1 /*
2  * Copyright 2022 Advanced Micro Devices, Inc.
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 shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  *
22  * Authors: AMD
23  *
24  */
25 
26 /* FILE POLICY AND INTENDED USAGE:
27  * This file manages link detection states and receiver states by using various
28  * link protocols. It also provides helper functions to interpret certain
29  * capabilities or status based on the states it manages or retrieve them
30  * directly from connected receivers.
31  */
32 
33 #include "link_dpms.h"
34 #include "link_detection.h"
35 #include "link_hwss.h"
36 #include "protocols/link_edp_panel_control.h"
37 #include "protocols/link_ddc.h"
38 #include "protocols/link_hpd.h"
39 #include "protocols/link_dpcd.h"
40 #include "protocols/link_dp_capability.h"
41 #include "protocols/link_dp_dpia.h"
42 #include "protocols/link_dp_phy.h"
43 #include "protocols/link_dp_training.h"
44 #include "accessories/link_dp_trace.h"
45 
46 #include "link_enc_cfg.h"
47 #include "dm_helpers.h"
48 #include "clk_mgr.h"
49 
50 #define DC_LOGGER_INIT(logger)
51 
52 #define LINK_INFO(...) \
53 	DC_LOG_HW_HOTPLUG(  \
54 		__VA_ARGS__)
55 /*
56  * Some receivers fail to train on first try and are good
57  * on subsequent tries. 2 retries should be plenty. If we
58  * don't have a successful training then we don't expect to
59  * ever get one.
60  */
61 #define LINK_TRAINING_MAX_VERIFY_RETRY 2
62 
63 static const u8 DP_SINK_BRANCH_DEV_NAME_7580[] = "7580\x80u";
64 
65 static const uint8_t dp_hdmi_dongle_signature_str[] = "DP-HDMI ADAPTOR";
66 
67 static enum ddc_transaction_type get_ddc_transaction_type(enum signal_type sink_signal)
68 {
69 	enum ddc_transaction_type transaction_type = DDC_TRANSACTION_TYPE_NONE;
70 
71 	switch (sink_signal) {
72 	case SIGNAL_TYPE_DVI_SINGLE_LINK:
73 	case SIGNAL_TYPE_DVI_DUAL_LINK:
74 	case SIGNAL_TYPE_HDMI_TYPE_A:
75 	case SIGNAL_TYPE_LVDS:
76 	case SIGNAL_TYPE_RGB:
77 		transaction_type = DDC_TRANSACTION_TYPE_I2C;
78 		break;
79 
80 	case SIGNAL_TYPE_DISPLAY_PORT:
81 	case SIGNAL_TYPE_EDP:
82 		transaction_type = DDC_TRANSACTION_TYPE_I2C_OVER_AUX;
83 		break;
84 
85 	case SIGNAL_TYPE_DISPLAY_PORT_MST:
86 		/* MST does not use I2COverAux, but there is the
87 		 * SPECIAL use case for "immediate dwnstrm device
88 		 * access" (EPR#370830).
89 		 */
90 		transaction_type = DDC_TRANSACTION_TYPE_I2C_OVER_AUX;
91 		break;
92 
93 	default:
94 		break;
95 	}
96 
97 	return transaction_type;
98 }
99 
100 static enum signal_type get_basic_signal_type(struct graphics_object_id encoder,
101 					      struct graphics_object_id downstream)
102 {
103 	if (downstream.type == OBJECT_TYPE_CONNECTOR) {
104 		switch (downstream.id) {
105 		case CONNECTOR_ID_SINGLE_LINK_DVII:
106 			switch (encoder.id) {
107 			case ENCODER_ID_INTERNAL_DAC1:
108 			case ENCODER_ID_INTERNAL_KLDSCP_DAC1:
109 			case ENCODER_ID_INTERNAL_DAC2:
110 			case ENCODER_ID_INTERNAL_KLDSCP_DAC2:
111 				return SIGNAL_TYPE_RGB;
112 			default:
113 				return SIGNAL_TYPE_DVI_SINGLE_LINK;
114 			}
115 		break;
116 		case CONNECTOR_ID_DUAL_LINK_DVII:
117 		{
118 			switch (encoder.id) {
119 			case ENCODER_ID_INTERNAL_DAC1:
120 			case ENCODER_ID_INTERNAL_KLDSCP_DAC1:
121 			case ENCODER_ID_INTERNAL_DAC2:
122 			case ENCODER_ID_INTERNAL_KLDSCP_DAC2:
123 				return SIGNAL_TYPE_RGB;
124 			default:
125 				return SIGNAL_TYPE_DVI_DUAL_LINK;
126 			}
127 		}
128 		break;
129 		case CONNECTOR_ID_SINGLE_LINK_DVID:
130 			return SIGNAL_TYPE_DVI_SINGLE_LINK;
131 		case CONNECTOR_ID_DUAL_LINK_DVID:
132 			return SIGNAL_TYPE_DVI_DUAL_LINK;
133 		case CONNECTOR_ID_VGA:
134 			return SIGNAL_TYPE_RGB;
135 		case CONNECTOR_ID_HDMI_TYPE_A:
136 			return SIGNAL_TYPE_HDMI_TYPE_A;
137 		case CONNECTOR_ID_LVDS:
138 			return SIGNAL_TYPE_LVDS;
139 		case CONNECTOR_ID_DISPLAY_PORT:
140 		case CONNECTOR_ID_USBC:
141 			return SIGNAL_TYPE_DISPLAY_PORT;
142 		case CONNECTOR_ID_EDP:
143 			return SIGNAL_TYPE_EDP;
144 		default:
145 			return SIGNAL_TYPE_NONE;
146 		}
147 	} else if (downstream.type == OBJECT_TYPE_ENCODER) {
148 		switch (downstream.id) {
149 		case ENCODER_ID_EXTERNAL_NUTMEG:
150 		case ENCODER_ID_EXTERNAL_TRAVIS:
151 			return SIGNAL_TYPE_DISPLAY_PORT;
152 		default:
153 			return SIGNAL_TYPE_NONE;
154 		}
155 	}
156 
157 	return SIGNAL_TYPE_NONE;
158 }
159 
160 /*
161  * @brief
162  * Detect output sink type
163  */
164 static enum signal_type link_detect_sink_signal_type(struct dc_link *link,
165 					 enum dc_detect_reason reason)
166 {
167 	enum signal_type result;
168 	struct graphics_object_id enc_id;
169 
170 	if (link->is_dig_mapping_flexible)
171 		enc_id = (struct graphics_object_id){.id = ENCODER_ID_UNKNOWN};
172 	else
173 		enc_id = link->link_enc->id;
174 	result = get_basic_signal_type(enc_id, link->link_id);
175 
176 	/* Use basic signal type for link without physical connector. */
177 	if (link->ep_type != DISPLAY_ENDPOINT_PHY)
178 		return result;
179 
180 	/* Internal digital encoder will detect only dongles
181 	 * that require digital signal
182 	 */
183 
184 	/* Detection mechanism is different
185 	 * for different native connectors.
186 	 * LVDS connector supports only LVDS signal;
187 	 * PCIE is a bus slot, the actual connector needs to be detected first;
188 	 * eDP connector supports only eDP signal;
189 	 * HDMI should check straps for audio
190 	 */
191 
192 	/* PCIE detects the actual connector on add-on board */
193 	if (link->link_id.id == CONNECTOR_ID_PCIE) {
194 		/* ZAZTODO implement PCIE add-on card detection */
195 	}
196 
197 	switch (link->link_id.id) {
198 	case CONNECTOR_ID_HDMI_TYPE_A: {
199 		/* check audio support:
200 		 * if native HDMI is not supported, switch to DVI
201 		 */
202 		struct audio_support *aud_support =
203 					&link->dc->res_pool->audio_support;
204 
205 		if (!aud_support->hdmi_audio_native)
206 			if (link->link_id.id == CONNECTOR_ID_HDMI_TYPE_A)
207 				result = SIGNAL_TYPE_DVI_SINGLE_LINK;
208 	}
209 	break;
210 	case CONNECTOR_ID_DISPLAY_PORT:
211 	case CONNECTOR_ID_USBC: {
212 		/* DP HPD short pulse. Passive DP dongle will not
213 		 * have short pulse
214 		 */
215 		if (reason != DETECT_REASON_HPDRX) {
216 			/* Check whether DP signal detected: if not -
217 			 * we assume signal is DVI; it could be corrected
218 			 * to HDMI after dongle detection
219 			 */
220 			if (!dm_helpers_is_dp_sink_present(link))
221 				result = SIGNAL_TYPE_DVI_SINGLE_LINK;
222 		}
223 	}
224 	break;
225 	default:
226 	break;
227 	}
228 
229 	return result;
230 }
231 
232 static enum signal_type decide_signal_from_strap_and_dongle_type(enum display_dongle_type dongle_type,
233 								 struct audio_support *audio_support)
234 {
235 	enum signal_type signal = SIGNAL_TYPE_NONE;
236 
237 	switch (dongle_type) {
238 	case DISPLAY_DONGLE_DP_HDMI_DONGLE:
239 		if (audio_support->hdmi_audio_on_dongle)
240 			signal = SIGNAL_TYPE_HDMI_TYPE_A;
241 		else
242 			signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
243 		break;
244 	case DISPLAY_DONGLE_DP_DVI_DONGLE:
245 		signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
246 		break;
247 	case DISPLAY_DONGLE_DP_HDMI_MISMATCHED_DONGLE:
248 		if (audio_support->hdmi_audio_native)
249 			signal =  SIGNAL_TYPE_HDMI_TYPE_A;
250 		else
251 			signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
252 		break;
253 	default:
254 		signal = SIGNAL_TYPE_NONE;
255 		break;
256 	}
257 
258 	return signal;
259 }
260 
261 static void read_scdc_caps(struct ddc_service *ddc_service,
262 		struct dc_sink *sink)
263 {
264 	uint8_t slave_address = HDMI_SCDC_ADDRESS;
265 	uint8_t offset = HDMI_SCDC_MANUFACTURER_OUI;
266 
267 	link_query_ddc_data(ddc_service, slave_address, &offset,
268 			sizeof(offset), sink->scdc_caps.manufacturer_OUI.byte,
269 			sizeof(sink->scdc_caps.manufacturer_OUI.byte));
270 
271 	offset = HDMI_SCDC_DEVICE_ID;
272 
273 	link_query_ddc_data(ddc_service, slave_address, &offset,
274 			sizeof(offset), &(sink->scdc_caps.device_id.byte),
275 			sizeof(sink->scdc_caps.device_id.byte));
276 }
277 
278 static bool i2c_read(
279 	struct ddc_service *ddc,
280 	uint32_t address,
281 	uint8_t *buffer,
282 	uint32_t len)
283 {
284 	uint8_t offs_data = 0;
285 	struct i2c_payload payloads[2] = {
286 		{
287 		.write = true,
288 		.address = address,
289 		.length = 1,
290 		.data = &offs_data },
291 		{
292 		.write = false,
293 		.address = address,
294 		.length = len,
295 		.data = buffer } };
296 
297 	struct i2c_command command = {
298 		.payloads = payloads,
299 		.number_of_payloads = 2,
300 		.engine = DDC_I2C_COMMAND_ENGINE,
301 		.speed = ddc->ctx->dc->caps.i2c_speed_in_khz };
302 
303 	return dm_helpers_submit_i2c(
304 			ddc->ctx,
305 			ddc->link,
306 			&command);
307 }
308 
309 enum {
310 	DP_SINK_CAP_SIZE =
311 		DP_EDP_CONFIGURATION_CAP - DP_DPCD_REV + 1
312 };
313 
314 static void query_dp_dual_mode_adaptor(
315 	struct ddc_service *ddc,
316 	struct display_sink_capability *sink_cap)
317 {
318 	uint8_t i;
319 	bool is_valid_hdmi_signature;
320 	enum display_dongle_type *dongle = &sink_cap->dongle_type;
321 	uint8_t type2_dongle_buf[DP_ADAPTOR_TYPE2_SIZE];
322 	bool is_type2_dongle = false;
323 	int retry_count = 2;
324 	struct dp_hdmi_dongle_signature_data *dongle_signature;
325 
326 	/* Assume we have no valid DP passive dongle connected */
327 	*dongle = DISPLAY_DONGLE_NONE;
328 	sink_cap->max_hdmi_pixel_clock = DP_ADAPTOR_HDMI_SAFE_MAX_TMDS_CLK;
329 
330 	/* Read DP-HDMI dongle I2c (no response interpreted as DP-DVI dongle)*/
331 	if (!i2c_read(
332 		ddc,
333 		DP_HDMI_DONGLE_ADDRESS,
334 		type2_dongle_buf,
335 		sizeof(type2_dongle_buf))) {
336 		/* Passive HDMI dongles can sometimes fail here without retrying*/
337 		while (retry_count > 0) {
338 			if (i2c_read(ddc,
339 				DP_HDMI_DONGLE_ADDRESS,
340 				type2_dongle_buf,
341 				sizeof(type2_dongle_buf)))
342 				break;
343 			retry_count--;
344 		}
345 		if (retry_count == 0) {
346 			*dongle = DISPLAY_DONGLE_DP_DVI_DONGLE;
347 			sink_cap->max_hdmi_pixel_clock = DP_ADAPTOR_DVI_MAX_TMDS_CLK;
348 
349 			CONN_DATA_DETECT(ddc->link, type2_dongle_buf, sizeof(type2_dongle_buf),
350 					"DP-DVI passive dongle %dMhz: ",
351 					DP_ADAPTOR_DVI_MAX_TMDS_CLK / 1000);
352 			return;
353 		}
354 	}
355 
356 	/* Check if Type 2 dongle.*/
357 	if (type2_dongle_buf[DP_ADAPTOR_TYPE2_REG_ID] == DP_ADAPTOR_TYPE2_ID)
358 		is_type2_dongle = true;
359 
360 	dongle_signature =
361 		(struct dp_hdmi_dongle_signature_data *)type2_dongle_buf;
362 
363 	is_valid_hdmi_signature = true;
364 
365 	/* Check EOT */
366 	if (dongle_signature->eot != DP_HDMI_DONGLE_SIGNATURE_EOT) {
367 		is_valid_hdmi_signature = false;
368 	}
369 
370 	/* Check signature */
371 	for (i = 0; i < sizeof(dongle_signature->id); ++i) {
372 		/* If its not the right signature,
373 		 * skip mismatch in subversion byte.*/
374 		if (dongle_signature->id[i] !=
375 			dp_hdmi_dongle_signature_str[i] && i != 3) {
376 
377 			if (is_type2_dongle) {
378 				is_valid_hdmi_signature = false;
379 				break;
380 			}
381 
382 		}
383 	}
384 
385 	if (is_type2_dongle) {
386 		uint32_t max_tmds_clk =
387 			type2_dongle_buf[DP_ADAPTOR_TYPE2_REG_MAX_TMDS_CLK];
388 
389 		max_tmds_clk = max_tmds_clk * 2 + max_tmds_clk / 2;
390 
391 		if (0 == max_tmds_clk ||
392 				max_tmds_clk < DP_ADAPTOR_TYPE2_MIN_TMDS_CLK ||
393 				max_tmds_clk > DP_ADAPTOR_TYPE2_MAX_TMDS_CLK) {
394 			*dongle = DISPLAY_DONGLE_DP_DVI_DONGLE;
395 
396 			CONN_DATA_DETECT(ddc->link, type2_dongle_buf,
397 					sizeof(type2_dongle_buf),
398 					"DP-DVI passive dongle %dMhz: ",
399 					DP_ADAPTOR_DVI_MAX_TMDS_CLK / 1000);
400 		} else {
401 			if (is_valid_hdmi_signature == true) {
402 				*dongle = DISPLAY_DONGLE_DP_HDMI_DONGLE;
403 
404 				CONN_DATA_DETECT(ddc->link, type2_dongle_buf,
405 						sizeof(type2_dongle_buf),
406 						"Type 2 DP-HDMI passive dongle %dMhz: ",
407 						max_tmds_clk);
408 			} else {
409 				*dongle = DISPLAY_DONGLE_DP_HDMI_MISMATCHED_DONGLE;
410 
411 				CONN_DATA_DETECT(ddc->link, type2_dongle_buf,
412 						sizeof(type2_dongle_buf),
413 						"Type 2 DP-HDMI passive dongle (no signature) %dMhz: ",
414 						max_tmds_clk);
415 
416 			}
417 
418 			/* Multiply by 1000 to convert to kHz. */
419 			sink_cap->max_hdmi_pixel_clock =
420 				max_tmds_clk * 1000;
421 		}
422 		sink_cap->is_dongle_type_one = false;
423 
424 	} else {
425 		if (is_valid_hdmi_signature == true) {
426 			*dongle = DISPLAY_DONGLE_DP_HDMI_DONGLE;
427 
428 			CONN_DATA_DETECT(ddc->link, type2_dongle_buf,
429 					sizeof(type2_dongle_buf),
430 					"Type 1 DP-HDMI passive dongle %dMhz: ",
431 					sink_cap->max_hdmi_pixel_clock / 1000);
432 		} else {
433 			*dongle = DISPLAY_DONGLE_DP_HDMI_MISMATCHED_DONGLE;
434 
435 			CONN_DATA_DETECT(ddc->link, type2_dongle_buf,
436 					sizeof(type2_dongle_buf),
437 					"Type 1 DP-HDMI passive dongle (no signature) %dMhz: ",
438 					sink_cap->max_hdmi_pixel_clock / 1000);
439 		}
440 		sink_cap->is_dongle_type_one = true;
441 	}
442 
443 	return;
444 }
445 
446 static enum signal_type dp_passive_dongle_detection(struct ddc_service *ddc,
447 						    struct display_sink_capability *sink_cap,
448 						    struct audio_support *audio_support)
449 {
450 	query_dp_dual_mode_adaptor(ddc, sink_cap);
451 
452 	return decide_signal_from_strap_and_dongle_type(sink_cap->dongle_type,
453 							audio_support);
454 }
455 
456 static void link_disconnect_sink(struct dc_link *link)
457 {
458 	if (link->local_sink) {
459 		dc_sink_release(link->local_sink);
460 		link->local_sink = NULL;
461 	}
462 
463 	link->dpcd_sink_count = 0;
464 	//link->dpcd_caps.dpcd_rev.raw = 0;
465 }
466 
467 static void link_disconnect_remap(struct dc_sink *prev_sink, struct dc_link *link)
468 {
469 	dc_sink_release(link->local_sink);
470 	link->local_sink = prev_sink;
471 }
472 
473 static void query_hdcp_capability(enum signal_type signal, struct dc_link *link)
474 {
475 	struct hdcp_protection_message msg22;
476 	struct hdcp_protection_message msg14;
477 
478 	memset(&msg22, 0, sizeof(struct hdcp_protection_message));
479 	memset(&msg14, 0, sizeof(struct hdcp_protection_message));
480 	memset(link->hdcp_caps.rx_caps.raw, 0,
481 		sizeof(link->hdcp_caps.rx_caps.raw));
482 
483 	if ((link->connector_signal == SIGNAL_TYPE_DISPLAY_PORT &&
484 			link->ddc->transaction_type ==
485 			DDC_TRANSACTION_TYPE_I2C_OVER_AUX) ||
486 			link->connector_signal == SIGNAL_TYPE_EDP) {
487 		msg22.data = link->hdcp_caps.rx_caps.raw;
488 		msg22.length = sizeof(link->hdcp_caps.rx_caps.raw);
489 		msg22.msg_id = HDCP_MESSAGE_ID_RX_CAPS;
490 	} else {
491 		msg22.data = &link->hdcp_caps.rx_caps.fields.version;
492 		msg22.length = sizeof(link->hdcp_caps.rx_caps.fields.version);
493 		msg22.msg_id = HDCP_MESSAGE_ID_HDCP2VERSION;
494 	}
495 	msg22.version = HDCP_VERSION_22;
496 	msg22.link = HDCP_LINK_PRIMARY;
497 	msg22.max_retries = 5;
498 	dc_process_hdcp_msg(signal, link, &msg22);
499 
500 	if (signal == SIGNAL_TYPE_DISPLAY_PORT || signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
501 		msg14.data = &link->hdcp_caps.bcaps.raw;
502 		msg14.length = sizeof(link->hdcp_caps.bcaps.raw);
503 		msg14.msg_id = HDCP_MESSAGE_ID_READ_BCAPS;
504 		msg14.version = HDCP_VERSION_14;
505 		msg14.link = HDCP_LINK_PRIMARY;
506 		msg14.max_retries = 5;
507 
508 		dc_process_hdcp_msg(signal, link, &msg14);
509 	}
510 
511 }
512 static void read_current_link_settings_on_detect(struct dc_link *link)
513 {
514 	union lane_count_set lane_count_set = {0};
515 	uint8_t link_bw_set;
516 	uint8_t link_rate_set;
517 	uint32_t read_dpcd_retry_cnt = 10;
518 	enum dc_status status = DC_ERROR_UNEXPECTED;
519 	int i;
520 	union max_down_spread max_down_spread = {0};
521 
522 	// Read DPCD 00101h to find out the number of lanes currently set
523 	for (i = 0; i < read_dpcd_retry_cnt; i++) {
524 		status = core_link_read_dpcd(link,
525 					     DP_LANE_COUNT_SET,
526 					     &lane_count_set.raw,
527 					     sizeof(lane_count_set));
528 		/* First DPCD read after VDD ON can fail if the particular board
529 		 * does not have HPD pin wired correctly. So if DPCD read fails,
530 		 * which it should never happen, retry a few times. Target worst
531 		 * case scenario of 80 ms.
532 		 */
533 		if (status == DC_OK) {
534 			link->cur_link_settings.lane_count =
535 					lane_count_set.bits.LANE_COUNT_SET;
536 			break;
537 		}
538 
539 		msleep(8);
540 	}
541 
542 	// Read DPCD 00100h to find if standard link rates are set
543 	core_link_read_dpcd(link, DP_LINK_BW_SET,
544 			    &link_bw_set, sizeof(link_bw_set));
545 
546 	if (link_bw_set == 0) {
547 		if (link->connector_signal == SIGNAL_TYPE_EDP) {
548 			/* If standard link rates are not being used,
549 			 * Read DPCD 00115h to find the edp link rate set used
550 			 */
551 			core_link_read_dpcd(link, DP_LINK_RATE_SET,
552 					    &link_rate_set, sizeof(link_rate_set));
553 
554 			// edp_supported_link_rates_count = 0 for DP
555 			if (link_rate_set < link->dpcd_caps.edp_supported_link_rates_count) {
556 				link->cur_link_settings.link_rate =
557 					link->dpcd_caps.edp_supported_link_rates[link_rate_set];
558 				link->cur_link_settings.link_rate_set = link_rate_set;
559 				link->cur_link_settings.use_link_rate_set = true;
560 			}
561 		} else {
562 			// Link Rate not found. Seamless boot may not work.
563 			ASSERT(false);
564 		}
565 	} else {
566 		link->cur_link_settings.link_rate = link_bw_set;
567 		link->cur_link_settings.use_link_rate_set = false;
568 	}
569 	// Read DPCD 00003h to find the max down spread.
570 	core_link_read_dpcd(link, DP_MAX_DOWNSPREAD,
571 			    &max_down_spread.raw, sizeof(max_down_spread));
572 	link->cur_link_settings.link_spread =
573 		max_down_spread.bits.MAX_DOWN_SPREAD ?
574 		LINK_SPREAD_05_DOWNSPREAD_30KHZ : LINK_SPREAD_DISABLED;
575 }
576 
577 static bool detect_dp(struct dc_link *link,
578 		      struct display_sink_capability *sink_caps,
579 		      enum dc_detect_reason reason)
580 {
581 	struct audio_support *audio_support = &link->dc->res_pool->audio_support;
582 
583 	sink_caps->signal = link_detect_sink_signal_type(link, reason);
584 	sink_caps->transaction_type =
585 		get_ddc_transaction_type(sink_caps->signal);
586 
587 	if (sink_caps->transaction_type == DDC_TRANSACTION_TYPE_I2C_OVER_AUX) {
588 		sink_caps->signal = SIGNAL_TYPE_DISPLAY_PORT;
589 		if (!detect_dp_sink_caps(link))
590 			return false;
591 
592 		if (is_dp_branch_device(link))
593 			/* DP SST branch */
594 			link->type = dc_connection_sst_branch;
595 	} else {
596 		if (link->dc->debug.disable_dp_plus_plus_wa &&
597 				link->link_enc->features.flags.bits.IS_UHBR20_CAPABLE)
598 			return false;
599 
600 		/* DP passive dongles */
601 		sink_caps->signal = dp_passive_dongle_detection(link->ddc,
602 								sink_caps,
603 								audio_support);
604 		link->dpcd_caps.dongle_type = sink_caps->dongle_type;
605 		link->dpcd_caps.is_dongle_type_one = sink_caps->is_dongle_type_one;
606 		link->dpcd_caps.dpcd_rev.raw = 0;
607 	}
608 
609 	return true;
610 }
611 
612 static bool is_same_edid(struct dc_edid *old_edid, struct dc_edid *new_edid)
613 {
614 	if (old_edid->length != new_edid->length)
615 		return false;
616 
617 	if (new_edid->length == 0)
618 		return false;
619 
620 	return (memcmp(old_edid->raw_edid,
621 		       new_edid->raw_edid, new_edid->length) == 0);
622 }
623 
624 static bool wait_for_entering_dp_alt_mode(struct dc_link *link)
625 {
626 
627 	/**
628 	 * something is terribly wrong if time out is > 200ms. (5Hz)
629 	 * 500 microseconds * 400 tries us 200 ms
630 	 **/
631 	unsigned int sleep_time_in_microseconds = 500;
632 	unsigned int tries_allowed = 400;
633 	bool is_in_alt_mode;
634 	unsigned long long enter_timestamp;
635 	unsigned long long finish_timestamp;
636 	unsigned long long time_taken_in_ns;
637 	int tries_taken;
638 
639 	DC_LOGGER_INIT(link->ctx->logger);
640 
641 	/**
642 	 * this function will only exist if we are on dcn21 (is_in_alt_mode is a
643 	 *  function pointer, so checking to see if it is equal to 0 is the same
644 	 *  as checking to see if it is null
645 	 **/
646 	if (!link->link_enc->funcs->is_in_alt_mode)
647 		return true;
648 
649 	is_in_alt_mode = link->link_enc->funcs->is_in_alt_mode(link->link_enc);
650 	DC_LOG_DC("DP Alt mode state on HPD: %d\n", is_in_alt_mode);
651 
652 	if (is_in_alt_mode)
653 		return true;
654 
655 	enter_timestamp = dm_get_timestamp(link->ctx);
656 
657 	for (tries_taken = 0; tries_taken < tries_allowed; tries_taken++) {
658 		udelay(sleep_time_in_microseconds);
659 		/* ask the link if alt mode is enabled, if so return ok */
660 		if (link->link_enc->funcs->is_in_alt_mode(link->link_enc)) {
661 			finish_timestamp = dm_get_timestamp(link->ctx);
662 			time_taken_in_ns =
663 				dm_get_elapse_time_in_ns(link->ctx,
664 							 finish_timestamp,
665 							 enter_timestamp);
666 			DC_LOG_WARNING("Alt mode entered finished after %llu ms\n",
667 				       div_u64(time_taken_in_ns, 1000000));
668 			return true;
669 		}
670 	}
671 	finish_timestamp = dm_get_timestamp(link->ctx);
672 	time_taken_in_ns = dm_get_elapse_time_in_ns(link->ctx, finish_timestamp,
673 						    enter_timestamp);
674 	DC_LOG_WARNING("Alt mode has timed out after %llu ms\n",
675 			div_u64(time_taken_in_ns, 1000000));
676 	return false;
677 }
678 
679 static void apply_dpia_mst_dsc_always_on_wa(struct dc_link *link)
680 {
681 	/* Apply work around for tunneled MST on certain USB4 docks. Always use DSC if dock
682 	 * reports DSC support.
683 	 */
684 	if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA &&
685 			link->type == dc_connection_mst_branch &&
686 			link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_90CC24 &&
687 			link->dpcd_caps.branch_hw_revision == DP_BRANCH_HW_REV_20 &&
688 			link->dpcd_caps.dsc_caps.dsc_basic_caps.fields.dsc_support.DSC_SUPPORT &&
689 			!link->dc->debug.dpia_debug.bits.disable_mst_dsc_work_around)
690 		link->wa_flags.dpia_mst_dsc_always_on = true;
691 }
692 
693 static void revert_dpia_mst_dsc_always_on_wa(struct dc_link *link)
694 {
695 	/* Disable work around which keeps DSC on for tunneled MST on certain USB4 docks. */
696 	if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA)
697 		link->wa_flags.dpia_mst_dsc_always_on = false;
698 }
699 
700 static bool discover_dp_mst_topology(struct dc_link *link, enum dc_detect_reason reason)
701 {
702 	DC_LOGGER_INIT(link->ctx->logger);
703 
704 	LINK_INFO("link=%d, mst branch is now Connected\n",
705 		  link->link_index);
706 
707 	link->type = dc_connection_mst_branch;
708 	apply_dpia_mst_dsc_always_on_wa(link);
709 
710 	dm_helpers_dp_update_branch_info(link->ctx, link);
711 	if (dm_helpers_dp_mst_start_top_mgr(link->ctx,
712 			link, (reason == DETECT_REASON_BOOT || reason == DETECT_REASON_RESUMEFROMS3S4))) {
713 		link_disconnect_sink(link);
714 	} else {
715 		link->type = dc_connection_sst_branch;
716 	}
717 
718 	return link->type == dc_connection_mst_branch;
719 }
720 
721 bool link_reset_cur_dp_mst_topology(struct dc_link *link)
722 {
723 	DC_LOGGER_INIT(link->ctx->logger);
724 
725 	LINK_INFO("link=%d, mst branch is now Disconnected\n",
726 		  link->link_index);
727 
728 	revert_dpia_mst_dsc_always_on_wa(link);
729 	return dm_helpers_dp_mst_stop_top_mgr(link->ctx, link);
730 }
731 
732 static bool should_prepare_phy_clocks_for_link_verification(const struct dc *dc,
733 		enum dc_detect_reason reason)
734 {
735 	int i;
736 	bool can_apply_seamless_boot = false;
737 
738 	for (i = 0; i < dc->current_state->stream_count; i++) {
739 		if (dc->current_state->streams[i]->apply_seamless_boot_optimization) {
740 			can_apply_seamless_boot = true;
741 			break;
742 		}
743 	}
744 
745 	return !can_apply_seamless_boot && reason != DETECT_REASON_BOOT;
746 }
747 
748 static void prepare_phy_clocks_for_destructive_link_verification(const struct dc *dc)
749 {
750 	dc_z10_restore(dc);
751 	clk_mgr_exit_optimized_pwr_state(dc, dc->clk_mgr);
752 }
753 
754 static void restore_phy_clocks_for_destructive_link_verification(const struct dc *dc)
755 {
756 	clk_mgr_optimize_pwr_state(dc, dc->clk_mgr);
757 }
758 
759 static void verify_link_capability_destructive(struct dc_link *link,
760 		struct dc_sink *sink,
761 		enum dc_detect_reason reason)
762 {
763 	bool should_prepare_phy_clocks =
764 			should_prepare_phy_clocks_for_link_verification(link->dc, reason);
765 
766 	if (should_prepare_phy_clocks)
767 		prepare_phy_clocks_for_destructive_link_verification(link->dc);
768 
769 	if (dc_is_dp_signal(link->local_sink->sink_signal)) {
770 		struct dc_link_settings known_limit_link_setting =
771 				dp_get_max_link_cap(link);
772 		link_set_all_streams_dpms_off_for_link(link);
773 		dp_verify_link_cap_with_retries(
774 				link, &known_limit_link_setting,
775 				LINK_TRAINING_MAX_VERIFY_RETRY);
776 	} else {
777 		ASSERT(0);
778 	}
779 
780 	if (should_prepare_phy_clocks)
781 		restore_phy_clocks_for_destructive_link_verification(link->dc);
782 }
783 
784 static void verify_link_capability_non_destructive(struct dc_link *link)
785 {
786 	if (dc_is_dp_signal(link->local_sink->sink_signal)) {
787 		if (dc_is_embedded_signal(link->local_sink->sink_signal) ||
788 				link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA)
789 			/* TODO - should we check link encoder's max link caps here?
790 			 * How do we know which link encoder to check from?
791 			 */
792 			link->verified_link_cap = link->reported_link_cap;
793 		else
794 			link->verified_link_cap = dp_get_max_link_cap(link);
795 	}
796 }
797 
798 static bool should_verify_link_capability_destructively(struct dc_link *link,
799 		enum dc_detect_reason reason)
800 {
801 	bool destrictive = false;
802 	struct dc_link_settings max_link_cap;
803 	bool is_link_enc_unavailable = link->link_enc &&
804 			link->dc->res_pool->funcs->link_encs_assign &&
805 			!link_enc_cfg_is_link_enc_avail(
806 					link->ctx->dc,
807 					link->link_enc->preferred_engine,
808 					link);
809 
810 	if (dc_is_dp_signal(link->local_sink->sink_signal)) {
811 		max_link_cap = dp_get_max_link_cap(link);
812 		destrictive = true;
813 
814 		if (link->dc->debug.skip_detection_link_training ||
815 				dc_is_embedded_signal(link->local_sink->sink_signal) ||
816 				link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA) {
817 			destrictive = false;
818 		} else if (link_dp_get_encoding_format(&max_link_cap) ==
819 				DP_8b_10b_ENCODING) {
820 			if (link->dpcd_caps.is_mst_capable ||
821 					is_link_enc_unavailable) {
822 				destrictive = false;
823 			}
824 		}
825 	}
826 
827 	return destrictive;
828 }
829 
830 static void verify_link_capability(struct dc_link *link, struct dc_sink *sink,
831 		enum dc_detect_reason reason)
832 {
833 	if (should_verify_link_capability_destructively(link, reason))
834 		verify_link_capability_destructive(link, sink, reason);
835 	else
836 		verify_link_capability_non_destructive(link);
837 }
838 
839 /*
840  * detect_link_and_local_sink() - Detect if a sink is attached to a given link
841  *
842  * link->local_sink is created or destroyed as needed.
843  *
844  * This does not create remote sinks.
845  */
846 static bool detect_link_and_local_sink(struct dc_link *link,
847 				  enum dc_detect_reason reason)
848 {
849 	struct dc_sink_init_data sink_init_data = { 0 };
850 	struct display_sink_capability sink_caps = { 0 };
851 	uint32_t i;
852 	bool converter_disable_audio = false;
853 	struct audio_support *aud_support = &link->dc->res_pool->audio_support;
854 	bool same_edid = false;
855 	enum dc_edid_status edid_status;
856 	struct dc_context *dc_ctx = link->ctx;
857 	struct dc *dc = dc_ctx->dc;
858 	struct dc_sink *sink = NULL;
859 	struct dc_sink *prev_sink = NULL;
860 	struct dpcd_caps prev_dpcd_caps;
861 	enum dc_connection_type new_connection_type = dc_connection_none;
862 	enum dc_connection_type pre_connection_type = link->type;
863 	const uint32_t post_oui_delay = 30; // 30ms
864 
865 	DC_LOGGER_INIT(link->ctx->logger);
866 
867 	if (dc_is_virtual_signal(link->connector_signal))
868 		return false;
869 
870 	if (((link->connector_signal == SIGNAL_TYPE_LVDS ||
871 		link->connector_signal == SIGNAL_TYPE_EDP) &&
872 		(!link->dc->config.allow_edp_hotplug_detection)) &&
873 		link->local_sink) {
874 		// need to re-write OUI and brightness in resume case
875 		if (link->connector_signal == SIGNAL_TYPE_EDP &&
876 			(link->dpcd_sink_ext_caps.bits.oled == 1)) {
877 			dpcd_set_source_specific_data(link);
878 			msleep(post_oui_delay);
879 			set_cached_brightness_aux(link);
880 		}
881 
882 		return true;
883 	}
884 
885 	if (!link_detect_connection_type(link, &new_connection_type)) {
886 		BREAK_TO_DEBUGGER();
887 		return false;
888 	}
889 
890 	prev_sink = link->local_sink;
891 	if (prev_sink) {
892 		dc_sink_retain(prev_sink);
893 		memcpy(&prev_dpcd_caps, &link->dpcd_caps, sizeof(struct dpcd_caps));
894 	}
895 
896 	link_disconnect_sink(link);
897 	if (new_connection_type != dc_connection_none) {
898 		link->type = new_connection_type;
899 		link->link_state_valid = false;
900 
901 		/* From Disconnected-to-Connected. */
902 		switch (link->connector_signal) {
903 		case SIGNAL_TYPE_HDMI_TYPE_A: {
904 			sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
905 			if (aud_support->hdmi_audio_native)
906 				sink_caps.signal = SIGNAL_TYPE_HDMI_TYPE_A;
907 			else
908 				sink_caps.signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
909 			break;
910 		}
911 
912 		case SIGNAL_TYPE_DVI_SINGLE_LINK: {
913 			sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
914 			sink_caps.signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
915 			break;
916 		}
917 
918 		case SIGNAL_TYPE_DVI_DUAL_LINK: {
919 			sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
920 			sink_caps.signal = SIGNAL_TYPE_DVI_DUAL_LINK;
921 			break;
922 		}
923 
924 		case SIGNAL_TYPE_LVDS: {
925 			sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
926 			sink_caps.signal = SIGNAL_TYPE_LVDS;
927 			break;
928 		}
929 
930 		case SIGNAL_TYPE_EDP: {
931 			detect_edp_sink_caps(link);
932 			read_current_link_settings_on_detect(link);
933 
934 			/* Disable power sequence on MIPI panel + converter
935 			 */
936 			if (dc->config.enable_mipi_converter_optimization &&
937 				dc_ctx->dce_version == DCN_VERSION_3_01 &&
938 				link->dpcd_caps.sink_dev_id == DP_BRANCH_DEVICE_ID_0022B9 &&
939 				memcmp(&link->dpcd_caps.branch_dev_name, DP_SINK_BRANCH_DEV_NAME_7580,
940 					sizeof(link->dpcd_caps.branch_dev_name)) == 0) {
941 				dc->config.edp_no_power_sequencing = true;
942 
943 				if (!link->dpcd_caps.set_power_state_capable_edp)
944 					link->wa_flags.dp_keep_receiver_powered = true;
945 			}
946 
947 			sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C_OVER_AUX;
948 			sink_caps.signal = SIGNAL_TYPE_EDP;
949 			break;
950 		}
951 
952 		case SIGNAL_TYPE_DISPLAY_PORT: {
953 
954 			/* wa HPD high coming too early*/
955 			if (link->ep_type == DISPLAY_ENDPOINT_PHY &&
956 			    link->link_enc->features.flags.bits.DP_IS_USB_C == 1) {
957 
958 				/* if alt mode times out, return false */
959 				if (!wait_for_entering_dp_alt_mode(link))
960 					return false;
961 			}
962 
963 			if (!detect_dp(link, &sink_caps, reason)) {
964 				link->type = pre_connection_type;
965 
966 				if (prev_sink)
967 					dc_sink_release(prev_sink);
968 				return false;
969 			}
970 
971 			/* Active SST downstream branch device unplug*/
972 			if (link->type == dc_connection_sst_branch &&
973 			    link->dpcd_caps.sink_count.bits.SINK_COUNT == 0) {
974 				if (prev_sink)
975 					/* Downstream unplug */
976 					dc_sink_release(prev_sink);
977 				return true;
978 			}
979 
980 			/* disable audio for non DP to HDMI active sst converter */
981 			if (link->type == dc_connection_sst_branch &&
982 					is_dp_active_dongle(link) &&
983 					(link->dpcd_caps.dongle_type !=
984 							DISPLAY_DONGLE_DP_HDMI_CONVERTER))
985 				converter_disable_audio = true;
986 
987 			/* limited link rate to HBR3 for DPIA until we implement USB4 V2 */
988 			if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA &&
989 					link->reported_link_cap.link_rate > LINK_RATE_HIGH3)
990 				link->reported_link_cap.link_rate = LINK_RATE_HIGH3;
991 			break;
992 		}
993 
994 		default:
995 			DC_ERROR("Invalid connector type! signal:%d\n",
996 				 link->connector_signal);
997 			if (prev_sink)
998 				dc_sink_release(prev_sink);
999 			return false;
1000 		} /* switch() */
1001 
1002 		if (link->dpcd_caps.sink_count.bits.SINK_COUNT)
1003 			link->dpcd_sink_count =
1004 				link->dpcd_caps.sink_count.bits.SINK_COUNT;
1005 		else
1006 			link->dpcd_sink_count = 1;
1007 
1008 		set_ddc_transaction_type(link->ddc,
1009 						     sink_caps.transaction_type);
1010 
1011 		link->aux_mode =
1012 			link_is_in_aux_transaction_mode(link->ddc);
1013 
1014 		sink_init_data.link = link;
1015 		sink_init_data.sink_signal = sink_caps.signal;
1016 
1017 		sink = dc_sink_create(&sink_init_data);
1018 		if (!sink) {
1019 			DC_ERROR("Failed to create sink!\n");
1020 			if (prev_sink)
1021 				dc_sink_release(prev_sink);
1022 			return false;
1023 		}
1024 
1025 		sink->link->dongle_max_pix_clk = sink_caps.max_hdmi_pixel_clock;
1026 		sink->converter_disable_audio = converter_disable_audio;
1027 
1028 		/* dc_sink_create returns a new reference */
1029 		link->local_sink = sink;
1030 
1031 		edid_status = dm_helpers_read_local_edid(link->ctx,
1032 							 link, sink);
1033 
1034 		switch (edid_status) {
1035 		case EDID_BAD_CHECKSUM:
1036 			DC_LOG_ERROR("EDID checksum invalid.\n");
1037 			break;
1038 		case EDID_PARTIAL_VALID:
1039 			DC_LOG_ERROR("Partial EDID valid, abandon invalid blocks.\n");
1040 			break;
1041 		case EDID_NO_RESPONSE:
1042 			DC_LOG_ERROR("No EDID read.\n");
1043 			/*
1044 			 * Abort detection for non-DP connectors if we have
1045 			 * no EDID
1046 			 *
1047 			 * DP needs to report as connected if HDP is high
1048 			 * even if we have no EDID in order to go to
1049 			 * fail-safe mode
1050 			 */
1051 			if (dc_is_hdmi_signal(link->connector_signal) ||
1052 			    dc_is_dvi_signal(link->connector_signal)) {
1053 				if (prev_sink)
1054 					dc_sink_release(prev_sink);
1055 
1056 				return false;
1057 			}
1058 
1059 			if (link->type == dc_connection_sst_branch &&
1060 					link->dpcd_caps.dongle_type ==
1061 						DISPLAY_DONGLE_DP_VGA_CONVERTER &&
1062 					reason == DETECT_REASON_HPDRX) {
1063 				/* Abort detection for DP-VGA adapters when EDID
1064 				 * can't be read and detection reason is VGA-side
1065 				 * hotplug
1066 				 */
1067 				if (prev_sink)
1068 					dc_sink_release(prev_sink);
1069 				link_disconnect_sink(link);
1070 
1071 				return true;
1072 			}
1073 
1074 			break;
1075 		default:
1076 			break;
1077 		}
1078 
1079 		// Check if edid is the same
1080 		if ((prev_sink) &&
1081 		    (edid_status == EDID_THE_SAME || edid_status == EDID_OK))
1082 			same_edid = is_same_edid(&prev_sink->dc_edid,
1083 						 &sink->dc_edid);
1084 
1085 		if (sink->edid_caps.panel_patch.skip_scdc_overwrite)
1086 			link->ctx->dc->debug.hdmi20_disable = true;
1087 
1088 		if (dc_is_hdmi_signal(link->connector_signal))
1089 			read_scdc_caps(link->ddc, link->local_sink);
1090 
1091 		if (link->connector_signal == SIGNAL_TYPE_DISPLAY_PORT &&
1092 		    sink_caps.transaction_type ==
1093 		    DDC_TRANSACTION_TYPE_I2C_OVER_AUX) {
1094 			/*
1095 			 * TODO debug why certain monitors don't like
1096 			 *  two link trainings
1097 			 */
1098 			query_hdcp_capability(sink->sink_signal, link);
1099 		} else {
1100 			// If edid is the same, then discard new sink and revert back to original sink
1101 			if (same_edid) {
1102 				link_disconnect_remap(prev_sink, link);
1103 				sink = prev_sink;
1104 				prev_sink = NULL;
1105 			}
1106 			query_hdcp_capability(sink->sink_signal, link);
1107 		}
1108 
1109 		/* HDMI-DVI Dongle */
1110 		if (sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A &&
1111 		    !sink->edid_caps.edid_hdmi)
1112 			sink->sink_signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
1113 
1114 		if (link->local_sink && dc_is_dp_signal(sink_caps.signal))
1115 			dp_trace_init(link);
1116 
1117 		/* Connectivity log: detection */
1118 		for (i = 0; i < sink->dc_edid.length / DC_EDID_BLOCK_SIZE; i++) {
1119 			CONN_DATA_DETECT(link,
1120 					 &sink->dc_edid.raw_edid[i * DC_EDID_BLOCK_SIZE],
1121 					 DC_EDID_BLOCK_SIZE,
1122 					 "%s: [Block %d] ", sink->edid_caps.display_name, i);
1123 		}
1124 
1125 		DC_LOG_DETECTION_EDID_PARSER("%s: "
1126 			"manufacturer_id = %X, "
1127 			"product_id = %X, "
1128 			"serial_number = %X, "
1129 			"manufacture_week = %d, "
1130 			"manufacture_year = %d, "
1131 			"display_name = %s, "
1132 			"speaker_flag = %d, "
1133 			"audio_mode_count = %d\n",
1134 			__func__,
1135 			sink->edid_caps.manufacturer_id,
1136 			sink->edid_caps.product_id,
1137 			sink->edid_caps.serial_number,
1138 			sink->edid_caps.manufacture_week,
1139 			sink->edid_caps.manufacture_year,
1140 			sink->edid_caps.display_name,
1141 			sink->edid_caps.speaker_flags,
1142 			sink->edid_caps.audio_mode_count);
1143 
1144 		for (i = 0; i < sink->edid_caps.audio_mode_count; i++) {
1145 			DC_LOG_DETECTION_EDID_PARSER("%s: mode number = %d, "
1146 				"format_code = %d, "
1147 				"channel_count = %d, "
1148 				"sample_rate = %d, "
1149 				"sample_size = %d\n",
1150 				__func__,
1151 				i,
1152 				sink->edid_caps.audio_modes[i].format_code,
1153 				sink->edid_caps.audio_modes[i].channel_count,
1154 				sink->edid_caps.audio_modes[i].sample_rate,
1155 				sink->edid_caps.audio_modes[i].sample_size);
1156 		}
1157 
1158 		if (link->connector_signal == SIGNAL_TYPE_EDP) {
1159 			// Init dc_panel_config by HW config
1160 			if (dc_ctx->dc->res_pool->funcs->get_panel_config_defaults)
1161 				dc_ctx->dc->res_pool->funcs->get_panel_config_defaults(&link->panel_config);
1162 			// Pickup base DM settings
1163 			dm_helpers_init_panel_settings(dc_ctx, &link->panel_config, sink);
1164 			// Override dc_panel_config if system has specific settings
1165 			dm_helpers_override_panel_settings(dc_ctx, &link->panel_config);
1166 		}
1167 
1168 	} else {
1169 		/* From Connected-to-Disconnected. */
1170 		link->type = dc_connection_none;
1171 		sink_caps.signal = SIGNAL_TYPE_NONE;
1172 		memset(&link->hdcp_caps, 0, sizeof(struct hdcp_caps));
1173 		/* When we unplug a passive DP-HDMI dongle connection, dongle_max_pix_clk
1174 		 *  is not cleared. If we emulate a DP signal on this connection, it thinks
1175 		 *  the dongle is still there and limits the number of modes we can emulate.
1176 		 *  Clear dongle_max_pix_clk on disconnect to fix this
1177 		 */
1178 		link->dongle_max_pix_clk = 0;
1179 
1180 		dc_link_clear_dprx_states(link);
1181 		dp_trace_reset(link);
1182 	}
1183 
1184 	LINK_INFO("link=%d, dc_sink_in=%p is now %s prev_sink=%p edid same=%d\n",
1185 		  link->link_index, sink,
1186 		  (sink_caps.signal ==
1187 		   SIGNAL_TYPE_NONE ? "Disconnected" : "Connected"),
1188 		  prev_sink, same_edid);
1189 
1190 	if (prev_sink)
1191 		dc_sink_release(prev_sink);
1192 
1193 	return true;
1194 }
1195 
1196 /*
1197  * link_detect_connection_type() - Determine if there is a sink connected
1198  *
1199  * @type: Returned connection type
1200  * Does not detect downstream devices, such as MST sinks
1201  * or display connected through active dongles
1202  */
1203 bool link_detect_connection_type(struct dc_link *link, enum dc_connection_type *type)
1204 {
1205 	uint32_t is_hpd_high = 0;
1206 
1207 	if (link->connector_signal == SIGNAL_TYPE_LVDS) {
1208 		*type = dc_connection_single;
1209 		return true;
1210 	}
1211 
1212 	if (link->connector_signal == SIGNAL_TYPE_EDP) {
1213 		/*in case it is not on*/
1214 		if (!link->dc->config.edp_no_power_sequencing)
1215 			link->dc->hwss.edp_power_control(link, true);
1216 		link->dc->hwss.edp_wait_for_hpd_ready(link, true);
1217 	}
1218 
1219 	/* Link may not have physical HPD pin. */
1220 	if (link->ep_type != DISPLAY_ENDPOINT_PHY) {
1221 		if (link->is_hpd_pending || !dpia_query_hpd_status(link))
1222 			*type = dc_connection_none;
1223 		else
1224 			*type = dc_connection_single;
1225 
1226 		return true;
1227 	}
1228 
1229 
1230 	if (!query_hpd_status(link, &is_hpd_high))
1231 		goto hpd_gpio_failure;
1232 
1233 	if (is_hpd_high) {
1234 		*type = dc_connection_single;
1235 		/* TODO: need to do the actual detection */
1236 	} else {
1237 		*type = dc_connection_none;
1238 		if (link->connector_signal == SIGNAL_TYPE_EDP) {
1239 			/* eDP is not connected, power down it */
1240 			if (!link->dc->config.edp_no_power_sequencing)
1241 				link->dc->hwss.edp_power_control(link, false);
1242 		}
1243 	}
1244 
1245 	return true;
1246 
1247 hpd_gpio_failure:
1248 	return false;
1249 }
1250 
1251 bool link_detect(struct dc_link *link, enum dc_detect_reason reason)
1252 {
1253 	bool is_local_sink_detect_success;
1254 	bool is_delegated_to_mst_top_mgr = false;
1255 	enum dc_connection_type pre_link_type = link->type;
1256 
1257 	DC_LOGGER_INIT(link->ctx->logger);
1258 
1259 	is_local_sink_detect_success = detect_link_and_local_sink(link, reason);
1260 
1261 	if (is_local_sink_detect_success && link->local_sink)
1262 		verify_link_capability(link, link->local_sink, reason);
1263 
1264 	DC_LOG_DC("%s: link_index=%d is_local_sink_detect_success=%d pre_link_type=%d link_type=%d\n", __func__,
1265 				link->link_index, is_local_sink_detect_success, pre_link_type, link->type);
1266 
1267 	if (is_local_sink_detect_success && link->local_sink &&
1268 			dc_is_dp_signal(link->local_sink->sink_signal) &&
1269 			link->dpcd_caps.is_mst_capable)
1270 		is_delegated_to_mst_top_mgr = discover_dp_mst_topology(link, reason);
1271 
1272 	if (is_local_sink_detect_success &&
1273 			pre_link_type == dc_connection_mst_branch &&
1274 			link->type != dc_connection_mst_branch)
1275 		is_delegated_to_mst_top_mgr = link_reset_cur_dp_mst_topology(link);
1276 
1277 	return is_local_sink_detect_success && !is_delegated_to_mst_top_mgr;
1278 }
1279 
1280 void link_clear_dprx_states(struct dc_link *link)
1281 {
1282 	memset(&link->dprx_states, 0, sizeof(link->dprx_states));
1283 }
1284 
1285 bool link_is_hdcp14(struct dc_link *link, enum signal_type signal)
1286 {
1287 	bool ret = false;
1288 
1289 	switch (signal)	{
1290 	case SIGNAL_TYPE_DISPLAY_PORT:
1291 	case SIGNAL_TYPE_DISPLAY_PORT_MST:
1292 		ret = link->hdcp_caps.bcaps.bits.HDCP_CAPABLE;
1293 		break;
1294 	case SIGNAL_TYPE_DVI_SINGLE_LINK:
1295 	case SIGNAL_TYPE_DVI_DUAL_LINK:
1296 	case SIGNAL_TYPE_HDMI_TYPE_A:
1297 	/* HDMI doesn't tell us its HDCP(1.4) capability, so assume to always be capable,
1298 	 * we can poll for bksv but some displays have an issue with this. Since its so rare
1299 	 * for a display to not be 1.4 capable, this assumtion is ok
1300 	 */
1301 		ret = true;
1302 		break;
1303 	default:
1304 		break;
1305 	}
1306 	return ret;
1307 }
1308 
1309 bool link_is_hdcp22(struct dc_link *link, enum signal_type signal)
1310 {
1311 	bool ret = false;
1312 
1313 	switch (signal)	{
1314 	case SIGNAL_TYPE_DISPLAY_PORT:
1315 	case SIGNAL_TYPE_DISPLAY_PORT_MST:
1316 		ret = (link->hdcp_caps.bcaps.bits.HDCP_CAPABLE &&
1317 				link->hdcp_caps.rx_caps.fields.byte0.hdcp_capable &&
1318 				(link->hdcp_caps.rx_caps.fields.version == 0x2)) ? 1 : 0;
1319 		break;
1320 	case SIGNAL_TYPE_DVI_SINGLE_LINK:
1321 	case SIGNAL_TYPE_DVI_DUAL_LINK:
1322 	case SIGNAL_TYPE_HDMI_TYPE_A:
1323 		ret = (link->hdcp_caps.rx_caps.fields.version == 0x4) ? 1:0;
1324 		break;
1325 	default:
1326 		break;
1327 	}
1328 
1329 	return ret;
1330 }
1331 
1332 const struct dc_link_status *link_get_status(const struct dc_link *link)
1333 {
1334 	return &link->link_status;
1335 }
1336 
1337 
1338 static bool link_add_remote_sink_helper(struct dc_link *dc_link, struct dc_sink *sink)
1339 {
1340 	if (dc_link->sink_count >= MAX_SINKS_PER_LINK) {
1341 		BREAK_TO_DEBUGGER();
1342 		return false;
1343 	}
1344 
1345 	dc_sink_retain(sink);
1346 
1347 	dc_link->remote_sinks[dc_link->sink_count] = sink;
1348 	dc_link->sink_count++;
1349 
1350 	return true;
1351 }
1352 
1353 struct dc_sink *link_add_remote_sink(
1354 		struct dc_link *link,
1355 		const uint8_t *edid,
1356 		int len,
1357 		struct dc_sink_init_data *init_data)
1358 {
1359 	struct dc_sink *dc_sink;
1360 	enum dc_edid_status edid_status;
1361 
1362 	if (len > DC_MAX_EDID_BUFFER_SIZE) {
1363 		dm_error("Max EDID buffer size breached!\n");
1364 		return NULL;
1365 	}
1366 
1367 	if (!init_data) {
1368 		BREAK_TO_DEBUGGER();
1369 		return NULL;
1370 	}
1371 
1372 	if (!init_data->link) {
1373 		BREAK_TO_DEBUGGER();
1374 		return NULL;
1375 	}
1376 
1377 	dc_sink = dc_sink_create(init_data);
1378 
1379 	if (!dc_sink)
1380 		return NULL;
1381 
1382 	memmove(dc_sink->dc_edid.raw_edid, edid, len);
1383 	dc_sink->dc_edid.length = len;
1384 
1385 	if (!link_add_remote_sink_helper(
1386 			link,
1387 			dc_sink))
1388 		goto fail_add_sink;
1389 
1390 	edid_status = dm_helpers_parse_edid_caps(
1391 			link,
1392 			&dc_sink->dc_edid,
1393 			&dc_sink->edid_caps);
1394 
1395 	/*
1396 	 * Treat device as no EDID device if EDID
1397 	 * parsing fails
1398 	 */
1399 	if (edid_status != EDID_OK && edid_status != EDID_PARTIAL_VALID) {
1400 		dc_sink->dc_edid.length = 0;
1401 		dm_error("Bad EDID, status%d!\n", edid_status);
1402 	}
1403 
1404 	return dc_sink;
1405 
1406 fail_add_sink:
1407 	dc_sink_release(dc_sink);
1408 	return NULL;
1409 }
1410 
1411 void link_remove_remote_sink(struct dc_link *link, struct dc_sink *sink)
1412 {
1413 	int i;
1414 
1415 	if (!link->sink_count) {
1416 		BREAK_TO_DEBUGGER();
1417 		return;
1418 	}
1419 
1420 	for (i = 0; i < link->sink_count; i++) {
1421 		if (link->remote_sinks[i] == sink) {
1422 			dc_sink_release(sink);
1423 			link->remote_sinks[i] = NULL;
1424 
1425 			/* shrink array to remove empty place */
1426 			while (i < link->sink_count - 1) {
1427 				link->remote_sinks[i] = link->remote_sinks[i+1];
1428 				i++;
1429 			}
1430 			link->remote_sinks[i] = NULL;
1431 			link->sink_count--;
1432 			return;
1433 		}
1434 	}
1435 }
1436