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
  71 enum port intel_hpd_pin_to_port(enum hpd_pin pin)
  72 {
  73         switch (pin) {
  74         case HPD_PORT_B:
  75                 return PORT_B;
  76         case HPD_PORT_C:
  77                 return PORT_C;
  78         case HPD_PORT_D:
  79                 return PORT_D;
  80         default:
  81                 return PORT_A; /* no hpd */
  82         }
  83 }
  84
  85 #define HPD_STORM_DETECT_PERIOD         1000
  86 #define HPD_STORM_THRESHOLD             5
  87 #define HPD_STORM_REENABLE_DELAY        (2 * 60 * 1000)
  88
  89 /**
  90  * intel_hpd_irq_storm_detect - gather stats and detect HPD irq storm on a pin
  91  * @dev_priv: private driver data pointer
  92  * @pin: the pin to gather stats on
  93  *
  94  * Gather stats about HPD irqs from the specified @pin, and detect irq
  95  * storms. Only the pin specific stats and state are changed, the caller is
  96  * responsible for further action.
  97  *
  98  * @HPD_STORM_THRESHOLD irqs are allowed within @HPD_STORM_DETECT_PERIOD ms,
  99  * otherwise it's considered an irq storm, and the irq state is set to
 100  * @HPD_MARK_DISABLED.
 101  *
 102  * Return true if an irq storm was detected on @pin.
 103  */
 104 static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
 105                                        enum hpd_pin pin)
 106 {
 107         unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies;
 108         unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
 109         bool storm = false;
 110
 111         if (!time_in_range(jiffies, start, end)) {
 112                 dev_priv->hotplug.stats[pin].last_jiffies = jiffies;
 113                 dev_priv->hotplug.stats[pin].count = 0;
 114                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", pin);
 115         } else if (dev_priv->hotplug.stats[pin].count > HPD_STORM_THRESHOLD) {
 116                 dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED;
 117                 DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);
 118                 storm = true;
 119         } else {
 120                 dev_priv->hotplug.stats[pin].count++;
 121                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,
 122                               dev_priv->hotplug.stats[pin].count);
 123         }
 124
 125         return storm;
 126 }
 127
 128 static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)
 129 {
 130         struct drm_device *dev = dev_priv->dev;
 131         struct drm_mode_config *mode_config = &dev->mode_config;
 132         struct intel_connector *intel_connector;
 133         struct intel_encoder *intel_encoder;
 134         struct drm_connector *connector;
 135         enum hpd_pin pin;
 136         bool hpd_disabled = false;
 137
 138         assert_spin_locked(&dev_priv->irq_lock);
 139
 140         list_for_each_entry(connector, &mode_config->connector_list, head) {
 141                 if (connector->polled != DRM_CONNECTOR_POLL_HPD)
 142                         continue;
 143
 144                 intel_connector = to_intel_connector(connector);
 145                 intel_encoder = intel_connector->encoder;
 146                 if (!intel_encoder)
 147                         continue;
 148
 149                 pin = intel_encoder->hpd_pin;
 150                 if (pin == HPD_NONE ||
 151                     dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
 152                         continue;
 153
 154                 DRM_INFO("HPD interrupt storm detected on connector %s: "
 155                          "switching from hotplug detection to polling\n",
 156                          connector->name);
 157
 158                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 159                 connector->polled = DRM_CONNECTOR_POLL_CONNECT
 160                         | DRM_CONNECTOR_POLL_DISCONNECT;
 161                 hpd_disabled = true;
 162         }
 163
 164         /* Enable polling and queue hotplug re-enabling. */
 165         if (hpd_disabled) {
 166                 drm_kms_helper_poll_enable(dev);
 167                 mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
 168                                  msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 169         }
 170 }
 171
 172 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 173 {
 174         struct drm_i915_private *dev_priv =
 175                 container_of(work, typeof(*dev_priv),
 176                              hotplug.reenable_work.work);
 177         struct drm_device *dev = dev_priv->dev;
 178         struct drm_mode_config *mode_config = &dev->mode_config;
 179         int i;
 180
 181         intel_runtime_pm_get(dev_priv);
 182
 183         spin_lock_irq(&dev_priv->irq_lock);
 184         for_each_hpd_pin(i) {
 185                 struct drm_connector *connector;
 186
 187                 if (dev_priv->hotplug.stats[i].state != HPD_DISABLED)
 188                         continue;
 189
 190                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 191
 192                 list_for_each_entry(connector, &mode_config->connector_list, head) {
 193                         struct intel_connector *intel_connector = to_intel_connector(connector);
 194
 195                         if (intel_connector->encoder->hpd_pin == i) {
 196                                 if (connector->polled != intel_connector->polled)
 197                                         DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
 198                                                          connector->name);
 199                                 connector->polled = intel_connector->polled;
 200                                 if (!connector->polled)
 201                                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 202                         }
 203                 }
 204         }
 205         if (dev_priv->display.hpd_irq_setup)
 206                 dev_priv->display.hpd_irq_setup(dev);
 207         spin_unlock_irq(&dev_priv->irq_lock);
 208
 209         intel_runtime_pm_put(dev_priv);
 210 }
 211
 212 static bool intel_hpd_irq_event(struct drm_device *dev,
 213                                 struct drm_connector *connector)
 214 {
 215         enum drm_connector_status old_status;
 216
 217         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 218         old_status = connector->status;
 219
 220         connector->status = connector->funcs->detect(connector, false);
 221         if (old_status == connector->status)
 222                 return false;
 223
 224         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 225                       connector->base.id,
 226                       connector->name,
 227                       drm_get_connector_status_name(old_status),
 228                       drm_get_connector_status_name(connector->status));
 229
 230         return true;
 231 }
 232
 233 static void i915_digport_work_func(struct work_struct *work)
 234 {
 235         struct drm_i915_private *dev_priv =
 236                 container_of(work, struct drm_i915_private, hotplug.dig_port_work);
 237         u32 long_port_mask, short_port_mask;
 238         struct intel_digital_port *intel_dig_port;
 239         int i;
 240         u32 old_bits = 0;
 241
 242         spin_lock_irq(&dev_priv->irq_lock);
 243         long_port_mask = dev_priv->hotplug.long_port_mask;
 244         dev_priv->hotplug.long_port_mask = 0;
 245         short_port_mask = dev_priv->hotplug.short_port_mask;
 246         dev_priv->hotplug.short_port_mask = 0;
 247         spin_unlock_irq(&dev_priv->irq_lock);
 248
 249         for (i = 0; i < I915_MAX_PORTS; i++) {
 250                 bool valid = false;
 251                 bool long_hpd = false;
 252                 intel_dig_port = dev_priv->hotplug.irq_port[i];
 253                 if (!intel_dig_port || !intel_dig_port->hpd_pulse)
 254                         continue;
 255
 256                 if (long_port_mask & (1 << i))  {
 257                         valid = true;
 258                         long_hpd = true;
 259                 } else if (short_port_mask & (1 << i))
 260                         valid = true;
 261
 262                 if (valid) {
 263                         enum irqreturn ret;
 264
 265                         ret = intel_dig_port->hpd_pulse(intel_dig_port, long_hpd);
 266                         if (ret == IRQ_NONE) {
 267                                 /* fall back to old school hpd */
 268                                 old_bits |= (1 << intel_dig_port->base.hpd_pin);
 269                         }
 270                 }
 271         }
 272
 273         if (old_bits) {
 274                 spin_lock_irq(&dev_priv->irq_lock);
 275                 dev_priv->hotplug.event_bits |= old_bits;
 276                 spin_unlock_irq(&dev_priv->irq_lock);
 277                 schedule_work(&dev_priv->hotplug.hotplug_work);
 278         }
 279 }
 280
 281 /*
 282  * Handle hotplug events outside the interrupt handler proper.
 283  */
 284 static void i915_hotplug_work_func(struct work_struct *work)
 285 {
 286         struct drm_i915_private *dev_priv =
 287                 container_of(work, struct drm_i915_private, hotplug.hotplug_work);
 288         struct drm_device *dev = dev_priv->dev;
 289         struct drm_mode_config *mode_config = &dev->mode_config;
 290         struct intel_connector *intel_connector;
 291         struct intel_encoder *intel_encoder;
 292         struct drm_connector *connector;
 293         bool changed = false;
 294         u32 hpd_event_bits;
 295
 296         mutex_lock(&mode_config->mutex);
 297         DRM_DEBUG_KMS("running encoder hotplug functions\n");
 298
 299         spin_lock_irq(&dev_priv->irq_lock);
 300
 301         hpd_event_bits = dev_priv->hotplug.event_bits;
 302         dev_priv->hotplug.event_bits = 0;
 303
 304         /* Disable hotplug on connectors that hit an irq storm. */
 305         intel_hpd_irq_storm_disable(dev_priv);
 306
 307         spin_unlock_irq(&dev_priv->irq_lock);
 308
 309         list_for_each_entry(connector, &mode_config->connector_list, head) {
 310                 intel_connector = to_intel_connector(connector);
 311                 if (!intel_connector->encoder)
 312                         continue;
 313                 intel_encoder = intel_connector->encoder;
 314                 if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
 315                         DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
 316                                       connector->name, intel_encoder->hpd_pin);
 317                         if (intel_encoder->hot_plug)
 318                                 intel_encoder->hot_plug(intel_encoder);
 319                         if (intel_hpd_irq_event(dev, connector))
 320                                 changed = true;
 321                 }
 322         }
 323         mutex_unlock(&mode_config->mutex);
 324
 325         if (changed)
 326                 drm_kms_helper_hotplug_event(dev);
 327 }
 328
 329
 330 /**
 331  * intel_hpd_irq_handler - main hotplug irq handler
 332  * @dev: drm device
 333  * @pin_mask: a mask of hpd pins that have triggered the irq
 334  * @long_mask: a mask of hpd pins that may be long hpd pulses
 335  *
 336  * This is the main hotplug irq handler for all platforms. The platform specific
 337  * irq handlers call the platform specific hotplug irq handlers, which read and
 338  * decode the appropriate registers into bitmasks about hpd pins that have
 339  * triggered (@pin_mask), and which of those pins may be long pulses
 340  * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
 341  * is not a digital port.
 342  *
 343  * Here, we do hotplug irq storm detection and mitigation, and pass further
 344  * processing to appropriate bottom halves.
 345  */
 346 void intel_hpd_irq_handler(struct drm_device *dev,
 347                            u32 pin_mask, u32 long_mask)
 348 {
 349         struct drm_i915_private *dev_priv = dev->dev_private;
 350         int i;
 351         enum port port;
 352         bool storm_detected = false;
 353         bool queue_dig = false, queue_hp = false;
 354         bool is_dig_port;
 355
 356         if (!pin_mask)
 357                 return;
 358
 359         spin_lock(&dev_priv->irq_lock);
 360         for_each_hpd_pin(i) {
 361                 if (!(BIT(i) & pin_mask))
 362                         continue;
 363
 364                 port = intel_hpd_pin_to_port(i);
 365                 is_dig_port = port && dev_priv->hotplug.irq_port[port];
 366
 367                 if (is_dig_port) {
 368                         bool long_hpd = long_mask & BIT(i);
 369
 370                         DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
 371                                          long_hpd ? "long" : "short");
 372                         /*
 373                          * For long HPD pulses we want to have the digital queue happen,
 374                          * but we still want HPD storm detection to function.
 375                          */
 376                         queue_dig = true;
 377                         if (long_hpd) {
 378                                 dev_priv->hotplug.long_port_mask |= (1 << port);
 379                         } else {
 380                                 /* for short HPD just trigger the digital queue */
 381                                 dev_priv->hotplug.short_port_mask |= (1 << port);
 382                                 continue;
 383                         }
 384                 }
 385
 386                 if (dev_priv->hotplug.stats[i].state == HPD_DISABLED) {
 387                         /*
 388                          * On GMCH platforms the interrupt mask bits only
 389                          * prevent irq generation, not the setting of the
 390                          * hotplug bits itself. So only WARN about unexpected
 391                          * interrupts on saner platforms.
 392                          */
 393                         WARN_ONCE(INTEL_INFO(dev)->gen >= 5 && !IS_VALLEYVIEW(dev),
 394                                   "Received HPD interrupt on pin %d although disabled\n", i);
 395                         continue;
 396                 }
 397
 398                 if (dev_priv->hotplug.stats[i].state != HPD_ENABLED)
 399                         continue;
 400
 401                 if (!is_dig_port) {
 402                         dev_priv->hotplug.event_bits |= BIT(i);
 403                         queue_hp = true;
 404                 }
 405
 406                 if (intel_hpd_irq_storm_detect(dev_priv, i)) {
 407                         dev_priv->hotplug.event_bits &= ~BIT(i);
 408                         storm_detected = true;
 409                 }
 410         }
 411
 412         if (storm_detected)
 413                 dev_priv->display.hpd_irq_setup(dev);
 414         spin_unlock(&dev_priv->irq_lock);
 415
 416         /*
 417          * Our hotplug handler can grab modeset locks (by calling down into the
 418          * fb helpers). Hence it must not be run on our own dev-priv->wq work
 419          * queue for otherwise the flush_work in the pageflip code will
 420          * deadlock.
 421          */
 422         if (queue_dig)
 423                 queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
 424         if (queue_hp)
 425                 schedule_work(&dev_priv->hotplug.hotplug_work);
 426 }
 427
 428 /**
 429  * intel_hpd_init - initializes and enables hpd support
 430  * @dev_priv: i915 device instance
 431  *
 432  * This function enables the hotplug support. It requires that interrupts have
 433  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
 434  * poll request can run concurrently to other code, so locking rules must be
 435  * obeyed.
 436  *
 437  * This is a separate step from interrupt enabling to simplify the locking rules
 438  * in the driver load and resume code.
 439  */
 440 void intel_hpd_init(struct drm_i915_private *dev_priv)
 441 {
 442         struct drm_device *dev = dev_priv->dev;
 443         struct drm_mode_config *mode_config = &dev->mode_config;
 444         struct drm_connector *connector;
 445         int i;
 446
 447         for_each_hpd_pin(i) {
 448                 dev_priv->hotplug.stats[i].count = 0;
 449                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 450         }
 451         list_for_each_entry(connector, &mode_config->connector_list, head) {
 452                 struct intel_connector *intel_connector = to_intel_connector(connector);
 453                 connector->polled = intel_connector->polled;
 454                 if (connector->encoder && !connector->polled && I915_HAS_HOTPLUG(dev) && intel_connector->encoder->hpd_pin > HPD_NONE)
 455                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 456                 if (intel_connector->mst_port)
 457                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 458         }
 459
 460         /*
 461          * Interrupt setup is already guaranteed to be single-threaded, this is
 462          * just to make the assert_spin_locked checks happy.
 463          */
 464         spin_lock_irq(&dev_priv->irq_lock);
 465         if (dev_priv->display.hpd_irq_setup)
 466                 dev_priv->display.hpd_irq_setup(dev);
 467         spin_unlock_irq(&dev_priv->irq_lock);
 468 }
 469
 470 void intel_hpd_init_work(struct drm_i915_private *dev_priv)
 471 {
 472         INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
 473         INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
 474         INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
 475                           intel_hpd_irq_storm_reenable_work);
 476 }
 477
 478 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 479 {
 480         spin_lock_irq(&dev_priv->irq_lock);
 481
 482         dev_priv->hotplug.long_port_mask = 0;
 483         dev_priv->hotplug.short_port_mask = 0;
 484         dev_priv->hotplug.event_bits = 0;
 485
 486         spin_unlock_irq(&dev_priv->irq_lock);
 487
 488         cancel_work_sync(&dev_priv->hotplug.dig_port_work);
 489         cancel_work_sync(&dev_priv->hotplug.hotplug_work);
 490         cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 491 }