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         case HPD_PORT_E:
  95                 *port = PORT_E;
  96                 return true;
  97         default:
  98                 return false;   /* no hpd */
  99         }
 100 }
 101
 102 #define HPD_STORM_DETECT_PERIOD         1000
 103 #define HPD_STORM_THRESHOLD             5
 104 #define HPD_STORM_REENABLE_DELAY        (2 * 60 * 1000)
 105
 106 /**
 107  * intel_hpd_irq_storm_detect - gather stats and detect HPD irq storm on a pin
 108  * @dev_priv: private driver data pointer
 109  * @pin: the pin to gather stats on
 110  *
 111  * Gather stats about HPD irqs from the specified @pin, and detect irq
 112  * storms. Only the pin specific stats and state are changed, the caller is
 113  * responsible for further action.
 114  *
 115  * @HPD_STORM_THRESHOLD irqs are allowed within @HPD_STORM_DETECT_PERIOD ms,
 116  * otherwise it's considered an irq storm, and the irq state is set to
 117  * @HPD_MARK_DISABLED.
 118  *
 119  * Return true if an irq storm was detected on @pin.
 120  */
 121 static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
 122                                        enum hpd_pin pin)
 123 {
 124         unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies;
 125         unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
 126         bool storm = false;
 127
 128         if (!time_in_range(jiffies, start, end)) {
 129                 dev_priv->hotplug.stats[pin].last_jiffies = jiffies;
 130                 dev_priv->hotplug.stats[pin].count = 0;
 131                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", pin);
 132         } else if (dev_priv->hotplug.stats[pin].count > HPD_STORM_THRESHOLD) {
 133                 dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED;
 134                 DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);
 135                 storm = true;
 136         } else {
 137                 dev_priv->hotplug.stats[pin].count++;
 138                 DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,
 139                               dev_priv->hotplug.stats[pin].count);
 140         }
 141
 142         return storm;
 143 }
 144
 145 static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)
 146 {
 147         struct drm_device *dev = dev_priv->dev;
 148         struct drm_mode_config *mode_config = &dev->mode_config;
 149         struct intel_connector *intel_connector;
 150         struct intel_encoder *intel_encoder;
 151         struct drm_connector *connector;
 152         enum hpd_pin pin;
 153         bool hpd_disabled = false;
 154
 155         assert_spin_locked(&dev_priv->irq_lock);
 156
 157         list_for_each_entry(connector, &mode_config->connector_list, head) {
 158                 if (connector->polled != DRM_CONNECTOR_POLL_HPD)
 159                         continue;
 160
 161                 intel_connector = to_intel_connector(connector);
 162                 intel_encoder = intel_connector->encoder;
 163                 if (!intel_encoder)
 164                         continue;
 165
 166                 pin = intel_encoder->hpd_pin;
 167                 if (pin == HPD_NONE ||
 168                     dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
 169                         continue;
 170
 171                 DRM_INFO("HPD interrupt storm detected on connector %s: "
 172                          "switching from hotplug detection to polling\n",
 173                          connector->name);
 174
 175                 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
 176                 connector->polled = DRM_CONNECTOR_POLL_CONNECT
 177                         | DRM_CONNECTOR_POLL_DISCONNECT;
 178                 hpd_disabled = true;
 179         }
 180
 181         /* Enable polling and queue hotplug re-enabling. */
 182         if (hpd_disabled) {
 183                 drm_kms_helper_poll_enable_locked(dev);
 184                 mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
 185                                  msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 186         }
 187 }
 188
 189 static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 190 {
 191         struct drm_i915_private *dev_priv =
 192                 container_of(work, typeof(*dev_priv),
 193                              hotplug.reenable_work.work);
 194         struct drm_device *dev = dev_priv->dev;
 195         struct drm_mode_config *mode_config = &dev->mode_config;
 196         int i;
 197
 198         intel_runtime_pm_get(dev_priv);
 199
 200         spin_lock_irq(&dev_priv->irq_lock);
 201         for_each_hpd_pin(i) {
 202                 struct drm_connector *connector;
 203
 204                 if (dev_priv->hotplug.stats[i].state != HPD_DISABLED)
 205                         continue;
 206
 207                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 208
 209                 list_for_each_entry(connector, &mode_config->connector_list, head) {
 210                         struct intel_connector *intel_connector = to_intel_connector(connector);
 211
 212                         if (intel_connector->encoder->hpd_pin == i) {
 213                                 if (connector->polled != intel_connector->polled)
 214                                         DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
 215                                                          connector->name);
 216                                 connector->polled = intel_connector->polled;
 217                                 if (!connector->polled)
 218                                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 219                         }
 220                 }
 221         }
 222         if (dev_priv->display.hpd_irq_setup)
 223                 dev_priv->display.hpd_irq_setup(dev);
 224         spin_unlock_irq(&dev_priv->irq_lock);
 225
 226         intel_runtime_pm_put(dev_priv);
 227 }
 228
 229 static bool intel_hpd_irq_event(struct drm_device *dev,
 230                                 struct drm_connector *connector)
 231 {
 232         enum drm_connector_status old_status;
 233
 234         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 235         old_status = connector->status;
 236
 237         connector->status = connector->funcs->detect(connector, false);
 238         if (old_status == connector->status)
 239                 return false;
 240
 241         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 242                       connector->base.id,
 243                       connector->name,
 244                       drm_get_connector_status_name(old_status),
 245                       drm_get_connector_status_name(connector->status));
 246
 247         return true;
 248 }
 249
 250 static void i915_digport_work_func(struct work_struct *work)
 251 {
 252         struct drm_i915_private *dev_priv =
 253                 container_of(work, struct drm_i915_private, hotplug.dig_port_work);
 254         u32 long_port_mask, short_port_mask;
 255         struct intel_digital_port *intel_dig_port;
 256         int i;
 257         u32 old_bits = 0;
 258
 259         spin_lock_irq(&dev_priv->irq_lock);
 260         long_port_mask = dev_priv->hotplug.long_port_mask;
 261         dev_priv->hotplug.long_port_mask = 0;
 262         short_port_mask = dev_priv->hotplug.short_port_mask;
 263         dev_priv->hotplug.short_port_mask = 0;
 264         spin_unlock_irq(&dev_priv->irq_lock);
 265
 266         for (i = 0; i < I915_MAX_PORTS; i++) {
 267                 bool valid = false;
 268                 bool long_hpd = false;
 269                 intel_dig_port = dev_priv->hotplug.irq_port[i];
 270                 if (!intel_dig_port || !intel_dig_port->hpd_pulse)
 271                         continue;
 272
 273                 if (long_port_mask & (1 << i))  {
 274                         valid = true;
 275                         long_hpd = true;
 276                 } else if (short_port_mask & (1 << i))
 277                         valid = true;
 278
 279                 if (valid) {
 280                         enum irqreturn ret;
 281
 282                         ret = intel_dig_port->hpd_pulse(intel_dig_port, long_hpd);
 283                         if (ret == IRQ_NONE) {
 284                                 /* fall back to old school hpd */
 285                                 old_bits |= (1 << intel_dig_port->base.hpd_pin);
 286                         }
 287                 }
 288         }
 289
 290         if (old_bits) {
 291                 spin_lock_irq(&dev_priv->irq_lock);
 292                 dev_priv->hotplug.event_bits |= old_bits;
 293                 spin_unlock_irq(&dev_priv->irq_lock);
 294                 schedule_work(&dev_priv->hotplug.hotplug_work);
 295         }
 296 }
 297
 298 /*
 299  * Handle hotplug events outside the interrupt handler proper.
 300  */
 301 static void i915_hotplug_work_func(struct work_struct *work)
 302 {
 303         struct drm_i915_private *dev_priv =
 304                 container_of(work, struct drm_i915_private, hotplug.hotplug_work);
 305         struct drm_device *dev = dev_priv->dev;
 306         struct drm_mode_config *mode_config = &dev->mode_config;
 307         struct intel_connector *intel_connector;
 308         struct intel_encoder *intel_encoder;
 309         struct drm_connector *connector;
 310         bool changed = false;
 311         u32 hpd_event_bits;
 312
 313         mutex_lock(&mode_config->mutex);
 314         DRM_DEBUG_KMS("running encoder hotplug functions\n");
 315
 316         spin_lock_irq(&dev_priv->irq_lock);
 317
 318         hpd_event_bits = dev_priv->hotplug.event_bits;
 319         dev_priv->hotplug.event_bits = 0;
 320
 321         /* Disable hotplug on connectors that hit an irq storm. */
 322         intel_hpd_irq_storm_disable(dev_priv);
 323
 324         spin_unlock_irq(&dev_priv->irq_lock);
 325
 326         list_for_each_entry(connector, &mode_config->connector_list, head) {
 327                 intel_connector = to_intel_connector(connector);
 328                 if (!intel_connector->encoder)
 329                         continue;
 330                 intel_encoder = intel_connector->encoder;
 331                 if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
 332                         DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
 333                                       connector->name, intel_encoder->hpd_pin);
 334                         if (intel_encoder->hot_plug)
 335                                 intel_encoder->hot_plug(intel_encoder);
 336                         if (intel_hpd_irq_event(dev, connector))
 337                                 changed = true;
 338                 }
 339         }
 340         mutex_unlock(&mode_config->mutex);
 341
 342         if (changed)
 343                 drm_kms_helper_hotplug_event(dev);
 344 }
 345
 346
 347 /**
 348  * intel_hpd_irq_handler - main hotplug irq handler
 349  * @dev: drm device
 350  * @pin_mask: a mask of hpd pins that have triggered the irq
 351  * @long_mask: a mask of hpd pins that may be long hpd pulses
 352  *
 353  * This is the main hotplug irq handler for all platforms. The platform specific
 354  * irq handlers call the platform specific hotplug irq handlers, which read and
 355  * decode the appropriate registers into bitmasks about hpd pins that have
 356  * triggered (@pin_mask), and which of those pins may be long pulses
 357  * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
 358  * is not a digital port.
 359  *
 360  * Here, we do hotplug irq storm detection and mitigation, and pass further
 361  * processing to appropriate bottom halves.
 362  */
 363 void intel_hpd_irq_handler(struct drm_device *dev,
 364                            u32 pin_mask, u32 long_mask)
 365 {
 366         struct drm_i915_private *dev_priv = dev->dev_private;
 367         int i;
 368         enum port port;
 369         bool storm_detected = false;
 370         bool queue_dig = false, queue_hp = false;
 371         bool is_dig_port;
 372
 373         if (!pin_mask)
 374                 return;
 375
 376         spin_lock(&dev_priv->irq_lock);
 377         for_each_hpd_pin(i) {
 378                 if (!(BIT(i) & pin_mask))
 379                         continue;
 380
 381                 is_dig_port = intel_hpd_pin_to_port(i, &port) &&
 382                               dev_priv->hotplug.irq_port[port];
 383
 384                 if (is_dig_port) {
 385                         bool long_hpd = long_mask & BIT(i);
 386
 387                         DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
 388                                          long_hpd ? "long" : "short");
 389                         /*
 390                          * For long HPD pulses we want to have the digital queue happen,
 391                          * but we still want HPD storm detection to function.
 392                          */
 393                         queue_dig = true;
 394                         if (long_hpd) {
 395                                 dev_priv->hotplug.long_port_mask |= (1 << port);
 396                         } else {
 397                                 /* for short HPD just trigger the digital queue */
 398                                 dev_priv->hotplug.short_port_mask |= (1 << port);
 399                                 continue;
 400                         }
 401                 }
 402
 403                 if (dev_priv->hotplug.stats[i].state == HPD_DISABLED) {
 404                         /*
 405                          * On GMCH platforms the interrupt mask bits only
 406                          * prevent irq generation, not the setting of the
 407                          * hotplug bits itself. So only WARN about unexpected
 408                          * interrupts on saner platforms.
 409                          */
 410                         WARN_ONCE(INTEL_INFO(dev)->gen >= 5 && !IS_VALLEYVIEW(dev),
 411                                   "Received HPD interrupt on pin %d although disabled\n", i);
 412                         continue;
 413                 }
 414
 415                 if (dev_priv->hotplug.stats[i].state != HPD_ENABLED)
 416                         continue;
 417
 418                 if (!is_dig_port) {
 419                         dev_priv->hotplug.event_bits |= BIT(i);
 420                         queue_hp = true;
 421                 }
 422
 423                 if (intel_hpd_irq_storm_detect(dev_priv, i)) {
 424                         dev_priv->hotplug.event_bits &= ~BIT(i);
 425                         storm_detected = true;
 426                 }
 427         }
 428
 429         if (storm_detected)
 430                 dev_priv->display.hpd_irq_setup(dev);
 431         spin_unlock(&dev_priv->irq_lock);
 432
 433         /*
 434          * Our hotplug handler can grab modeset locks (by calling down into the
 435          * fb helpers). Hence it must not be run on our own dev-priv->wq work
 436          * queue for otherwise the flush_work in the pageflip code will
 437          * deadlock.
 438          */
 439         if (queue_dig)
 440                 queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
 441         if (queue_hp)
 442                 schedule_work(&dev_priv->hotplug.hotplug_work);
 443 }
 444
 445 /**
 446  * intel_hpd_init - initializes and enables hpd support
 447  * @dev_priv: i915 device instance
 448  *
 449  * This function enables the hotplug support. It requires that interrupts have
 450  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
 451  * poll request can run concurrently to other code, so locking rules must be
 452  * obeyed.
 453  *
 454  * This is a separate step from interrupt enabling to simplify the locking rules
 455  * in the driver load and resume code.
 456  */
 457 void intel_hpd_init(struct drm_i915_private *dev_priv)
 458 {
 459         struct drm_device *dev = dev_priv->dev;
 460         struct drm_mode_config *mode_config = &dev->mode_config;
 461         struct drm_connector *connector;
 462         int i;
 463
 464         for_each_hpd_pin(i) {
 465                 dev_priv->hotplug.stats[i].count = 0;
 466                 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 467         }
 468         list_for_each_entry(connector, &mode_config->connector_list, head) {
 469                 struct intel_connector *intel_connector = to_intel_connector(connector);
 470                 connector->polled = intel_connector->polled;
 471                 if (connector->encoder && !connector->polled && I915_HAS_HOTPLUG(dev) && intel_connector->encoder->hpd_pin > HPD_NONE)
 472                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 473                 if (intel_connector->mst_port)
 474                         connector->polled = DRM_CONNECTOR_POLL_HPD;
 475         }
 476
 477         /*
 478          * Interrupt setup is already guaranteed to be single-threaded, this is
 479          * just to make the assert_spin_locked checks happy.
 480          */
 481         spin_lock_irq(&dev_priv->irq_lock);
 482         if (dev_priv->display.hpd_irq_setup)
 483                 dev_priv->display.hpd_irq_setup(dev);
 484         spin_unlock_irq(&dev_priv->irq_lock);
 485 }
 486
 487 void intel_hpd_init_work(struct drm_i915_private *dev_priv)
 488 {
 489         INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
 490         INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
 491         INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
 492                           intel_hpd_irq_storm_reenable_work);
 493 }
 494
 495 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 496 {
 497         spin_lock_irq(&dev_priv->irq_lock);
 498
 499         dev_priv->hotplug.long_port_mask = 0;
 500         dev_priv->hotplug.short_port_mask = 0;
 501         dev_priv->hotplug.event_bits = 0;
 502
 503         spin_unlock_irq(&dev_priv->irq_lock);
 504
 505         cancel_work_sync(&dev_priv->hotplug.dig_port_work);
 506         cancel_work_sync(&dev_priv->hotplug.hotplug_work);
 507         cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 508 }