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

DEFINITIONS

1. intel_hpd_pin_default
2. intel_hpd_irq_storm_detect
3. intel_hpd_irq_storm_switch_to_polling
4. intel_hpd_irq_storm_reenable_work
5. intel_encoder_hotplug
6. intel_encoder_has_hpd_pulse
7. i915_digport_work_func
8. i915_hotplug_work_func
9. intel_hpd_irq_handler
10. intel_hpd_init
11. i915_hpd_poll_init_work
12. intel_hpd_poll_init
13. intel_hpd_init_work
14. intel_hpd_cancel_work
15. intel_hpd_disable
16. intel_hpd_enable

   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/i915_drm.h>
  27 
  28 #include "i915_drv.h"
  29 #include "intel_display_types.h"
  30 #include "intel_hotplug.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         case PORT_G:
 108                 return HPD_PORT_G;
 109         case PORT_H:
 110                 return HPD_PORT_H;
 111         case PORT_I:
 112                 return HPD_PORT_I;
 113         default:
 114                 MISSING_CASE(port);
 115                 return HPD_NONE;
 116         }
 117 }
 118 
 119 #define HPD_STORM_DETECT_PERIOD         1000
 120 #define HPD_STORM_REENABLE_DELAY        (2 * 60 * 1000)
 121 #define HPD_RETRY_DELAY                 1000
 122 
 123 /**
 124  * intel_hpd_irq_storm_detect - gather stats and detect HPD IRQ storm on a pin
 125  * @dev_priv: private driver data pointer
 126  * @pin: the pin to gather stats on
 127  * @long_hpd: whether the HPD IRQ was long or short
 128  *
 129  * Gather stats about HPD IRQs from the specified @pin, and detect IRQ
 130  * storms. Only the pin specific stats and state are changed, the caller is
 131  * responsible for further action.
 132  *
 133  * The number of IRQs that are allowed within @HPD_STORM_DETECT_PERIOD is
 134  * stored in @dev_priv->hotplug.hpd_storm_threshold which defaults to
 135  * @HPD_STORM_DEFAULT_THRESHOLD. Long IRQs count as +10 to this threshold, and
 136  * short IRQs count as +1. If this threshold is exceeded, it's considered an
 137  * IRQ storm and the IRQ state is set to @HPD_MARK_DISABLED.
 138  *
 139  * By default, most systems will only count long IRQs towards
 140  * &dev_priv->hotplug.hpd_storm_threshold. However, some older systems also
 141  * suffer from short IRQ storms and must also track these. Because short IRQ
 142  * storms are naturally caused by sideband interactions with DP MST devices,
 143  * short IRQ detection is only enabled for systems without DP MST support.
 144  * Systems which are new enough to support DP MST are far less likely to
 145  * suffer from IRQ storms at all, so this is fine.
 146  *
 147  * The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
 148  * and should only be adjusted for automated hotplug testing.
 149  *
 150  * Return true if an IRQ storm was detected on @pin.
 151  */
 152 static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
 153                                        enum hpd_pin pin, bool long_hpd)
 154 {
 155         struct i915_hotplug *hpd = &dev_priv->hotplug;
 156         unsigned long start = hpd->stats[pin].last_jiffies;
 157         unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
 158         const int increment = long_hpd ? 10 : 1;
 159         const int threshold = hpd->hpd_storm_threshold;
 160         bool storm = false;
 161 
 162         if (!threshold ||
 163             (!long_hpd && !dev_priv->hotplug.hpd_short_storm_enabled))
 164                 return false;
 165 
 166         if (!time_in_range(jiffies, start, end)) {
 167                 hpd->stats[pin].last_jiffies = jiffies;
 168                 hpd->stats[pin].count = 0;
 169         }
 170 
 171         hpd->stats[pin].count += increment;
 172         if (hpd->stats[pin].count > threshold) {
 173                 hpd->stats[pin].state = HPD_MARK_DISABLED;
 174                 DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);
 175                 storm = true;
 176         } else {
 177                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,
 178                               hpd->stats[pin].count);
 179         }
 180 
 181         return storm;
 182 }
 183 
 184 static void
 185 intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
 186 {
 187         struct drm_device *dev = &dev_priv->drm;
 188         struct intel_connector *intel_connector;
 189         struct intel_encoder *intel_encoder;
 190         struct drm_connector *connector;
 191         struct drm_connector_list_iter conn_iter;
 192         enum hpd_pin pin;
 193         bool hpd_disabled = false;
 194 
 195         lockdep_assert_held(&dev_priv->irq_lock);
 196 
 197         drm_connector_list_iter_begin(dev, &conn_iter);
 198         drm_for_each_connector_iter(connector, &conn_iter) {
 199                 if (connector->polled != DRM_CONNECTOR_POLL_HPD)
 200                         continue;
 201 
 202                 intel_connector = to_intel_connector(connector);
 203                 intel_encoder = intel_connector->encoder;
 204                 if (!intel_encoder)
 205                         continue;
 206 
 207                 pin = intel_encoder->hpd_pin;
 208                 if (pin == HPD_NONE ||
 209                     dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
 210                         continue;
 211 
 212                 DRM_INFO("HPD interrupt storm detected on connector %s: "
 213                          "switching from hotplug detection to polling\n",
 214                          connector->name);
 215 
 216                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 217                 connector->polled = DRM_CONNECTOR_POLL_CONNECT
 218                         | DRM_CONNECTOR_POLL_DISCONNECT;
 219                 hpd_disabled = true;
 220         }
 221         drm_connector_list_iter_end(&conn_iter);
 222 
 223         /* Enable polling and queue hotplug re-enabling. */
 224         if (hpd_disabled) {
 225                 drm_kms_helper_poll_enable(dev);
 226                 mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
 227                                  msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 228         }
 229 }
 230 
 231 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 232 {
 233         struct drm_i915_private *dev_priv =
 234                 container_of(work, typeof(*dev_priv),
 235                              hotplug.reenable_work.work);
 236         struct drm_device *dev = &dev_priv->drm;
 237         intel_wakeref_t wakeref;
 238         enum hpd_pin pin;
 239 
 240         wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
 241 
 242         spin_lock_irq(&dev_priv->irq_lock);
 243         for_each_hpd_pin(pin) {
 244                 struct drm_connector *connector;
 245                 struct drm_connector_list_iter conn_iter;
 246 
 247                 if (dev_priv->hotplug.stats[pin].state != HPD_DISABLED)
 248                         continue;
 249 
 250                 dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
 251 
 252                 drm_connector_list_iter_begin(dev, &conn_iter);
 253                 drm_for_each_connector_iter(connector, &conn_iter) {
 254                         struct intel_connector *intel_connector = to_intel_connector(connector);
 255 
 256                         /* Don't check MST ports, they don't have pins */
 257                         if (!intel_connector->mst_port &&
 258                             intel_connector->encoder->hpd_pin == pin) {
 259                                 if (connector->polled != intel_connector->polled)
 260                                         DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
 261                                                          connector->name);
 262                                 connector->polled = intel_connector->polled;
 263                                 if (!connector->polled)
 264                                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 265                         }
 266                 }
 267                 drm_connector_list_iter_end(&conn_iter);
 268         }
 269         if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup)
 270                 dev_priv->display.hpd_irq_setup(dev_priv);
 271         spin_unlock_irq(&dev_priv->irq_lock);
 272 
 273         intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
 274 }
 275 
 276 enum intel_hotplug_state
 277 intel_encoder_hotplug(struct intel_encoder *encoder,
 278                       struct intel_connector *connector,
 279                       bool irq_received)
 280 {
 281         struct drm_device *dev = connector->base.dev;
 282         enum drm_connector_status old_status;
 283 
 284         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 285         old_status = connector->base.status;
 286 
 287         connector->base.status =
 288                 drm_helper_probe_detect(&connector->base, NULL, false);
 289 
 290         if (old_status == connector->base.status)
 291                 return INTEL_HOTPLUG_UNCHANGED;
 292 
 293         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 294                       connector->base.base.id,
 295                       connector->base.name,
 296                       drm_get_connector_status_name(old_status),
 297                       drm_get_connector_status_name(connector->base.status));
 298 
 299         return INTEL_HOTPLUG_CHANGED;
 300 }
 301 
 302 static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
 303 {
 304         return intel_encoder_is_dig_port(encoder) &&
 305                 enc_to_dig_port(&encoder->base)->hpd_pulse != NULL;
 306 }
 307 
 308 static void i915_digport_work_func(struct work_struct *work)
 309 {
 310         struct drm_i915_private *dev_priv =
 311                 container_of(work, struct drm_i915_private, hotplug.dig_port_work);
 312         u32 long_port_mask, short_port_mask;
 313         struct intel_encoder *encoder;
 314         u32 old_bits = 0;
 315 
 316         spin_lock_irq(&dev_priv->irq_lock);
 317         long_port_mask = dev_priv->hotplug.long_port_mask;
 318         dev_priv->hotplug.long_port_mask = 0;
 319         short_port_mask = dev_priv->hotplug.short_port_mask;
 320         dev_priv->hotplug.short_port_mask = 0;
 321         spin_unlock_irq(&dev_priv->irq_lock);
 322 
 323         for_each_intel_encoder(&dev_priv->drm, encoder) {
 324                 struct intel_digital_port *dig_port;
 325                 enum port port = encoder->port;
 326                 bool long_hpd, short_hpd;
 327                 enum irqreturn ret;
 328 
 329                 if (!intel_encoder_has_hpd_pulse(encoder))
 330                         continue;
 331 
 332                 long_hpd = long_port_mask & BIT(port);
 333                 short_hpd = short_port_mask & BIT(port);
 334 
 335                 if (!long_hpd && !short_hpd)
 336                         continue;
 337 
 338                 dig_port = enc_to_dig_port(&encoder->base);
 339 
 340                 ret = dig_port->hpd_pulse(dig_port, long_hpd);
 341                 if (ret == IRQ_NONE) {
 342                         /* fall back to old school hpd */
 343                         old_bits |= BIT(encoder->hpd_pin);
 344                 }
 345         }
 346 
 347         if (old_bits) {
 348                 spin_lock_irq(&dev_priv->irq_lock);
 349                 dev_priv->hotplug.event_bits |= old_bits;
 350                 spin_unlock_irq(&dev_priv->irq_lock);
 351                 queue_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work, 0);
 352         }
 353 }
 354 
 355 /*
 356  * Handle hotplug events outside the interrupt handler proper.
 357  */
 358 static void i915_hotplug_work_func(struct work_struct *work)
 359 {
 360         struct drm_i915_private *dev_priv =
 361                 container_of(work, struct drm_i915_private,
 362                              hotplug.hotplug_work.work);
 363         struct drm_device *dev = &dev_priv->drm;
 364         struct intel_connector *intel_connector;
 365         struct intel_encoder *intel_encoder;
 366         struct drm_connector *connector;
 367         struct drm_connector_list_iter conn_iter;
 368         u32 changed = 0, retry = 0;
 369         u32 hpd_event_bits;
 370         u32 hpd_retry_bits;
 371 
 372         mutex_lock(&dev->mode_config.mutex);
 373         DRM_DEBUG_KMS("running encoder hotplug functions\n");
 374 
 375         spin_lock_irq(&dev_priv->irq_lock);
 376 
 377         hpd_event_bits = dev_priv->hotplug.event_bits;
 378         dev_priv->hotplug.event_bits = 0;
 379         hpd_retry_bits = dev_priv->hotplug.retry_bits;
 380         dev_priv->hotplug.retry_bits = 0;
 381 
 382         /* Enable polling for connectors which had HPD IRQ storms */
 383         intel_hpd_irq_storm_switch_to_polling(dev_priv);
 384 
 385         spin_unlock_irq(&dev_priv->irq_lock);
 386 
 387         drm_connector_list_iter_begin(dev, &conn_iter);
 388         drm_for_each_connector_iter(connector, &conn_iter) {
 389                 u32 hpd_bit;
 390 
 391                 intel_connector = to_intel_connector(connector);
 392                 if (!intel_connector->encoder)
 393                         continue;
 394                 intel_encoder = intel_connector->encoder;
 395                 hpd_bit = BIT(intel_encoder->hpd_pin);
 396                 if ((hpd_event_bits | hpd_retry_bits) & hpd_bit) {
 397                         DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
 398                                       connector->name, intel_encoder->hpd_pin);
 399 
 400                         switch (intel_encoder->hotplug(intel_encoder,
 401                                                        intel_connector,
 402                                                        hpd_event_bits & hpd_bit)) {
 403                         case INTEL_HOTPLUG_UNCHANGED:
 404                                 break;
 405                         case INTEL_HOTPLUG_CHANGED:
 406                                 changed |= hpd_bit;
 407                                 break;
 408                         case INTEL_HOTPLUG_RETRY:
 409                                 retry |= hpd_bit;
 410                                 break;
 411                         }
 412                 }
 413         }
 414         drm_connector_list_iter_end(&conn_iter);
 415         mutex_unlock(&dev->mode_config.mutex);
 416 
 417         if (changed)
 418                 drm_kms_helper_hotplug_event(dev);
 419 
 420         /* Remove shared HPD pins that have changed */
 421         retry &= ~changed;
 422         if (retry) {
 423                 spin_lock_irq(&dev_priv->irq_lock);
 424                 dev_priv->hotplug.retry_bits |= retry;
 425                 spin_unlock_irq(&dev_priv->irq_lock);
 426 
 427                 mod_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work,
 428                                  msecs_to_jiffies(HPD_RETRY_DELAY));
 429         }
 430 }
 431 
 432 
 433 /**
 434  * intel_hpd_irq_handler - main hotplug irq handler
 435  * @dev_priv: drm_i915_private
 436  * @pin_mask: a mask of hpd pins that have triggered the irq
 437  * @long_mask: a mask of hpd pins that may be long hpd pulses
 438  *
 439  * This is the main hotplug irq handler for all platforms. The platform specific
 440  * irq handlers call the platform specific hotplug irq handlers, which read and
 441  * decode the appropriate registers into bitmasks about hpd pins that have
 442  * triggered (@pin_mask), and which of those pins may be long pulses
 443  * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
 444  * is not a digital port.
 445  *
 446  * Here, we do hotplug irq storm detection and mitigation, and pass further
 447  * processing to appropriate bottom halves.
 448  */
 449 void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 450                            u32 pin_mask, u32 long_mask)
 451 {
 452         struct intel_encoder *encoder;
 453         bool storm_detected = false;
 454         bool queue_dig = false, queue_hp = false;
 455         u32 long_hpd_pulse_mask = 0;
 456         u32 short_hpd_pulse_mask = 0;
 457         enum hpd_pin pin;
 458 
 459         if (!pin_mask)
 460                 return;
 461 
 462         spin_lock(&dev_priv->irq_lock);
 463 
 464         /*
 465          * Determine whether ->hpd_pulse() exists for each pin, and
 466          * whether we have a short or a long pulse. This is needed
 467          * as each pin may have up to two encoders (HDMI and DP) and
 468          * only the one of them (DP) will have ->hpd_pulse().
 469          */
 470         for_each_intel_encoder(&dev_priv->drm, encoder) {
 471                 bool has_hpd_pulse = intel_encoder_has_hpd_pulse(encoder);
 472                 enum port port = encoder->port;
 473                 bool long_hpd;
 474 
 475                 pin = encoder->hpd_pin;
 476                 if (!(BIT(pin) & pin_mask))
 477                         continue;
 478 
 479                 if (!has_hpd_pulse)
 480                         continue;
 481 
 482                 long_hpd = long_mask & BIT(pin);
 483 
 484                 DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
 485                                  long_hpd ? "long" : "short");
 486                 queue_dig = true;
 487 
 488                 if (long_hpd) {
 489                         long_hpd_pulse_mask |= BIT(pin);
 490                         dev_priv->hotplug.long_port_mask |= BIT(port);
 491                 } else {
 492                         short_hpd_pulse_mask |= BIT(pin);
 493                         dev_priv->hotplug.short_port_mask |= BIT(port);
 494                 }
 495         }
 496 
 497         /* Now process each pin just once */
 498         for_each_hpd_pin(pin) {
 499                 bool long_hpd;
 500 
 501                 if (!(BIT(pin) & pin_mask))
 502                         continue;
 503 
 504                 if (dev_priv->hotplug.stats[pin].state == HPD_DISABLED) {
 505                         /*
 506                          * On GMCH platforms the interrupt mask bits only
 507                          * prevent irq generation, not the setting of the
 508                          * hotplug bits itself. So only WARN about unexpected
 509                          * interrupts on saner platforms.
 510                          */
 511                         WARN_ONCE(!HAS_GMCH(dev_priv),
 512                                   "Received HPD interrupt on pin %d although disabled\n", pin);
 513                         continue;
 514                 }
 515 
 516                 if (dev_priv->hotplug.stats[pin].state != HPD_ENABLED)
 517                         continue;
 518 
 519                 /*
 520                  * Delegate to ->hpd_pulse() if one of the encoders for this
 521                  * pin has it, otherwise let the hotplug_work deal with this
 522                  * pin directly.
 523                  */
 524                 if (((short_hpd_pulse_mask | long_hpd_pulse_mask) & BIT(pin))) {
 525                         long_hpd = long_hpd_pulse_mask & BIT(pin);
 526                 } else {
 527                         dev_priv->hotplug.event_bits |= BIT(pin);
 528                         long_hpd = true;
 529                         queue_hp = true;
 530                 }
 531 
 532                 if (intel_hpd_irq_storm_detect(dev_priv, pin, long_hpd)) {
 533                         dev_priv->hotplug.event_bits &= ~BIT(pin);
 534                         storm_detected = true;
 535                         queue_hp = true;
 536                 }
 537         }
 538 
 539         /*
 540          * Disable any IRQs that storms were detected on. Polling enablement
 541          * happens later in our hotplug work.
 542          */
 543         if (storm_detected && dev_priv->display_irqs_enabled)
 544                 dev_priv->display.hpd_irq_setup(dev_priv);
 545         spin_unlock(&dev_priv->irq_lock);
 546 
 547         /*
 548          * Our hotplug handler can grab modeset locks (by calling down into the
 549          * fb helpers). Hence it must not be run on our own dev-priv->wq work
 550          * queue for otherwise the flush_work in the pageflip code will
 551          * deadlock.
 552          */
 553         if (queue_dig)
 554                 queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
 555         if (queue_hp)
 556                 queue_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work, 0);
 557 }
 558 
 559 /**
 560  * intel_hpd_init - initializes and enables hpd support
 561  * @dev_priv: i915 device instance
 562  *
 563  * This function enables the hotplug support. It requires that interrupts have
 564  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
 565  * poll request can run concurrently to other code, so locking rules must be
 566  * obeyed.
 567  *
 568  * This is a separate step from interrupt enabling to simplify the locking rules
 569  * in the driver load and resume code.
 570  *
 571  * Also see: intel_hpd_poll_init(), which enables connector polling
 572  */
 573 void intel_hpd_init(struct drm_i915_private *dev_priv)
 574 {
 575         int i;
 576 
 577         for_each_hpd_pin(i) {
 578                 dev_priv->hotplug.stats[i].count = 0;
 579                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 580         }
 581 
 582         WRITE_ONCE(dev_priv->hotplug.poll_enabled, false);
 583         schedule_work(&dev_priv->hotplug.poll_init_work);
 584 
 585         /*
 586          * Interrupt setup is already guaranteed to be single-threaded, this is
 587          * just to make the assert_spin_locked checks happy.
 588          */
 589         if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup) {
 590                 spin_lock_irq(&dev_priv->irq_lock);
 591                 if (dev_priv->display_irqs_enabled)
 592                         dev_priv->display.hpd_irq_setup(dev_priv);
 593                 spin_unlock_irq(&dev_priv->irq_lock);
 594         }
 595 }
 596 
 597 static void i915_hpd_poll_init_work(struct work_struct *work)
 598 {
 599         struct drm_i915_private *dev_priv =
 600                 container_of(work, struct drm_i915_private,
 601                              hotplug.poll_init_work);
 602         struct drm_device *dev = &dev_priv->drm;
 603         struct drm_connector *connector;
 604         struct drm_connector_list_iter conn_iter;
 605         bool enabled;
 606 
 607         mutex_lock(&dev->mode_config.mutex);
 608 
 609         enabled = READ_ONCE(dev_priv->hotplug.poll_enabled);
 610 
 611         drm_connector_list_iter_begin(dev, &conn_iter);
 612         drm_for_each_connector_iter(connector, &conn_iter) {
 613                 struct intel_connector *intel_connector =
 614                         to_intel_connector(connector);
 615                 connector->polled = intel_connector->polled;
 616 
 617                 /* MST has a dynamic intel_connector->encoder and it's reprobing
 618                  * is all handled by the MST helpers. */
 619                 if (intel_connector->mst_port)
 620                         continue;
 621 
 622                 if (!connector->polled && I915_HAS_HOTPLUG(dev_priv) &&
 623                     intel_connector->encoder->hpd_pin > HPD_NONE) {
 624                         connector->polled = enabled ?
 625                                 DRM_CONNECTOR_POLL_CONNECT |
 626                                 DRM_CONNECTOR_POLL_DISCONNECT :
 627                                 DRM_CONNECTOR_POLL_HPD;
 628                 }
 629         }
 630         drm_connector_list_iter_end(&conn_iter);
 631 
 632         if (enabled)
 633                 drm_kms_helper_poll_enable(dev);
 634 
 635         mutex_unlock(&dev->mode_config.mutex);
 636 
 637         /*
 638          * We might have missed any hotplugs that happened while we were
 639          * in the middle of disabling polling
 640          */
 641         if (!enabled)
 642                 drm_helper_hpd_irq_event(dev);
 643 }
 644 
 645 /**
 646  * intel_hpd_poll_init - enables/disables polling for connectors with hpd
 647  * @dev_priv: i915 device instance
 648  *
 649  * This function enables polling for all connectors, regardless of whether or
 650  * not they support hotplug detection. Under certain conditions HPD may not be
 651  * functional. On most Intel GPUs, this happens when we enter runtime suspend.
 652  * On Valleyview and Cherryview systems, this also happens when we shut off all
 653  * of the powerwells.
 654  *
 655  * Since this function can get called in contexts where we're already holding
 656  * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
 657  * worker.
 658  *
 659  * Also see: intel_hpd_init(), which restores hpd handling.
 660  */
 661 void intel_hpd_poll_init(struct drm_i915_private *dev_priv)
 662 {
 663         WRITE_ONCE(dev_priv->hotplug.poll_enabled, true);
 664 
 665         /*
 666          * We might already be holding dev->mode_config.mutex, so do this in a
 667          * seperate worker
 668          * As well, there's no issue if we race here since we always reschedule
 669          * this worker anyway
 670          */
 671         schedule_work(&dev_priv->hotplug.poll_init_work);
 672 }
 673 
 674 void intel_hpd_init_work(struct drm_i915_private *dev_priv)
 675 {
 676         INIT_DELAYED_WORK(&dev_priv->hotplug.hotplug_work,
 677                           i915_hotplug_work_func);
 678         INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
 679         INIT_WORK(&dev_priv->hotplug.poll_init_work, i915_hpd_poll_init_work);
 680         INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
 681                           intel_hpd_irq_storm_reenable_work);
 682 }
 683 
 684 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 685 {
 686         spin_lock_irq(&dev_priv->irq_lock);
 687 
 688         dev_priv->hotplug.long_port_mask = 0;
 689         dev_priv->hotplug.short_port_mask = 0;
 690         dev_priv->hotplug.event_bits = 0;
 691         dev_priv->hotplug.retry_bits = 0;
 692 
 693         spin_unlock_irq(&dev_priv->irq_lock);
 694 
 695         cancel_work_sync(&dev_priv->hotplug.dig_port_work);
 696         cancel_delayed_work_sync(&dev_priv->hotplug.hotplug_work);
 697         cancel_work_sync(&dev_priv->hotplug.poll_init_work);
 698         cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 699 }
 700 
 701 bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 702 {
 703         bool ret = false;
 704 
 705         if (pin == HPD_NONE)
 706                 return false;
 707 
 708         spin_lock_irq(&dev_priv->irq_lock);
 709         if (dev_priv->hotplug.stats[pin].state == HPD_ENABLED) {
 710                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 711                 ret = true;
 712         }
 713         spin_unlock_irq(&dev_priv->irq_lock);
 714 
 715         return ret;
 716 }
 717 
 718 void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 719 {
 720         if (pin == HPD_NONE)
 721                 return;
 722 
 723         spin_lock_irq(&dev_priv->irq_lock);
 724         dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
 725         spin_unlock_irq(&dev_priv->irq_lock);
 726 }