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 bool intel_hpd_pin_to_port(enum hpd_pin pin, enum port *port)
  80 {
  81         switch (pin) {
  82         case HPD_PORT_A:
  83                 *port = PORT_A;
  84                 return true;
  85         case HPD_PORT_B:
  86                 *port = PORT_B;
  87                 return true;
  88         case HPD_PORT_C:
  89                 *port = PORT_C;
  90                 return true;
  91         case HPD_PORT_D:
  92                 *port = PORT_D;
  93                 return true;
  94         default:
  95                 return false;   /* no hpd */
  96         }
  97 }
  98
  99 #define HPD_STORM_DETECT_PERIOD         1000
 100 #define HPD_STORM_THRESHOLD             5
 101 #define HPD_STORM_REENABLE_DELAY        (2 * 60 * 1000)
 102
 103 /**
 104  * intel_hpd_irq_storm_detect - gather stats and detect HPD irq storm on a pin
 105  * @dev_priv: private driver data pointer
 106  * @pin: the pin to gather stats on
 107  *
 108  * Gather stats about HPD irqs from the specified @pin, and detect irq
 109  * storms. Only the pin specific stats and state are changed, the caller is
 110  * responsible for further action.
 111  *
 112  * @HPD_STORM_THRESHOLD irqs are allowed within @HPD_STORM_DETECT_PERIOD ms,
 113  * otherwise it's considered an irq storm, and the irq state is set to
 114  * @HPD_MARK_DISABLED.
 115  *
 116  * Return true if an irq storm was detected on @pin.
 117  */
 118 static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
 119                                        enum hpd_pin pin)
 120 {
 121         unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies;
 122         unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
 123         bool storm = false;
 124
 125         if (!time_in_range(jiffies, start, end)) {
 126                 dev_priv->hotplug.stats[pin].last_jiffies = jiffies;
 127                 dev_priv->hotplug.stats[pin].count = 0;
 128                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", pin);
 129         } else if (dev_priv->hotplug.stats[pin].count > HPD_STORM_THRESHOLD) {
 130                 dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED;
 131                 DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);
 132                 storm = true;
 133         } else {
 134                 dev_priv->hotplug.stats[pin].count++;
 135                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,
 136                               dev_priv->hotplug.stats[pin].count);
 137         }
 138
 139         return storm;
 140 }
 141
 142 static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)
 143 {
 144         struct drm_device *dev = dev_priv->dev;
 145         struct drm_mode_config *mode_config = &dev->mode_config;
 146         struct intel_connector *intel_connector;
 147         struct intel_encoder *intel_encoder;
 148         struct drm_connector *connector;
 149         enum hpd_pin pin;
 150         bool hpd_disabled = false;
 151
 152         assert_spin_locked(&dev_priv->irq_lock);
 153
 154         list_for_each_entry(connector, &mode_config->connector_list, head) {
 155                 if (connector->polled != DRM_CONNECTOR_POLL_HPD)
 156                         continue;
 157
 158                 intel_connector = to_intel_connector(connector);
 159                 intel_encoder = intel_connector->encoder;
 160                 if (!intel_encoder)
 161                         continue;
 162
 163                 pin = intel_encoder->hpd_pin;
 164                 if (pin == HPD_NONE ||
 165                     dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
 166                         continue;
 167
 168                 DRM_INFO("HPD interrupt storm detected on connector %s: "
 169                          "switching from hotplug detection to polling\n",
 170                          connector->name);
 171
 172                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 173                 connector->polled = DRM_CONNECTOR_POLL_CONNECT
 174                         | DRM_CONNECTOR_POLL_DISCONNECT;
 175                 hpd_disabled = true;
 176         }
 177
 178         /* Enable polling and queue hotplug re-enabling. */
 179         if (hpd_disabled) {
 180                 drm_kms_helper_poll_enable(dev);
 181                 mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
 182                                  msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 183         }
 184 }
 185
 186 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 187 {
 188         struct drm_i915_private *dev_priv =
 189                 container_of(work, typeof(*dev_priv),
 190                              hotplug.reenable_work.work);
 191         struct drm_device *dev = dev_priv->dev;
 192         struct drm_mode_config *mode_config = &dev->mode_config;
 193         int i;
 194
 195         intel_runtime_pm_get(dev_priv);
 196
 197         spin_lock_irq(&dev_priv->irq_lock);
 198         for_each_hpd_pin(i) {
 199                 struct drm_connector *connector;
 200
 201                 if (dev_priv->hotplug.stats[i].state != HPD_DISABLED)
 202                         continue;
 203
 204                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 205
 206                 list_for_each_entry(connector, &mode_config->connector_list, head) {
 207                         struct intel_connector *intel_connector = to_intel_connector(connector);
 208
 209                         if (intel_connector->encoder->hpd_pin == i) {
 210                                 if (connector->polled != intel_connector->polled)
 211                                         DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
 212                                                          connector->name);
 213                                 connector->polled = intel_connector->polled;
 214                                 if (!connector->polled)
 215                                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 216                         }
 217                 }
 218         }
 219         if (dev_priv->display.hpd_irq_setup)
 220                 dev_priv->display.hpd_irq_setup(dev);
 221         spin_unlock_irq(&dev_priv->irq_lock);
 222
 223         intel_runtime_pm_put(dev_priv);
 224 }
 225
 226 static bool intel_hpd_irq_event(struct drm_device *dev,
 227                                 struct drm_connector *connector)
 228 {
 229         enum drm_connector_status old_status;
 230
 231         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 232         old_status = connector->status;
 233
 234         connector->status = connector->funcs->detect(connector, false);
 235         if (old_status == connector->status)
 236                 return false;
 237
 238         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 239                       connector->base.id,
 240                       connector->name,
 241                       drm_get_connector_status_name(old_status),
 242                       drm_get_connector_status_name(connector->status));
 243
 244         return true;
 245 }
 246
 247 static void i915_digport_work_func(struct work_struct *work)
 248 {
 249         struct drm_i915_private *dev_priv =
 250                 container_of(work, struct drm_i915_private, hotplug.dig_port_work);
 251         u32 long_port_mask, short_port_mask;
 252         struct intel_digital_port *intel_dig_port;
 253         int i;
 254         u32 old_bits = 0;
 255
 256         spin_lock_irq(&dev_priv->irq_lock);
 257         long_port_mask = dev_priv->hotplug.long_port_mask;
 258         dev_priv->hotplug.long_port_mask = 0;
 259         short_port_mask = dev_priv->hotplug.short_port_mask;
 260         dev_priv->hotplug.short_port_mask = 0;
 261         spin_unlock_irq(&dev_priv->irq_lock);
 262
 263         for (i = 0; i < I915_MAX_PORTS; i++) {
 264                 bool valid = false;
 265                 bool long_hpd = false;
 266                 intel_dig_port = dev_priv->hotplug.irq_port[i];
 267                 if (!intel_dig_port || !intel_dig_port->hpd_pulse)
 268                         continue;
 269
 270                 if (long_port_mask & (1 << i))  {
 271                         valid = true;
 272                         long_hpd = true;
 273                 } else if (short_port_mask & (1 << i))
 274                         valid = true;
 275
 276                 if (valid) {
 277                         enum irqreturn ret;
 278
 279                         ret = intel_dig_port->hpd_pulse(intel_dig_port, long_hpd);
 280                         if (ret == IRQ_NONE) {
 281                                 /* fall back to old school hpd */
 282                                 old_bits |= (1 << intel_dig_port->base.hpd_pin);
 283                         }
 284                 }
 285         }
 286
 287         if (old_bits) {
 288                 spin_lock_irq(&dev_priv->irq_lock);
 289                 dev_priv->hotplug.event_bits |= old_bits;
 290                 spin_unlock_irq(&dev_priv->irq_lock);
 291                 schedule_work(&dev_priv->hotplug.hotplug_work);
 292         }
 293 }
 294
 295 /*
 296  * Handle hotplug events outside the interrupt handler proper.
 297  */
 298 static void i915_hotplug_work_func(struct work_struct *work)
 299 {
 300         struct drm_i915_private *dev_priv =
 301                 container_of(work, struct drm_i915_private, hotplug.hotplug_work);
 302         struct drm_device *dev = dev_priv->dev;
 303         struct drm_mode_config *mode_config = &dev->mode_config;
 304         struct intel_connector *intel_connector;
 305         struct intel_encoder *intel_encoder;
 306         struct drm_connector *connector;
 307         bool changed = false;
 308         u32 hpd_event_bits;
 309
 310         mutex_lock(&mode_config->mutex);
 311         DRM_DEBUG_KMS("running encoder hotplug functions\n");
 312
 313         spin_lock_irq(&dev_priv->irq_lock);
 314
 315         hpd_event_bits = dev_priv->hotplug.event_bits;
 316         dev_priv->hotplug.event_bits = 0;
 317
 318         /* Disable hotplug on connectors that hit an irq storm. */
 319         intel_hpd_irq_storm_disable(dev_priv);
 320
 321         spin_unlock_irq(&dev_priv->irq_lock);
 322
 323         list_for_each_entry(connector, &mode_config->connector_list, head) {
 324                 intel_connector = to_intel_connector(connector);
 325                 if (!intel_connector->encoder)
 326                         continue;
 327                 intel_encoder = intel_connector->encoder;
 328                 if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
 329                         DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
 330                                       connector->name, intel_encoder->hpd_pin);
 331                         if (intel_encoder->hot_plug)
 332                                 intel_encoder->hot_plug(intel_encoder);
 333                         if (intel_hpd_irq_event(dev, connector))
 334                                 changed = true;
 335                 }
 336         }
 337         mutex_unlock(&mode_config->mutex);
 338
 339         if (changed)
 340                 drm_kms_helper_hotplug_event(dev);
 341 }
 342
 343
 344 /**
 345  * intel_hpd_irq_handler - main hotplug irq handler
 346  * @dev: drm device
 347  * @pin_mask: a mask of hpd pins that have triggered the irq
 348  * @long_mask: a mask of hpd pins that may be long hpd pulses
 349  *
 350  * This is the main hotplug irq handler for all platforms. The platform specific
 351  * irq handlers call the platform specific hotplug irq handlers, which read and
 352  * decode the appropriate registers into bitmasks about hpd pins that have
 353  * triggered (@pin_mask), and which of those pins may be long pulses
 354  * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
 355  * is not a digital port.
 356  *
 357  * Here, we do hotplug irq storm detection and mitigation, and pass further
 358  * processing to appropriate bottom halves.
 359  */
 360 void intel_hpd_irq_handler(struct drm_device *dev,
 361                            u32 pin_mask, u32 long_mask)
 362 {
 363         struct drm_i915_private *dev_priv = dev->dev_private;
 364         int i;
 365         enum port port;
 366         bool storm_detected = false;
 367         bool queue_dig = false, queue_hp = false;
 368         bool is_dig_port;
 369
 370         if (!pin_mask)
 371                 return;
 372
 373         spin_lock(&dev_priv->irq_lock);
 374         for_each_hpd_pin(i) {
 375                 if (!(BIT(i) & pin_mask))
 376                         continue;
 377
 378                 is_dig_port = intel_hpd_pin_to_port(i, &port) &&
 379                               dev_priv->hotplug.irq_port[port];
 380
 381                 if (is_dig_port) {
 382                         bool long_hpd = long_mask & BIT(i);
 383
 384                         DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
 385                                          long_hpd ? "long" : "short");
 386                         /*
 387                          * For long HPD pulses we want to have the digital queue happen,
 388                          * but we still want HPD storm detection to function.
 389                          */
 390                         queue_dig = true;
 391                         if (long_hpd) {
 392                                 dev_priv->hotplug.long_port_mask |= (1 << port);
 393                         } else {
 394                                 /* for short HPD just trigger the digital queue */
 395                                 dev_priv->hotplug.short_port_mask |= (1 << port);
 396                                 continue;
 397                         }
 398                 }
 399
 400                 if (dev_priv->hotplug.stats[i].state == HPD_DISABLED) {
 401                         /*
 402                          * On GMCH platforms the interrupt mask bits only
 403                          * prevent irq generation, not the setting of the
 404                          * hotplug bits itself. So only WARN about unexpected
 405                          * interrupts on saner platforms.
 406                          */
 407                         WARN_ONCE(INTEL_INFO(dev)->gen >= 5 && !IS_VALLEYVIEW(dev),
 408                                   "Received HPD interrupt on pin %d although disabled\n", i);
 409                         continue;
 410                 }
 411
 412                 if (dev_priv->hotplug.stats[i].state != HPD_ENABLED)
 413                         continue;
 414
 415                 if (!is_dig_port) {
 416                         dev_priv->hotplug.event_bits |= BIT(i);
 417                         queue_hp = true;
 418                 }
 419
 420                 if (intel_hpd_irq_storm_detect(dev_priv, i)) {
 421                         dev_priv->hotplug.event_bits &= ~BIT(i);
 422                         storm_detected = true;
 423                 }
 424         }
 425
 426         if (storm_detected)
 427                 dev_priv->display.hpd_irq_setup(dev);
 428         spin_unlock(&dev_priv->irq_lock);
 429
 430         /*
 431          * Our hotplug handler can grab modeset locks (by calling down into the
 432          * fb helpers). Hence it must not be run on our own dev-priv->wq work
 433          * queue for otherwise the flush_work in the pageflip code will
 434          * deadlock.
 435          */
 436         if (queue_dig)
 437                 queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
 438         if (queue_hp)
 439                 schedule_work(&dev_priv->hotplug.hotplug_work);
 440 }
 441
 442 /**
 443  * intel_hpd_init - initializes and enables hpd support
 444  * @dev_priv: i915 device instance
 445  *
 446  * This function enables the hotplug support. It requires that interrupts have
 447  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
 448  * poll request can run concurrently to other code, so locking rules must be
 449  * obeyed.
 450  *
 451  * This is a separate step from interrupt enabling to simplify the locking rules
 452  * in the driver load and resume code.
 453  */
 454 void intel_hpd_init(struct drm_i915_private *dev_priv)
 455 {
 456         struct drm_device *dev = dev_priv->dev;
 457         struct drm_mode_config *mode_config = &dev->mode_config;
 458         struct drm_connector *connector;
 459         int i;
 460
 461         for_each_hpd_pin(i) {
 462                 dev_priv->hotplug.stats[i].count = 0;
 463                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 464         }
 465         list_for_each_entry(connector, &mode_config->connector_list, head) {
 466                 struct intel_connector *intel_connector = to_intel_connector(connector);
 467                 connector->polled = intel_connector->polled;
 468                 if (connector->encoder && !connector->polled && I915_HAS_HOTPLUG(dev) && intel_connector->encoder->hpd_pin > HPD_NONE)
 469                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 470                 if (intel_connector->mst_port)
 471                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 472         }
 473
 474         /*
 475          * Interrupt setup is already guaranteed to be single-threaded, this is
 476          * just to make the assert_spin_locked checks happy.
 477          */
 478         spin_lock_irq(&dev_priv->irq_lock);
 479         if (dev_priv->display.hpd_irq_setup)
 480                 dev_priv->display.hpd_irq_setup(dev);
 481         spin_unlock_irq(&dev_priv->irq_lock);
 482 }
 483
 484 void intel_hpd_init_work(struct drm_i915_private *dev_priv)
 485 {
 486         INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
 487         INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
 488         INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
 489                           intel_hpd_irq_storm_reenable_work);
 490 }
 491
 492 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 493 {
 494         spin_lock_irq(&dev_priv->irq_lock);
 495
 496         dev_priv->hotplug.long_port_mask = 0;
 497         dev_priv->hotplug.short_port_mask = 0;
 498         dev_priv->hotplug.event_bits = 0;
 499
 500         spin_unlock_irq(&dev_priv->irq_lock);
 501
 502         cancel_work_sync(&dev_priv->hotplug.dig_port_work);
 503         cancel_work_sync(&dev_priv->hotplug.hotplug_work);
 504         cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 505 }