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_port - return port hard associated with certain pin.
  81  * @dev_priv: private driver data pointer
  82  * @pin: the hpd pin to get associated port
  83  *
  84  * Return port that is associatade with @pin and PORT_NONE if no port is
  85  * hard associated with that @pin.
  86  */
  87 enum port intel_hpd_pin_to_port(struct drm_i915_private *dev_priv,
  88                                 enum hpd_pin pin)
  89 {
  90         switch (pin) {
  91         case HPD_PORT_A:
  92                 return PORT_A;
  93         case HPD_PORT_B:
  94                 return PORT_B;
  95         case HPD_PORT_C:
  96                 return PORT_C;
  97         case HPD_PORT_D:
  98                 return PORT_D;
  99         case HPD_PORT_E:
 100                 if (IS_CNL_WITH_PORT_F(dev_priv))
 101                         return PORT_F;
 102                 return PORT_E;
 103         case HPD_PORT_F:
 104                 return PORT_F;
 105         default:
 106                 return PORT_NONE; /* no port for this pin */
 107         }
 108 }
 109
 110 /**
 111  * intel_hpd_pin_default - return default pin associated with certain port.
 112  * @dev_priv: private driver data pointer
 113  * @port: the hpd port to get associated pin
 114  *
 115  * It is only valid and used by digital port encoder.
 116  *
 117  * Return pin that is associatade with @port and HDP_NONE if no pin is
 118  * hard associated with that @port.
 119  */
 120 enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
 121                                    enum port port)
 122 {
 123         switch (port) {
 124         case PORT_A:
 125                 return HPD_PORT_A;
 126         case PORT_B:
 127                 return HPD_PORT_B;
 128         case PORT_C:
 129                 return HPD_PORT_C;
 130         case PORT_D:
 131                 return HPD_PORT_D;
 132         case PORT_E:
 133                 return HPD_PORT_E;
 134         case PORT_F:
 135                 if (IS_CNL_WITH_PORT_F(dev_priv))
 136                         return HPD_PORT_E;
 137                 return HPD_PORT_F;
 138         default:
 139                 MISSING_CASE(port);
 140                 return HPD_NONE;
 141         }
 142 }
 143
 144 #define HPD_STORM_DETECT_PERIOD         1000
 145 #define HPD_STORM_REENABLE_DELAY        (2 * 60 * 1000)
 146
 147 /**
 148  * intel_hpd_irq_storm_detect - gather stats and detect HPD irq storm on a pin
 149  * @dev_priv: private driver data pointer
 150  * @pin: the pin to gather stats on
 151  *
 152  * Gather stats about HPD irqs from the specified @pin, and detect irq
 153  * storms. Only the pin specific stats and state are changed, the caller is
 154  * responsible for further action.
 155  *
 156  * The number of irqs that are allowed within @HPD_STORM_DETECT_PERIOD is
 157  * stored in @dev_priv->hotplug.hpd_storm_threshold which defaults to
 158  * @HPD_STORM_DEFAULT_THRESHOLD. If this threshold is exceeded, it's
 159  * considered an irq storm and the irq state is set to @HPD_MARK_DISABLED.
 160  *
 161  * The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
 162  * and should only be adjusted for automated hotplug testing.
 163  *
 164  * Return true if an irq storm was detected on @pin.
 165  */
 166 static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
 167                                        enum hpd_pin pin)
 168 {
 169         unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies;
 170         unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
 171         const int threshold = dev_priv->hotplug.hpd_storm_threshold;
 172         bool storm = false;
 173
 174         if (!time_in_range(jiffies, start, end)) {
 175                 dev_priv->hotplug.stats[pin].last_jiffies = jiffies;
 176                 dev_priv->hotplug.stats[pin].count = 0;
 177                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", pin);
 178         } else if (dev_priv->hotplug.stats[pin].count > threshold &&
 179                    threshold) {
 180                 dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED;
 181                 DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);
 182                 storm = true;
 183         } else {
 184                 dev_priv->hotplug.stats[pin].count++;
 185                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,
 186                               dev_priv->hotplug.stats[pin].count);
 187         }
 188
 189         return storm;
 190 }
 191
 192 static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)
 193 {
 194         struct drm_device *dev = &dev_priv->drm;
 195         struct intel_connector *intel_connector;
 196         struct intel_encoder *intel_encoder;
 197         struct drm_connector *connector;
 198         struct drm_connector_list_iter conn_iter;
 199         enum hpd_pin pin;
 200         bool hpd_disabled = false;
 201
 202         lockdep_assert_held(&dev_priv->irq_lock);
 203
 204         drm_connector_list_iter_begin(dev, &conn_iter);
 205         drm_for_each_connector_iter(connector, &conn_iter) {
 206                 if (connector->polled != DRM_CONNECTOR_POLL_HPD)
 207                         continue;
 208
 209                 intel_connector = to_intel_connector(connector);
 210                 intel_encoder = intel_connector->encoder;
 211                 if (!intel_encoder)
 212                         continue;
 213
 214                 pin = intel_encoder->hpd_pin;
 215                 if (pin == HPD_NONE ||
 216                     dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
 217                         continue;
 218
 219                 DRM_INFO("HPD interrupt storm detected on connector %s: "
 220                          "switching from hotplug detection to polling\n",
 221                          connector->name);
 222
 223                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 224                 connector->polled = DRM_CONNECTOR_POLL_CONNECT
 225                         | DRM_CONNECTOR_POLL_DISCONNECT;
 226                 hpd_disabled = true;
 227         }
 228         drm_connector_list_iter_end(&conn_iter);
 229
 230         /* Enable polling and queue hotplug re-enabling. */
 231         if (hpd_disabled) {
 232                 drm_kms_helper_poll_enable(dev);
 233                 mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
 234                                  msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 235         }
 236 }
 237
 238 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 239 {
 240         struct drm_i915_private *dev_priv =
 241                 container_of(work, typeof(*dev_priv),
 242                              hotplug.reenable_work.work);
 243         struct drm_device *dev = &dev_priv->drm;
 244         int i;
 245
 246         intel_runtime_pm_get(dev_priv);
 247
 248         spin_lock_irq(&dev_priv->irq_lock);
 249         for_each_hpd_pin(i) {
 250                 struct drm_connector *connector;
 251                 struct drm_connector_list_iter conn_iter;
 252
 253                 if (dev_priv->hotplug.stats[i].state != HPD_DISABLED)
 254                         continue;
 255
 256                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 257
 258                 drm_connector_list_iter_begin(dev, &conn_iter);
 259                 drm_for_each_connector_iter(connector, &conn_iter) {
 260                         struct intel_connector *intel_connector = to_intel_connector(connector);
 261
 262                         if (intel_connector->encoder->hpd_pin == i) {
 263                                 if (connector->polled != intel_connector->polled)
 264                                         DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
 265                                                          connector->name);
 266                                 connector->polled = intel_connector->polled;
 267                                 if (!connector->polled)
 268                                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 269                         }
 270                 }
 271                 drm_connector_list_iter_end(&conn_iter);
 272         }
 273         if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup)
 274                 dev_priv->display.hpd_irq_setup(dev_priv);
 275         spin_unlock_irq(&dev_priv->irq_lock);
 276
 277         intel_runtime_pm_put(dev_priv);
 278 }
 279
 280 bool intel_encoder_hotplug(struct intel_encoder *encoder,
 281                            struct intel_connector *connector)
 282 {
 283         struct drm_device *dev = connector->base.dev;
 284         enum drm_connector_status old_status;
 285
 286         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 287         old_status = connector->base.status;
 288
 289         connector->base.status =
 290                 drm_helper_probe_detect(&connector->base, NULL, false);
 291
 292         if (old_status == connector->base.status)
 293                 return false;
 294
 295         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 296                       connector->base.base.id,
 297                       connector->base.name,
 298                       drm_get_connector_status_name(old_status),
 299                       drm_get_connector_status_name(connector->base.status));
 300
 301         return true;
 302 }
 303
 304 static void i915_digport_work_func(struct work_struct *work)
 305 {
 306         struct drm_i915_private *dev_priv =
 307                 container_of(work, struct drm_i915_private, hotplug.dig_port_work);
 308         u32 long_port_mask, short_port_mask;
 309         struct intel_digital_port *intel_dig_port;
 310         int i;
 311         u32 old_bits = 0;
 312
 313         spin_lock_irq(&dev_priv->irq_lock);
 314         long_port_mask = dev_priv->hotplug.long_port_mask;
 315         dev_priv->hotplug.long_port_mask = 0;
 316         short_port_mask = dev_priv->hotplug.short_port_mask;
 317         dev_priv->hotplug.short_port_mask = 0;
 318         spin_unlock_irq(&dev_priv->irq_lock);
 319
 320         for (i = 0; i < I915_MAX_PORTS; i++) {
 321                 bool valid = false;
 322                 bool long_hpd = false;
 323                 intel_dig_port = dev_priv->hotplug.irq_port[i];
 324                 if (!intel_dig_port || !intel_dig_port->hpd_pulse)
 325                         continue;
 326
 327                 if (long_port_mask & (1 << i))  {
 328                         valid = true;
 329                         long_hpd = true;
 330                 } else if (short_port_mask & (1 << i))
 331                         valid = true;
 332
 333                 if (valid) {
 334                         enum irqreturn ret;
 335
 336                         ret = intel_dig_port->hpd_pulse(intel_dig_port, long_hpd);
 337                         if (ret == IRQ_NONE) {
 338                                 /* fall back to old school hpd */
 339                                 old_bits |= (1 << intel_dig_port->base.hpd_pin);
 340                         }
 341                 }
 342         }
 343
 344         if (old_bits) {
 345                 spin_lock_irq(&dev_priv->irq_lock);
 346                 dev_priv->hotplug.event_bits |= old_bits;
 347                 spin_unlock_irq(&dev_priv->irq_lock);
 348                 schedule_work(&dev_priv->hotplug.hotplug_work);
 349         }
 350 }
 351
 352 /*
 353  * Handle hotplug events outside the interrupt handler proper.
 354  */
 355 static void i915_hotplug_work_func(struct work_struct *work)
 356 {
 357         struct drm_i915_private *dev_priv =
 358                 container_of(work, struct drm_i915_private, hotplug.hotplug_work);
 359         struct drm_device *dev = &dev_priv->drm;
 360         struct intel_connector *intel_connector;
 361         struct intel_encoder *intel_encoder;
 362         struct drm_connector *connector;
 363         struct drm_connector_list_iter conn_iter;
 364         bool changed = false;
 365         u32 hpd_event_bits;
 366
 367         mutex_lock(&dev->mode_config.mutex);
 368         DRM_DEBUG_KMS("running encoder hotplug functions\n");
 369
 370         spin_lock_irq(&dev_priv->irq_lock);
 371
 372         hpd_event_bits = dev_priv->hotplug.event_bits;
 373         dev_priv->hotplug.event_bits = 0;
 374
 375         /* Disable hotplug on connectors that hit an irq storm. */
 376         intel_hpd_irq_storm_disable(dev_priv);
 377
 378         spin_unlock_irq(&dev_priv->irq_lock);
 379
 380         drm_connector_list_iter_begin(dev, &conn_iter);
 381         drm_for_each_connector_iter(connector, &conn_iter) {
 382                 intel_connector = to_intel_connector(connector);
 383                 if (!intel_connector->encoder)
 384                         continue;
 385                 intel_encoder = intel_connector->encoder;
 386                 if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
 387                         DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
 388                                       connector->name, intel_encoder->hpd_pin);
 389
 390                         changed |= intel_encoder->hotplug(intel_encoder,
 391                                                           intel_connector);
 392                 }
 393         }
 394         drm_connector_list_iter_end(&conn_iter);
 395         mutex_unlock(&dev->mode_config.mutex);
 396
 397         if (changed)
 398                 drm_kms_helper_hotplug_event(dev);
 399 }
 400
 401
 402 /**
 403  * intel_hpd_irq_handler - main hotplug irq handler
 404  * @dev_priv: drm_i915_private
 405  * @pin_mask: a mask of hpd pins that have triggered the irq
 406  * @long_mask: a mask of hpd pins that may be long hpd pulses
 407  *
 408  * This is the main hotplug irq handler for all platforms. The platform specific
 409  * irq handlers call the platform specific hotplug irq handlers, which read and
 410  * decode the appropriate registers into bitmasks about hpd pins that have
 411  * triggered (@pin_mask), and which of those pins may be long pulses
 412  * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
 413  * is not a digital port.
 414  *
 415  * Here, we do hotplug irq storm detection and mitigation, and pass further
 416  * processing to appropriate bottom halves.
 417  */
 418 void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 419                            u32 pin_mask, u32 long_mask)
 420 {
 421         int i;
 422         enum port port;
 423         bool storm_detected = false;
 424         bool queue_dig = false, queue_hp = false;
 425         bool is_dig_port;
 426
 427         if (!pin_mask)
 428                 return;
 429
 430         spin_lock(&dev_priv->irq_lock);
 431         for_each_hpd_pin(i) {
 432                 if (!(BIT(i) & pin_mask))
 433                         continue;
 434
 435                 port = intel_hpd_pin_to_port(dev_priv, i);
 436                 is_dig_port = port != PORT_NONE &&
 437                         dev_priv->hotplug.irq_port[port];
 438
 439                 if (is_dig_port) {
 440                         bool long_hpd = long_mask & BIT(i);
 441
 442                         DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
 443                                          long_hpd ? "long" : "short");
 444                         /*
 445                          * For long HPD pulses we want to have the digital queue happen,
 446                          * but we still want HPD storm detection to function.
 447                          */
 448                         queue_dig = true;
 449                         if (long_hpd) {
 450                                 dev_priv->hotplug.long_port_mask |= (1 << port);
 451                         } else {
 452                                 /* for short HPD just trigger the digital queue */
 453                                 dev_priv->hotplug.short_port_mask |= (1 << port);
 454                                 continue;
 455                         }
 456                 }
 457
 458                 if (dev_priv->hotplug.stats[i].state == HPD_DISABLED) {
 459                         /*
 460                          * On GMCH platforms the interrupt mask bits only
 461                          * prevent irq generation, not the setting of the
 462                          * hotplug bits itself. So only WARN about unexpected
 463                          * interrupts on saner platforms.
 464                          */
 465                         WARN_ONCE(!HAS_GMCH_DISPLAY(dev_priv),
 466                                   "Received HPD interrupt on pin %d although disabled\n", i);
 467                         continue;
 468                 }
 469
 470                 if (dev_priv->hotplug.stats[i].state != HPD_ENABLED)
 471                         continue;
 472
 473                 if (!is_dig_port) {
 474                         dev_priv->hotplug.event_bits |= BIT(i);
 475                         queue_hp = true;
 476                 }
 477
 478                 if (intel_hpd_irq_storm_detect(dev_priv, i)) {
 479                         dev_priv->hotplug.event_bits &= ~BIT(i);
 480                         storm_detected = true;
 481                 }
 482         }
 483
 484         if (storm_detected && dev_priv->display_irqs_enabled)
 485                 dev_priv->display.hpd_irq_setup(dev_priv);
 486         spin_unlock(&dev_priv->irq_lock);
 487
 488         /*
 489          * Our hotplug handler can grab modeset locks (by calling down into the
 490          * fb helpers). Hence it must not be run on our own dev-priv->wq work
 491          * queue for otherwise the flush_work in the pageflip code will
 492          * deadlock.
 493          */
 494         if (queue_dig)
 495                 queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
 496         if (queue_hp)
 497                 schedule_work(&dev_priv->hotplug.hotplug_work);
 498 }
 499
 500 /**
 501  * intel_hpd_init - initializes and enables hpd support
 502  * @dev_priv: i915 device instance
 503  *
 504  * This function enables the hotplug support. It requires that interrupts have
 505  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
 506  * poll request can run concurrently to other code, so locking rules must be
 507  * obeyed.
 508  *
 509  * This is a separate step from interrupt enabling to simplify the locking rules
 510  * in the driver load and resume code.
 511  *
 512  * Also see: intel_hpd_poll_init(), which enables connector polling
 513  */
 514 void intel_hpd_init(struct drm_i915_private *dev_priv)
 515 {
 516         int i;
 517
 518         for_each_hpd_pin(i) {
 519                 dev_priv->hotplug.stats[i].count = 0;
 520                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 521         }
 522
 523         WRITE_ONCE(dev_priv->hotplug.poll_enabled, false);
 524         schedule_work(&dev_priv->hotplug.poll_init_work);
 525
 526         /*
 527          * Interrupt setup is already guaranteed to be single-threaded, this is
 528          * just to make the assert_spin_locked checks happy.
 529          */
 530         if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup) {
 531                 spin_lock_irq(&dev_priv->irq_lock);
 532                 if (dev_priv->display_irqs_enabled)
 533                         dev_priv->display.hpd_irq_setup(dev_priv);
 534                 spin_unlock_irq(&dev_priv->irq_lock);
 535         }
 536 }
 537
 538 static void i915_hpd_poll_init_work(struct work_struct *work)
 539 {
 540         struct drm_i915_private *dev_priv =
 541                 container_of(work, struct drm_i915_private,
 542                              hotplug.poll_init_work);
 543         struct drm_device *dev = &dev_priv->drm;
 544         struct drm_connector *connector;
 545         struct drm_connector_list_iter conn_iter;
 546         bool enabled;
 547
 548         mutex_lock(&dev->mode_config.mutex);
 549
 550         enabled = READ_ONCE(dev_priv->hotplug.poll_enabled);
 551
 552         drm_connector_list_iter_begin(dev, &conn_iter);
 553         drm_for_each_connector_iter(connector, &conn_iter) {
 554                 struct intel_connector *intel_connector =
 555                         to_intel_connector(connector);
 556                 connector->polled = intel_connector->polled;
 557
 558                 /* MST has a dynamic intel_connector->encoder and it's reprobing
 559                  * is all handled by the MST helpers. */
 560                 if (intel_connector->mst_port)
 561                         continue;
 562
 563                 if (!connector->polled && I915_HAS_HOTPLUG(dev_priv) &&
 564                     intel_connector->encoder->hpd_pin > HPD_NONE) {
 565                         connector->polled = enabled ?
 566                                 DRM_CONNECTOR_POLL_CONNECT |
 567                                 DRM_CONNECTOR_POLL_DISCONNECT :
 568                                 DRM_CONNECTOR_POLL_HPD;
 569                 }
 570         }
 571         drm_connector_list_iter_end(&conn_iter);
 572
 573         if (enabled)
 574                 drm_kms_helper_poll_enable(dev);
 575
 576         mutex_unlock(&dev->mode_config.mutex);
 577
 578         /*
 579          * We might have missed any hotplugs that happened while we were
 580          * in the middle of disabling polling
 581          */
 582         if (!enabled)
 583                 drm_helper_hpd_irq_event(dev);
 584 }
 585
 586 /**
 587  * intel_hpd_poll_init - enables/disables polling for connectors with hpd
 588  * @dev_priv: i915 device instance
 589  *
 590  * This function enables polling for all connectors, regardless of whether or
 591  * not they support hotplug detection. Under certain conditions HPD may not be
 592  * functional. On most Intel GPUs, this happens when we enter runtime suspend.
 593  * On Valleyview and Cherryview systems, this also happens when we shut off all
 594  * of the powerwells.
 595  *
 596  * Since this function can get called in contexts where we're already holding
 597  * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
 598  * worker.
 599  *
 600  * Also see: intel_hpd_init(), which restores hpd handling.
 601  */
 602 void intel_hpd_poll_init(struct drm_i915_private *dev_priv)
 603 {
 604         WRITE_ONCE(dev_priv->hotplug.poll_enabled, true);
 605
 606         /*
 607          * We might already be holding dev->mode_config.mutex, so do this in a
 608          * seperate worker
 609          * As well, there's no issue if we race here since we always reschedule
 610          * this worker anyway
 611          */
 612         schedule_work(&dev_priv->hotplug.poll_init_work);
 613 }
 614
 615 void intel_hpd_init_work(struct drm_i915_private *dev_priv)
 616 {
 617         INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
 618         INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
 619         INIT_WORK(&dev_priv->hotplug.poll_init_work, i915_hpd_poll_init_work);
 620         INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
 621                           intel_hpd_irq_storm_reenable_work);
 622 }
 623
 624 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 625 {
 626         spin_lock_irq(&dev_priv->irq_lock);
 627
 628         dev_priv->hotplug.long_port_mask = 0;
 629         dev_priv->hotplug.short_port_mask = 0;
 630         dev_priv->hotplug.event_bits = 0;
 631
 632         spin_unlock_irq(&dev_priv->irq_lock);
 633
 634         cancel_work_sync(&dev_priv->hotplug.dig_port_work);
 635         cancel_work_sync(&dev_priv->hotplug.hotplug_work);
 636         cancel_work_sync(&dev_priv->hotplug.poll_init_work);
 637         cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 638 }
 639
 640 bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 641 {
 642         bool ret = false;
 643
 644         if (pin == HPD_NONE)
 645                 return false;
 646
 647         spin_lock_irq(&dev_priv->irq_lock);
 648         if (dev_priv->hotplug.stats[pin].state == HPD_ENABLED) {
 649                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 650                 ret = true;
 651         }
 652         spin_unlock_irq(&dev_priv->irq_lock);
 653
 654         return ret;
 655 }
 656
 657 void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 658 {
 659         if (pin == HPD_NONE)
 660                 return;
 661
 662         spin_lock_irq(&dev_priv->irq_lock);
 663         dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
 664         spin_unlock_irq(&dev_priv->irq_lock);
 665 }