_priv->hotplug.short_port_mask = 0;
 294         spin_unlock_irq(&dev_priv->irq_lock);
 295
 296         for_each_intel_encoder(&dev_priv->drm, encoder) {
 297                 struct intel_digital_port *dig_port;
 298                 enum port port = encoder->port;
 299                 bool long_hpd, short_hpd;
 300                 enum irqreturn ret;
 301
 302                 if (!intel_encoder_has_hpd_pulse(encoder))
 303                         continue;
 304
 305                 long_hpd = long_port_mask & BIT(port);
 306                 short_hpd = short_port_mask & BIT(port);
 307
 308                 if (!long_hpd && !short_hpd)
 309                         continue;
 310
 311                 dig_port = enc_to_dig_port(&encoder->base);
 312
 313                 ret = dig_port->hpd_pulse(dig_port, long_hpd);
 314                 if (ret == IRQ_NONE) {
 315                         /* fall back to old school hpd */
 316                         old_bits |= BIT(encoder->hpd_pin);
 317                 }
 318         }
 319
 320         if (old_bits) {
 321                 spin_lock_irq(&dev_priv->irq_lock);
 322                 dev_priv->hotplug.event_bits |= old_bits;
 323                 spin_unlock_irq(&dev_priv->irq_lock);
 324                 schedule_work(&dev_priv->hotplug.hotplug_work);
 325         }
 326 }
 327
 328 /*
 329  * Handle hotplug events outside the interrupt handler proper.
 330  */
 331 static void i915_hotplug_work_func(struct work_struct *work)
 332 {
 333         struct drm_i915_private *dev_priv =
 334                 container_of(work, struct drm_i915_private, hotplug.hotplug_work);
 335         struct drm_device *dev = &dev_priv->drm;
 336         struct intel_connector *intel_connector;
 337         struct intel_encoder *intel_encoder;
 338         struct drm_connector *connector;
 339         struct drm_connector_list_iter conn_iter;
 340         bool changed = false;
 341         u32 hpd_event_bits;
 342
 343         mutex_lock(&dev->mode_config.mutex);
 344         DRM_DEBUG_KMS("running encoder hotplug functions\n");
 345
 346         spin_lock_irq(&dev_priv->irq_lock);
 347
 348         hpd_event_bits = dev_priv->hotplug.event_bits;
 349         dev_priv->hotplug.event_bits = 0;
 350
 351         /* Disable hotplug on connectors that hit an irq storm. */
 352         intel_hpd_irq_storm_disable(dev_priv);
 353
 354         spin_unlock_irq(&dev_priv->irq_lock);
 355
 356         drm_connector_list_iter_begin(dev, &conn_iter);
 357         drm_for_each_connector_iter(connector, &conn_iter) {
 358                 intel_connector = to_intel_connector(connector);
 359                 if (!intel_connector->encoder)
 360                         continue;
 361                 intel_encoder = intel_connector->encoder;
 362                 if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
 363                         DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
 364                                       connector->name, intel_encoder->hpd_pin);
 365
 366                         changed |= intel_encoder->hotplug(intel_encoder,
 367                                                           intel_connector);
 368                 }
 369         }
 370         drm_connector_list_iter_end(&conn_iter);
 371         mutex_unlock(&dev->mode_config.mutex);
 372
 373         if (changed)
 374                 drm_kms_helper_hotplug_event(dev);
 375 }
 376
 377
 378 /**
 379  * intel_hpd_irq_handler - main hotplug irq handler
 380  * @dev_priv: drm_i915_private
 381  * @pin_mask: a mask of hpd pins that have triggered the irq
 382  * @long_mask: a mask of hpd pins that may be long hpd pulses
 383  *
 384  * This is the main hotplug irq handler for all platforms. The platform specific
 385  * irq handlers call the platform specific hotplug irq handlers, which read and
 386  * decode the appropriate registers into bitmasks about hpd pins that have
 387  * triggered (@pin_mask), and which of those pins may be long pulses
 388  * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
 389  * is not a digital port.
 390  *
 391  * Here, we do hotplug irq storm detection and mitigation, and pass further
 392  * processing to appropriate bottom halves.
 393  */
 394 void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 395                            u32 pin_mask, u32 long_mask)
 396 {
 397         struct intel_encoder *encoder;
 398         bool storm_detected = false;
 399         bool queue_dig = false, queue_hp = false;
 400         u32 long_hpd_pulse_mask = 0;
 401         u32 short_hpd_pulse_mask = 0;
 402         enum hpd_pin pin;
 403
 404         if (!pin_mask)
 405                 return;
 406
 407         spin_lock(&dev_priv->irq_lock);
 408
 409         /*
 410          * Determine whether ->hpd_pulse() exists for each pin, and
 411          * whether we have a short or a long pulse. This is needed
 412          * as each pin may have up to two encoders (HDMI and DP) and
 413          * only the one of them (DP) will have ->hpd_pulse().
 414          */
 415         for_each_intel_encoder(&dev_priv->drm, encoder) {
 416                 bool has_hpd_pulse = intel_encoder_has_hpd_pulse(encoder);
 417                 enum port port = encoder->port;
 418                 bool long_hpd;
 419
 420                 pin = encoder->hpd_pin;
 421                 if (!(BIT(pin) & pin_mask))
 422                         continue;
 423
 424                 if (!has_hpd_pulse)
 425                         continue;
 426
 427                 long_hpd = long_mask & BIT(pin);
 428
 429                 DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
 430                                  long_hpd ? "long" : "short");
 431                 queue_dig = true;
 432
 433                 if (long_hpd) {
 434                         long_hpd_pulse_mask |= BIT(pin);
 435                         dev_priv->hotplug.long_port_mask |= BIT(port);
 436                 } else {
 437                         short_hpd_pulse_mask |= BIT(pin);
 438                         dev_priv->hotplug.short_port_mask |= BIT(port);
 439                 }
 440         }
 441
 442         /* Now process each pin just once */
 443         for_each_hpd_pin(pin) {
 444                 bool long_hpd;
 445
 446                 if (!(BIT(pin) & pin_mask))
 447                         continue;
 448
 449                 if (dev_priv->hotplug.stats[pin].state == HPD_DISABLED) {
 450                         /*
 451                          * On GMCH platforms the interrupt mask bits only
 452                          * prevent irq generation, not the setting of the
 453                          * hotplug bits itself. So only WARN about unexpected
 454                          * interrupts on saner platforms.
 455                          */
 456                         WARN_ONCE(!HAS_GMCH_DISPLAY(dev_priv),
 457                                   "Received HPD interrupt on pin %d although disabled\n", pin);
 458                         continue;
 459                 }
 460
 461                 if (dev_priv->hotplug.stats[pin].state != HPD_ENABLED)
 462                         continue;
 463
 464                 /*
 465                  * Delegate to ->hpd_pulse() if one of the encoders for this
 466                  * pin has it, otherwise let the hotplug_work deal with this
 467                  * pin directly.
 468                  */
 469                 if (((short_hpd_pulse_mask | long_hpd_pulse_mask) & BIT(pin))) {
 470                         long_hpd = long_hpd_pulse_mask & BIT(pin);
 471                 } else {
 472                         dev_priv->hotplug.event_bits |= BIT(pin);
 473                         long_hpd = true;
 474                         queue_hp = true;
 475                 }
 476
 477                 if (!long_hpd)
 478                         continue;
 479
 480                 if (intel_hpd_irq_storm_detect(dev_priv, pin)) {
 481                         dev_priv->hotplug.event_bits &= ~BIT(pin);
 482                         storm_detected = true;
 483                 }
 484         }
 485
 486         if (storm_detected && dev_priv->display_irqs_enabled)
 487                 dev_priv->display.hpd_irq_setup(dev_priv);
 488         spin_unlock(&dev_priv->irq_lock);
 489
 490         /*
 491          * Our hotplug handler can grab modeset locks (by calling down into the
 492          * fb helpers). Hence it must not be run on our own dev-priv->wq work
 493          * queue for otherwise the flush_work in the pageflip code will
 494          * deadlock.
 495          */
 496         if (queue_dig)
 497                 queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
 498         if (queue_hp)
 499                 schedule_work(&dev_priv->hotplug.hotplug_work);
 500 }
 501
 502 /**
 503  * intel_hpd_init - initializes and enables hpd support
 504  * @dev_priv: i915 device instance
 505  *
 506  * This function enables the hotplug support. It requires that interrupts have
 507  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
 508  * poll request can run concurrently to other code, so locking rules must be
 509  * obeyed.
 510  *
 511  * This is a separate step from interrupt enabling to simplify the locking rules
 512  * in the driver load and resume code.
 513  *
 514  * Also see: intel_hpd_poll_init(), which enables connector polling
 515  */
 516 void intel_hpd_init(struct drm_i915_private *dev_priv)
 517 {
 518         int i;
 519
 520         for_each_hpd_pin(i) {
 521                 dev_priv->hotplug.stats[i].count = 0;
 522                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 523         }
 524
 525         WRITE_ONCE(dev_priv->hotplug.poll_enabled, false);
 526         schedule_work(&dev_priv->hotplug.poll_init_work);
 527
 528         /*
 529          * Interrupt setup is already guaranteed to be single-threaded, this is
 530          * just to make the assert_spin_locked checks happy.
 531          */
 532         if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup) {
 533                 spin_lock_irq(&dev_priv->irq_lock);
 534                 if (dev_priv->display_irqs_enabled)
 535                         dev_priv->display.hpd_irq_setup(dev_priv);
 536                 spin_unlock_irq(&dev_priv->irq_lock);
 537         }
 538 }
 539
 540 static void i915_hpd_poll_init_work(struct work_struct *work)
 541 {
 542         struct drm_i915_private *dev_priv =
 543                 container_of(work, struct drm_i915_private,
 544                              hotplug.poll_init_work);
 545         struct drm_device *dev = &dev_priv->drm;
 546         struct drm_connector *connector;
 547         struct drm_connector_list_iter conn_iter;
 548         bool enabled;
 549
 550         mutex_lock(&dev->mode_config.mutex);
 551
 552         enabled = READ_ONCE(dev_priv->hotplug.poll_enabled);
 553
 554         drm_connector_list_iter_begin(dev, &conn_iter);
 555         drm_for_each_connector_iter(connector, &conn_iter) {
 556                 struct intel_connector *intel_connector =
 557                         to_intel_connector(connector);
 558                 connector->polled = intel_connector->polled;
 559
 560                 /* MST has a dynamic intel_connector->encoder and it's reprobing
 561                  * is all handled by the MST helpers. */
 562                 if (intel_connector->mst_port)
 563                         continue;
 564
 565                 if (!connector->polled && I915_HAS_HOTPLUG(dev_priv) &&
 566                     intel_connector->encoder->hpd_pin > HPD_NONE) {
 567                         connector->polled = enabled ?
 568                                 DRM_CONNECTOR_POLL_CONNECT |
 569                                 DRM_CONNECTOR_POLL_DISCONNECT :
 570                                 DRM_CONNECTOR_POLL_HPD;
 571                 }
 572         }
 573         drm_connector_list_iter_end(&conn_iter);
 574
 575         if (enabled)
 576                 drm_kms_helper_poll_enable(dev);
 577
 578         mutex_unlock(&dev->mode_config.mutex);
 579
 580         /*
 581          * We might have missed any hotplugs that happened while we were
 582          * in the middle of disabling polling
 583          */
 584         if (!enabled)
 585                 drm_helper_hpd_irq_event(dev);
 586 }
 587
 588 /**
 589  * intel_hpd_poll_init - enables/disables polling for connectors with hpd
 590  * @dev_priv: i915 device instance
 591  *
 592  * This function enables polling for all connectors, regardless of whether or
 593  * not they support hotplug detection. Under certain conditions HPD may not be
 594  * functional. On most Intel GPUs, this happens when we enter runtime suspend.
 595  * On Valleyview and Cherryview systems, this also happens when we shut off all
 596  * of the powerwells.
 597  *
 598  * Since this function can get called in contexts where we're already holding
 599  * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
 600  * worker.
 601  *
 602  * Also see: intel_hpd_init(), which restores hpd handling.
 603  */
 604 void intel_hpd_poll_init(struct drm_i915_private *dev_priv)
 605 {
 606         WRITE_ONCE(dev_priv->hotplug.poll_enabled, true);
 607
 608         /*
 609          * We might already be holding dev->mode_config.mutex, so do this in a
 610          * seperate worker
 611          * As well, there's no issue if we race here since we always reschedule
 612          * this worker anyway
 613          */
 614         schedule_work(&dev_priv->hotplug.poll_init_work);
 615 }
 616
 617 void intel_hpd_init_work(struct drm_i915_private *dev_priv)
 618 {
 619         INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
 620         INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
 621         INIT_WORK(&dev_priv->hotplug.poll_init_work, i915_hpd_poll_init_work);
 622         INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
 623                           intel_hpd_irq_storm_reenable_work);
 624 }
 625
 626 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 627 {
 628         spin_lock_irq(&dev_priv->irq_lock);
 629
 630         dev_priv->hotplug.long_port_mask = 0;
 631         dev_priv->hotplug.short_port_mask = 0;
 632         dev_priv->hotplug.event_bits = 0;
 633
 634         spin_unlock_irq(&dev_priv->irq_lock);
 635
 636         cancel_work_sync(&dev_priv->hotplug.dig_port_work);
 637         cancel_work_sync(&dev_priv->hotplug.hotplug_work);
 638         cancel_work_sync(&dev_priv->hotplug.poll_init_work);
 639         cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 640 }
 641
 642 bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 643 {
 644         bool ret = false;
 645
 646         if (pin == HPD_NONE)
 647                 return false;
 648
 649         spin_lock_irq(&dev_priv->irq_lock);
 650         if (dev_priv->hotplug.stats[pin].state == HPD_ENABLED) {
 651                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 652                 ret = true;
 653         }
 654         spin_unlock_irq(&dev_priv->irq_lock);
 655
 656         return ret;
 657 }
 658
 659 void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 660 {
 661         if (pin == HPD_NONE)
 662                 return;
 663
 664         spin_lock_irq(&dev_priv->irq_lock);
 665         dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
 666         spin_unlock_irq(&dev_priv->irq_lock);
 667 }