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 int ret; 281 282 ret = intel_dig_port->hpd_pulse(intel_dig_port, long_hpd); 283 if (ret == true) { 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 lockmgr(&dev_priv->irq_lock, LK_EXCLUSIVE); 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 lockmgr(&dev_priv->irq_lock, LK_RELEASE); 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 } 509