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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/debugfs.h>
25#include <linux/kernel.h>
26
27#include <drm/drm_probe_helper.h>
28
29#include "i915_drv.h"
30#include "i915_irq.h"
31#include "intel_display_power.h"
32#include "intel_display_types.h"
33#include "intel_hotplug.h"
34#include "intel_hotplug_irq.h"
35
36/**
37 * DOC: Hotplug
38 *
39 * Simply put, hotplug occurs when a display is connected to or disconnected
40 * from the system. However, there may be adapters and docking stations and
41 * Display Port short pulses and MST devices involved, complicating matters.
42 *
43 * Hotplug in i915 is handled in many different levels of abstraction.
44 *
45 * The platform dependent interrupt handling code in i915_irq.c enables,
46 * disables, and does preliminary handling of the interrupts. The interrupt
47 * handlers gather the hotplug detect (HPD) information from relevant registers
48 * into a platform independent mask of hotplug pins that have fired.
49 *
50 * The platform independent interrupt handler intel_hpd_irq_handler() in
51 * intel_hotplug.c does hotplug irq storm detection and mitigation, and passes
52 * further processing to appropriate bottom halves (Display Port specific and
53 * regular hotplug).
54 *
55 * The Display Port work function i915_digport_work_func() calls into
56 * intel_dp_hpd_pulse() via hooks, which handles DP short pulses and DP MST long
57 * pulses, with failures and non-MST long pulses triggering regular hotplug
58 * processing on the connector.
59 *
60 * The regular hotplug work function i915_hotplug_work_func() calls connector
61 * detect hooks, and, if connector status changes, triggers sending of hotplug
62 * uevent to userspace via drm_kms_helper_hotplug_event().
63 *
64 * Finally, the userspace is responsible for triggering a modeset upon receiving
65 * the hotplug uevent, disabling or enabling the crtc as needed.
66 *
67 * The hotplug interrupt storm detection and mitigation code keeps track of the
68 * number of interrupts per hotplug pin per a period of time, and if the number
69 * of interrupts exceeds a certain threshold, the interrupt is disabled for a
70 * while before being re-enabled. The intention is to mitigate issues raising
71 * from broken hardware triggering massive amounts of interrupts and grinding
72 * the system to a halt.
73 *
74 * Current implementation expects that hotplug interrupt storm will not be
75 * seen when display port sink is connected, hence on platforms whose DP
76 * callback is handled by i915_digport_work_func reenabling of hpd is not
77 * performed (it was never expected to be disabled in the first place ;) )
78 * this is specific to DP sinks handled by this routine and any other display
79 * such as HDMI or DVI enabled on the same port will have proper logic since
80 * it will use i915_hotplug_work_func where this logic is handled.
81 */
82
83/**
84 * intel_hpd_pin_default - return default pin associated with certain port.
85 * @dev_priv: private driver data pointer
86 * @port: the hpd port to get associated pin
87 *
88 * It is only valid and used by digital port encoder.
89 *
90 * Return pin that is associatade with @port.
91 */
92enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
93 enum port port)
94{
95 return HPD_PORT_A + port - PORT_A;
96}
97
98/* Threshold == 5 for long IRQs, 50 for short */
99#define HPD_STORM_DEFAULT_THRESHOLD 50
100
101#define HPD_STORM_DETECT_PERIOD 1000
102#define HPD_STORM_REENABLE_DELAY (2 * 60 * 1000)
103#define HPD_RETRY_DELAY 1000
104
105static enum hpd_pin
106intel_connector_hpd_pin(struct intel_connector *connector)
107{
108 struct intel_encoder *encoder = intel_attached_encoder(connector);
109
110 /*
111 * MST connectors get their encoder attached dynamically
112 * so need to make sure we have an encoder here. But since
113 * MST encoders have their hpd_pin set to HPD_NONE we don't
114 * have to special case them beyond that.
115 */
116 return encoder ? encoder->hpd_pin : HPD_NONE;
117}
118
119/**
120 * intel_hpd_irq_storm_detect - gather stats and detect HPD IRQ storm on a pin
121 * @dev_priv: private driver data pointer
122 * @pin: the pin to gather stats on
123 * @long_hpd: whether the HPD IRQ was long or short
124 *
125 * Gather stats about HPD IRQs from the specified @pin, and detect IRQ
126 * storms. Only the pin specific stats and state are changed, the caller is
127 * responsible for further action.
128 *
129 * The number of IRQs that are allowed within @HPD_STORM_DETECT_PERIOD is
130 * stored in @dev_priv->display.hotplug.hpd_storm_threshold which defaults to
131 * @HPD_STORM_DEFAULT_THRESHOLD. Long IRQs count as +10 to this threshold, and
132 * short IRQs count as +1. If this threshold is exceeded, it's considered an
133 * IRQ storm and the IRQ state is set to @HPD_MARK_DISABLED.
134 *
135 * By default, most systems will only count long IRQs towards
136 * &dev_priv->display.hotplug.hpd_storm_threshold. However, some older systems also
137 * suffer from short IRQ storms and must also track these. Because short IRQ
138 * storms are naturally caused by sideband interactions with DP MST devices,
139 * short IRQ detection is only enabled for systems without DP MST support.
140 * Systems which are new enough to support DP MST are far less likely to
141 * suffer from IRQ storms at all, so this is fine.
142 *
143 * The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
144 * and should only be adjusted for automated hotplug testing.
145 *
146 * Return true if an IRQ storm was detected on @pin.
147 */
148static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
149 enum hpd_pin pin, bool long_hpd)
150{
151 struct intel_hotplug *hpd = &dev_priv->display.hotplug;
152 unsigned long start = hpd->stats[pin].last_jiffies;
153 unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
154 const int increment = long_hpd ? 10 : 1;
155 const int threshold = hpd->hpd_storm_threshold;
156 bool storm = false;
157
158 if (!threshold ||
159 (!long_hpd && !dev_priv->display.hotplug.hpd_short_storm_enabled))
160 return false;
161
162 if (!time_in_range(jiffies, start, end)) {
163 hpd->stats[pin].last_jiffies = jiffies;
164 hpd->stats[pin].count = 0;
165 }
166
167 hpd->stats[pin].count += increment;
168 if (hpd->stats[pin].count > threshold) {
169 hpd->stats[pin].state = HPD_MARK_DISABLED;
170 drm_dbg_kms(&dev_priv->drm,
171 "HPD interrupt storm detected on PIN %d\n", pin);
172 storm = true;
173 } else {
174 drm_dbg_kms(&dev_priv->drm,
175 "Received HPD interrupt on PIN %d - cnt: %d\n",
176 pin,
177 hpd->stats[pin].count);
178 }
179
180 return storm;
181}
182
183static bool detection_work_enabled(struct drm_i915_private *i915)
184{
185 lockdep_assert_held(&i915->irq_lock);
186
187 return i915->display.hotplug.detection_work_enabled;
188}
189
190static bool
191mod_delayed_detection_work(struct drm_i915_private *i915, struct delayed_work *work, int delay)
192{
193 lockdep_assert_held(&i915->irq_lock);
194
195 if (!detection_work_enabled(i915))
196 return false;
197
198 return mod_delayed_work(i915->unordered_wq, work, delay);
199}
200
201static bool
202queue_delayed_detection_work(struct drm_i915_private *i915, struct delayed_work *work, int delay)
203{
204 lockdep_assert_held(&i915->irq_lock);
205
206 if (!detection_work_enabled(i915))
207 return false;
208
209 return queue_delayed_work(i915->unordered_wq, work, delay);
210}
211
212static bool
213queue_detection_work(struct drm_i915_private *i915, struct work_struct *work)
214{
215 lockdep_assert_held(&i915->irq_lock);
216
217 if (!detection_work_enabled(i915))
218 return false;
219
220 return queue_work(i915->unordered_wq, work);
221}
222
223static void
224intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
225{
226 struct drm_connector_list_iter conn_iter;
227 struct intel_connector *connector;
228 bool hpd_disabled = false;
229
230 lockdep_assert_held(&dev_priv->irq_lock);
231
232 drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
233 for_each_intel_connector_iter(connector, &conn_iter) {
234 enum hpd_pin pin;
235
236 if (connector->base.polled != DRM_CONNECTOR_POLL_HPD)
237 continue;
238
239 pin = intel_connector_hpd_pin(connector);
240 if (pin == HPD_NONE ||
241 dev_priv->display.hotplug.stats[pin].state != HPD_MARK_DISABLED)
242 continue;
243
244 drm_info(&dev_priv->drm,
245 "HPD interrupt storm detected on connector %s: "
246 "switching from hotplug detection to polling\n",
247 connector->base.name);
248
249 dev_priv->display.hotplug.stats[pin].state = HPD_DISABLED;
250 connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
251 DRM_CONNECTOR_POLL_DISCONNECT;
252 hpd_disabled = true;
253 }
254 drm_connector_list_iter_end(&conn_iter);
255
256 /* Enable polling and queue hotplug re-enabling. */
257 if (hpd_disabled) {
258 drm_kms_helper_poll_reschedule(&dev_priv->drm);
259 mod_delayed_detection_work(dev_priv,
260 &dev_priv->display.hotplug.reenable_work,
261 msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
262 }
263}
264
265static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
266{
267 struct drm_i915_private *dev_priv =
268 container_of(work, typeof(*dev_priv),
269 display.hotplug.reenable_work.work);
270 struct drm_connector_list_iter conn_iter;
271 struct intel_connector *connector;
272 intel_wakeref_t wakeref;
273 enum hpd_pin pin;
274
275 wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
276
277 spin_lock_irq(&dev_priv->irq_lock);
278
279 drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
280 for_each_intel_connector_iter(connector, &conn_iter) {
281 pin = intel_connector_hpd_pin(connector);
282 if (pin == HPD_NONE ||
283 dev_priv->display.hotplug.stats[pin].state != HPD_DISABLED)
284 continue;
285
286 if (connector->base.polled != connector->polled)
287 drm_dbg(&dev_priv->drm,
288 "Reenabling HPD on connector %s\n",
289 connector->base.name);
290 connector->base.polled = connector->polled;
291 }
292 drm_connector_list_iter_end(&conn_iter);
293
294 for_each_hpd_pin(pin) {
295 if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED)
296 dev_priv->display.hotplug.stats[pin].state = HPD_ENABLED;
297 }
298
299 intel_hpd_irq_setup(dev_priv);
300
301 spin_unlock_irq(&dev_priv->irq_lock);
302
303 intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
304}
305
306static enum intel_hotplug_state
307intel_hotplug_detect_connector(struct intel_connector *connector)
308{
309 struct drm_device *dev = connector->base.dev;
310 enum drm_connector_status old_status;
311 u64 old_epoch_counter;
312 int status;
313 bool ret = false;
314
315 drm_WARN_ON(dev, !mutex_is_locked(&dev->mode_config.mutex));
316 old_status = connector->base.status;
317 old_epoch_counter = connector->base.epoch_counter;
318
319 status = drm_helper_probe_detect(&connector->base, NULL, false);
320 if (!connector->base.force)
321 connector->base.status = status;
322
323 if (old_epoch_counter != connector->base.epoch_counter)
324 ret = true;
325
326 if (ret) {
327 drm_dbg_kms(dev, "[CONNECTOR:%d:%s] status updated from %s to %s (epoch counter %llu->%llu)\n",
328 connector->base.base.id,
329 connector->base.name,
330 drm_get_connector_status_name(old_status),
331 drm_get_connector_status_name(connector->base.status),
332 old_epoch_counter,
333 connector->base.epoch_counter);
334 return INTEL_HOTPLUG_CHANGED;
335 }
336 return INTEL_HOTPLUG_UNCHANGED;
337}
338
339enum intel_hotplug_state
340intel_encoder_hotplug(struct intel_encoder *encoder,
341 struct intel_connector *connector)
342{
343 return intel_hotplug_detect_connector(connector);
344}
345
346static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
347{
348 return intel_encoder_is_dig_port(encoder) &&
349 enc_to_dig_port(encoder)->hpd_pulse != NULL;
350}
351
352static void i915_digport_work_func(struct work_struct *work)
353{
354 struct drm_i915_private *dev_priv =
355 container_of(work, struct drm_i915_private, display.hotplug.dig_port_work);
356 u32 long_port_mask, short_port_mask;
357 struct intel_encoder *encoder;
358 u32 old_bits = 0;
359
360 spin_lock_irq(&dev_priv->irq_lock);
361 long_port_mask = dev_priv->display.hotplug.long_port_mask;
362 dev_priv->display.hotplug.long_port_mask = 0;
363 short_port_mask = dev_priv->display.hotplug.short_port_mask;
364 dev_priv->display.hotplug.short_port_mask = 0;
365 spin_unlock_irq(&dev_priv->irq_lock);
366
367 for_each_intel_encoder(&dev_priv->drm, encoder) {
368 struct intel_digital_port *dig_port;
369 enum port port = encoder->port;
370 bool long_hpd, short_hpd;
371 enum irqreturn ret;
372
373 if (!intel_encoder_has_hpd_pulse(encoder))
374 continue;
375
376 long_hpd = long_port_mask & BIT(port);
377 short_hpd = short_port_mask & BIT(port);
378
379 if (!long_hpd && !short_hpd)
380 continue;
381
382 dig_port = enc_to_dig_port(encoder);
383
384 ret = dig_port->hpd_pulse(dig_port, long_hpd);
385 if (ret == IRQ_NONE) {
386 /* fall back to old school hpd */
387 old_bits |= BIT(encoder->hpd_pin);
388 }
389 }
390
391 if (old_bits) {
392 spin_lock_irq(&dev_priv->irq_lock);
393 dev_priv->display.hotplug.event_bits |= old_bits;
394 queue_delayed_detection_work(dev_priv,
395 &dev_priv->display.hotplug.hotplug_work, 0);
396 spin_unlock_irq(&dev_priv->irq_lock);
397 }
398}
399
400/**
401 * intel_hpd_trigger_irq - trigger an hpd irq event for a port
402 * @dig_port: digital port
403 *
404 * Trigger an HPD interrupt event for the given port, emulating a short pulse
405 * generated by the sink, and schedule the dig port work to handle it.
406 */
407void intel_hpd_trigger_irq(struct intel_digital_port *dig_port)
408{
409 struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
410
411 spin_lock_irq(&i915->irq_lock);
412 i915->display.hotplug.short_port_mask |= BIT(dig_port->base.port);
413 spin_unlock_irq(&i915->irq_lock);
414
415 queue_work(i915->display.hotplug.dp_wq, &i915->display.hotplug.dig_port_work);
416}
417
418/*
419 * Handle hotplug events outside the interrupt handler proper.
420 */
421static void i915_hotplug_work_func(struct work_struct *work)
422{
423 struct drm_i915_private *dev_priv =
424 container_of(work, struct drm_i915_private,
425 display.hotplug.hotplug_work.work);
426 struct drm_connector_list_iter conn_iter;
427 struct intel_connector *connector;
428 u32 changed = 0, retry = 0;
429 u32 hpd_event_bits;
430 u32 hpd_retry_bits;
431 struct drm_connector *first_changed_connector = NULL;
432 int changed_connectors = 0;
433
434 mutex_lock(&dev_priv->drm.mode_config.mutex);
435 drm_dbg_kms(&dev_priv->drm, "running encoder hotplug functions\n");
436
437 spin_lock_irq(&dev_priv->irq_lock);
438
439 hpd_event_bits = dev_priv->display.hotplug.event_bits;
440 dev_priv->display.hotplug.event_bits = 0;
441 hpd_retry_bits = dev_priv->display.hotplug.retry_bits;
442 dev_priv->display.hotplug.retry_bits = 0;
443
444 /* Enable polling for connectors which had HPD IRQ storms */
445 intel_hpd_irq_storm_switch_to_polling(dev_priv);
446
447 spin_unlock_irq(&dev_priv->irq_lock);
448
449 /* Skip calling encode hotplug handlers if ignore long HPD set*/
450 if (dev_priv->display.hotplug.ignore_long_hpd) {
451 drm_dbg_kms(&dev_priv->drm, "Ignore HPD flag on - skip encoder hotplug handlers\n");
452 mutex_unlock(&dev_priv->drm.mode_config.mutex);
453 return;
454 }
455
456 drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
457 for_each_intel_connector_iter(connector, &conn_iter) {
458 enum hpd_pin pin;
459 u32 hpd_bit;
460
461 pin = intel_connector_hpd_pin(connector);
462 if (pin == HPD_NONE)
463 continue;
464
465 hpd_bit = BIT(pin);
466 if ((hpd_event_bits | hpd_retry_bits) & hpd_bit) {
467 struct intel_encoder *encoder =
468 intel_attached_encoder(connector);
469
470 if (hpd_event_bits & hpd_bit)
471 connector->hotplug_retries = 0;
472 else
473 connector->hotplug_retries++;
474
475 drm_dbg_kms(&dev_priv->drm,
476 "Connector %s (pin %i) received hotplug event. (retry %d)\n",
477 connector->base.name, pin,
478 connector->hotplug_retries);
479
480 switch (encoder->hotplug(encoder, connector)) {
481 case INTEL_HOTPLUG_UNCHANGED:
482 break;
483 case INTEL_HOTPLUG_CHANGED:
484 changed |= hpd_bit;
485 changed_connectors++;
486 if (!first_changed_connector) {
487 drm_connector_get(&connector->base);
488 first_changed_connector = &connector->base;
489 }
490 break;
491 case INTEL_HOTPLUG_RETRY:
492 retry |= hpd_bit;
493 break;
494 }
495 }
496 }
497 drm_connector_list_iter_end(&conn_iter);
498 mutex_unlock(&dev_priv->drm.mode_config.mutex);
499
500 if (changed_connectors == 1)
501 drm_kms_helper_connector_hotplug_event(first_changed_connector);
502 else if (changed_connectors > 0)
503 drm_kms_helper_hotplug_event(&dev_priv->drm);
504
505 if (first_changed_connector)
506 drm_connector_put(first_changed_connector);
507
508 /* Remove shared HPD pins that have changed */
509 retry &= ~changed;
510 if (retry) {
511 spin_lock_irq(&dev_priv->irq_lock);
512 dev_priv->display.hotplug.retry_bits |= retry;
513
514 mod_delayed_detection_work(dev_priv,
515 &dev_priv->display.hotplug.hotplug_work,
516 msecs_to_jiffies(HPD_RETRY_DELAY));
517 spin_unlock_irq(&dev_priv->irq_lock);
518 }
519}
520
521
522/**
523 * intel_hpd_irq_handler - main hotplug irq handler
524 * @dev_priv: drm_i915_private
525 * @pin_mask: a mask of hpd pins that have triggered the irq
526 * @long_mask: a mask of hpd pins that may be long hpd pulses
527 *
528 * This is the main hotplug irq handler for all platforms. The platform specific
529 * irq handlers call the platform specific hotplug irq handlers, which read and
530 * decode the appropriate registers into bitmasks about hpd pins that have
531 * triggered (@pin_mask), and which of those pins may be long pulses
532 * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
533 * is not a digital port.
534 *
535 * Here, we do hotplug irq storm detection and mitigation, and pass further
536 * processing to appropriate bottom halves.
537 */
538void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
539 u32 pin_mask, u32 long_mask)
540{
541 struct intel_encoder *encoder;
542 bool storm_detected = false;
543 bool queue_dig = false, queue_hp = false;
544 u32 long_hpd_pulse_mask = 0;
545 u32 short_hpd_pulse_mask = 0;
546 enum hpd_pin pin;
547
548 if (!pin_mask)
549 return;
550
551 spin_lock(&dev_priv->irq_lock);
552
553 /*
554 * Determine whether ->hpd_pulse() exists for each pin, and
555 * whether we have a short or a long pulse. This is needed
556 * as each pin may have up to two encoders (HDMI and DP) and
557 * only the one of them (DP) will have ->hpd_pulse().
558 */
559 for_each_intel_encoder(&dev_priv->drm, encoder) {
560 enum port port = encoder->port;
561 bool long_hpd;
562
563 pin = encoder->hpd_pin;
564 if (!(BIT(pin) & pin_mask))
565 continue;
566
567 if (!intel_encoder_has_hpd_pulse(encoder))
568 continue;
569
570 long_hpd = long_mask & BIT(pin);
571
572 drm_dbg(&dev_priv->drm,
573 "digital hpd on [ENCODER:%d:%s] - %s\n",
574 encoder->base.base.id, encoder->base.name,
575 long_hpd ? "long" : "short");
576 queue_dig = true;
577
578 if (long_hpd) {
579 long_hpd_pulse_mask |= BIT(pin);
580 dev_priv->display.hotplug.long_port_mask |= BIT(port);
581 } else {
582 short_hpd_pulse_mask |= BIT(pin);
583 dev_priv->display.hotplug.short_port_mask |= BIT(port);
584 }
585 }
586
587 /* Now process each pin just once */
588 for_each_hpd_pin(pin) {
589 bool long_hpd;
590
591 if (!(BIT(pin) & pin_mask))
592 continue;
593
594 if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED) {
595 /*
596 * On GMCH platforms the interrupt mask bits only
597 * prevent irq generation, not the setting of the
598 * hotplug bits itself. So only WARN about unexpected
599 * interrupts on saner platforms.
600 */
601 drm_WARN_ONCE(&dev_priv->drm, !HAS_GMCH(dev_priv),
602 "Received HPD interrupt on pin %d although disabled\n",
603 pin);
604 continue;
605 }
606
607 if (dev_priv->display.hotplug.stats[pin].state != HPD_ENABLED)
608 continue;
609
610 /*
611 * Delegate to ->hpd_pulse() if one of the encoders for this
612 * pin has it, otherwise let the hotplug_work deal with this
613 * pin directly.
614 */
615 if (((short_hpd_pulse_mask | long_hpd_pulse_mask) & BIT(pin))) {
616 long_hpd = long_hpd_pulse_mask & BIT(pin);
617 } else {
618 dev_priv->display.hotplug.event_bits |= BIT(pin);
619 long_hpd = true;
620 queue_hp = true;
621 }
622
623 if (intel_hpd_irq_storm_detect(dev_priv, pin, long_hpd)) {
624 dev_priv->display.hotplug.event_bits &= ~BIT(pin);
625 storm_detected = true;
626 queue_hp = true;
627 }
628 }
629
630 /*
631 * Disable any IRQs that storms were detected on. Polling enablement
632 * happens later in our hotplug work.
633 */
634 if (storm_detected)
635 intel_hpd_irq_setup(dev_priv);
636
637 /*
638 * Our hotplug handler can grab modeset locks (by calling down into the
639 * fb helpers). Hence it must not be run on our own dev-priv->wq work
640 * queue for otherwise the flush_work in the pageflip code will
641 * deadlock.
642 */
643 if (queue_dig)
644 queue_work(dev_priv->display.hotplug.dp_wq, &dev_priv->display.hotplug.dig_port_work);
645 if (queue_hp)
646 queue_delayed_detection_work(dev_priv,
647 &dev_priv->display.hotplug.hotplug_work, 0);
648
649 spin_unlock(&dev_priv->irq_lock);
650}
651
652/**
653 * intel_hpd_init - initializes and enables hpd support
654 * @dev_priv: i915 device instance
655 *
656 * This function enables the hotplug support. It requires that interrupts have
657 * already been enabled with intel_irq_init_hw(). From this point on hotplug and
658 * poll request can run concurrently to other code, so locking rules must be
659 * obeyed.
660 *
661 * This is a separate step from interrupt enabling to simplify the locking rules
662 * in the driver load and resume code.
663 *
664 * Also see: intel_hpd_poll_enable() and intel_hpd_poll_disable().
665 */
666void intel_hpd_init(struct drm_i915_private *dev_priv)
667{
668 int i;
669
670 if (!HAS_DISPLAY(dev_priv))
671 return;
672
673 for_each_hpd_pin(i) {
674 dev_priv->display.hotplug.stats[i].count = 0;
675 dev_priv->display.hotplug.stats[i].state = HPD_ENABLED;
676 }
677
678 /*
679 * Interrupt setup is already guaranteed to be single-threaded, this is
680 * just to make the assert_spin_locked checks happy.
681 */
682 spin_lock_irq(&dev_priv->irq_lock);
683 intel_hpd_irq_setup(dev_priv);
684 spin_unlock_irq(&dev_priv->irq_lock);
685}
686
687static void i915_hpd_poll_detect_connectors(struct drm_i915_private *i915)
688{
689 struct drm_connector_list_iter conn_iter;
690 struct intel_connector *connector;
691 struct intel_connector *first_changed_connector = NULL;
692 int changed = 0;
693
694 mutex_lock(&i915->drm.mode_config.mutex);
695
696 if (!i915->drm.mode_config.poll_enabled)
697 goto out;
698
699 drm_connector_list_iter_begin(&i915->drm, &conn_iter);
700 for_each_intel_connector_iter(connector, &conn_iter) {
701 if (!(connector->base.polled & DRM_CONNECTOR_POLL_HPD))
702 continue;
703
704 if (intel_hotplug_detect_connector(connector) != INTEL_HOTPLUG_CHANGED)
705 continue;
706
707 changed++;
708
709 if (changed == 1) {
710 drm_connector_get(&connector->base);
711 first_changed_connector = connector;
712 }
713 }
714 drm_connector_list_iter_end(&conn_iter);
715
716out:
717 mutex_unlock(&i915->drm.mode_config.mutex);
718
719 if (!changed)
720 return;
721
722 if (changed == 1)
723 drm_kms_helper_connector_hotplug_event(&first_changed_connector->base);
724 else
725 drm_kms_helper_hotplug_event(&i915->drm);
726
727 drm_connector_put(&first_changed_connector->base);
728}
729
730static void i915_hpd_poll_init_work(struct work_struct *work)
731{
732 struct drm_i915_private *dev_priv =
733 container_of(work, struct drm_i915_private,
734 display.hotplug.poll_init_work);
735 struct drm_connector_list_iter conn_iter;
736 struct intel_connector *connector;
737 intel_wakeref_t wakeref;
738 bool enabled;
739
740 mutex_lock(&dev_priv->drm.mode_config.mutex);
741
742 enabled = READ_ONCE(dev_priv->display.hotplug.poll_enabled);
743 /*
744 * Prevent taking a power reference from this sequence of
745 * i915_hpd_poll_init_work() -> drm_helper_hpd_irq_event() ->
746 * connector detect which would requeue i915_hpd_poll_init_work()
747 * and so risk an endless loop of this same sequence.
748 */
749 if (!enabled) {
750 wakeref = intel_display_power_get(dev_priv,
751 POWER_DOMAIN_DISPLAY_CORE);
752 drm_WARN_ON(&dev_priv->drm,
753 READ_ONCE(dev_priv->display.hotplug.poll_enabled));
754 cancel_work(&dev_priv->display.hotplug.poll_init_work);
755 }
756
757 spin_lock_irq(&dev_priv->irq_lock);
758
759 drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
760 for_each_intel_connector_iter(connector, &conn_iter) {
761 enum hpd_pin pin;
762
763 pin = intel_connector_hpd_pin(connector);
764 if (pin == HPD_NONE)
765 continue;
766
767 if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED)
768 continue;
769
770 connector->base.polled = connector->polled;
771
772 if (enabled && connector->base.polled == DRM_CONNECTOR_POLL_HPD)
773 connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
774 DRM_CONNECTOR_POLL_DISCONNECT;
775 }
776 drm_connector_list_iter_end(&conn_iter);
777
778 spin_unlock_irq(&dev_priv->irq_lock);
779
780 if (enabled)
781 drm_kms_helper_poll_reschedule(&dev_priv->drm);
782
783 mutex_unlock(&dev_priv->drm.mode_config.mutex);
784
785 /*
786 * We might have missed any hotplugs that happened while we were
787 * in the middle of disabling polling
788 */
789 if (!enabled) {
790 i915_hpd_poll_detect_connectors(dev_priv);
791
792 intel_display_power_put(dev_priv,
793 POWER_DOMAIN_DISPLAY_CORE,
794 wakeref);
795 }
796}
797
798/**
799 * intel_hpd_poll_enable - enable polling for connectors with hpd
800 * @dev_priv: i915 device instance
801 *
802 * This function enables polling for all connectors which support HPD.
803 * Under certain conditions HPD may not be functional. On most Intel GPUs,
804 * this happens when we enter runtime suspend.
805 * On Valleyview and Cherryview systems, this also happens when we shut off all
806 * of the powerwells.
807 *
808 * Since this function can get called in contexts where we're already holding
809 * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
810 * worker.
811 *
812 * Also see: intel_hpd_init() and intel_hpd_poll_disable().
813 */
814void intel_hpd_poll_enable(struct drm_i915_private *dev_priv)
815{
816 if (!HAS_DISPLAY(dev_priv) ||
817 !intel_display_device_enabled(dev_priv))
818 return;
819
820 WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, true);
821
822 /*
823 * We might already be holding dev->mode_config.mutex, so do this in a
824 * seperate worker
825 * As well, there's no issue if we race here since we always reschedule
826 * this worker anyway
827 */
828 spin_lock_irq(&dev_priv->irq_lock);
829 queue_detection_work(dev_priv,
830 &dev_priv->display.hotplug.poll_init_work);
831 spin_unlock_irq(&dev_priv->irq_lock);
832}
833
834/**
835 * intel_hpd_poll_disable - disable polling for connectors with hpd
836 * @dev_priv: i915 device instance
837 *
838 * This function disables polling for all connectors which support HPD.
839 * Under certain conditions HPD may not be functional. On most Intel GPUs,
840 * this happens when we enter runtime suspend.
841 * On Valleyview and Cherryview systems, this also happens when we shut off all
842 * of the powerwells.
843 *
844 * Since this function can get called in contexts where we're already holding
845 * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
846 * worker.
847 *
848 * Also used during driver init to initialize connector->polled
849 * appropriately for all connectors.
850 *
851 * Also see: intel_hpd_init() and intel_hpd_poll_enable().
852 */
853void intel_hpd_poll_disable(struct drm_i915_private *dev_priv)
854{
855 if (!HAS_DISPLAY(dev_priv))
856 return;
857
858 WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, false);
859
860 spin_lock_irq(&dev_priv->irq_lock);
861 queue_detection_work(dev_priv,
862 &dev_priv->display.hotplug.poll_init_work);
863 spin_unlock_irq(&dev_priv->irq_lock);
864}
865
866void intel_hpd_init_early(struct drm_i915_private *i915)
867{
868 INIT_DELAYED_WORK(&i915->display.hotplug.hotplug_work,
869 i915_hotplug_work_func);
870 INIT_WORK(&i915->display.hotplug.dig_port_work, i915_digport_work_func);
871 INIT_WORK(&i915->display.hotplug.poll_init_work, i915_hpd_poll_init_work);
872 INIT_DELAYED_WORK(&i915->display.hotplug.reenable_work,
873 intel_hpd_irq_storm_reenable_work);
874
875 i915->display.hotplug.hpd_storm_threshold = HPD_STORM_DEFAULT_THRESHOLD;
876 /* If we have MST support, we want to avoid doing short HPD IRQ storm
877 * detection, as short HPD storms will occur as a natural part of
878 * sideband messaging with MST.
879 * On older platforms however, IRQ storms can occur with both long and
880 * short pulses, as seen on some G4x systems.
881 */
882 i915->display.hotplug.hpd_short_storm_enabled = !HAS_DP_MST(i915);
883}
884
885static bool cancel_all_detection_work(struct drm_i915_private *i915)
886{
887 bool was_pending = false;
888
889 if (cancel_delayed_work_sync(&i915->display.hotplug.hotplug_work))
890 was_pending = true;
891 if (cancel_work_sync(&i915->display.hotplug.poll_init_work))
892 was_pending = true;
893 if (cancel_delayed_work_sync(&i915->display.hotplug.reenable_work))
894 was_pending = true;
895
896 return was_pending;
897}
898
899void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
900{
901 if (!HAS_DISPLAY(dev_priv))
902 return;
903
904 spin_lock_irq(&dev_priv->irq_lock);
905
906 dev_priv->display.hotplug.long_port_mask = 0;
907 dev_priv->display.hotplug.short_port_mask = 0;
908 dev_priv->display.hotplug.event_bits = 0;
909 dev_priv->display.hotplug.retry_bits = 0;
910
911 spin_unlock_irq(&dev_priv->irq_lock);
912
913 cancel_work_sync(&dev_priv->display.hotplug.dig_port_work);
914
915 /*
916 * All other work triggered by hotplug events should be canceled by
917 * now.
918 */
919 if (cancel_all_detection_work(dev_priv))
920 drm_dbg_kms(&dev_priv->drm, "Hotplug detection work still active\n");
921}
922
923bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
924{
925 bool ret = false;
926
927 if (pin == HPD_NONE)
928 return false;
929
930 spin_lock_irq(&dev_priv->irq_lock);
931 if (dev_priv->display.hotplug.stats[pin].state == HPD_ENABLED) {
932 dev_priv->display.hotplug.stats[pin].state = HPD_DISABLED;
933 ret = true;
934 }
935 spin_unlock_irq(&dev_priv->irq_lock);
936
937 return ret;
938}
939
940void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
941{
942 if (pin == HPD_NONE)
943 return;
944
945 spin_lock_irq(&dev_priv->irq_lock);
946 dev_priv->display.hotplug.stats[pin].state = HPD_ENABLED;
947 spin_unlock_irq(&dev_priv->irq_lock);
948}
949
950static void queue_work_for_missed_irqs(struct drm_i915_private *i915)
951{
952 bool queue_work = false;
953 enum hpd_pin pin;
954
955 lockdep_assert_held(&i915->irq_lock);
956
957 if (i915->display.hotplug.event_bits ||
958 i915->display.hotplug.retry_bits)
959 queue_work = true;
960
961 for_each_hpd_pin(pin) {
962 switch (i915->display.hotplug.stats[pin].state) {
963 case HPD_MARK_DISABLED:
964 queue_work = true;
965 break;
966 case HPD_ENABLED:
967 break;
968 default:
969 MISSING_CASE(i915->display.hotplug.stats[pin].state);
970 }
971 }
972
973 if (queue_work)
974 queue_delayed_detection_work(i915, &i915->display.hotplug.hotplug_work, 0);
975}
976
977void intel_hpd_enable_detection_work(struct drm_i915_private *i915)
978{
979 spin_lock_irq(&i915->irq_lock);
980 i915->display.hotplug.detection_work_enabled = true;
981 queue_work_for_missed_irqs(i915);
982 spin_unlock_irq(&i915->irq_lock);
983}
984
985void intel_hpd_disable_detection_work(struct drm_i915_private *i915)
986{
987 spin_lock_irq(&i915->irq_lock);
988 i915->display.hotplug.detection_work_enabled = false;
989 spin_unlock_irq(&i915->irq_lock);
990
991 cancel_all_detection_work(i915);
992}
993
994bool intel_hpd_schedule_detection(struct drm_i915_private *i915)
995{
996 unsigned long flags;
997 bool ret;
998
999 spin_lock_irqsave(&i915->irq_lock, flags);
1000 ret = queue_delayed_detection_work(i915, &i915->display.hotplug.hotplug_work, 0);
1001 spin_unlock_irqrestore(&i915->irq_lock, flags);
1002
1003 return ret;
1004}
1005
1006static int i915_hpd_storm_ctl_show(struct seq_file *m, void *data)
1007{
1008 struct drm_i915_private *dev_priv = m->private;
1009 struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
1010
1011 /* Synchronize with everything first in case there's been an HPD
1012 * storm, but we haven't finished handling it in the kernel yet
1013 */
1014 intel_synchronize_irq(dev_priv);
1015 flush_work(&dev_priv->display.hotplug.dig_port_work);
1016 flush_delayed_work(&dev_priv->display.hotplug.hotplug_work);
1017
1018 seq_printf(m, "Threshold: %d\n", hotplug->hpd_storm_threshold);
1019 seq_printf(m, "Detected: %s\n",
1020 str_yes_no(delayed_work_pending(&hotplug->reenable_work)));
1021
1022 return 0;
1023}
1024
1025static ssize_t i915_hpd_storm_ctl_write(struct file *file,
1026 const char __user *ubuf, size_t len,
1027 loff_t *offp)
1028{
1029 struct seq_file *m = file->private_data;
1030 struct drm_i915_private *dev_priv = m->private;
1031 struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
1032 unsigned int new_threshold;
1033 int i;
1034 char *newline;
1035 char tmp[16];
1036
1037 if (len >= sizeof(tmp))
1038 return -EINVAL;
1039
1040 if (copy_from_user(tmp, ubuf, len))
1041 return -EFAULT;
1042
1043 tmp[len] = '\0';
1044
1045 /* Strip newline, if any */
1046 newline = strchr(tmp, '\n');
1047 if (newline)
1048 *newline = '\0';
1049
1050 if (strcmp(tmp, "reset") == 0)
1051 new_threshold = HPD_STORM_DEFAULT_THRESHOLD;
1052 else if (kstrtouint(tmp, 10, &new_threshold) != 0)
1053 return -EINVAL;
1054
1055 if (new_threshold > 0)
1056 drm_dbg_kms(&dev_priv->drm,
1057 "Setting HPD storm detection threshold to %d\n",
1058 new_threshold);
1059 else
1060 drm_dbg_kms(&dev_priv->drm, "Disabling HPD storm detection\n");
1061
1062 spin_lock_irq(&dev_priv->irq_lock);
1063 hotplug->hpd_storm_threshold = new_threshold;
1064 /* Reset the HPD storm stats so we don't accidentally trigger a storm */
1065 for_each_hpd_pin(i)
1066 hotplug->stats[i].count = 0;
1067 spin_unlock_irq(&dev_priv->irq_lock);
1068
1069 /* Re-enable hpd immediately if we were in an irq storm */
1070 flush_delayed_work(&dev_priv->display.hotplug.reenable_work);
1071
1072 return len;
1073}
1074
1075static int i915_hpd_storm_ctl_open(struct inode *inode, struct file *file)
1076{
1077 return single_open(file, i915_hpd_storm_ctl_show, inode->i_private);
1078}
1079
1080static const struct file_operations i915_hpd_storm_ctl_fops = {
1081 .owner = THIS_MODULE,
1082 .open = i915_hpd_storm_ctl_open,
1083 .read = seq_read,
1084 .llseek = seq_lseek,
1085 .release = single_release,
1086 .write = i915_hpd_storm_ctl_write
1087};
1088
1089static int i915_hpd_short_storm_ctl_show(struct seq_file *m, void *data)
1090{
1091 struct drm_i915_private *dev_priv = m->private;
1092
1093 seq_printf(m, "Enabled: %s\n",
1094 str_yes_no(dev_priv->display.hotplug.hpd_short_storm_enabled));
1095
1096 return 0;
1097}
1098
1099static int
1100i915_hpd_short_storm_ctl_open(struct inode *inode, struct file *file)
1101{
1102 return single_open(file, i915_hpd_short_storm_ctl_show,
1103 inode->i_private);
1104}
1105
1106static ssize_t i915_hpd_short_storm_ctl_write(struct file *file,
1107 const char __user *ubuf,
1108 size_t len, loff_t *offp)
1109{
1110 struct seq_file *m = file->private_data;
1111 struct drm_i915_private *dev_priv = m->private;
1112 struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
1113 char *newline;
1114 char tmp[16];
1115 int i;
1116 bool new_state;
1117
1118 if (len >= sizeof(tmp))
1119 return -EINVAL;
1120
1121 if (copy_from_user(tmp, ubuf, len))
1122 return -EFAULT;
1123
1124 tmp[len] = '\0';
1125
1126 /* Strip newline, if any */
1127 newline = strchr(tmp, '\n');
1128 if (newline)
1129 *newline = '\0';
1130
1131 /* Reset to the "default" state for this system */
1132 if (strcmp(tmp, "reset") == 0)
1133 new_state = !HAS_DP_MST(dev_priv);
1134 else if (kstrtobool(tmp, &new_state) != 0)
1135 return -EINVAL;
1136
1137 drm_dbg_kms(&dev_priv->drm, "%sabling HPD short storm detection\n",
1138 new_state ? "En" : "Dis");
1139
1140 spin_lock_irq(&dev_priv->irq_lock);
1141 hotplug->hpd_short_storm_enabled = new_state;
1142 /* Reset the HPD storm stats so we don't accidentally trigger a storm */
1143 for_each_hpd_pin(i)
1144 hotplug->stats[i].count = 0;
1145 spin_unlock_irq(&dev_priv->irq_lock);
1146
1147 /* Re-enable hpd immediately if we were in an irq storm */
1148 flush_delayed_work(&dev_priv->display.hotplug.reenable_work);
1149
1150 return len;
1151}
1152
1153static const struct file_operations i915_hpd_short_storm_ctl_fops = {
1154 .owner = THIS_MODULE,
1155 .open = i915_hpd_short_storm_ctl_open,
1156 .read = seq_read,
1157 .llseek = seq_lseek,
1158 .release = single_release,
1159 .write = i915_hpd_short_storm_ctl_write,
1160};
1161
1162void intel_hpd_debugfs_register(struct drm_i915_private *i915)
1163{
1164 struct drm_minor *minor = i915->drm.primary;
1165
1166 debugfs_create_file("i915_hpd_storm_ctl", 0644, minor->debugfs_root,
1167 i915, &i915_hpd_storm_ctl_fops);
1168 debugfs_create_file("i915_hpd_short_storm_ctl", 0644, minor->debugfs_root,
1169 i915, &i915_hpd_short_storm_ctl_fops);
1170 debugfs_create_bool("i915_ignore_long_hpd", 0644, minor->debugfs_root,
1171 &i915->display.hotplug.ignore_long_hpd);
1172}