drivers/gpu/drm/i915/intel_hotplug.c

   1 /*
   2  * Copyright © 2015 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #include <linux/kernel.h>
  25
  26 #include <drm/drmP.h>
  27 #include <drm/i915_drm.h>
  28
  29 #include "i915_drv.h"
  30 #include "intel_drv.h"
  31
  32 /**
  33  * DOC: Hotplug
  34  *
  35  * Simply put, hotplug occurs when a display is connected to or disconnected
  36  * from the system. However, there may be adapters and docking stations and
  37  * Display Port short pulses and MST devices involved, complicating matters.
  38  *
  39  * Hotplug in i915 is handled in many different levels of abstraction.
  40  *
  41  * The platform dependent interrupt handling code in i915_irq.c enables,
  42  * disables, and does preliminary handling of the interrupts. The interrupt
  43  * handlers gather the hotplug detect (HPD) information from relevant registers
  44  * into a platform independent mask of hotplug pins that have fired.
  45  *
  46  * The platform independent interrupt handler intel_hpd_irq_handler() in
  47  * intel_hotplug.c does hotplug irq storm detection and mitigation, and passes
  48  * further processing to appropriate bottom halves (Display Port specific and
  49  * regular hotplug).
  50  *
  51  * The Display Port work function i915_digport_work_func() calls into
  52  * intel_dp_hpd_pulse() via hooks, which handles DP short pulses and DP MST long
  53  * pulses, with failures and non-MST long pulses triggering regular hotplug
  54  * processing on the connector.
  55  *
  56  * The regular hotplug work function i915_hotplug_work_func() calls connector
  57  * detect hooks, and, if connector status changes, triggers sending of hotplug
  58  * uevent to userspace via drm_kms_helper_hotplug_event().
  59  *
  60  * Finally, the userspace is responsible for triggering a modeset upon receiving
  61  * the hotplug uevent, disabling or enabling the crtc as needed.
  62  *
  63  * The hotplug interrupt storm detection and mitigation code keeps track of the
  64  * number of interrupts per hotplug pin per a period of time, and if the number
  65  * of interrupts exceeds a certain threshold, the interrupt is disabled for a
  66  * while before being re-enabled. The intention is to mitigate issues raising
  67  * from broken hardware triggering massive amounts of interrupts and grinding
  68  * the system to a halt.
  69  *
  70  * Current implementation expects that hotplug interrupt storm will not be
  71  * seen when display port sink is connected, hence on platforms whose DP
  72  * callback is handled by i915_digport_work_func reenabling of hpd is not
  73  * performed (it was never expected to be disabled in the first place ;) )
  74  * this is specific to DP sinks handled by this routine and any other display
  75  * such as HDMI or DVI enabled on the same port will have proper logic since
  76  * it will use i915_hotplug_work_func where this logic is handled.
  77  */
  78
  79 /**
  80  * intel_hpd_pin_default - return default pin associated with certain port.
  81  * @dev_priv: private driver data pointer
  82  * @port: the hpd port to get associated pin
  83  *
  84  * It is only valid and used by digital port encoder.
  85  *
  86  * Return pin that is associatade with @port and HDP_NONE if no pin is
  87  * hard associated with that @port.
  88  */
  89 enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
  90                                    enum port port)
  91 {
  92         switch (port) {
  93         case PORT_A:
  94                 return HPD_PORT_A;
  95         case PORT_B:
  96                 return HPD_PORT_B;
  97         case PORT_C:
  98                 return HPD_PORT_C;
  99         case PORT_D:
 100                 return HPD_PORT_D;
 101         case PORT_E:
 102                 return HPD_PORT_E;
 103         case PORT_F:
 104                 if (IS_CNL_WITH_PORT_F(dev_priv))
 105                         return HPD_PORT_E;
 106                 return HPD_PORT_F;
 107         default:
 108                 MISSING_CASE(port);
 109                 return HPD_NONE;
 110         }
 111 }
 112
 113 #define HPD_STORM_DETECT_PERIOD         1000
 114 #define HPD_STORM_REENABLE_DELAY        (2 * 60 * 1000)
 115
 116 /**
 117  * intel_hpd_irq_storm_detect - gather stats and detect HPD irq storm on a pin
 118  * @dev_priv: private driver data pointer
 119  * @pin: the pin to gather stats on
 120  *
 121  * Gather stats about HPD irqs from the specified @pin, and detect irq
 122  * storms. Only the pin specific stats and state are changed, the caller is
 123  * responsible for further action.
 124  *
 125  * The number of irqs that are allowed within @HPD_STORM_DETECT_PERIOD is
 126  * stored in @dev_priv->hotplug.hpd_storm_threshold which defaults to
 127  * @HPD_STORM_DEFAULT_THRESHOLD. If this threshold is exceeded, it's
 128  * considered an irq storm and the irq state is set to @HPD_MARK_DISABLED.
 129  *
 130  * The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
 131  * and should only be adjusted for automated hotplug testing.
 132  *
 133  * Return true if an irq storm was detected on @pin.
 134  */
 135 static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
 136                                        enum hpd_pin pin)
 137 {
 138         unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies;
 139         unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
 140         const int threshold = dev_priv->hotplug.hpd_storm_threshold;
 141         bool storm = false;
 142
 143         if (!time_in_range(jiffies, start, end)) {
 144                 dev_priv->hotplug.stats[pin].last_jiffies = jiffies;
 145                 dev_priv->hotplug.stats[pin].count = 0;
 146                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", pin);
 147         } else if (dev_priv->hotplug.stats[pin].count > threshold &&
 148                    threshold) {
 149                 dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED;
 150                 DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);
 151                 storm = true;
 152         } else {
 153                 dev_priv->hotplug.stats[pin].count++;
 154                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,
 155                               dev_priv->hotplug.stats[pin].count);
 156         }
 157
 158         return storm;
 159 }
 160
 161 static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)
 162 {
 163         struct drm_device *dev = &dev_priv->drm;
 164         struct intel_connector *intel_connector;
 165         struct intel_encoder *intel_encoder;
 166         struct drm_connector *connector;
 167         struct drm_connector_list_iter conn_iter;
 168         enum hpd_pin pin;
 169         bool hpd_disabled = false;
 170
 171         lockdep_assert_held(&dev_priv->irq_lock);
 172
 173         drm_connector_list_iter_begin(dev, &conn_iter);
 174         drm_for_each_connector_iter(connector, &conn_iter) {
 175                 if (connector->polled != DRM_CONNECTOR_POLL_HPD)
 176                         continue;
 177
 178                 intel_connector = to_intel_connector(connector);
 179                 intel_encoder = intel_connector->encoder;
 180                 if (!intel_encoder)
 181                         continue;
 182
 183                 pin = intel_encoder->hpd_pin;
 184                 if (pin == HPD_NONE ||
 185                     dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
 186                         continue;
 187
 188                 DRM_INFO("HPD interrupt storm detected on connector %s: "
 189                          "switching from hotplug detection to polling\n",
 190                          connector->name);
 191
 192                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 193                 connector->polled = DRM_CONNECTOR_POLL_CONNECT
 194                         | DRM_CONNECTOR_POLL_DISCONNECT;
 195                 hpd_disabled = true;
 196         }
 197         drm_connector_list_iter_end(&conn_iter);
 198
 199         /* Enable polling and queue hotplug re-enabling. */
 200         if (hpd_disabled) {
 201                 drm_kms_helper_poll_enable(dev);
 202                 mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
 203                                  msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 204         }
 205 }
 206
 207 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 208 {
 209         struct drm_i915_private *dev_priv =
 210                 container_of(work, typeof(*dev_priv),
 211                              hotplug.reenable_work.work);
 212         struct drm_device *dev = &dev_priv->drm;
 213         enum hpd_pin pin;
 214
 215         intel_runtime_pm_get(dev_priv);
 216
 217         spin_lock_irq(&dev_priv->irq_lock);
 218         for_each_hpd_pin(pin) {
 219                 struct drm_connector *connector;
 220                 struct drm_connector_list_iter conn_iter;
 221
 222                 if (dev_priv->hotplug.stats[pin].state != HPD_DISABLED)
 223                         continue;
 224
 225                 dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
 226
 227                 drm_connector_list_iter_begin(dev, &conn_iter);
 228                 drm_for_each_connector_iter(connector, &conn_iter) {
 229                         struct intel_connector *intel_connector = to_intel_connector(connector);
 230
 231                         if (intel_connector->encoder->hpd_pin == pin) {
 232                                 if (connector->polled != intel_connector->polled)
 233                                         DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
 234                                                          connector->name);
 235                                 connector->polled = intel_connector->polled;
 236                                 if (!connector->polled)
 237                                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 238                         }
 239                 }
 240                 drm_connector_list_iter_end(&conn_iter);
 241         }
 242         if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup)
 243                 dev_priv->display.hpd_irq_setup(dev_priv);
 244         spin_unlock_irq(&dev_priv->irq_lock);
 245
 246         intel_runtime_pm_put(dev_priv);
 247 }
 248
 249 bool intel_encoder_hotplug(struct intel_encoder *encoder,
 250                            struct intel_connector *connector)
 251 {
 252         struct drm_device *dev = connector->base.dev;
 253         enum drm_connector_status old_status;
 254
 255         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 256         old_status = connector->base.status;
 257
 258         connector->base.status =
 259                 drm_helper_probe_detect(&connector->base, NULL, false);
 260
 261         if (old_status == connector->base.status)
 262                 return false;
 263
 264         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 265                       connector->base.base.id,
 266                       connector->base.name,
 267                       drm_get_connector_status_name(old_status),
 268                       drm_get_connector_status_name(connector->base.status));
 269
 270         return true;
 271 }
 272
 273 static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
 274 {
 275         return intel_encoder_is_dig_port(encoder) &&
 276                 enc_to_dig_port(&encoder->base)->hpd_pulse != NULL;
 277 }
 278
 279 static void i915_digport_work_func(struct work_struct *work)
 280 {
 281         struct drm_i915_private *dev_priv =
 282                 container_of(work, struct drm_i915_private, hotplug.dig_port_work);
 283         u32 long_port_mask, short_port_mask;
 284         struct intel_encoder *encoder;
 285         u32 old_bits = 0;
 286
 287         spin_lock_irq(&dev_priv->irq_lock);
 288         long_port_mask = dev_priv->hotplug.long_port_mask;
 289         dev_priv->hotplug.long_port_mask = 0;
 290         short_port_mask = dev_priv->hotplug.short_port_mask;
 291         dev_priv->hotplug.short_port_mask = 0;
 292         spin_unlock_irq(&dev_priv->irq_lock);
 293
 294         for_each_intel_encoder(&dev_priv->drm, encoder) {
 295                 struct intel_digital_port *dig_port;
 296                 enum port port = encoder->port;
 297                 bool long_hpd, short_hpd;
 298                 enum irqreturn ret;
 299
 300                 if (!intel_encoder_has_hpd_pulse(encoder))
 301                         continue;
 302
 303                 long_hpd = long_port_mask & BIT(port);
 304                 short_hpd = short_port_mask & BIT(port);
 305
 306                 if (!long_hpd && !short_hpd)
 307                         continue;
 308
 309                 dig_port = enc_to_dig_port(&encoder->base);
 310
 311                 ret = dig_port->hpd_pulse(dig_port, long_hpd);
 312                 if (ret == IRQ_NONE) {
 313                         /* fall back to old school hpd */
 314                         old_bits |= BIT(encoder->hpd_pin);
 315                 }
 316         }
 317
 318         if (old_bits) {
 319                 spin_lock_irq(&dev_priv->irq_lock);
 320                 dev_priv->hotplug.event_bits |= old_bits;
 321                 spin_unlock_irq(&dev_priv->irq_lock);
 322                 schedule_work(&dev_priv->hotplug.hotplug_work);
 323         }
 324 }
 325
 326 /*
 327  * Handle hotplug events outside the interrupt handler proper.
 328  */
 329 static void i915_hotplug_work_func(struct work_struct *work)
 330 {
 331         struct drm_i915_private *dev_priv =
 332                 container_of(work, struct drm_i915_private, hotplug.hotplug_work);
 333         struct drm_device *dev = &dev_priv->drm;
 334         struct intel_connector *intel_connector;
 335         struct intel_encoder *intel_encoder;
 336         struct drm_connector *connector;
 337         struct drm_connector_list_iter conn_iter;
 338         bool changed = false;
 339         u32 hpd_event_bits;
 340
 341         mutex_lock(&dev->mode_config.mutex);
 342         DRM_DEBUG_KMS("running encoder hotplug functions\n");
 343
 344         spin_lock_irq(&dev_priv->irq_lock);
 345
 346         hpd_event_bits = dev_priv->hotplug.event_bits;
 347         dev_priv->hotplug.event_bits = 0;
 348
 349         /* Disable hotplug on connectors that hit an irq storm. */
 350         intel_hpd_irq_storm_disable(dev_priv);
 351
 352         spin_unlock_irq(&dev_priv->irq_lock);
 353
 354         drm_connector_list_iter_begin(dev, &conn_iter);
 355         drm_for_each_connector_iter(connector, &conn_iter) {
 356                 intel_connector = to_intel_connector(connector);
 357                 if (!intel_connector->encoder)
 358                         continue;
 359                 intel_encoder = intel_connector->encoder;
 360                 if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
 361                         DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
 362                                       connector->name, intel_encoder->hpd_pin);
 363
 364                         changed |= intel_encoder->hotplug(intel_encoder,
 365                                                           intel_connector);
 366                 }
 367         }
 368         drm_connector_list_iter_end(&conn_iter);
 369         mutex_unlock(&dev->mode_config.mutex);
 370
 371         if (changed)
 372                 drm_kms_helper_hotplug_event(dev);
 373 }
 374
 375
 376 /**
 377  * intel_hpd_irq_handler - main hotplug irq handler
 378  * @dev_priv: drm_i915_private
 379  * @pin_mask: a mask of hpd pins that have triggered the irq
 380  * @long_mask: a mask of hpd pins that may be long hpd pulses
 381  *
 382  * This is the main hotplug irq handler for all platforms. The platform specific
 383  * irq handlers call the platform specific hotplug irq handlers, which read and
 384  * decode the appropriate registers into bitmasks about hpd pins that have
 385  * triggered (@pin_mask), and which of those pins may be long pulses
 386  * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
 387  * is not a digital port.
 388  *
 389  * Here, we do hotplug irq storm detection and mitigation, and pass further
 390  * processing to appropriate bottom halves.
 391  */
 392 void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 393                            u32 pin_mask, u32 long_mask)
 394 {
 395         struct intel_encoder *encoder;
 396         bool storm_detected = false;
 397         bool queue_dig = false, queue_hp = false;
 398
 399         if (!pin_mask)
 400                 return;
 401
 402         spin_lock(&dev_priv->irq_lock);
 403         for_each_intel_encoder(&dev_priv->drm, encoder) {
 404                 enum hpd_pin pin = encoder->hpd_pin;
 405                 bool has_hpd_pulse = intel_encoder_has_hpd_pulse(encoder);
 406
 407                 if (!(BIT(pin) & pin_mask))
 408                         continue;
 409
 410                 if (has_hpd_pulse) {
 411                         bool long_hpd = long_mask & BIT(pin);
 412                         enum port port = encoder->port;
 413
 414                         DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
 415                                          long_hpd ? "long" : "short");
 416                         /*
 417                          * For long HPD pulses we want to have the digital queue happen,
 418                          * but we still want HPD storm detection to function.
 419                          */
 420                         queue_dig = true;
 421                         if (long_hpd) {
 422                                 dev_priv->hotplug.long_port_mask |= (1 << port);
 423                         } else {
 424                                 /* for short HPD just trigger the digital queue */
 425                                 dev_priv->hotplug.short_port_mask |= (1 << port);
 426                                 continue;
 427                         }
 428                 }
 429
 430                 if (dev_priv->hotplug.stats[pin].state == HPD_DISABLED) {
 431                         /*
 432                          * On GMCH platforms the interrupt mask bits only
 433                          * prevent irq generation, not the setting of the
 434                          * hotplug bits itself. So only WARN about unexpected
 435                          * interrupts on saner platforms.
 436                          */
 437                         WARN_ONCE(!HAS_GMCH_DISPLAY(dev_priv),
 438                                   "Received HPD interrupt on pin %d although disabled\n", pin);
 439                         continue;
 440                 }
 441
 442                 if (dev_priv->hotplug.stats[pin].state != HPD_ENABLED)
 443                         continue;
 444
 445                 if (!has_hpd_pulse) {
 446                         dev_priv->hotplug.event_bits |= BIT(pin);
 447                         queue_hp = true;
 448                 }
 449
 450                 if (intel_hpd_irq_storm_detect(dev_priv, pin)) {
 451                         dev_priv->hotplug.event_bits &= ~BIT(pin);
 452                         storm_detected = true;
 453                 }
 454         }
 455
 456         if (storm_detected && dev_priv->display_irqs_enabled)
 457                 dev_priv->display.hpd_irq_setup(dev_priv);
 458         spin_unlock(&dev_priv->irq_lock);
 459
 460         /*
 461          * Our hotplug handler can grab modeset locks (by calling down into the
 462          * fb helpers). Hence it must not be run on our own dev-priv->wq work
 463          * queue for otherwise the flush_work in the pageflip code will
 464          * deadlock.
 465          */
 466         if (queue_dig)
 467                 queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
 468         if (queue_hp)
 469                 schedule_work(&dev_priv->hotplug.hotplug_work);
 470 }
 471
 472 /**
 473  * intel_hpd_init - initializes and enables hpd support
 474  * @dev_priv: i915 device instance
 475  *
 476  * This function enables the hotplug support. It requires that interrupts have
 477  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
 478  * poll request can run concurrently to other code, so locking rules must be
 479  * obeyed.
 480  *
 481  * This is a separate step from interrupt enabling to simplify the locking rules
 482  * in the driver load and resume code.
 483  *
 484  * Also see: intel_hpd_poll_init(), which enables connector polling
 485  */
 486 void intel_hpd_init(struct drm_i915_private *dev_priv)
 487 {
 488         int i;
 489
 490         for_each_hpd_pin(i) {
 491                 dev_priv->hotplug.stats[i].count = 0;
 492                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 493         }
 494
 495         WRITE_ONCE(dev_priv->hotplug.poll_enabled, false);
 496         schedule_work(&dev_priv->hotplug.poll_init_work);
 497
 498         /*
 499          * Interrupt setup is already guaranteed to be single-threaded, this is
 500          * just to make the assert_spin_locked checks happy.
 501          */
 502         if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup) {
 503                 spin_lock_irq(&dev_priv->irq_lock);
 504                 if (dev_priv->display_irqs_enabled)
 505                         dev_priv->display.hpd_irq_setup(dev_priv);
 506                 spin_unlock_irq(&dev_priv->irq_lock);
 507         }
 508 }
 509
 510 static void i915_hpd_poll_init_work(struct work_struct *work)
 511 {
 512         struct drm_i915_private *dev_priv =
 513                 container_of(work, struct drm_i915_private,
 514                              hotplug.poll_init_work);
 515         struct drm_device *dev = &dev_priv->drm;
 516         struct drm_connector *connector;
 517         struct drm_connector_list_iter conn_iter;
 518         bool enabled;
 519
 520         mutex_lock(&dev->mode_config.mutex);
 521
 522         enabled = READ_ONCE(dev_priv->hotplug.poll_enabled);
 523
 524         drm_connector_list_iter_begin(dev, &conn_iter);
 525         drm_for_each_connector_iter(connector, &conn_iter) {
 526                 struct intel_connector *intel_connector =
 527                         to_intel_connector(connector);
 528                 connector->polled = intel_connector->polled;
 529
 530                 /* MST has a dynamic intel_connector->encoder and it's reprobing
 531                  * is all handled by the MST helpers. */
 532                 if (intel_connector->mst_port)
 533                         continue;
 534
 535                 if (!connector->polled && I915_HAS_HOTPLUG(dev_priv) &&
 536                     intel_connector->encoder->hpd_pin > HPD_NONE) {
 537                         connector->polled = enabled ?
 538                                 DRM_CONNECTOR_POLL_CONNECT |
 539                                 DRM_CONNECTOR_POLL_DISCONNECT :
 540                                 DRM_CONNECTOR_POLL_HPD;
 541                 }
 542         }
 543         drm_connector_list_iter_end(&conn_iter);
 544
 545         if (enabled)
 546                 drm_kms_helper_poll_enable(dev);
 547
 548         mutex_unlock(&dev->mode_config.mutex);
 549
 550         /*
 551          * We might have missed any hotplugs that happened while we were
 552          * in the middle of disabling polling
 553          */
 554         if (!enabled)
 555                 drm_helper_hpd_irq_event(dev);
 556 }
 557
 558 /**
 559  * intel_hpd_poll_init - enables/disables polling for connectors with hpd
 560  * @dev_priv: i915 device instance
 561  *
 562  * This function enables polling for all connectors, regardless of whether or
 563  * not they support hotplug detection. Under certain conditions HPD may not be
 564  * functional. On most Intel GPUs, this happens when we enter runtime suspend.
 565  * On Valleyview and Cherryview systems, this also happens when we shut off all
 566  * of the powerwells.
 567  *
 568  * Since this function can get called in contexts where we're already holding
 569  * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
 570  * worker.
 571  *
 572  * Also see: intel_hpd_init(), which restores hpd handling.
 573  */
 574 void intel_hpd_poll_init(struct drm_i915_private *dev_priv)
 575 {
 576         WRITE_ONCE(dev_priv->hotplug.poll_enabled, true);
 577
 578         /*
 579          * We might already be holding dev->mode_config.mutex, so do this in a
 580          * seperate worker
 581          * As well, there's no issue if we race here since we always reschedule
 582          * this worker anyway
 583          */
 584         schedule_work(&dev_priv->hotplug.poll_init_work);
 585 }
 586
 587 void intel_hpd_init_work(struct drm_i915_private *dev_priv)
 588 {
 589         INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
 590         INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
 591         INIT_WORK(&dev_priv->hotplug.poll_init_work, i915_hpd_poll_init_work);
 592         INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
 593                           intel_hpd_irq_storm_reenable_work);
 594 }
 595
 596 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 597 {
 598         spin_lock_irq(&dev_priv->irq_lock);
 599
 600         dev_priv->hotplug.long_port_mask = 0;
 601         dev_priv->hotplug.short_port_mask = 0;
 602         dev_priv->hotplug.event_bits = 0;
 603
 604         spin_unlock_irq(&dev_priv->irq_lock);
 605
 606         cancel_work_sync(&dev_priv->hotplug.dig_port_work);
 607         cancel_work_sync(&dev_priv->hotplug.hotplug_work);
 608         cancel_work_sync(&dev_priv->hotplug.poll_init_work);
 609         cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 610 }
 611
 612 bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 613 {
 614         bool ret = false;
 615
 616         if (pin == HPD_NONE)
 617                 return false;
 618
 619         spin_lock_irq(&dev_priv->irq_lock);
 620         if (dev_priv->hotplug.stats[pin].state == HPD_ENABLED) {
 621                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 622                 ret = true;
 623         }
 624         spin_unlock_irq(&dev_priv->irq_lock);
 625
 626         return ret;
 627 }
 628
 629 void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
 630 {
 631         if (pin == HPD_NONE)
 632                 return;
 633
 634         spin_lock_irq(&dev_priv->irq_lock);
 635         dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
 636         spin_unlock_irq(&dev_priv->irq_lock);
 637 }