xref: /linux/drivers/gpu/drm/i915/display/intel_alpm.c (revision e78f70bad29c5ae1e1076698b690b15794e9b81e)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright 2024, Intel Corporation.
4  */
5 
6 #include <linux/debugfs.h>
7 
8 #include <drm/drm_print.h>
9 
10 #include "intel_alpm.h"
11 #include "intel_crtc.h"
12 #include "intel_de.h"
13 #include "intel_display_types.h"
14 #include "intel_dp.h"
15 #include "intel_dp_aux.h"
16 #include "intel_psr.h"
17 #include "intel_psr_regs.h"
18 
19 bool intel_alpm_aux_wake_supported(struct intel_dp *intel_dp)
20 {
21 	return intel_dp->alpm_dpcd & DP_ALPM_CAP;
22 }
23 
24 bool intel_alpm_aux_less_wake_supported(struct intel_dp *intel_dp)
25 {
26 	return intel_dp->alpm_dpcd & DP_ALPM_AUX_LESS_CAP;
27 }
28 
29 void intel_alpm_init(struct intel_dp *intel_dp)
30 {
31 	u8 dpcd;
32 
33 	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_RECEIVER_ALPM_CAP, &dpcd) < 0)
34 		return;
35 
36 	intel_dp->alpm_dpcd = dpcd;
37 	mutex_init(&intel_dp->alpm_parameters.lock);
38 }
39 
40 /*
41  * See Bspec: 71632 for the table
42  *
43  * Silence_period = tSilence,Min + ((tSilence,Max - tSilence,Min) / 2)
44  *
45  * Half cycle duration:
46  *
47  * Link rates 1.62 - 4.32 and tLFPS_Cycle = 70 ns
48  * FLOOR( (Link Rate * tLFPS_Cycle) / (2 * 10) )
49  *
50  * Link rates 5.4 - 8.1
51  * PORT_ALPM_LFPS_CTL[ LFPS Cycle Count ] = 10
52  * LFPS Period chosen is the mid-point of the min:max values from the table
53  * FLOOR( LFPS Period in Symbol clocks /
54  * (2 * PORT_ALPM_LFPS_CTL[ LFPS Cycle Count ]) )
55  */
56 static bool _lnl_get_silence_period_and_lfps_half_cycle(int link_rate,
57 							int *silence_period,
58 							int *lfps_half_cycle)
59 {
60 	switch (link_rate) {
61 	case 162000:
62 		*silence_period = 20;
63 		*lfps_half_cycle = 5;
64 		break;
65 	case 216000:
66 		*silence_period = 27;
67 		*lfps_half_cycle = 7;
68 		break;
69 	case 243000:
70 		*silence_period = 31;
71 		*lfps_half_cycle = 8;
72 		break;
73 	case 270000:
74 		*silence_period = 34;
75 		*lfps_half_cycle = 9;
76 		break;
77 	case 324000:
78 		*silence_period = 41;
79 		*lfps_half_cycle = 11;
80 		break;
81 	case 432000:
82 		*silence_period = 56;
83 		*lfps_half_cycle = 15;
84 		break;
85 	case 540000:
86 		*silence_period = 69;
87 		*lfps_half_cycle = 12;
88 		break;
89 	case 648000:
90 		*silence_period = 84;
91 		*lfps_half_cycle = 15;
92 		break;
93 	case 675000:
94 		*silence_period = 87;
95 		*lfps_half_cycle = 15;
96 		break;
97 	case 810000:
98 		*silence_period = 104;
99 		*lfps_half_cycle = 19;
100 		break;
101 	default:
102 		*silence_period = *lfps_half_cycle = -1;
103 		return false;
104 	}
105 	return true;
106 }
107 
108 /*
109  * AUX-Less Wake Time = CEILING( ((PHY P2 to P0) + tLFPS_Period, Max+
110  * tSilence, Max+ tPHY Establishment + tCDS) / tline)
111  * For the "PHY P2 to P0" latency see the PHY Power Control page
112  * (PHY P2 to P0) : https://gfxspecs.intel.com/Predator/Home/Index/68965
113  * : 12 us
114  * The tLFPS_Period, Max term is 800ns
115  * The tSilence, Max term is 180ns
116  * The tPHY Establishment (a.k.a. t1) term is 50us
117  * The tCDS term is 1 or 2 times t2
118  * t2 = Number ML_PHY_LOCK * tML_PHY_LOCK
119  * Number ML_PHY_LOCK = ( 7 + CEILING( 6.5us / tML_PHY_LOCK ) + 1)
120  * Rounding up the 6.5us padding to the next ML_PHY_LOCK boundary and
121  * adding the "+ 1" term ensures all ML_PHY_LOCK sequences that start
122  * within the CDS period complete within the CDS period regardless of
123  * entry into the period
124  * tML_PHY_LOCK = TPS4 Length * ( 10 / (Link Rate in MHz) )
125  * TPS4 Length = 252 Symbols
126  */
127 static int _lnl_compute_aux_less_wake_time(int port_clock)
128 {
129 	int tphy2_p2_to_p0 = 12 * 1000;
130 	int tlfps_period_max = 800;
131 	int tsilence_max = 180;
132 	int t1 = 50 * 1000;
133 	int tps4 = 252;
134 	/* port_clock is link rate in 10kbit/s units */
135 	int tml_phy_lock = 1000 * 1000 * tps4 / port_clock;
136 	int num_ml_phy_lock = 7 + DIV_ROUND_UP(6500, tml_phy_lock) + 1;
137 	int t2 = num_ml_phy_lock * tml_phy_lock;
138 	int tcds = 1 * t2;
139 
140 	return DIV_ROUND_UP(tphy2_p2_to_p0 + tlfps_period_max + tsilence_max +
141 			    t1 + tcds, 1000);
142 }
143 
144 static int
145 _lnl_compute_aux_less_alpm_params(struct intel_dp *intel_dp,
146 				  const struct intel_crtc_state *crtc_state)
147 {
148 	struct intel_display *display = to_intel_display(intel_dp);
149 	int aux_less_wake_time, aux_less_wake_lines, silence_period,
150 		lfps_half_cycle;
151 
152 	aux_less_wake_time =
153 		_lnl_compute_aux_less_wake_time(crtc_state->port_clock);
154 	aux_less_wake_lines = intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode,
155 						       aux_less_wake_time);
156 
157 	if (!_lnl_get_silence_period_and_lfps_half_cycle(crtc_state->port_clock,
158 							 &silence_period,
159 							 &lfps_half_cycle))
160 		return false;
161 
162 	if (aux_less_wake_lines > ALPM_CTL_AUX_LESS_WAKE_TIME_MASK ||
163 	    silence_period > PORT_ALPM_CTL_SILENCE_PERIOD_MASK ||
164 	    lfps_half_cycle > PORT_ALPM_LFPS_CTL_LAST_LFPS_HALF_CYCLE_DURATION_MASK)
165 		return false;
166 
167 	if (display->params.psr_safest_params)
168 		aux_less_wake_lines = ALPM_CTL_AUX_LESS_WAKE_TIME_MASK;
169 
170 	intel_dp->alpm_parameters.aux_less_wake_lines = aux_less_wake_lines;
171 	intel_dp->alpm_parameters.silence_period_sym_clocks = silence_period;
172 	intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms = lfps_half_cycle;
173 
174 	return true;
175 }
176 
177 static bool _lnl_compute_alpm_params(struct intel_dp *intel_dp,
178 				     const struct intel_crtc_state *crtc_state)
179 {
180 	struct intel_display *display = to_intel_display(intel_dp);
181 	int check_entry_lines;
182 
183 	if (DISPLAY_VER(display) < 20)
184 		return true;
185 
186 	/* ALPM Entry Check = 2 + CEILING( 5us /tline ) */
187 	check_entry_lines = 2 +
188 		intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode, 5);
189 
190 	if (check_entry_lines > 15)
191 		return false;
192 
193 	if (!_lnl_compute_aux_less_alpm_params(intel_dp, crtc_state))
194 		return false;
195 
196 	if (display->params.psr_safest_params)
197 		check_entry_lines = 15;
198 
199 	intel_dp->alpm_parameters.check_entry_lines = check_entry_lines;
200 
201 	return true;
202 }
203 
204 /*
205  * IO wake time for DISPLAY_VER < 12 is not directly mentioned in Bspec. There
206  * are 50 us io wake time and 32 us fast wake time. Clearly preharge pulses are
207  * not (improperly) included in 32 us fast wake time. 50 us - 32 us = 18 us.
208  */
209 static int skl_io_buffer_wake_time(void)
210 {
211 	return 18;
212 }
213 
214 static int tgl_io_buffer_wake_time(void)
215 {
216 	return 10;
217 }
218 
219 static int io_buffer_wake_time(const struct intel_crtc_state *crtc_state)
220 {
221 	struct intel_display *display = to_intel_display(crtc_state);
222 
223 	if (DISPLAY_VER(display) >= 12)
224 		return tgl_io_buffer_wake_time();
225 	else
226 		return skl_io_buffer_wake_time();
227 }
228 
229 bool intel_alpm_compute_params(struct intel_dp *intel_dp,
230 			       const struct intel_crtc_state *crtc_state)
231 {
232 	struct intel_display *display = to_intel_display(intel_dp);
233 	int io_wake_lines, io_wake_time, fast_wake_lines, fast_wake_time;
234 	int tfw_exit_latency = 20; /* eDP spec */
235 	int phy_wake = 4;	   /* eDP spec */
236 	int preamble = 8;	   /* eDP spec */
237 	int precharge = intel_dp_aux_fw_sync_len(intel_dp) - preamble;
238 	u8 max_wake_lines;
239 
240 	io_wake_time = max(precharge, io_buffer_wake_time(crtc_state)) +
241 		preamble + phy_wake + tfw_exit_latency;
242 	fast_wake_time = precharge + preamble + phy_wake +
243 		tfw_exit_latency;
244 
245 	if (DISPLAY_VER(display) >= 20)
246 		max_wake_lines = 68;
247 	else if (DISPLAY_VER(display) >= 12)
248 		max_wake_lines = 12;
249 	else
250 		max_wake_lines = 8;
251 
252 	io_wake_lines = intel_usecs_to_scanlines(
253 		&crtc_state->hw.adjusted_mode, io_wake_time);
254 	fast_wake_lines = intel_usecs_to_scanlines(
255 		&crtc_state->hw.adjusted_mode, fast_wake_time);
256 
257 	if (io_wake_lines > max_wake_lines ||
258 	    fast_wake_lines > max_wake_lines)
259 		return false;
260 
261 	if (!_lnl_compute_alpm_params(intel_dp, crtc_state))
262 		return false;
263 
264 	if (display->params.psr_safest_params)
265 		io_wake_lines = fast_wake_lines = max_wake_lines;
266 
267 	/* According to Bspec lower limit should be set as 7 lines. */
268 	intel_dp->alpm_parameters.io_wake_lines = max(io_wake_lines, 7);
269 	intel_dp->alpm_parameters.fast_wake_lines = max(fast_wake_lines, 7);
270 
271 	return true;
272 }
273 
274 void intel_alpm_lobf_compute_config(struct intel_dp *intel_dp,
275 				    struct intel_crtc_state *crtc_state,
276 				    struct drm_connector_state *conn_state)
277 {
278 	struct intel_display *display = to_intel_display(intel_dp);
279 	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
280 	int waketime_in_lines, first_sdp_position;
281 	int context_latency, guardband;
282 
283 	if (intel_dp->alpm_parameters.lobf_disable_debug) {
284 		drm_dbg_kms(display->drm, "LOBF is disabled by debug flag\n");
285 		return;
286 	}
287 
288 	if (intel_dp->alpm_parameters.sink_alpm_error)
289 		return;
290 
291 	if (!intel_dp_is_edp(intel_dp))
292 		return;
293 
294 	if (DISPLAY_VER(display) < 20)
295 		return;
296 
297 	if (!intel_dp->as_sdp_supported)
298 		return;
299 
300 	if (crtc_state->has_psr)
301 		return;
302 
303 	if (crtc_state->vrr.vmin != crtc_state->vrr.vmax ||
304 	    crtc_state->vrr.vmin != crtc_state->vrr.flipline)
305 		return;
306 
307 	if (!(intel_alpm_aux_wake_supported(intel_dp) ||
308 	      intel_alpm_aux_less_wake_supported(intel_dp)))
309 		return;
310 
311 	if (!intel_alpm_compute_params(intel_dp, crtc_state))
312 		return;
313 
314 	context_latency = adjusted_mode->crtc_vblank_start - adjusted_mode->crtc_vdisplay;
315 	guardband = adjusted_mode->crtc_vtotal -
316 		    adjusted_mode->crtc_vdisplay - context_latency;
317 	first_sdp_position = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vsync_start;
318 	if (intel_alpm_aux_less_wake_supported(intel_dp))
319 		waketime_in_lines = intel_dp->alpm_parameters.io_wake_lines;
320 	else
321 		waketime_in_lines = intel_dp->alpm_parameters.aux_less_wake_lines;
322 
323 	crtc_state->has_lobf = (context_latency + guardband) >
324 		(first_sdp_position + waketime_in_lines);
325 }
326 
327 static void lnl_alpm_configure(struct intel_dp *intel_dp,
328 			       const struct intel_crtc_state *crtc_state)
329 {
330 	struct intel_display *display = to_intel_display(intel_dp);
331 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
332 	enum port port = dp_to_dig_port(intel_dp)->base.port;
333 	u32 alpm_ctl;
334 
335 	if (DISPLAY_VER(display) < 20 || (!intel_psr_needs_alpm(intel_dp, crtc_state) &&
336 					  !crtc_state->has_lobf))
337 		return;
338 
339 	mutex_lock(&intel_dp->alpm_parameters.lock);
340 	/*
341 	 * Panel Replay on eDP is always using ALPM aux less. I.e. no need to
342 	 * check panel support at this point.
343 	 */
344 	if ((crtc_state->has_panel_replay && intel_dp_is_edp(intel_dp)) ||
345 	    (crtc_state->has_lobf && intel_alpm_aux_less_wake_supported(intel_dp))) {
346 		alpm_ctl = ALPM_CTL_ALPM_ENABLE |
347 			ALPM_CTL_ALPM_AUX_LESS_ENABLE |
348 			ALPM_CTL_AUX_LESS_SLEEP_HOLD_TIME_50_SYMBOLS |
349 			ALPM_CTL_AUX_LESS_WAKE_TIME(intel_dp->alpm_parameters.aux_less_wake_lines);
350 
351 		intel_de_write(display,
352 			       PORT_ALPM_CTL(port),
353 			       PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE |
354 			       PORT_ALPM_CTL_MAX_PHY_SWING_SETUP(15) |
355 			       PORT_ALPM_CTL_MAX_PHY_SWING_HOLD(0) |
356 			       PORT_ALPM_CTL_SILENCE_PERIOD(
357 				       intel_dp->alpm_parameters.silence_period_sym_clocks));
358 
359 		intel_de_write(display,
360 			       PORT_ALPM_LFPS_CTL(port),
361 			       PORT_ALPM_LFPS_CTL_LFPS_CYCLE_COUNT(10) |
362 			       PORT_ALPM_LFPS_CTL_LFPS_HALF_CYCLE_DURATION(
363 				       intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms) |
364 			       PORT_ALPM_LFPS_CTL_FIRST_LFPS_HALF_CYCLE_DURATION(
365 				       intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms) |
366 			       PORT_ALPM_LFPS_CTL_LAST_LFPS_HALF_CYCLE_DURATION(
367 				       intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms));
368 	} else {
369 		alpm_ctl = ALPM_CTL_EXTENDED_FAST_WAKE_ENABLE |
370 			ALPM_CTL_EXTENDED_FAST_WAKE_TIME(intel_dp->alpm_parameters.fast_wake_lines);
371 	}
372 
373 	if (crtc_state->has_lobf) {
374 		alpm_ctl |= ALPM_CTL_LOBF_ENABLE;
375 		drm_dbg_kms(display->drm, "Link off between frames (LOBF) enabled\n");
376 	}
377 
378 	alpm_ctl |= ALPM_CTL_ALPM_ENTRY_CHECK(intel_dp->alpm_parameters.check_entry_lines);
379 
380 	intel_de_write(display, ALPM_CTL(display, cpu_transcoder), alpm_ctl);
381 	mutex_unlock(&intel_dp->alpm_parameters.lock);
382 }
383 
384 void intel_alpm_configure(struct intel_dp *intel_dp,
385 			  const struct intel_crtc_state *crtc_state)
386 {
387 	lnl_alpm_configure(intel_dp, crtc_state);
388 	intel_dp->alpm_parameters.transcoder = crtc_state->cpu_transcoder;
389 }
390 
391 void intel_alpm_pre_plane_update(struct intel_atomic_state *state,
392 				 struct intel_crtc *crtc)
393 {
394 	struct intel_display *display = to_intel_display(state);
395 	const struct intel_crtc_state *crtc_state =
396 		intel_atomic_get_new_crtc_state(state, crtc);
397 	const struct intel_crtc_state *old_crtc_state =
398 		intel_atomic_get_old_crtc_state(state, crtc);
399 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
400 	struct intel_encoder *encoder;
401 
402 	if (DISPLAY_VER(display) < 20)
403 		return;
404 
405 	if (crtc_state->has_lobf || crtc_state->has_lobf == old_crtc_state->has_lobf)
406 		return;
407 
408 	for_each_intel_encoder_mask(display->drm, encoder,
409 				    crtc_state->uapi.encoder_mask) {
410 		struct intel_dp *intel_dp;
411 
412 		if (!intel_encoder_is_dp(encoder))
413 			continue;
414 
415 		intel_dp = enc_to_intel_dp(encoder);
416 
417 		if (!intel_dp_is_edp(intel_dp))
418 			continue;
419 
420 		if (old_crtc_state->has_lobf) {
421 			mutex_lock(&intel_dp->alpm_parameters.lock);
422 			intel_de_write(display, ALPM_CTL(display, cpu_transcoder), 0);
423 			drm_dbg_kms(display->drm, "Link off between frames (LOBF) disabled\n");
424 			mutex_unlock(&intel_dp->alpm_parameters.lock);
425 		}
426 	}
427 }
428 
429 void intel_alpm_enable_sink(struct intel_dp *intel_dp,
430 			    const struct intel_crtc_state *crtc_state)
431 {
432 	u8 val;
433 
434 	if (!intel_psr_needs_alpm(intel_dp, crtc_state) && !crtc_state->has_lobf)
435 		return;
436 
437 	val = DP_ALPM_ENABLE | DP_ALPM_LOCK_ERROR_IRQ_HPD_ENABLE;
438 
439 	if (crtc_state->has_panel_replay || (crtc_state->has_lobf &&
440 					     intel_alpm_aux_less_wake_supported(intel_dp)))
441 		val |= DP_ALPM_MODE_AUX_LESS;
442 
443 	drm_dp_dpcd_writeb(&intel_dp->aux, DP_RECEIVER_ALPM_CONFIG, val);
444 }
445 
446 void intel_alpm_post_plane_update(struct intel_atomic_state *state,
447 				  struct intel_crtc *crtc)
448 {
449 	struct intel_display *display = to_intel_display(state);
450 	const struct intel_crtc_state *crtc_state =
451 		intel_atomic_get_new_crtc_state(state, crtc);
452 	const struct intel_crtc_state *old_crtc_state =
453 		intel_atomic_get_old_crtc_state(state, crtc);
454 	struct intel_encoder *encoder;
455 
456 	if (crtc_state->has_psr || !crtc_state->has_lobf ||
457 	    crtc_state->has_lobf == old_crtc_state->has_lobf)
458 		return;
459 
460 	for_each_intel_encoder_mask(display->drm, encoder,
461 				    crtc_state->uapi.encoder_mask) {
462 		struct intel_dp *intel_dp;
463 
464 		if (!intel_encoder_is_dp(encoder))
465 			continue;
466 
467 		intel_dp = enc_to_intel_dp(encoder);
468 
469 		if (intel_dp_is_edp(intel_dp)) {
470 			intel_alpm_enable_sink(intel_dp, crtc_state);
471 			intel_alpm_configure(intel_dp, crtc_state);
472 		}
473 	}
474 }
475 
476 static int i915_edp_lobf_info_show(struct seq_file *m, void *data)
477 {
478 	struct intel_connector *connector = m->private;
479 	struct intel_display *display = to_intel_display(connector);
480 	struct drm_crtc *crtc;
481 	struct intel_crtc_state *crtc_state;
482 	enum transcoder cpu_transcoder;
483 	u32 alpm_ctl;
484 	int ret;
485 
486 	ret = drm_modeset_lock_single_interruptible(&display->drm->mode_config.connection_mutex);
487 	if (ret)
488 		return ret;
489 
490 	crtc = connector->base.state->crtc;
491 	if (connector->base.status != connector_status_connected || !crtc) {
492 		ret = -ENODEV;
493 		goto out;
494 	}
495 
496 	crtc_state = to_intel_crtc_state(crtc->state);
497 	cpu_transcoder = crtc_state->cpu_transcoder;
498 	alpm_ctl = intel_de_read(display, ALPM_CTL(display, cpu_transcoder));
499 	seq_printf(m, "LOBF status: %s\n", str_enabled_disabled(alpm_ctl & ALPM_CTL_LOBF_ENABLE));
500 	seq_printf(m, "Aux-wake alpm status: %s\n",
501 		   str_enabled_disabled(!(alpm_ctl & ALPM_CTL_ALPM_AUX_LESS_ENABLE)));
502 	seq_printf(m, "Aux-less alpm status: %s\n",
503 		   str_enabled_disabled(alpm_ctl & ALPM_CTL_ALPM_AUX_LESS_ENABLE));
504 out:
505 	drm_modeset_unlock(&display->drm->mode_config.connection_mutex);
506 
507 	return ret;
508 }
509 
510 DEFINE_SHOW_ATTRIBUTE(i915_edp_lobf_info);
511 
512 static int
513 i915_edp_lobf_debug_get(void *data, u64 *val)
514 {
515 	struct intel_connector *connector = data;
516 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
517 
518 	*val = intel_dp->alpm_parameters.lobf_disable_debug;
519 
520 	return 0;
521 }
522 
523 static int
524 i915_edp_lobf_debug_set(void *data, u64 val)
525 {
526 	struct intel_connector *connector = data;
527 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
528 
529 	intel_dp->alpm_parameters.lobf_disable_debug = val;
530 
531 	return 0;
532 }
533 
534 DEFINE_SIMPLE_ATTRIBUTE(i915_edp_lobf_debug_fops,
535 			i915_edp_lobf_debug_get, i915_edp_lobf_debug_set,
536 			"%llu\n");
537 
538 void intel_alpm_lobf_debugfs_add(struct intel_connector *connector)
539 {
540 	struct intel_display *display = to_intel_display(connector);
541 	struct dentry *root = connector->base.debugfs_entry;
542 
543 	if (DISPLAY_VER(display) < 20 ||
544 	    connector->base.connector_type != DRM_MODE_CONNECTOR_eDP)
545 		return;
546 
547 	debugfs_create_file("i915_edp_lobf_debug", 0644, root,
548 			    connector, &i915_edp_lobf_debug_fops);
549 
550 	debugfs_create_file("i915_edp_lobf_info", 0444, root,
551 			    connector, &i915_edp_lobf_info_fops);
552 }
553 
554 void intel_alpm_disable(struct intel_dp *intel_dp)
555 {
556 	struct intel_display *display = to_intel_display(intel_dp);
557 	enum transcoder cpu_transcoder = intel_dp->alpm_parameters.transcoder;
558 
559 	if (DISPLAY_VER(display) < 20 || !intel_dp->alpm_dpcd)
560 		return;
561 
562 	mutex_lock(&intel_dp->alpm_parameters.lock);
563 
564 	intel_de_rmw(display, ALPM_CTL(display, cpu_transcoder),
565 		     ALPM_CTL_ALPM_ENABLE | ALPM_CTL_LOBF_ENABLE |
566 		     ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
567 
568 	intel_de_rmw(display,
569 		     PORT_ALPM_CTL(cpu_transcoder),
570 		     PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
571 
572 	drm_dbg_kms(display->drm, "Disabling ALPM\n");
573 	mutex_unlock(&intel_dp->alpm_parameters.lock);
574 }
575 
576 bool intel_alpm_get_error(struct intel_dp *intel_dp)
577 {
578 	struct intel_display *display = to_intel_display(intel_dp);
579 	struct drm_dp_aux *aux = &intel_dp->aux;
580 	u8 val;
581 	int r;
582 
583 	r = drm_dp_dpcd_readb(aux, DP_RECEIVER_ALPM_STATUS, &val);
584 	if (r != 1) {
585 		drm_err(display->drm, "Error reading ALPM status\n");
586 		return true;
587 	}
588 
589 	if (val & DP_ALPM_LOCK_TIMEOUT_ERROR) {
590 		drm_dbg_kms(display->drm, "ALPM lock timeout error\n");
591 
592 		/* Clearing error */
593 		drm_dp_dpcd_writeb(aux, DP_RECEIVER_ALPM_STATUS, val);
594 		return true;
595 	}
596 
597 	return false;
598 }
599