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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 "intel_display_types.h"
28#include "intel_hotplug.h"
29
30/**
31 * DOC: Hotplug
32 *
33 * Simply put, hotplug occurs when a display is connected to or disconnected
34 * from the system. However, there may be adapters and docking stations and
35 * Display Port short pulses and MST devices involved, complicating matters.
36 *
37 * Hotplug in i915 is handled in many different levels of abstraction.
38 *
39 * The platform dependent interrupt handling code in i915_irq.c enables,
40 * disables, and does preliminary handling of the interrupts. The interrupt
41 * handlers gather the hotplug detect (HPD) information from relevant registers
42 * into a platform independent mask of hotplug pins that have fired.
43 *
44 * The platform independent interrupt handler intel_hpd_irq_handler() in
45 * intel_hotplug.c does hotplug irq storm detection and mitigation, and passes
46 * further processing to appropriate bottom halves (Display Port specific and
47 * regular hotplug).
48 *
49 * The Display Port work function i915_digport_work_func() calls into
50 * intel_dp_hpd_pulse() via hooks, which handles DP short pulses and DP MST long
51 * pulses, with failures and non-MST long pulses triggering regular hotplug
52 * processing on the connector.
53 *
54 * The regular hotplug work function i915_hotplug_work_func() calls connector
55 * detect hooks, and, if connector status changes, triggers sending of hotplug
56 * uevent to userspace via drm_kms_helper_hotplug_event().
57 *
58 * Finally, the userspace is responsible for triggering a modeset upon receiving
59 * the hotplug uevent, disabling or enabling the crtc as needed.
60 *
61 * The hotplug interrupt storm detection and mitigation code keeps track of the
62 * number of interrupts per hotplug pin per a period of time, and if the number
63 * of interrupts exceeds a certain threshold, the interrupt is disabled for a
64 * while before being re-enabled. The intention is to mitigate issues raising
65 * from broken hardware triggering massive amounts of interrupts and grinding
66 * the system to a halt.
67 *
68 * Current implementation expects that hotplug interrupt storm will not be
69 * seen when display port sink is connected, hence on platforms whose DP
70 * callback is handled by i915_digport_work_func reenabling of hpd is not
71 * performed (it was never expected to be disabled in the first place ;) )
72 * this is specific to DP sinks handled by this routine and any other display
73 * such as HDMI or DVI enabled on the same port will have proper logic since
74 * it will use i915_hotplug_work_func where this logic is handled.
75 */
76
77/**
78 * intel_hpd_pin_default - return default pin associated with certain port.
79 * @dev_priv: private driver data pointer
80 * @port: the hpd port to get associated pin
81 *
82 * It is only valid and used by digital port encoder.
83 *
84 * Return pin that is associatade with @port.
85 */
86enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
87 enum port port)
88{
89 return HPD_PORT_A + port - PORT_A;
90}
91
92#define HPD_STORM_DETECT_PERIOD 1000
93#define HPD_STORM_REENABLE_DELAY (2 * 60 * 1000)
94#define HPD_RETRY_DELAY 1000
95
96static enum hpd_pin
97intel_connector_hpd_pin(struct intel_connector *connector)
98{
99 struct intel_encoder *encoder = intel_attached_encoder(connector);
100
101 /*
102 * MST connectors get their encoder attached dynamically
103 * so need to make sure we have an encoder here. But since
104 * MST encoders have their hpd_pin set to HPD_NONE we don't
105 * have to special case them beyond that.
106 */
107 return encoder ? encoder->hpd_pin : HPD_NONE;
108}
109
110/**
111 * intel_hpd_irq_storm_detect - gather stats and detect HPD IRQ storm on a pin
112 * @dev_priv: private driver data pointer
113 * @pin: the pin to gather stats on
114 * @long_hpd: whether the HPD IRQ was long or short
115 *
116 * Gather stats about HPD IRQs from the specified @pin, and detect IRQ
117 * storms. Only the pin specific stats and state are changed, the caller is
118 * responsible for further action.
119 *
120 * The number of IRQs that are allowed within @HPD_STORM_DETECT_PERIOD is
121 * stored in @dev_priv->hotplug.hpd_storm_threshold which defaults to
122 * @HPD_STORM_DEFAULT_THRESHOLD. Long IRQs count as +10 to this threshold, and
123 * short IRQs count as +1. If this threshold is exceeded, it's considered an
124 * IRQ storm and the IRQ state is set to @HPD_MARK_DISABLED.
125 *
126 * By default, most systems will only count long IRQs towards
127 * &dev_priv->hotplug.hpd_storm_threshold. However, some older systems also
128 * suffer from short IRQ storms and must also track these. Because short IRQ
129 * storms are naturally caused by sideband interactions with DP MST devices,
130 * short IRQ detection is only enabled for systems without DP MST support.
131 * Systems which are new enough to support DP MST are far less likely to
132 * suffer from IRQ storms at all, so this is fine.
133 *
134 * The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
135 * and should only be adjusted for automated hotplug testing.
136 *
137 * Return true if an IRQ storm was detected on @pin.
138 */
139static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
140 enum hpd_pin pin, bool long_hpd)
141{
142 struct i915_hotplug *hpd = &dev_priv->hotplug;
143 unsigned long start = hpd->stats[pin].last_jiffies;
144 unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
145 const int increment = long_hpd ? 10 : 1;
146 const int threshold = hpd->hpd_storm_threshold;
147 bool storm = false;
148
149 if (!threshold ||
150 (!long_hpd && !dev_priv->hotplug.hpd_short_storm_enabled))
151 return false;
152
153 if (!time_in_range(jiffies, start, end)) {
154 hpd->stats[pin].last_jiffies = jiffies;
155 hpd->stats[pin].count = 0;
156 }
157
158 hpd->stats[pin].count += increment;
159 if (hpd->stats[pin].count > threshold) {
160 hpd->stats[pin].state = HPD_MARK_DISABLED;
161 drm_dbg_kms(&dev_priv->drm,
162 "HPD interrupt storm detected on PIN %d\n", pin);
163 storm = true;
164 } else {
165 drm_dbg_kms(&dev_priv->drm,
166 "Received HPD interrupt on PIN %d - cnt: %d\n",
167 pin,
168 hpd->stats[pin].count);
169 }
170
171 return storm;
172}
173
174static void
175intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
176{
177 struct drm_device *dev = &dev_priv->drm;
178 struct drm_connector_list_iter conn_iter;
179 struct intel_connector *connector;
180 bool hpd_disabled = false;
181
182 lockdep_assert_held(&dev_priv->irq_lock);
183
184 drm_connector_list_iter_begin(dev, &conn_iter);
185 for_each_intel_connector_iter(connector, &conn_iter) {
186 enum hpd_pin pin;
187
188 if (connector->base.polled != DRM_CONNECTOR_POLL_HPD)
189 continue;
190
191 pin = intel_connector_hpd_pin(connector);
192 if (pin == HPD_NONE ||
193 dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
194 continue;
195
196 drm_info(&dev_priv->drm,
197 "HPD interrupt storm detected on connector %s: "
198 "switching from hotplug detection to polling\n",
199 connector->base.name);
200
201 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
202 connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
203 DRM_CONNECTOR_POLL_DISCONNECT;
204 hpd_disabled = true;
205 }
206 drm_connector_list_iter_end(&conn_iter);
207
208 /* Enable polling and queue hotplug re-enabling. */
209 if (hpd_disabled) {
210 drm_kms_helper_poll_enable(dev);
211 mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
212 msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
213 }
214}
215
216static void intel_hpd_irq_setup(struct drm_i915_private *i915)
217{
218 if (i915->display_irqs_enabled && i915->display.hpd_irq_setup)
219 i915->display.hpd_irq_setup(i915);
220}
221
222static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
223{
224 struct drm_i915_private *dev_priv =
225 container_of(work, typeof(*dev_priv),
226 hotplug.reenable_work.work);
227 struct drm_device *dev = &dev_priv->drm;
228 struct drm_connector_list_iter conn_iter;
229 struct intel_connector *connector;
230 intel_wakeref_t wakeref;
231 enum hpd_pin pin;
232
233 wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
234
235 spin_lock_irq(&dev_priv->irq_lock);
236
237 drm_connector_list_iter_begin(dev, &conn_iter);
238 for_each_intel_connector_iter(connector, &conn_iter) {
239 pin = intel_connector_hpd_pin(connector);
240 if (pin == HPD_NONE ||
241 dev_priv->hotplug.stats[pin].state != HPD_DISABLED)
242 continue;
243
244 if (connector->base.polled != connector->polled)
245 drm_dbg(&dev_priv->drm,
246 "Reenabling HPD on connector %s\n",
247 connector->base.name);
248 connector->base.polled = connector->polled;
249 }
250 drm_connector_list_iter_end(&conn_iter);
251
252 for_each_hpd_pin(pin) {
253 if (dev_priv->hotplug.stats[pin].state == HPD_DISABLED)
254 dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
255 }
256
257 intel_hpd_irq_setup(dev_priv);
258
259 spin_unlock_irq(&dev_priv->irq_lock);
260
261 intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
262}
263
264enum intel_hotplug_state
265intel_encoder_hotplug(struct intel_encoder *encoder,
266 struct intel_connector *connector)
267{
268 struct drm_device *dev = connector->base.dev;
269 enum drm_connector_status old_status;
270 u64 old_epoch_counter;
271 bool ret = false;
272
273 drm_WARN_ON(dev, !mutex_is_locked(&dev->mode_config.mutex));
274 old_status = connector->base.status;
275 old_epoch_counter = connector->base.epoch_counter;
276
277 connector->base.status =
278 drm_helper_probe_detect(&connector->base, NULL, false);
279
280 if (old_epoch_counter != connector->base.epoch_counter)
281 ret = true;
282
283 if (ret) {
284 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s (epoch counter %llu->%llu)\n",
285 connector->base.base.id,
286 connector->base.name,
287 drm_get_connector_status_name(old_status),
288 drm_get_connector_status_name(connector->base.status),
289 old_epoch_counter,
290 connector->base.epoch_counter);
291 return INTEL_HOTPLUG_CHANGED;
292 }
293 return INTEL_HOTPLUG_UNCHANGED;
294}
295
296static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
297{
298 return intel_encoder_is_dig_port(encoder) &&
299 enc_to_dig_port(encoder)->hpd_pulse != NULL;
300}
301
302static void i915_digport_work_func(struct work_struct *work)
303{
304 struct drm_i915_private *dev_priv =
305 container_of(work, struct drm_i915_private, hotplug.dig_port_work);
306 u32 long_port_mask, short_port_mask;
307 struct intel_encoder *encoder;
308 u32 old_bits = 0;
309
310 spin_lock_irq(&dev_priv->irq_lock);
311 long_port_mask = dev_priv->hotplug.long_port_mask;
312 dev_priv->hotplug.long_port_mask = 0;
313 short_port_mask = dev_priv->hotplug.short_port_mask;
314 dev_priv->hotplug.short_port_mask = 0;
315 spin_unlock_irq(&dev_priv->irq_lock);
316
317 for_each_intel_encoder(&dev_priv->drm, encoder) {
318 struct intel_digital_port *dig_port;
319 enum port port = encoder->port;
320 bool long_hpd, short_hpd;
321 enum irqreturn ret;
322
323 if (!intel_encoder_has_hpd_pulse(encoder))
324 continue;
325
326 long_hpd = long_port_mask & BIT(port);
327 short_hpd = short_port_mask & BIT(port);
328
329 if (!long_hpd && !short_hpd)
330 continue;
331
332 dig_port = enc_to_dig_port(encoder);
333
334 ret = dig_port->hpd_pulse(dig_port, long_hpd);
335 if (ret == IRQ_NONE) {
336 /* fall back to old school hpd */
337 old_bits |= BIT(encoder->hpd_pin);
338 }
339 }
340
341 if (old_bits) {
342 spin_lock_irq(&dev_priv->irq_lock);
343 dev_priv->hotplug.event_bits |= old_bits;
344 spin_unlock_irq(&dev_priv->irq_lock);
345 queue_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work, 0);
346 }
347}
348
349/**
350 * intel_hpd_trigger_irq - trigger an hpd irq event for a port
351 * @dig_port: digital port
352 *
353 * Trigger an HPD interrupt event for the given port, emulating a short pulse
354 * generated by the sink, and schedule the dig port work to handle it.
355 */
356void intel_hpd_trigger_irq(struct intel_digital_port *dig_port)
357{
358 struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
359
360 spin_lock_irq(&i915->irq_lock);
361 i915->hotplug.short_port_mask |= BIT(dig_port->base.port);
362 spin_unlock_irq(&i915->irq_lock);
363
364 queue_work(i915->hotplug.dp_wq, &i915->hotplug.dig_port_work);
365}
366
367/*
368 * Handle hotplug events outside the interrupt handler proper.
369 */
370static void i915_hotplug_work_func(struct work_struct *work)
371{
372 struct drm_i915_private *dev_priv =
373 container_of(work, struct drm_i915_private,
374 hotplug.hotplug_work.work);
375 struct drm_device *dev = &dev_priv->drm;
376 struct drm_connector_list_iter conn_iter;
377 struct intel_connector *connector;
378 u32 changed = 0, retry = 0;
379 u32 hpd_event_bits;
380 u32 hpd_retry_bits;
381
382 mutex_lock(&dev->mode_config.mutex);
383 drm_dbg_kms(&dev_priv->drm, "running encoder hotplug functions\n");
384
385 spin_lock_irq(&dev_priv->irq_lock);
386
387 hpd_event_bits = dev_priv->hotplug.event_bits;
388 dev_priv->hotplug.event_bits = 0;
389 hpd_retry_bits = dev_priv->hotplug.retry_bits;
390 dev_priv->hotplug.retry_bits = 0;
391
392 /* Enable polling for connectors which had HPD IRQ storms */
393 intel_hpd_irq_storm_switch_to_polling(dev_priv);
394
395 spin_unlock_irq(&dev_priv->irq_lock);
396
397 drm_connector_list_iter_begin(dev, &conn_iter);
398 for_each_intel_connector_iter(connector, &conn_iter) {
399 enum hpd_pin pin;
400 u32 hpd_bit;
401
402 pin = intel_connector_hpd_pin(connector);
403 if (pin == HPD_NONE)
404 continue;
405
406 hpd_bit = BIT(pin);
407 if ((hpd_event_bits | hpd_retry_bits) & hpd_bit) {
408 struct intel_encoder *encoder =
409 intel_attached_encoder(connector);
410
411 if (hpd_event_bits & hpd_bit)
412 connector->hotplug_retries = 0;
413 else
414 connector->hotplug_retries++;
415
416 drm_dbg_kms(&dev_priv->drm,
417 "Connector %s (pin %i) received hotplug event. (retry %d)\n",
418 connector->base.name, pin,
419 connector->hotplug_retries);
420
421 switch (encoder->hotplug(encoder, connector)) {
422 case INTEL_HOTPLUG_UNCHANGED:
423 break;
424 case INTEL_HOTPLUG_CHANGED:
425 changed |= hpd_bit;
426 break;
427 case INTEL_HOTPLUG_RETRY:
428 retry |= hpd_bit;
429 break;
430 }
431 }
432 }
433 drm_connector_list_iter_end(&conn_iter);
434 mutex_unlock(&dev->mode_config.mutex);
435
436 if (changed)
437 drm_kms_helper_hotplug_event(dev);
438
439 /* Remove shared HPD pins that have changed */
440 retry &= ~changed;
441 if (retry) {
442 spin_lock_irq(&dev_priv->irq_lock);
443 dev_priv->hotplug.retry_bits |= retry;
444 spin_unlock_irq(&dev_priv->irq_lock);
445
446 mod_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work,
447 msecs_to_jiffies(HPD_RETRY_DELAY));
448 }
449}
450
451
452/**
453 * intel_hpd_irq_handler - main hotplug irq handler
454 * @dev_priv: drm_i915_private
455 * @pin_mask: a mask of hpd pins that have triggered the irq
456 * @long_mask: a mask of hpd pins that may be long hpd pulses
457 *
458 * This is the main hotplug irq handler for all platforms. The platform specific
459 * irq handlers call the platform specific hotplug irq handlers, which read and
460 * decode the appropriate registers into bitmasks about hpd pins that have
461 * triggered (@pin_mask), and which of those pins may be long pulses
462 * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
463 * is not a digital port.
464 *
465 * Here, we do hotplug irq storm detection and mitigation, and pass further
466 * processing to appropriate bottom halves.
467 */
468void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
469 u32 pin_mask, u32 long_mask)
470{
471 struct intel_encoder *encoder;
472 bool storm_detected = false;
473 bool queue_dig = false, queue_hp = false;
474 u32 long_hpd_pulse_mask = 0;
475 u32 short_hpd_pulse_mask = 0;
476 enum hpd_pin pin;
477
478 if (!pin_mask)
479 return;
480
481 spin_lock(&dev_priv->irq_lock);
482
483 /*
484 * Determine whether ->hpd_pulse() exists for each pin, and
485 * whether we have a short or a long pulse. This is needed
486 * as each pin may have up to two encoders (HDMI and DP) and
487 * only the one of them (DP) will have ->hpd_pulse().
488 */
489 for_each_intel_encoder(&dev_priv->drm, encoder) {
490 enum port port = encoder->port;
491 bool long_hpd;
492
493 pin = encoder->hpd_pin;
494 if (!(BIT(pin) & pin_mask))
495 continue;
496
497 if (!intel_encoder_has_hpd_pulse(encoder))
498 continue;
499
500 long_hpd = long_mask & BIT(pin);
501
502 drm_dbg(&dev_priv->drm,
503 "digital hpd on [ENCODER:%d:%s] - %s\n",
504 encoder->base.base.id, encoder->base.name,
505 long_hpd ? "long" : "short");
506 queue_dig = true;
507
508 if (long_hpd) {
509 long_hpd_pulse_mask |= BIT(pin);
510 dev_priv->hotplug.long_port_mask |= BIT(port);
511 } else {
512 short_hpd_pulse_mask |= BIT(pin);
513 dev_priv->hotplug.short_port_mask |= BIT(port);
514 }
515 }
516
517 /* Now process each pin just once */
518 for_each_hpd_pin(pin) {
519 bool long_hpd;
520
521 if (!(BIT(pin) & pin_mask))
522 continue;
523
524 if (dev_priv->hotplug.stats[pin].state == HPD_DISABLED) {
525 /*
526 * On GMCH platforms the interrupt mask bits only
527 * prevent irq generation, not the setting of the
528 * hotplug bits itself. So only WARN about unexpected
529 * interrupts on saner platforms.
530 */
531 drm_WARN_ONCE(&dev_priv->drm, !HAS_GMCH(dev_priv),
532 "Received HPD interrupt on pin %d although disabled\n",
533 pin);
534 continue;
535 }
536
537 if (dev_priv->hotplug.stats[pin].state != HPD_ENABLED)
538 continue;
539
540 /*
541 * Delegate to ->hpd_pulse() if one of the encoders for this
542 * pin has it, otherwise let the hotplug_work deal with this
543 * pin directly.
544 */
545 if (((short_hpd_pulse_mask | long_hpd_pulse_mask) & BIT(pin))) {
546 long_hpd = long_hpd_pulse_mask & BIT(pin);
547 } else {
548 dev_priv->hotplug.event_bits |= BIT(pin);
549 long_hpd = true;
550 queue_hp = true;
551 }
552
553 if (intel_hpd_irq_storm_detect(dev_priv, pin, long_hpd)) {
554 dev_priv->hotplug.event_bits &= ~BIT(pin);
555 storm_detected = true;
556 queue_hp = true;
557 }
558 }
559
560 /*
561 * Disable any IRQs that storms were detected on. Polling enablement
562 * happens later in our hotplug work.
563 */
564 if (storm_detected)
565 intel_hpd_irq_setup(dev_priv);
566 spin_unlock(&dev_priv->irq_lock);
567
568 /*
569 * Our hotplug handler can grab modeset locks (by calling down into the
570 * fb helpers). Hence it must not be run on our own dev-priv->wq work
571 * queue for otherwise the flush_work in the pageflip code will
572 * deadlock.
573 */
574 if (queue_dig)
575 queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
576 if (queue_hp)
577 queue_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work, 0);
578}
579
580/**
581 * intel_hpd_init - initializes and enables hpd support
582 * @dev_priv: i915 device instance
583 *
584 * This function enables the hotplug support. It requires that interrupts have
585 * already been enabled with intel_irq_init_hw(). From this point on hotplug and
586 * poll request can run concurrently to other code, so locking rules must be
587 * obeyed.
588 *
589 * This is a separate step from interrupt enabling to simplify the locking rules
590 * in the driver load and resume code.
591 *
592 * Also see: intel_hpd_poll_enable() and intel_hpd_poll_disable().
593 */
594void intel_hpd_init(struct drm_i915_private *dev_priv)
595{
596 int i;
597
598 if (!HAS_DISPLAY(dev_priv))
599 return;
600
601 for_each_hpd_pin(i) {
602 dev_priv->hotplug.stats[i].count = 0;
603 dev_priv->hotplug.stats[i].state = HPD_ENABLED;
604 }
605
606 /*
607 * Interrupt setup is already guaranteed to be single-threaded, this is
608 * just to make the assert_spin_locked checks happy.
609 */
610 spin_lock_irq(&dev_priv->irq_lock);
611 intel_hpd_irq_setup(dev_priv);
612 spin_unlock_irq(&dev_priv->irq_lock);
613}
614
615static void i915_hpd_poll_init_work(struct work_struct *work)
616{
617 struct drm_i915_private *dev_priv =
618 container_of(work, struct drm_i915_private,
619 hotplug.poll_init_work);
620 struct drm_device *dev = &dev_priv->drm;
621 struct drm_connector_list_iter conn_iter;
622 struct intel_connector *connector;
623 bool enabled;
624
625 mutex_lock(&dev->mode_config.mutex);
626
627 enabled = READ_ONCE(dev_priv->hotplug.poll_enabled);
628
629 drm_connector_list_iter_begin(dev, &conn_iter);
630 for_each_intel_connector_iter(connector, &conn_iter) {
631 enum hpd_pin pin;
632
633 pin = intel_connector_hpd_pin(connector);
634 if (pin == HPD_NONE)
635 continue;
636
637 connector->base.polled = connector->polled;
638
639 if (enabled && connector->base.polled == DRM_CONNECTOR_POLL_HPD)
640 connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
641 DRM_CONNECTOR_POLL_DISCONNECT;
642 }
643 drm_connector_list_iter_end(&conn_iter);
644
645 if (enabled)
646 drm_kms_helper_poll_enable(dev);
647
648 mutex_unlock(&dev->mode_config.mutex);
649
650 /*
651 * We might have missed any hotplugs that happened while we were
652 * in the middle of disabling polling
653 */
654 if (!enabled)
655 drm_helper_hpd_irq_event(dev);
656}
657
658/**
659 * intel_hpd_poll_enable - enable polling for connectors with hpd
660 * @dev_priv: i915 device instance
661 *
662 * This function enables polling for all connectors which support HPD.
663 * Under certain conditions HPD may not be functional. On most Intel GPUs,
664 * this happens when we enter runtime suspend.
665 * On Valleyview and Cherryview systems, this also happens when we shut off all
666 * of the powerwells.
667 *
668 * Since this function can get called in contexts where we're already holding
669 * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
670 * worker.
671 *
672 * Also see: intel_hpd_init() and intel_hpd_poll_disable().
673 */
674void intel_hpd_poll_enable(struct drm_i915_private *dev_priv)
675{
676 if (!HAS_DISPLAY(dev_priv))
677 return;
678
679 WRITE_ONCE(dev_priv->hotplug.poll_enabled, true);
680
681 /*
682 * We might already be holding dev->mode_config.mutex, so do this in a
683 * seperate worker
684 * As well, there's no issue if we race here since we always reschedule
685 * this worker anyway
686 */
687 schedule_work(&dev_priv->hotplug.poll_init_work);
688}
689
690/**
691 * intel_hpd_poll_disable - disable polling for connectors with hpd
692 * @dev_priv: i915 device instance
693 *
694 * This function disables polling for all connectors which support HPD.
695 * Under certain conditions HPD may not be functional. On most Intel GPUs,
696 * this happens when we enter runtime suspend.
697 * On Valleyview and Cherryview systems, this also happens when we shut off all
698 * of the powerwells.
699 *
700 * Since this function can get called in contexts where we're already holding
701 * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
702 * worker.
703 *
704 * Also used during driver init to initialize connector->polled
705 * appropriately for all connectors.
706 *
707 * Also see: intel_hpd_init() and intel_hpd_poll_enable().
708 */
709void intel_hpd_poll_disable(struct drm_i915_private *dev_priv)
710{
711 if (!HAS_DISPLAY(dev_priv))
712 return;
713
714 WRITE_ONCE(dev_priv->hotplug.poll_enabled, false);
715 schedule_work(&dev_priv->hotplug.poll_init_work);
716}
717
718void intel_hpd_init_work(struct drm_i915_private *dev_priv)
719{
720 INIT_DELAYED_WORK(&dev_priv->hotplug.hotplug_work,
721 i915_hotplug_work_func);
722 INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
723 INIT_WORK(&dev_priv->hotplug.poll_init_work, i915_hpd_poll_init_work);
724 INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
725 intel_hpd_irq_storm_reenable_work);
726}
727
728void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
729{
730 if (!HAS_DISPLAY(dev_priv))
731 return;
732
733 spin_lock_irq(&dev_priv->irq_lock);
734
735 dev_priv->hotplug.long_port_mask = 0;
736 dev_priv->hotplug.short_port_mask = 0;
737 dev_priv->hotplug.event_bits = 0;
738 dev_priv->hotplug.retry_bits = 0;
739
740 spin_unlock_irq(&dev_priv->irq_lock);
741
742 cancel_work_sync(&dev_priv->hotplug.dig_port_work);
743 cancel_delayed_work_sync(&dev_priv->hotplug.hotplug_work);
744 cancel_work_sync(&dev_priv->hotplug.poll_init_work);
745 cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
746}
747
748bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
749{
750 bool ret = false;
751
752 if (pin == HPD_NONE)
753 return false;
754
755 spin_lock_irq(&dev_priv->irq_lock);
756 if (dev_priv->hotplug.stats[pin].state == HPD_ENABLED) {
757 dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
758 ret = true;
759 }
760 spin_unlock_irq(&dev_priv->irq_lock);
761
762 return ret;
763}
764
765void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
766{
767 if (pin == HPD_NONE)
768 return;
769
770 spin_lock_irq(&dev_priv->irq_lock);
771 dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
772 spin_unlock_irq(&dev_priv->irq_lock);
773}
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 void
181intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
182{
183 struct drm_connector_list_iter conn_iter;
184 struct intel_connector *connector;
185 bool hpd_disabled = false;
186
187 lockdep_assert_held(&dev_priv->irq_lock);
188
189 drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
190 for_each_intel_connector_iter(connector, &conn_iter) {
191 enum hpd_pin pin;
192
193 if (connector->base.polled != DRM_CONNECTOR_POLL_HPD)
194 continue;
195
196 pin = intel_connector_hpd_pin(connector);
197 if (pin == HPD_NONE ||
198 dev_priv->display.hotplug.stats[pin].state != HPD_MARK_DISABLED)
199 continue;
200
201 drm_info(&dev_priv->drm,
202 "HPD interrupt storm detected on connector %s: "
203 "switching from hotplug detection to polling\n",
204 connector->base.name);
205
206 dev_priv->display.hotplug.stats[pin].state = HPD_DISABLED;
207 connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
208 DRM_CONNECTOR_POLL_DISCONNECT;
209 hpd_disabled = true;
210 }
211 drm_connector_list_iter_end(&conn_iter);
212
213 /* Enable polling and queue hotplug re-enabling. */
214 if (hpd_disabled) {
215 drm_kms_helper_poll_reschedule(&dev_priv->drm);
216 mod_delayed_work(dev_priv->unordered_wq,
217 &dev_priv->display.hotplug.reenable_work,
218 msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
219 }
220}
221
222static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
223{
224 struct drm_i915_private *dev_priv =
225 container_of(work, typeof(*dev_priv),
226 display.hotplug.reenable_work.work);
227 struct drm_connector_list_iter conn_iter;
228 struct intel_connector *connector;
229 intel_wakeref_t wakeref;
230 enum hpd_pin pin;
231
232 wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
233
234 spin_lock_irq(&dev_priv->irq_lock);
235
236 drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
237 for_each_intel_connector_iter(connector, &conn_iter) {
238 pin = intel_connector_hpd_pin(connector);
239 if (pin == HPD_NONE ||
240 dev_priv->display.hotplug.stats[pin].state != HPD_DISABLED)
241 continue;
242
243 if (connector->base.polled != connector->polled)
244 drm_dbg(&dev_priv->drm,
245 "Reenabling HPD on connector %s\n",
246 connector->base.name);
247 connector->base.polled = connector->polled;
248 }
249 drm_connector_list_iter_end(&conn_iter);
250
251 for_each_hpd_pin(pin) {
252 if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED)
253 dev_priv->display.hotplug.stats[pin].state = HPD_ENABLED;
254 }
255
256 intel_hpd_irq_setup(dev_priv);
257
258 spin_unlock_irq(&dev_priv->irq_lock);
259
260 intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
261}
262
263static enum intel_hotplug_state
264intel_hotplug_detect_connector(struct intel_connector *connector)
265{
266 struct drm_device *dev = connector->base.dev;
267 enum drm_connector_status old_status;
268 u64 old_epoch_counter;
269 int status;
270 bool ret = false;
271
272 drm_WARN_ON(dev, !mutex_is_locked(&dev->mode_config.mutex));
273 old_status = connector->base.status;
274 old_epoch_counter = connector->base.epoch_counter;
275
276 status = drm_helper_probe_detect(&connector->base, NULL, false);
277 if (!connector->base.force)
278 connector->base.status = status;
279
280 if (old_epoch_counter != connector->base.epoch_counter)
281 ret = true;
282
283 if (ret) {
284 drm_dbg_kms(dev, "[CONNECTOR:%d:%s] status updated from %s to %s (epoch counter %llu->%llu)\n",
285 connector->base.base.id,
286 connector->base.name,
287 drm_get_connector_status_name(old_status),
288 drm_get_connector_status_name(connector->base.status),
289 old_epoch_counter,
290 connector->base.epoch_counter);
291 return INTEL_HOTPLUG_CHANGED;
292 }
293 return INTEL_HOTPLUG_UNCHANGED;
294}
295
296enum intel_hotplug_state
297intel_encoder_hotplug(struct intel_encoder *encoder,
298 struct intel_connector *connector)
299{
300 return intel_hotplug_detect_connector(connector);
301}
302
303static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
304{
305 return intel_encoder_is_dig_port(encoder) &&
306 enc_to_dig_port(encoder)->hpd_pulse != NULL;
307}
308
309static void i915_digport_work_func(struct work_struct *work)
310{
311 struct drm_i915_private *dev_priv =
312 container_of(work, struct drm_i915_private, display.hotplug.dig_port_work);
313 u32 long_port_mask, short_port_mask;
314 struct intel_encoder *encoder;
315 u32 old_bits = 0;
316
317 spin_lock_irq(&dev_priv->irq_lock);
318 long_port_mask = dev_priv->display.hotplug.long_port_mask;
319 dev_priv->display.hotplug.long_port_mask = 0;
320 short_port_mask = dev_priv->display.hotplug.short_port_mask;
321 dev_priv->display.hotplug.short_port_mask = 0;
322 spin_unlock_irq(&dev_priv->irq_lock);
323
324 for_each_intel_encoder(&dev_priv->drm, encoder) {
325 struct intel_digital_port *dig_port;
326 enum port port = encoder->port;
327 bool long_hpd, short_hpd;
328 enum irqreturn ret;
329
330 if (!intel_encoder_has_hpd_pulse(encoder))
331 continue;
332
333 long_hpd = long_port_mask & BIT(port);
334 short_hpd = short_port_mask & BIT(port);
335
336 if (!long_hpd && !short_hpd)
337 continue;
338
339 dig_port = enc_to_dig_port(encoder);
340
341 ret = dig_port->hpd_pulse(dig_port, long_hpd);
342 if (ret == IRQ_NONE) {
343 /* fall back to old school hpd */
344 old_bits |= BIT(encoder->hpd_pin);
345 }
346 }
347
348 if (old_bits) {
349 spin_lock_irq(&dev_priv->irq_lock);
350 dev_priv->display.hotplug.event_bits |= old_bits;
351 spin_unlock_irq(&dev_priv->irq_lock);
352 queue_delayed_work(dev_priv->unordered_wq,
353 &dev_priv->display.hotplug.hotplug_work, 0);
354 }
355}
356
357/**
358 * intel_hpd_trigger_irq - trigger an hpd irq event for a port
359 * @dig_port: digital port
360 *
361 * Trigger an HPD interrupt event for the given port, emulating a short pulse
362 * generated by the sink, and schedule the dig port work to handle it.
363 */
364void intel_hpd_trigger_irq(struct intel_digital_port *dig_port)
365{
366 struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
367
368 spin_lock_irq(&i915->irq_lock);
369 i915->display.hotplug.short_port_mask |= BIT(dig_port->base.port);
370 spin_unlock_irq(&i915->irq_lock);
371
372 queue_work(i915->display.hotplug.dp_wq, &i915->display.hotplug.dig_port_work);
373}
374
375/*
376 * Handle hotplug events outside the interrupt handler proper.
377 */
378static void i915_hotplug_work_func(struct work_struct *work)
379{
380 struct drm_i915_private *dev_priv =
381 container_of(work, struct drm_i915_private,
382 display.hotplug.hotplug_work.work);
383 struct drm_connector_list_iter conn_iter;
384 struct intel_connector *connector;
385 u32 changed = 0, retry = 0;
386 u32 hpd_event_bits;
387 u32 hpd_retry_bits;
388 struct drm_connector *first_changed_connector = NULL;
389 int changed_connectors = 0;
390
391 mutex_lock(&dev_priv->drm.mode_config.mutex);
392 drm_dbg_kms(&dev_priv->drm, "running encoder hotplug functions\n");
393
394 spin_lock_irq(&dev_priv->irq_lock);
395
396 hpd_event_bits = dev_priv->display.hotplug.event_bits;
397 dev_priv->display.hotplug.event_bits = 0;
398 hpd_retry_bits = dev_priv->display.hotplug.retry_bits;
399 dev_priv->display.hotplug.retry_bits = 0;
400
401 /* Enable polling for connectors which had HPD IRQ storms */
402 intel_hpd_irq_storm_switch_to_polling(dev_priv);
403
404 spin_unlock_irq(&dev_priv->irq_lock);
405
406 /* Skip calling encode hotplug handlers if ignore long HPD set*/
407 if (dev_priv->display.hotplug.ignore_long_hpd) {
408 drm_dbg_kms(&dev_priv->drm, "Ignore HPD flag on - skip encoder hotplug handlers\n");
409 mutex_unlock(&dev_priv->drm.mode_config.mutex);
410 return;
411 }
412
413 drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
414 for_each_intel_connector_iter(connector, &conn_iter) {
415 enum hpd_pin pin;
416 u32 hpd_bit;
417
418 pin = intel_connector_hpd_pin(connector);
419 if (pin == HPD_NONE)
420 continue;
421
422 hpd_bit = BIT(pin);
423 if ((hpd_event_bits | hpd_retry_bits) & hpd_bit) {
424 struct intel_encoder *encoder =
425 intel_attached_encoder(connector);
426
427 if (hpd_event_bits & hpd_bit)
428 connector->hotplug_retries = 0;
429 else
430 connector->hotplug_retries++;
431
432 drm_dbg_kms(&dev_priv->drm,
433 "Connector %s (pin %i) received hotplug event. (retry %d)\n",
434 connector->base.name, pin,
435 connector->hotplug_retries);
436
437 switch (encoder->hotplug(encoder, connector)) {
438 case INTEL_HOTPLUG_UNCHANGED:
439 break;
440 case INTEL_HOTPLUG_CHANGED:
441 changed |= hpd_bit;
442 changed_connectors++;
443 if (!first_changed_connector) {
444 drm_connector_get(&connector->base);
445 first_changed_connector = &connector->base;
446 }
447 break;
448 case INTEL_HOTPLUG_RETRY:
449 retry |= hpd_bit;
450 break;
451 }
452 }
453 }
454 drm_connector_list_iter_end(&conn_iter);
455 mutex_unlock(&dev_priv->drm.mode_config.mutex);
456
457 if (changed_connectors == 1)
458 drm_kms_helper_connector_hotplug_event(first_changed_connector);
459 else if (changed_connectors > 0)
460 drm_kms_helper_hotplug_event(&dev_priv->drm);
461
462 if (first_changed_connector)
463 drm_connector_put(first_changed_connector);
464
465 /* Remove shared HPD pins that have changed */
466 retry &= ~changed;
467 if (retry) {
468 spin_lock_irq(&dev_priv->irq_lock);
469 dev_priv->display.hotplug.retry_bits |= retry;
470 spin_unlock_irq(&dev_priv->irq_lock);
471
472 mod_delayed_work(dev_priv->unordered_wq,
473 &dev_priv->display.hotplug.hotplug_work,
474 msecs_to_jiffies(HPD_RETRY_DELAY));
475 }
476}
477
478
479/**
480 * intel_hpd_irq_handler - main hotplug irq handler
481 * @dev_priv: drm_i915_private
482 * @pin_mask: a mask of hpd pins that have triggered the irq
483 * @long_mask: a mask of hpd pins that may be long hpd pulses
484 *
485 * This is the main hotplug irq handler for all platforms. The platform specific
486 * irq handlers call the platform specific hotplug irq handlers, which read and
487 * decode the appropriate registers into bitmasks about hpd pins that have
488 * triggered (@pin_mask), and which of those pins may be long pulses
489 * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
490 * is not a digital port.
491 *
492 * Here, we do hotplug irq storm detection and mitigation, and pass further
493 * processing to appropriate bottom halves.
494 */
495void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
496 u32 pin_mask, u32 long_mask)
497{
498 struct intel_encoder *encoder;
499 bool storm_detected = false;
500 bool queue_dig = false, queue_hp = false;
501 u32 long_hpd_pulse_mask = 0;
502 u32 short_hpd_pulse_mask = 0;
503 enum hpd_pin pin;
504
505 if (!pin_mask)
506 return;
507
508 spin_lock(&dev_priv->irq_lock);
509
510 /*
511 * Determine whether ->hpd_pulse() exists for each pin, and
512 * whether we have a short or a long pulse. This is needed
513 * as each pin may have up to two encoders (HDMI and DP) and
514 * only the one of them (DP) will have ->hpd_pulse().
515 */
516 for_each_intel_encoder(&dev_priv->drm, encoder) {
517 enum port port = encoder->port;
518 bool long_hpd;
519
520 pin = encoder->hpd_pin;
521 if (!(BIT(pin) & pin_mask))
522 continue;
523
524 if (!intel_encoder_has_hpd_pulse(encoder))
525 continue;
526
527 long_hpd = long_mask & BIT(pin);
528
529 drm_dbg(&dev_priv->drm,
530 "digital hpd on [ENCODER:%d:%s] - %s\n",
531 encoder->base.base.id, encoder->base.name,
532 long_hpd ? "long" : "short");
533 queue_dig = true;
534
535 if (long_hpd) {
536 long_hpd_pulse_mask |= BIT(pin);
537 dev_priv->display.hotplug.long_port_mask |= BIT(port);
538 } else {
539 short_hpd_pulse_mask |= BIT(pin);
540 dev_priv->display.hotplug.short_port_mask |= BIT(port);
541 }
542 }
543
544 /* Now process each pin just once */
545 for_each_hpd_pin(pin) {
546 bool long_hpd;
547
548 if (!(BIT(pin) & pin_mask))
549 continue;
550
551 if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED) {
552 /*
553 * On GMCH platforms the interrupt mask bits only
554 * prevent irq generation, not the setting of the
555 * hotplug bits itself. So only WARN about unexpected
556 * interrupts on saner platforms.
557 */
558 drm_WARN_ONCE(&dev_priv->drm, !HAS_GMCH(dev_priv),
559 "Received HPD interrupt on pin %d although disabled\n",
560 pin);
561 continue;
562 }
563
564 if (dev_priv->display.hotplug.stats[pin].state != HPD_ENABLED)
565 continue;
566
567 /*
568 * Delegate to ->hpd_pulse() if one of the encoders for this
569 * pin has it, otherwise let the hotplug_work deal with this
570 * pin directly.
571 */
572 if (((short_hpd_pulse_mask | long_hpd_pulse_mask) & BIT(pin))) {
573 long_hpd = long_hpd_pulse_mask & BIT(pin);
574 } else {
575 dev_priv->display.hotplug.event_bits |= BIT(pin);
576 long_hpd = true;
577 queue_hp = true;
578 }
579
580 if (intel_hpd_irq_storm_detect(dev_priv, pin, long_hpd)) {
581 dev_priv->display.hotplug.event_bits &= ~BIT(pin);
582 storm_detected = true;
583 queue_hp = true;
584 }
585 }
586
587 /*
588 * Disable any IRQs that storms were detected on. Polling enablement
589 * happens later in our hotplug work.
590 */
591 if (storm_detected)
592 intel_hpd_irq_setup(dev_priv);
593 spin_unlock(&dev_priv->irq_lock);
594
595 /*
596 * Our hotplug handler can grab modeset locks (by calling down into the
597 * fb helpers). Hence it must not be run on our own dev-priv->wq work
598 * queue for otherwise the flush_work in the pageflip code will
599 * deadlock.
600 */
601 if (queue_dig)
602 queue_work(dev_priv->display.hotplug.dp_wq, &dev_priv->display.hotplug.dig_port_work);
603 if (queue_hp)
604 queue_delayed_work(dev_priv->unordered_wq,
605 &dev_priv->display.hotplug.hotplug_work, 0);
606}
607
608/**
609 * intel_hpd_init - initializes and enables hpd support
610 * @dev_priv: i915 device instance
611 *
612 * This function enables the hotplug support. It requires that interrupts have
613 * already been enabled with intel_irq_init_hw(). From this point on hotplug and
614 * poll request can run concurrently to other code, so locking rules must be
615 * obeyed.
616 *
617 * This is a separate step from interrupt enabling to simplify the locking rules
618 * in the driver load and resume code.
619 *
620 * Also see: intel_hpd_poll_enable() and intel_hpd_poll_disable().
621 */
622void intel_hpd_init(struct drm_i915_private *dev_priv)
623{
624 int i;
625
626 if (!HAS_DISPLAY(dev_priv))
627 return;
628
629 for_each_hpd_pin(i) {
630 dev_priv->display.hotplug.stats[i].count = 0;
631 dev_priv->display.hotplug.stats[i].state = HPD_ENABLED;
632 }
633
634 /*
635 * Interrupt setup is already guaranteed to be single-threaded, this is
636 * just to make the assert_spin_locked checks happy.
637 */
638 spin_lock_irq(&dev_priv->irq_lock);
639 intel_hpd_irq_setup(dev_priv);
640 spin_unlock_irq(&dev_priv->irq_lock);
641}
642
643static void i915_hpd_poll_detect_connectors(struct drm_i915_private *i915)
644{
645 struct drm_connector_list_iter conn_iter;
646 struct intel_connector *connector;
647 struct intel_connector *first_changed_connector = NULL;
648 int changed = 0;
649
650 mutex_lock(&i915->drm.mode_config.mutex);
651
652 if (!i915->drm.mode_config.poll_enabled)
653 goto out;
654
655 drm_connector_list_iter_begin(&i915->drm, &conn_iter);
656 for_each_intel_connector_iter(connector, &conn_iter) {
657 if (!(connector->base.polled & DRM_CONNECTOR_POLL_HPD))
658 continue;
659
660 if (intel_hotplug_detect_connector(connector) != INTEL_HOTPLUG_CHANGED)
661 continue;
662
663 changed++;
664
665 if (changed == 1) {
666 drm_connector_get(&connector->base);
667 first_changed_connector = connector;
668 }
669 }
670 drm_connector_list_iter_end(&conn_iter);
671
672out:
673 mutex_unlock(&i915->drm.mode_config.mutex);
674
675 if (!changed)
676 return;
677
678 if (changed == 1)
679 drm_kms_helper_connector_hotplug_event(&first_changed_connector->base);
680 else
681 drm_kms_helper_hotplug_event(&i915->drm);
682
683 drm_connector_put(&first_changed_connector->base);
684}
685
686static void i915_hpd_poll_init_work(struct work_struct *work)
687{
688 struct drm_i915_private *dev_priv =
689 container_of(work, struct drm_i915_private,
690 display.hotplug.poll_init_work);
691 struct drm_connector_list_iter conn_iter;
692 struct intel_connector *connector;
693 intel_wakeref_t wakeref;
694 bool enabled;
695
696 mutex_lock(&dev_priv->drm.mode_config.mutex);
697
698 enabled = READ_ONCE(dev_priv->display.hotplug.poll_enabled);
699 /*
700 * Prevent taking a power reference from this sequence of
701 * i915_hpd_poll_init_work() -> drm_helper_hpd_irq_event() ->
702 * connector detect which would requeue i915_hpd_poll_init_work()
703 * and so risk an endless loop of this same sequence.
704 */
705 if (!enabled) {
706 wakeref = intel_display_power_get(dev_priv,
707 POWER_DOMAIN_DISPLAY_CORE);
708 drm_WARN_ON(&dev_priv->drm,
709 READ_ONCE(dev_priv->display.hotplug.poll_enabled));
710 cancel_work(&dev_priv->display.hotplug.poll_init_work);
711 }
712
713 drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
714 for_each_intel_connector_iter(connector, &conn_iter) {
715 enum hpd_pin pin;
716
717 pin = intel_connector_hpd_pin(connector);
718 if (pin == HPD_NONE)
719 continue;
720
721 connector->base.polled = connector->polled;
722
723 if (enabled && connector->base.polled == DRM_CONNECTOR_POLL_HPD)
724 connector->base.polled = DRM_CONNECTOR_POLL_CONNECT |
725 DRM_CONNECTOR_POLL_DISCONNECT;
726 }
727 drm_connector_list_iter_end(&conn_iter);
728
729 if (enabled)
730 drm_kms_helper_poll_reschedule(&dev_priv->drm);
731
732 mutex_unlock(&dev_priv->drm.mode_config.mutex);
733
734 /*
735 * We might have missed any hotplugs that happened while we were
736 * in the middle of disabling polling
737 */
738 if (!enabled) {
739 i915_hpd_poll_detect_connectors(dev_priv);
740
741 intel_display_power_put(dev_priv,
742 POWER_DOMAIN_DISPLAY_CORE,
743 wakeref);
744 }
745}
746
747/**
748 * intel_hpd_poll_enable - enable polling for connectors with hpd
749 * @dev_priv: i915 device instance
750 *
751 * This function enables polling for all connectors which support HPD.
752 * Under certain conditions HPD may not be functional. On most Intel GPUs,
753 * this happens when we enter runtime suspend.
754 * On Valleyview and Cherryview systems, this also happens when we shut off all
755 * of the powerwells.
756 *
757 * Since this function can get called in contexts where we're already holding
758 * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
759 * worker.
760 *
761 * Also see: intel_hpd_init() and intel_hpd_poll_disable().
762 */
763void intel_hpd_poll_enable(struct drm_i915_private *dev_priv)
764{
765 if (!HAS_DISPLAY(dev_priv) ||
766 !intel_display_device_enabled(dev_priv))
767 return;
768
769 WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, true);
770
771 /*
772 * We might already be holding dev->mode_config.mutex, so do this in a
773 * seperate worker
774 * As well, there's no issue if we race here since we always reschedule
775 * this worker anyway
776 */
777 queue_work(dev_priv->unordered_wq,
778 &dev_priv->display.hotplug.poll_init_work);
779}
780
781/**
782 * intel_hpd_poll_disable - disable polling for connectors with hpd
783 * @dev_priv: i915 device instance
784 *
785 * This function disables polling for all connectors which support HPD.
786 * Under certain conditions HPD may not be functional. On most Intel GPUs,
787 * this happens when we enter runtime suspend.
788 * On Valleyview and Cherryview systems, this also happens when we shut off all
789 * of the powerwells.
790 *
791 * Since this function can get called in contexts where we're already holding
792 * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
793 * worker.
794 *
795 * Also used during driver init to initialize connector->polled
796 * appropriately for all connectors.
797 *
798 * Also see: intel_hpd_init() and intel_hpd_poll_enable().
799 */
800void intel_hpd_poll_disable(struct drm_i915_private *dev_priv)
801{
802 if (!HAS_DISPLAY(dev_priv))
803 return;
804
805 WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, false);
806 queue_work(dev_priv->unordered_wq,
807 &dev_priv->display.hotplug.poll_init_work);
808}
809
810void intel_hpd_init_early(struct drm_i915_private *i915)
811{
812 INIT_DELAYED_WORK(&i915->display.hotplug.hotplug_work,
813 i915_hotplug_work_func);
814 INIT_WORK(&i915->display.hotplug.dig_port_work, i915_digport_work_func);
815 INIT_WORK(&i915->display.hotplug.poll_init_work, i915_hpd_poll_init_work);
816 INIT_DELAYED_WORK(&i915->display.hotplug.reenable_work,
817 intel_hpd_irq_storm_reenable_work);
818
819 i915->display.hotplug.hpd_storm_threshold = HPD_STORM_DEFAULT_THRESHOLD;
820 /* If we have MST support, we want to avoid doing short HPD IRQ storm
821 * detection, as short HPD storms will occur as a natural part of
822 * sideband messaging with MST.
823 * On older platforms however, IRQ storms can occur with both long and
824 * short pulses, as seen on some G4x systems.
825 */
826 i915->display.hotplug.hpd_short_storm_enabled = !HAS_DP_MST(i915);
827}
828
829void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
830{
831 if (!HAS_DISPLAY(dev_priv))
832 return;
833
834 spin_lock_irq(&dev_priv->irq_lock);
835
836 dev_priv->display.hotplug.long_port_mask = 0;
837 dev_priv->display.hotplug.short_port_mask = 0;
838 dev_priv->display.hotplug.event_bits = 0;
839 dev_priv->display.hotplug.retry_bits = 0;
840
841 spin_unlock_irq(&dev_priv->irq_lock);
842
843 cancel_work_sync(&dev_priv->display.hotplug.dig_port_work);
844 cancel_delayed_work_sync(&dev_priv->display.hotplug.hotplug_work);
845 cancel_work_sync(&dev_priv->display.hotplug.poll_init_work);
846 cancel_delayed_work_sync(&dev_priv->display.hotplug.reenable_work);
847}
848
849bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
850{
851 bool ret = false;
852
853 if (pin == HPD_NONE)
854 return false;
855
856 spin_lock_irq(&dev_priv->irq_lock);
857 if (dev_priv->display.hotplug.stats[pin].state == HPD_ENABLED) {
858 dev_priv->display.hotplug.stats[pin].state = HPD_DISABLED;
859 ret = true;
860 }
861 spin_unlock_irq(&dev_priv->irq_lock);
862
863 return ret;
864}
865
866void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
867{
868 if (pin == HPD_NONE)
869 return;
870
871 spin_lock_irq(&dev_priv->irq_lock);
872 dev_priv->display.hotplug.stats[pin].state = HPD_ENABLED;
873 spin_unlock_irq(&dev_priv->irq_lock);
874}
875
876static int i915_hpd_storm_ctl_show(struct seq_file *m, void *data)
877{
878 struct drm_i915_private *dev_priv = m->private;
879 struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
880
881 /* Synchronize with everything first in case there's been an HPD
882 * storm, but we haven't finished handling it in the kernel yet
883 */
884 intel_synchronize_irq(dev_priv);
885 flush_work(&dev_priv->display.hotplug.dig_port_work);
886 flush_delayed_work(&dev_priv->display.hotplug.hotplug_work);
887
888 seq_printf(m, "Threshold: %d\n", hotplug->hpd_storm_threshold);
889 seq_printf(m, "Detected: %s\n",
890 str_yes_no(delayed_work_pending(&hotplug->reenable_work)));
891
892 return 0;
893}
894
895static ssize_t i915_hpd_storm_ctl_write(struct file *file,
896 const char __user *ubuf, size_t len,
897 loff_t *offp)
898{
899 struct seq_file *m = file->private_data;
900 struct drm_i915_private *dev_priv = m->private;
901 struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
902 unsigned int new_threshold;
903 int i;
904 char *newline;
905 char tmp[16];
906
907 if (len >= sizeof(tmp))
908 return -EINVAL;
909
910 if (copy_from_user(tmp, ubuf, len))
911 return -EFAULT;
912
913 tmp[len] = '\0';
914
915 /* Strip newline, if any */
916 newline = strchr(tmp, '\n');
917 if (newline)
918 *newline = '\0';
919
920 if (strcmp(tmp, "reset") == 0)
921 new_threshold = HPD_STORM_DEFAULT_THRESHOLD;
922 else if (kstrtouint(tmp, 10, &new_threshold) != 0)
923 return -EINVAL;
924
925 if (new_threshold > 0)
926 drm_dbg_kms(&dev_priv->drm,
927 "Setting HPD storm detection threshold to %d\n",
928 new_threshold);
929 else
930 drm_dbg_kms(&dev_priv->drm, "Disabling HPD storm detection\n");
931
932 spin_lock_irq(&dev_priv->irq_lock);
933 hotplug->hpd_storm_threshold = new_threshold;
934 /* Reset the HPD storm stats so we don't accidentally trigger a storm */
935 for_each_hpd_pin(i)
936 hotplug->stats[i].count = 0;
937 spin_unlock_irq(&dev_priv->irq_lock);
938
939 /* Re-enable hpd immediately if we were in an irq storm */
940 flush_delayed_work(&dev_priv->display.hotplug.reenable_work);
941
942 return len;
943}
944
945static int i915_hpd_storm_ctl_open(struct inode *inode, struct file *file)
946{
947 return single_open(file, i915_hpd_storm_ctl_show, inode->i_private);
948}
949
950static const struct file_operations i915_hpd_storm_ctl_fops = {
951 .owner = THIS_MODULE,
952 .open = i915_hpd_storm_ctl_open,
953 .read = seq_read,
954 .llseek = seq_lseek,
955 .release = single_release,
956 .write = i915_hpd_storm_ctl_write
957};
958
959static int i915_hpd_short_storm_ctl_show(struct seq_file *m, void *data)
960{
961 struct drm_i915_private *dev_priv = m->private;
962
963 seq_printf(m, "Enabled: %s\n",
964 str_yes_no(dev_priv->display.hotplug.hpd_short_storm_enabled));
965
966 return 0;
967}
968
969static int
970i915_hpd_short_storm_ctl_open(struct inode *inode, struct file *file)
971{
972 return single_open(file, i915_hpd_short_storm_ctl_show,
973 inode->i_private);
974}
975
976static ssize_t i915_hpd_short_storm_ctl_write(struct file *file,
977 const char __user *ubuf,
978 size_t len, loff_t *offp)
979{
980 struct seq_file *m = file->private_data;
981 struct drm_i915_private *dev_priv = m->private;
982 struct intel_hotplug *hotplug = &dev_priv->display.hotplug;
983 char *newline;
984 char tmp[16];
985 int i;
986 bool new_state;
987
988 if (len >= sizeof(tmp))
989 return -EINVAL;
990
991 if (copy_from_user(tmp, ubuf, len))
992 return -EFAULT;
993
994 tmp[len] = '\0';
995
996 /* Strip newline, if any */
997 newline = strchr(tmp, '\n');
998 if (newline)
999 *newline = '\0';
1000
1001 /* Reset to the "default" state for this system */
1002 if (strcmp(tmp, "reset") == 0)
1003 new_state = !HAS_DP_MST(dev_priv);
1004 else if (kstrtobool(tmp, &new_state) != 0)
1005 return -EINVAL;
1006
1007 drm_dbg_kms(&dev_priv->drm, "%sabling HPD short storm detection\n",
1008 new_state ? "En" : "Dis");
1009
1010 spin_lock_irq(&dev_priv->irq_lock);
1011 hotplug->hpd_short_storm_enabled = new_state;
1012 /* Reset the HPD storm stats so we don't accidentally trigger a storm */
1013 for_each_hpd_pin(i)
1014 hotplug->stats[i].count = 0;
1015 spin_unlock_irq(&dev_priv->irq_lock);
1016
1017 /* Re-enable hpd immediately if we were in an irq storm */
1018 flush_delayed_work(&dev_priv->display.hotplug.reenable_work);
1019
1020 return len;
1021}
1022
1023static const struct file_operations i915_hpd_short_storm_ctl_fops = {
1024 .owner = THIS_MODULE,
1025 .open = i915_hpd_short_storm_ctl_open,
1026 .read = seq_read,
1027 .llseek = seq_lseek,
1028 .release = single_release,
1029 .write = i915_hpd_short_storm_ctl_write,
1030};
1031
1032void intel_hpd_debugfs_register(struct drm_i915_private *i915)
1033{
1034 struct drm_minor *minor = i915->drm.primary;
1035
1036 debugfs_create_file("i915_hpd_storm_ctl", 0644, minor->debugfs_root,
1037 i915, &i915_hpd_storm_ctl_fops);
1038 debugfs_create_file("i915_hpd_short_storm_ctl", 0644, minor->debugfs_root,
1039 i915, &i915_hpd_short_storm_ctl_fops);
1040 debugfs_create_bool("i915_ignore_long_hpd", 0644, minor->debugfs_root,
1041 &i915->display.hotplug.ignore_long_hpd);
1042}