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