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

   1 /*
   2  * Copyright © 2015 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #include <linux/debugfs.h>
  25 #include <linux/kernel.h>
  26
  27 #include <drm/drm_probe_helper.h>
  28
  29 #include "i915_drv.h"
  30 #include "i915_irq.h"
  31 #include "intel_display_power.h"
  32 #include "intel_display_types.h"
  33 #include "intel_hotplug.h"
  34 #include "intel_hotplug_irq.h"
  35
  36 /**
  37  * DOC: Hotplug
  38  *
  39  * Simply put, hotplug occurs when a display is connected to or disconnected
  40  * from the system. However, there may be adapters and docking stations and
  41  * Display Port short pulses and MST devices involved, complicating matters.
  42  *
  43  * Hotplug in i915 is handled in many different levels of abstraction.
  44  *
  45  * The platform dependent interrupt handling code in i915_irq.c enables,
  46  * disables, and does preliminary handling of the interrupts. The interrupt
  47  * handlers gather the hotplug detect (HPD) information from relevant registers
  48  * into a platform independent mask of hotplug pins that have fired.
  49  *
  50  * The platform independent interrupt handler intel_hpd_irq_handler() in
  51  * intel_hotplug.c does hotplug irq storm detection and mitigation, and passes
  52  * further processing to appropriate bottom halves (Display Port specific and
  53  * regular hotplug).
  54  *
  55  * The Display Port work function i915_digport_work_func() calls into
  56  * intel_dp_hpd_pulse() via hooks, which handles DP short pulses and DP MST long
  57  * pulses, with failures and non-MST long pulses triggering regular hotplug
  58  * processing on the connector.
  59  *
  60  * The regular hotplug work function i915_hotplug_work_func() calls connector
  61  * detect hooks, and, if connector status changes, triggers sending of hotplug
  62  * uevent to userspace via drm_kms_helper_hotplug_event().
  63  *
  64  * Finally, the userspace is responsible for triggering a modeset upon receiving
  65  * the hotplug uevent, disabling or enabling the crtc as needed.
  66  *
  67  * The hotplug interrupt storm detection and mitigation code keeps track of the
  68  * number of interrupts per hotplug pin per a period of time, and if the number
  69  * of interrupts exceeds a certain threshold, the interrupt is disabled for a
  70  * while before being re-enabled. The intention is to mitigate issues raising
  71  * from broken hardware triggering massive amounts of interrupts and grinding
  72  * the system to a halt.
  73  *
  74  * Current implementation expects that hotplug interrupt storm will not be
  75  * seen when display port sink is connected, hence on platforms whose DP
  76  * callback is handled by i915_digport_work_func reenabling of hpd is not
  77  * performed (it was never expected to be disabled in the first place ;) )
  78  * this is specific to DP sinks handled by this routine and any other display
  79  * such as HDMI or DVI enabled on the same port will have proper logic since
  80  * it will use i915_hotplug_work_func where this logic is handled.
  81  */
  82
  83 /**
  84  * intel_hpd_pin_default - return default pin associated with certain port.
  85  * @dev_priv: private driver data pointer
  86  * @port: the hpd port to get associated pin
  87  *
  88  * It is only valid and used by digital port encoder.
  89  *
  90  * Return pin that is associatade with @port.
  91  */
  92 enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
  93                                    enum port port)
  94 {
  95         return HPD_PORT_A + port - PORT_A;
  96 }
  97
  98 /* Threshold == 5 for long IRQs, 50 for short */
  99 #define HPD_STORM_DEFAULT_THRESHOLD     50
 100
 101 #define HPD_STORM_DETECT_PERIOD         1000
 102 #define HPD_STORM_REENABLE_DELAY        (2 * 60 * 1000)
 103 #define HPD_RETRY_DELAY                 1000
 104
 105 static enum hpd_pin
 106 intel_connector_hpd_pin(struct intel_connector *connector)
 107 {
 108         struct intel_encoder *encoder = intel_attached_encoder(connector);
 109
 110         /*
 111          * MST connectors get their encoder attached dynamically
 112          * so need to make sure we have an encoder here. But since
 113          * MST encoders have their hpd_pin set to HPD_NONE we don't
 114          * have to special case them beyond that.
 115          */
 116         return encoder ? encoder->hpd_pin : HPD_NONE;
 117 }
 118
 119 /**
 120  * intel_hpd_irq_storm_detect - gather stats and detect HPD IRQ storm on a pin
 121  * @dev_priv: private driver data pointer
 122  * @pin: the pin to gather stats on
 123  * @long_hpd: whether the HPD IRQ was long or short
 124  *
 125  * Gather stats about HPD IRQs from the specified @pin, and detect IRQ
 126  * storms. Only the pin specific stats and state are changed, the caller is
 127  * responsible for further action.
 128  *
 129  * The number of IRQs that are allowed within @HPD_STORM_DETECT_PERIOD is
 130  * stored in @dev_priv->display.hotplug.hpd_storm_threshold which defaults to
 131  * @HPD_STORM_DEFAULT_THRESHOLD. Long IRQs count as +10 to this threshold, and
 132  * short IRQs count as +1. If this threshold is exceeded, it's considered an
 133  * IRQ storm and the IRQ state is set to @HPD_MARK_DISABLED.
 134  *
 135  * By default, most systems will only count long IRQs towards
 136  * &dev_priv->display.hotplug.hpd_storm_threshold. However, some older systems also
 137  * suffer from short IRQ storms and must also track these. Because short IRQ
 138  * storms are naturally caused by sideband interactions with DP MST devices,
 139  * short IRQ detection is only enabled for systems without DP MST support.
 140  * Systems which are new enough to support DP MST are far less likely to
 141  * suffer from IRQ storms at all, so this is fine.
 142  *
 143  * The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
 144  * and should only be adjusted for automated hotplug testing.
 145  *
 146  * Return true if an IRQ storm was detected on @pin.
 147  */
 148 static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
 149                                        enum hpd_pin pin, bool long_hpd)
 150 {
 151         struct intel_hotplug *hpd = &dev_priv->display.hotplug;
 152         unsigned long start = hpd->stats[pin].last_jiffies;
 153         unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
 154         const int increment = long_hpd ? 10 : 1;
 155         const int threshold = hpd->hpd_storm_threshold;
 156         bool storm = false;
 157
 158         if (!threshold ||
 159             (!long_hpd && !dev_priv->display.hotplug.hpd_short_storm_enabled))
 160                 return false;
 161
 162         if (!time_in_range(jiffies, start, end)) {
 163                 hpd->stats[pin].last_jiffies = jiffies;
 164                 hpd->stats[pin].count = 0;
 165         }
 166
 167         hpd->stats[pin].count += increment;
 168         if (hpd->stats[pin].count > threshold) {
 169                 hpd->stats[pin].state = HPD_MARK_DISABLED;
 170                 drm_dbg_kms(&dev_priv->drm,
 171                             "HPD interrupt storm detected on PIN %d\n", pin);
 172                 storm = true;
 173         } else {
 174                 drm_dbg_kms(&dev_priv->drm,
 175                             "Received HPD interrupt on PIN %d - cnt: %d\n",
 176                               pin,
 177                               hpd->stats[pin].count);
 178         }
 179
 180         return storm;
 181 }
 182
 183 static bool detection_work_enabled(struct drm_i915_private *i915)
 184 {
 185         lockdep_assert_held(&i915->irq_lock);
 186
 187         return i915->display.hotplug.detection_work_enabled;
 188 }
 189
 190 static bool
 191 mod_delayed_detection_work(struct drm_i915_private *i915, struct delayed_work *work, int delay)
 192 {
 193         lockdep_assert_held(&i915->irq_lock);
 194
 195         if (!detection_work_enabled(i915))
 196                 return false;
 197
 198         return mod_delayed_work(i915->unordered_wq, work, delay);
 199 }
 200
 201 static bool
 202 queue_delayed_detection_work(struct drm_i915_private *i915, struct delayed_work *work, int delay)
 203 {
 204         lockdep_assert_held(&i915->irq_lock);
 205
 206         if (!detection_work_enabled(i915))
 207                 return false;
 208
 209         return queue_delayed_work(i915->unordered_wq, work, delay);
 210 }
 211
 212 static bool
 213 queue_detection_work(struct drm_i915_private *i915, struct work_struct *work)
 214 {
 215         lockdep_assert_held(&i915->irq_lock);
 216
 217         if (!detection_work_enabled(i915))
 218                 return false;
 219
 220         return queue_work(i915->unordered_wq, work);
 221 }
 222
 223 static void
 224 intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
 225 {
 226         struct drm_connector_list_iter conn_iter;
 227         struct intel_connector *connector;
 228         bool hpd_disabled = false;
 229
 230         lockdep_assert_held(&dev_priv->irq_lock);
 231
 232         drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
 233         for_each_intel_connector_iter(connector, &conn_iter) {
 234                 enum hpd_pin pin;
 235
 236                 if (connector->base.polled != DRM_CONNECTOR_POLL_HPD)
 237                         continue;
 238
 239                 pin = intel_connector_hpd_pin(connector);
 240                 if (pin == HPD_NONE ||
 241                     dev_priv->display.hotplug.stats[pin].state != HPD_MARK_DISABLED)
 242                         continue;
 243
 244                 drm_info(&dev_priv->drm,
 245                          "HPD interrupt storm detected on connector %s: "
 246                          "switching from hotplug detection to polling\n",
 247                          connector->base.name);
 248
 249                 dev_priv->display.hotplug.stats[pin].state = HPD_DISABLED;
 250                 connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
 251                         DRM_CONNECTOR_POLL_DISCONNECT;
 252                 hpd_disabled = true;
 253         }
 254         drm_connector_list_iter_end(&conn_iter);
 255
 256         /* Enable polling and queue hotplug re-enabling. */
 257         if (hpd_disabled) {
 258                 drm_kms_helper_poll_reschedule(&dev_priv->drm);
 259                 mod_delayed_detection_work(dev_priv,
 260                                            &dev_priv->display.hotplug.reenable_work,
 261                                            msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 262         }
 263 }
 264
 265 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 266 {
 267         struct drm_i915_private *dev_priv =
 268                 container_of(work, typeof(*dev_priv),
 269                              display.hotplug.reenable_work.work);
 270         struct drm_connector_list_iter conn_iter;
 271         struct intel_connector *connector;
 272         intel_wakeref_t wakeref;
 273         enum hpd_pin pin;
 274
 275         wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
 276
 277         spin_lock_irq(&dev_priv->irq_lock);
 278
 279         drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
 280         for_each_intel_connector_iter(connector, &conn_iter) {
 281                 pin = intel_connector_hpd_pin(connector);
 282                 if (pin == HPD_NONE ||
 283                     dev_priv->display.hotplug.stats[pin].state != HPD_DISABLED)
 284                         continue;
 285
 286                 if (connector->base.polled != connector->polled)
 287                         drm_dbg(&dev_priv->drm,
 288                                 "Reenabling HPD on connector %s\n",
 289                                 connector->base.name);
 290                 connector->base.polled = connector->polled;
 291         }
 292         drm_connector_list_iter_end(&conn_iter);
 293
 294         for_each_hpd_pin(pin) {
 295                 if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED)
 296                         dev_priv->display.hotplug.stats[pin].state = HPD_ENABLED;
 297         }
 298
 299         intel_hpd_irq_setup(dev_priv);
 300
 301         spin_unlock_irq(&dev_priv->irq_lock);
 302
 303         intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
 304 }
 305
 306 static enum intel_hotplug_state
 307 intel_hotplug_detect_connector(struct intel_connector *connector)
 308 {
 309         struct drm_device *dev = connector->base.dev;
 310         enum drm_connector_status old_status;
 311         u64 old_epoch_counter;
 312         int status;
 313         bool ret = false;
 314
 315         drm_WARN_ON(dev, !mutex_is_locked(&dev->mode_config.mutex));
 316         old_status = connector->base.status;
 317         old_epoch_counter = connector->base.epoch_counter;
 318
 319         status = drm_helper_probe_detect(&connector->base, NULL, false);
 320         if (!connector->base.force)
 321                 connector->base.status = status;
 322
 323         if (old_epoch_counter != connector->base.epoch_counter)
 324                 ret = true;
 325
 326         if (ret) {
 327                 drm_dbg_kms(dev, "[CONNECTOR:%d:%s] status updated from %s to %s (epoch counter %llu->%llu)\n",
 328                             connector->base.base.id,
 329                             connector->base.name,
 330                             drm_get_connector_status_name(old_status),
 331                             drm_get_connector_status_name(connector->base.status),
 332                             old_epoch_counter,
 333                             connector->base.epoch_counter);
 334                 return INTEL_HOTPLUG_CHANGED;
 335         }
 336         return INTEL_HOTPLUG_UNCHANGED;
 337 }
 338
 339 enum intel_hotplug_state
 340 intel_encoder_hotplug(struct intel_encoder *encoder,
 341                       struct intel_connector *connector)
 342 {
 343         return intel_hotplug_detect_connector(connector);
 344 }
 345
 346 static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
 347 {
 348         return intel_encoder_is_dig_port(encoder) &&
 349                 enc_to_dig_port(encoder)->hpd_pulse != NULL;
 350 }
 351
 352 static void i915_digport_work_func(struct work_struct *work)
 353 {
 354         struct drm_i915_private *dev_priv =
 355                 container_of(work, struct drm_i915_private, display.hotplug.dig_port_work);
 356         u32 long_port_mask, short_port_mask;
 357         struct intel_encoder *encoder;
 358         u32 old_bits = 0;
 359
 360         spin_lock_irq(&dev_priv->irq_lock);
 361         long_port_mask = dev_priv->display.hotplug.long_port_mask;
 362         dev_priv->display.hotplug.long_port_mask = 0;
 363         short_port_mask = dev_priv->display.hotplug.short_port_mask;
 364         dev_priv->display.hotplug.short_port_mask = 0;
 365         spin_unlock_irq(&dev_priv->irq_lock);
 366
 367         for_each_intel_encoder(&dev_priv->drm, encoder) {
 368                 struct intel_digital_port *dig_port;
 369                 enum port port = encoder->port;
 370                 bool long_hpd, short_hpd;
 371                 enum irqreturn ret;
 372
 373                 if (!intel_encoder_has_hpd_pulse(encoder))
 374                         continue;
 375
 376                 long_hpd = long_port_mask & BIT(port);
 377                 short_hpd = short_port_mask & BIT(port);
 378
 379                 if (!long_hpd && !short_hpd)
 380                         continue;
 381
 382                 dig_port = enc_to_dig_port(encoder);
 383
 384                 ret = dig_port->hpd_pulse(dig_port, long_hpd);
 385                 if (ret == IRQ_NONE) {
 386                         /* fall back to old school hpd */
 387                         old_bits |= BIT(encoder->hpd_pin);
 388                 }
 389         }
 390
 391         if (old_bits) {
 392                 spin_lock_irq(&dev_priv->irq_lock);
 393                 dev_priv->display.hotplug.event_bits |= old_bits;
 394                 queue_delayed_detection_work(dev_priv,
 395                                              &dev_priv->display.hotplug.hotplug_work, 0);
 396                 spin_unlock_irq(&dev_priv->irq_lock);
 397         }
 398 }
 399
 400 /**
 401  * intel_hpd_trigger_irq - trigger an hpd irq event for a port
 402  * @dig_port: digital port
 403  *
 404  * Trigger an HPD interrupt event for the given port, emulating a short pulse
 405  * generated by the sink, and schedule the dig port work to handle it.
 406  */
 407 void intel_hpd_trigger_irq(struct intel_digital_port *dig_port)
 408 {
 409         struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
 410
 411         spin_lock_irq(&i915->irq_lock);
 412         i915->display.hotplug.short_port_mask |= BIT(dig_port->base.port);
 413         spin_unlock_irq(&i915->irq_lock);
 414
 415         queue_work(i915->display.hotplug.dp_wq, &i915->display.hotplug.dig_port_work);
 416 }
 417
 418 /*
 419  * Handle hotplug events outside the interrupt handler proper.
 420  */
 421 static void i915_hotplug_work_func(struct work_struct *work)
 422 {
 423         struct drm_i915_private *dev_priv =
 424                 container_of(work, struct drm_i915_private,
 425                              display.hotplug.hotplug_work.work);
 426         struct drm_connector_list_iter conn_iter;
 427         struct intel_connector *connector;
 428         u32 changed = 0, retry = 0;
 429         u32 hpd_event_bits;
 430         u32 hpd_retry_bits;
 431         struct drm_connector *first_changed_connector = NULL;
 432         int changed_connectors = 0;
 433
 434         mutex_lock(&dev_priv->drm.mode_config.mutex);
 435         drm_dbg_kms(&dev_priv->drm, "running encoder hotplug functions\n");
 436
 437         spin_lock_irq(&dev_priv->irq_lock);
 438
 439         hpd_event_bits = dev_priv->display.hotplug.event_bits;
 440         dev_priv->display.hotplug.event_bits = 0;
 441         hpd_retry_bits = dev_priv->display.hotplug.retry_bits;
 442         dev_priv->display.hotplug.retry_bits = 0;
 443
 444         /* Enable polling for connectors which had HPD IRQ storms */
 445         intel_hpd_irq_storm_switch_to_polling(dev_priv);
 446
 447         spin_unlock_irq(&dev_priv->irq_lock);
 448
 449         /* Skip calling encode hotplug handlers if ignore long HPD set*/
 450         if (dev_priv->display.hotplug.ignore_long_hpd) {
 451                 drm_dbg_kms(&dev_priv->drm, "Ignore HPD flag on - skip encoder hotplug handlers\n");
 452                 mutex_unlock(&dev_priv->drm.mode_config.mutex);
 453                 return;
 454         }
 455
 456         drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
 457         for_each_intel_connector_iter(connector, &conn_iter) {
 458                 enum hpd_pin pin;
 459                 u32 hpd_bit;
 460
 461                 pin = intel_connector_hpd_pin(connector);
 462                 if (pin == HPD_NONE)
 463                         continue;
 464
 465                 hpd_bit = BIT(pin);
 466                 if ((hpd_event_bits | hpd_retry_bits) & hpd_bit) {
 467                         struct intel_encoder *encoder =
 468                                 intel_attached_encoder(connector);
 469
 470                         if (hpd_event_bits & hpd_bit)
 471                                 connector->hotplug_retries = 0;
 472                         else
 473                                 connector->hotplug_retries++;
 474
 475                         drm_dbg_kms(&dev_priv->drm,
 476                                     "Connector %s (pin %i) received hotplug event. (retry %d)\n",
 477                                     connector->base.name, pin,
 478                                     connector->hotplug_retries);
 479
 480                         switch (encoder->hotplug(encoder, connector)) {
 481                         case INTEL_HOTPLUG_UNCHANGED:
 482                                 break;
 483                         case INTEL_HOTPLUG_CHANGED:
 484                                 changed |= hpd_bit;
 485                                 changed_connectors++;
 486                                 if (!first_changed_connector) {
 487                                         drm_connector_get(&connector->base);
 488                                         first_changed_connector = &connector->base;
 489                                 }
 490                                 break;
 491                         case INTEL_HOTPLUG_RETRY:
 492                                 retry |= hpd_bit;
 493                                 break;
 494                         }
 495                 }
 496         }
 497         drm_connector_list_iter_end(&conn_iter);
 498         mutex_unlock(&dev_priv->drm.mode_config.mutex);
 499
 500         if (changed_connectors == 1)
 501                 drm_kms_helper_connector_hotplug_event(first_changed_connector);
 502         else if (changed_connectors > 0)
 503                 drm_kms_helper_hotplug_event(&dev_priv->drm);
 504
 505         if (first_changed_connector)
 506                 drm_connector_put(first_changed_connector);
 507
 508         /* Remove shared HPD pins that have changed */
 509         retry &= ~changed;
 510         if (retry) {
 511                 spin_lock_irq(&dev_priv->irq_lock);
 512                 dev_priv->display.hotplug.retry_bits |= retry;
 513
 514                 mod_delayed_detection_work(dev_priv,
 515                                            &dev_priv->display.hotplug.hotplug_work,
 516                                            msecs_to_jiffies(HPD_RETRY_DELAY));
 517                 spin_unlock_irq(&dev_priv->irq_lock);
 518         }
 519 }
 520
 521
 522 /**
 523  * intel_hpd_irq_handler - main hotplug irq handler
 524  * @dev_priv: drm_i915_private
 525  * @pin_mask: a mask of hpd pins that have triggered the irq
 526  * @long_mask: a mask of hpd pins that may be long hpd pulses
 527  *
 528  * This is the main hotplug irq handler for all platforms. The platform specific
 529  * irq handlers call the platform specific hotplug irq handlers, which read and
 530  * decode the appropriate registers into bitmasks about hpd pins that have
 531  * triggered (@pin_mask), and which of those pins may be long pulses
 532  * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
 533  * is not a digital port.
 534  *
 535  * Here, we do hotplug irq storm detection and mitigation, and pass further
 536  * processing to appropriate bottom halves.
 537  */
 538 void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 539                            u32 pin_mask, u32 long_mask)
 540 {
 541         struct intel_encoder *encoder;
 542         bool storm_detected = false;
 543         bool queue_dig = false, queue_hp = false;
 544         u32 long_hpd_pulse_mask = 0;
 545         u32 short_hpd_pulse_mask = 0;
 546         enum hpd_pin pin;
 547
 548         if (!pin_mask)
 549                 return;
 550
 551         spin_lock(&dev_priv->irq_lock);
 552
 553         /*
 554          * Determine whether ->hpd_pulse() exists for each pin, and
 555          * whether we have a short or a long pulse. This is needed
 556          * as each pin may have up to two encoders (HDMI and DP) and
 557          * only the one of them (DP) will have ->hpd_pulse().
 558          */
 559         for_each_intel_encoder(&dev_priv->drm, encoder) {
 560                 enum port port = encoder->port;
 561                 bool long_hpd;
 562
 563                 pin = encoder->hpd_pin;
 564                 if (!(BIT(pin) & pin_mask))
 565                         continue;
 566
 567                 if (!intel_encoder_has_hpd_pulse(encoder))
 568                         continue;
 569
 570                 long_hpd = long_mask & BIT(pin);
 571
 572                 drm_dbg(&dev_priv->drm,
 573                         "digital hpd on [ENCODER:%d:%s] - %s\n",
 574                         encoder->base.base.id, encoder->base.name,
 575                         long_hpd ? "long" : "short");
 576                 queue_dig = true;
 577
 578                 if (long_hpd) {
 579                         long_hpd_pulse_mask |= BIT(pin);
 580                         dev_priv->display.hotplug.long_port_mask |= BIT(port);
 581                 } else {
 582                         short_hpd_pulse_mask |= BIT(pin);
 583                         dev_priv->display.hotplug.short_port_mask |= BIT(port);
 584                 }
 585         }
 586
 587         /* Now process each pin just once */
 588         for_each_hpd_pin(pin) {
 589                 bool long_hpd;
 590
 591                 if (!(BIT(pin) & pin_mask))
 592                         continue;
 593
 594                 if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED) {
 595                         /*
 596                          * On GMCH platforms the interrupt mask bits only
 597                          * prevent irq generation, not the setting of the
 598                          * hotplug bits itself. So only WARN about unexpected
 599                          * interrupts on saner platforms.
 600                          */
 601                         drm_WARN_ONCE(&dev_priv->drm, !HAS_GMCH(dev_priv),
 602                                       "Received HPD interrupt on pin %d although disabled\n",
 603                                       pin);
 604                         continue;
 605                 }
 606
 607                 if (dev_priv->display.hotplug.stats[pin].state != HPD_ENABLED)
 608                         continue;
 609
 610                 /*
 611                  * Delegate to ->hpd_pulse() if one of the encoders for this
 612                  * pin has it, otherwise let the hotplug_work deal with this
 613                  * pin directly.
 614                  */
 615                 if (((short_hpd_pulse_mask | long_hpd_pulse_mask) & BIT(pin))) {
 616                         long_hpd = long_hpd_pulse_mask & BIT(pin);
 617                 } else {
 618                         dev_priv->display.hotplug.event_bits |= BIT(pin);
 619                         long_hpd = true;
 620                         queue_hp = true;
 621                 }
 622
 623                 if (intel_hpd_irq_storm_detect(dev_priv, pin, long_hpd)) {
 624                         dev_priv->display.hotplug.event_bits &= ~BIT(pin);
 625                         storm_detected = true;
 626                         queue_hp = true;
 627                 }
 628         }
 629
 630         /*
 631          * Disable any IRQs that storms were detected on. Polling enablement
 632          * happens later in our hotplug work.
 633          */
 634         if (storm_detected)
 635                 intel_hpd_irq_setup(dev_priv);
 636
 637         /*
 638          * Our hotplug handler can grab modeset locks (by calling down into the
 639          * fb helpers). Hence it must not be run on our own dev-priv->wq work
 640          * queue for otherwise the flush_work in the pageflip code will
 641          * deadlock.
 642          */
 643         if (queue_dig)
 644                 queue_work(dev_priv->display.hotplug.dp_wq, &dev_priv->display.hotplug.dig_port_work);
 645         if (queue_hp)
 646                 queue_delayed_detection_work(dev_priv,
 647                                              &dev_priv->display.hotplug.hotplug_work, 0);
 648
 649         spin_unlock(&dev_priv->irq_lock);
 650 }
 651
 652 /**
 653  * intel_hpd_init - initializes and enables hpd support
 654  * @dev_priv: i915 device instance
 655  *
 656  * This function enables the hotplug support. It requires that interrupts have
 657  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
 658  * poll request can run concurrently to other code, so locking rules must be
 659  * obeyed.
 660  *
 661  * This is a separate step from interrupt enabling to simplify the locking rules
 662  * in the driver load and resume code.
 663  *
 664  * Also see: intel_hpd_poll_enable() and intel_hpd_poll_disable().
 665  */
 666 void intel_hpd_init(struct drm_i915_private *dev_priv)
 667 {
 668         int i;
 669
 670         if (!HAS_DISPLAY(dev_priv))
 671                 return;
 672
 673         for_each_hpd_pin(i) {
 674                 dev_priv->display.hotplug.stats[i].count = 0;
 675                 dev_priv->display.hotplug.stats[i].state = HPD_ENABLED;
 676         }
 677
 678         /*
 679          * Interrupt setup is already guaranteed to be single-threaded, this is
 680          * just to make the assert_spin_locked checks happy.
 681          */
 682         spin_lock_irq(&dev_priv->irq_lock);
 683         intel_hpd_irq_setup(dev_priv);
 684         spin_unlock_irq(&dev_priv->irq_lock);
 685 }
 686
 687 static void i915_hpd_poll_detect_connectors(struct drm_i915_private *i915)
 688 {
 689         struct drm_connector_list_iter conn_iter;
 690         struct intel_connector *connector;
 691         struct intel_connector *first_changed_connector = NULL;
 692         int changed = 0;
 693
 694         mutex_lock(&i915->drm.mode_config.mutex);
 695
 696         if (!i915->drm.mode_config.poll_enabled)
 697                 goto out;
 698
 699         drm_connector_list_iter_begin(&i915->drm, &conn_iter);
 700         for_each_intel_connector_iter(connector, &conn_iter) {
 701                 if (!(connector->base.polled & DRM_CONNECTOR_POLL_HPD))
 702                         continue;
 703
 704                 if (intel_hotplug_detect_connector(connector) != INTEL_HOTPLUG_CHANGED)
 705                         continue;
 706
 707                 changed++;
 708
 709                 if (changed == 1) {
 710                         drm_connector_get(&connector->base);
 711                         first_changed_connector = connector;
 712                 }
 713         }
 714         drm_connector_list_iter_end(&conn_iter);
 715
 716 out:
 717         mutex_unlock(&i915->drm.mode_config.mutex);
 718
 719         if (!changed)
 720                 return;
 721
 722         if (changed == 1)
 723                 drm_kms_helper_connector_hotplug_event(&first_changed_connector->base);
 724         else
 725                 drm_kms_helper_hotplug_event(&i915->drm);
 726
 727         drm_connector_put(&first_changed_connector->base);
 728 }
 729
 730 static void i915_hpd_poll_init_work(struct work_struct *work)
 731 {
 732         struct drm_i915_private *dev_priv =
 733                 container_of(work, struct drm_i915_private,
 734                              display.hotplug.poll_init_work);
 735         struct drm_connector_list_iter conn_iter;
 736         struct intel_connector *connector;
 737         intel_wakeref_t wakeref;
 738         bool enabled;
 739
 740         mutex_lock(&dev_priv->drm.mode_config.mutex);
 741
 742         enabled = READ_ONCE(dev_priv->display.hotplug.poll_enabled);
 743         /*
 744          * Prevent taking a power reference from this sequence of
 745          * i915_hpd_poll_init_work() -> drm_helper_hpd_irq_event() ->
 746          * connector detect which would requeue i915_hpd_poll_init_work()
 747          * and so risk an endless loop of this same sequence.
 748          */
 749         if (!enabled) {
 750                 wakeref = intel_display_power_get(dev_priv,
 751                                                   POWER_DOMAIN_DISPLAY_CORE);
 752                 drm_WARN_ON(&dev_priv->drm,
 753                             READ_ONCE(dev_priv->display.hotplug.poll_enabled));
 754                 cancel_work(&dev_priv->display.hotplug.poll_init_work);
 755         }
 756
 757         spin_lock_irq(&dev_priv->irq_lock);
 758
 759         drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
 760         for_each_intel_connector_iter(connector, &conn_iter) {
 761                 enum hpd_pin pin;
 762
 763                 pin = intel_connector_hpd_pin(connector);
 764                 if (pin == HPD_NONE)
 765                         continue;
 766
 767                 if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED)
 768                         continue;
 769
 770                 connector->base.polled = connector->polled;
 771
 772                 if (enabled && connector->base.polled == DRM_CONNECTOR_POLL_HPD)
 773                         connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
 774                                 DRM_CONNECTOR_POLL_DISCONNECT;
 775         }
 776         drm_connector_list_iter_end(&conn_iter);
 777
 778         spin_unlock_irq(&dev_priv->irq_lock);
 779
 780         if (enabled)
 781                 drm_kms_helper_poll_reschedule(&dev_priv->drm);
 782
 783         mutex_unlock(&dev_priv->drm.mode_config.mutex);
 784
 785         /*
 786          * We might have missed any hotplugs that happened while we were
 787          * in the middle of disabling polling
 788          */
 789         if (!enabled) {
 790                 i915_hpd_poll_detect_connectors(dev_priv);
 791
 792                 intel_display_power_put(dev_priv,
 793                                         POWER_DOMAIN_DISPLAY_CORE,
 794                                         wakeref);
 795         }
 796 }
 797
 798 /**
 799  * intel_hpd_poll_enable - enable polling for connectors with hpd
 800  * @dev_priv: i915 device instance
 801  *
 802  * This function enables polling for all connectors which support HPD.
 803  * Under certain conditions HPD may not be functional. On most Intel GPUs,
 804  * this happens when we enter runtime suspend.
 805  * On Valleyview and Cherryview systems, this also happens when we shut off all
 806  * of the powerwells.
 807  *
 808  * Since this function can get called in contexts where we're already holding
 809  * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
 810  * worker.
 811  *
 812  * Also see: intel_hpd_init() and intel_hpd_poll_disable().
 813  */
 814 void intel_hpd_poll_enable(struct drm_i915_private *dev_priv)
 815 {
 816         struct intel_display *display = &dev_priv->display;
 817
 818         if (!HAS_DISPLAY(dev_priv) ||
 819             !intel_display_device_enabled(display))
 820                 return;
 821
 822         WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, true);
 823
 824         /*
 825          * We might already be holding dev->mode_config.mutex, so do this in a
 826          * seperate worker
 827          * As well, there's no issue if we race here since we always reschedule
 828          * this worker anyway
 829          */
 830         spin_lock_irq(&dev_priv->irq_lock);
 831         queue_detection_work(dev_priv,
 832                              &dev_priv->display.hotplug.poll_init_work);
 833         spin_unlock_irq(&dev_priv->irq_lock);
 834 }
 835
 836 /**
 837  * intel_hpd_poll_disable - disable polling for connectors with hpd
 838  * @dev_priv: i915 device instance
 839  *
 840  * This function disables polling for all connectors which support HPD.
 841  * Under certain conditions HPD may not be functional. On most Intel GPUs,
 842  * this happens when we enter runtime suspend.
 843  * On Valleyview and Cherryview systems, this also happens when we shut off all
 844  * of the powerwells.
 845  *
 846  * Since this function can get called in contexts where we're already holding
 847  * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
 848  * worker.
 849  *
 850  * Also used during driver init to initialize connector->polled
 851  * appropriately for all connectors.
 852  *
 853  * Also see: intel_hpd_init() and intel_hpd_poll_enable().
 854  */
 855 void intel_hpd_poll_disable(struct drm_i915_private *dev_priv)
 856 {
 857         if (!HAS_DISPLAY(dev_priv))
 858                 return;
 859
 860         WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, false);
 861
 862         spin_lock_irq(&dev_priv->irq_lock);
 863         queue_detection_work(dev_priv,
 864                              &dev_priv->display.hotplug.poll_init_work);
 865         spin_unlock_irq(&dev_priv->irq_lock);
 866 }
 867
 868 void intel_hpd_init_early(struct drm_i915_private *i915)
 869 {
 870         INIT_DELAYED_WORK(&i915->display.hotplug.hotplug_work,
 871                           i915_hotplug_work_func);
 872         INIT_WORK(&i915->display.hotplug.dig_port_work, i915_digport_work_func);
 873         INIT_WORK(&i915->display.hotplug.poll_init_work, i915_hpd_poll_init_work);
 874         INIT_DELAYED_WORK(&i915->display.hotplug.reenable_work,
 875                           intel_hpd_irq_storm_reenable_work);
 876
 877         i915->display.hotplug.hpd_storm_threshold = HPD_STORM_DEFAULT_THRESHOLD;
 878         /* If we have MST support, we want to avoid doing short HPD IRQ storm
 879          * detection, as short HPD storms will occur as a natural part of
 880          * sideband messaging with MST.
 881          * On older platforms however, IRQ storms can occur with both long and
 882          * short pulses, as seen on some G4x systems.
 883          */
 884         i915->display.hotplug.hpd_short_storm_enabled = !HAS_DP_MST(i915);
 885 }
 886
 887 static bool cancel_all_detection_work(struct drm_i915_private *i915)
 888 {
 889         bool was_pending = false;
 890
 891         if (cancel_delayed_work_sync(&i915->display.hotplug.hotplug_work))
 892                 was_pending = true;
 893         if (cancel_work_sync(&i915->display.hotplug.poll_init_work))
 894                 was_pending = true;
 895         if (cancel_delayed_work_sync(&i915->display.hotplug.reenable_work))
 896                 was_pending = true;
 897
 898         return was_pending;
 899 }
 900
 901 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 902 {
 903         if (!HAS_DISPLAY(dev_priv))
 904                 return;
 905
 906         spin_lock_irq(&dev_priv->irq_lock);
 907
 908         dev_priv->display.hotplug.long_port_mask = 0;
 909         dev_priv->display.hotplug.short_port_mask = 0;
 910         dev_priv->display.hotplug.event_bits = 0;
 911         dev_priv->display.hotplug.retry_bits = 0;
 912
 913         spin_unlock_irq(&dev_priv->irq_lock);
 914
 915         cancel_work_sync(&dev_priv->display.hotplug.dig_port_work);
 916
 917         /*
 918          * All other work triggered by hotplug events should be canceled by
 919          * now.
 920          */
 921         if (cancel_all_detection_work(dev_priv))
 922                 drm_dbg_kms(&dev_priv->drm, "Hotplug detection work still active\n");
 923 }
 924
 925 bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 926 {
 927         bool ret = false;
 928
 929         if (pin == HPD_NONE)
 930                 return false;
 931
 932         spin_lock_irq(&dev_priv->irq_lock);
 933         if (dev_priv->display.hotplug.stats[pin].state == HPD_ENABLED) {
 934                 dev_priv->display.hotplug.stats[pin].state = HPD_DISABLED;
 935                 ret = true;
 936         }
 937         spin_unlock_irq(&dev_priv->irq_lock);
 938
 939         return ret;
 940 }
 941
 942 void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 943 {
 944         if (pin == HPD_NONE)
 945                 return;
 946
 947         spin_lock_irq(&dev_priv->irq_lock);
 948         dev_priv->display.hotplug.stats[pin].state = HPD_ENABLED;
 949         spin_unlock_irq(&dev_priv->irq_lock);
 950 }
 951
 952 static void queue_work_for_missed_irqs(struct drm_i915_private *i915)
 953 {
 954         bool queue_work = false;
 955         enum hpd_pin pin;
 956
 957         lockdep_assert_held(&i915->irq_lock);
 958
 959         if (i915->display.hotplug.event_bits ||
 960             i915->display.hotplug.retry_bits)
 961                 queue_work = true;
 962
 963         for_each_hpd_pin(pin) {
 964                 switch (i915->display.hotplug.stats[pin].state) {
 965                 case HPD_MARK_DISABLED:
 966                         queue_work = true;
 967                         break;
 968                 case HPD_ENABLED:
 969                         break;
 970                 default:
 971                         MISSING_CASE(i915->display.hotplug.stats[pin].state);
 972                 }
 973         }
 974
 975         if (queue_work)
 976                 queue_delayed_detection_work(i915, &i915->display.hotplug.hotplug_work, 0);
 977 }
 978
 979 void intel_hpd_enable_detection_work(struct drm_i915_private *i915)
 980 {
 981         spin_lock_irq(&i915->irq_lock);
 982         i915->display.hotplug.detection_work_enabled = true;
 983         queue_work_for_missed_irqs(i915);
 984         spin_unlock_irq(&i915->irq_lock);
 985 }
 986
 987 void intel_hpd_disable_detection_work(struct drm_i915_private *i915)
 988 {
 989         spin_lock_irq(&i915->irq_lock);
 990         i915->display.hotplug.detection_work_enabled = false;
 991         spin_unlock_irq(&i915->irq_lock);
 992
 993         cancel_all_detection_work(i915);
 994 }
 995
 996 bool intel_hpd_schedule_detection(struct drm_i915_private *i915)
 997 {
 998         unsigned long flags;
 999         bool ret;
1000
1001         spin_lock_irqsave(&i915->irq_lock, flags);
1002         ret = queue_delayed_detection_work(i915, &i915->display.hotplug.hotplug_work, 0);
1003         spin_unlock_irqrestore(&i915->irq_lock, flags);
1004
1005         return ret;
1006 }
1007
1008 static int i915_hpd_storm_ctl_show(struct seq_file *m, void *data)
1009 {
1010         struct drm_i915_private *dev_priv = m->private;
1011         struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
1012
1013         /* Synchronize with everything first in case there's been an HPD
1014          * storm, but we haven't finished handling it in the kernel yet
1015          */
1016         intel_synchronize_irq(dev_priv);
1017         flush_work(&dev_priv->display.hotplug.dig_port_work);
1018         flush_delayed_work(&dev_priv->display.hotplug.hotplug_work);
1019
1020         seq_printf(m, "Threshold: %d\n", hotplug->hpd_storm_threshold);
1021         seq_printf(m, "Detected: %s\n",
1022                    str_yes_no(delayed_work_pending(&hotplug->reenable_work)));
1023
1024         return 0;
1025 }
1026
1027 static ssize_t i915_hpd_storm_ctl_write(struct file *file,
1028                                         const char __user *ubuf, size_t len,
1029                                         loff_t *offp)
1030 {
1031         struct seq_file *m = file->private_data;
1032         struct drm_i915_private *dev_priv = m->private;
1033         struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
1034         unsigned int new_threshold;
1035         int i;
1036         char *newline;
1037         char tmp[16];
1038
1039         if (len >= sizeof(tmp))
1040                 return -EINVAL;
1041
1042         if (copy_from_user(tmp, ubuf, len))
1043                 return -EFAULT;
1044
1045         tmp[len] = '\0';
1046
1047         /* Strip newline, if any */
1048         newline = strchr(tmp, '\n');
1049         if (newline)
1050                 *newline = '\0';
1051
1052         if (strcmp(tmp, "reset") == 0)
1053                 new_threshold = HPD_STORM_DEFAULT_THRESHOLD;
1054         else if (kstrtouint(tmp, 10, &new_threshold) != 0)
1055                 return -EINVAL;
1056
1057         if (new_threshold > 0)
1058                 drm_dbg_kms(&dev_priv->drm,
1059                             "Setting HPD storm detection threshold to %d\n",
1060                             new_threshold);
1061         else
1062                 drm_dbg_kms(&dev_priv->drm, "Disabling HPD storm detection\n");
1063
1064         spin_lock_irq(&dev_priv->irq_lock);
1065         hotplug->hpd_storm_threshold = new_threshold;
1066         /* Reset the HPD storm stats so we don't accidentally trigger a storm */
1067         for_each_hpd_pin(i)
1068                 hotplug->stats[i].count = 0;
1069         spin_unlock_irq(&dev_priv->irq_lock);
1070
1071         /* Re-enable hpd immediately if we were in an irq storm */
1072         flush_delayed_work(&dev_priv->display.hotplug.reenable_work);
1073
1074         return len;
1075 }
1076
1077 static int i915_hpd_storm_ctl_open(struct inode *inode, struct file *file)
1078 {
1079         return single_open(file, i915_hpd_storm_ctl_show, inode->i_private);
1080 }
1081
1082 static const struct file_operations i915_hpd_storm_ctl_fops = {
1083         .owner = THIS_MODULE,
1084         .open = i915_hpd_storm_ctl_open,
1085         .read = seq_read,
1086         .llseek = seq_lseek,
1087         .release = single_release,
1088         .write = i915_hpd_storm_ctl_write
1089 };
1090
1091 static int i915_hpd_short_storm_ctl_show(struct seq_file *m, void *data)
1092 {
1093         struct drm_i915_private *dev_priv = m->private;
1094
1095         seq_printf(m, "Enabled: %s\n",
1096                    str_yes_no(dev_priv->display.hotplug.hpd_short_storm_enabled));
1097
1098         return 0;
1099 }
1100
1101 static int
1102 i915_hpd_short_storm_ctl_open(struct inode *inode, struct file *file)
1103 {
1104         return single_open(file, i915_hpd_short_storm_ctl_show,
1105                            inode->i_private);
1106 }
1107
1108 static ssize_t i915_hpd_short_storm_ctl_write(struct file *file,
1109                                               const char __user *ubuf,
1110                                               size_t len, loff_t *offp)
1111 {
1112         struct seq_file *m = file->private_data;
1113         struct drm_i915_private *dev_priv = m->private;
1114         struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
1115         char *newline;
1116         char tmp[16];
1117         int i;
1118         bool new_state;
1119
1120         if (len >= sizeof(tmp))
1121                 return -EINVAL;
1122
1123         if (copy_from_user(tmp, ubuf, len))
1124                 return -EFAULT;
1125
1126         tmp[len] = '\0';
1127
1128         /* Strip newline, if any */
1129         newline = strchr(tmp, '\n');
1130         if (newline)
1131                 *newline = '\0';
1132
1133         /* Reset to the "default" state for this system */
1134         if (strcmp(tmp, "reset") == 0)
1135                 new_state = !HAS_DP_MST(dev_priv);
1136         else if (kstrtobool(tmp, &new_state) != 0)
1137                 return -EINVAL;
1138
1139         drm_dbg_kms(&dev_priv->drm, "%sabling HPD short storm detection\n",
1140                     new_state ? "En" : "Dis");
1141
1142         spin_lock_irq(&dev_priv->irq_lock);
1143         hotplug->hpd_short_storm_enabled = new_state;
1144         /* Reset the HPD storm stats so we don't accidentally trigger a storm */
1145         for_each_hpd_pin(i)
1146                 hotplug->stats[i].count = 0;
1147         spin_unlock_irq(&dev_priv->irq_lock);
1148
1149         /* Re-enable hpd immediately if we were in an irq storm */
1150         flush_delayed_work(&dev_priv->display.hotplug.reenable_work);
1151
1152         return len;
1153 }
1154
1155 static const struct file_operations i915_hpd_short_storm_ctl_fops = {
1156         .owner = THIS_MODULE,
1157         .open = i915_hpd_short_storm_ctl_open,
1158         .read = seq_read,
1159         .llseek = seq_lseek,
1160         .release = single_release,
1161         .write = i915_hpd_short_storm_ctl_write,
1162 };
1163
1164 void intel_hpd_debugfs_register(struct drm_i915_private *i915)
1165 {
1166         struct drm_minor *minor = i915->drm.primary;
1167
1168         debugfs_create_file("i915_hpd_storm_ctl", 0644, minor->debugfs_root,
1169                             i915, &i915_hpd_storm_ctl_fops);
1170         debugfs_create_file("i915_hpd_short_storm_ctl", 0644, minor->debugfs_root,
1171                             i915, &i915_hpd_short_storm_ctl_fops);
1172         debugfs_create_bool("i915_ignore_long_hpd", 0644, minor->debugfs_root,
1173                             &i915->display.hotplug.ignore_long_hpd);
1174 }