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