1 /*
2  * Copyright (c) 2006-2008 Intel Corporation
3  * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
4  *
5  * DRM core CRTC related functions
6  *
7  * Permission to use, copy, modify, distribute, and sell this software and its
8  * documentation for any purpose is hereby granted without fee, provided that
9  * the above copyright notice appear in all copies and that both that copyright
10  * notice and this permission notice appear in supporting documentation, and
11  * that the name of the copyright holders not be used in advertising or
12  * publicity pertaining to distribution of the software without specific,
13  * written prior permission.  The copyright holders make no representations
14  * about the suitability of this software for any purpose.  It is provided "as
15  * is" without express or implied warranty.
16  *
17  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
18  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
19  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
20  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
21  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
22  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
23  * OF THIS SOFTWARE.
24  *
25  * Authors:
26  *      Keith Packard
27  *	Eric Anholt <eric@anholt.net>
28  *      Dave Airlie <airlied@linux.ie>
29  *      Jesse Barnes <jesse.barnes@intel.com>
30  */
31 
32 #include <linux/export.h>
33 #include <linux/kernel.h>
34 #include <linux/moduleparam.h>
35 
36 #include <drm/drm_atomic.h>
37 #include <drm/drm_atomic_helper.h>
38 #include <drm/drm_atomic_uapi.h>
39 #include <drm/drm_bridge.h>
40 #include <drm/drm_crtc.h>
41 #include <drm/drm_crtc_helper.h>
42 #include <drm/drm_drv.h>
43 #include <drm/drm_edid.h>
44 #include <drm/drm_encoder.h>
45 #include <drm/drm_fb_helper.h>
46 #include <drm/drm_fourcc.h>
47 #include <drm/drm_framebuffer.h>
48 #include <drm/drm_plane_helper.h>
49 #include <drm/drm_print.h>
50 #include <drm/drm_vblank.h>
51 
52 #include "drm_crtc_helper_internal.h"
53 
54 /**
55  * DOC: overview
56  *
57  * The CRTC modeset helper library provides a default set_config implementation
58  * in drm_crtc_helper_set_config(). Plus a few other convenience functions using
59  * the same callbacks which drivers can use to e.g. restore the modeset
60  * configuration on resume with drm_helper_resume_force_mode().
61  *
62  * Note that this helper library doesn't track the current power state of CRTCs
63  * and encoders. It can call callbacks like &drm_encoder_helper_funcs.dpms even
64  * though the hardware is already in the desired state. This deficiency has been
65  * fixed in the atomic helpers.
66  *
67  * The driver callbacks are mostly compatible with the atomic modeset helpers,
68  * except for the handling of the primary plane: Atomic helpers require that the
69  * primary plane is implemented as a real standalone plane and not directly tied
70  * to the CRTC state. For easier transition this library provides functions to
71  * implement the old semantics required by the CRTC helpers using the new plane
72  * and atomic helper callbacks.
73  *
74  * Drivers are strongly urged to convert to the atomic helpers (by way of first
75  * converting to the plane helpers). New drivers must not use these functions
76  * but need to implement the atomic interface instead, potentially using the
77  * atomic helpers for that.
78  *
79  * These legacy modeset helpers use the same function table structures as
80  * all other modesetting helpers. See the documentation for struct
81  * &drm_crtc_helper_funcs, &struct drm_encoder_helper_funcs and struct
82  * &drm_connector_helper_funcs.
83  */
84 
85 /**
86  * drm_helper_encoder_in_use - check if a given encoder is in use
87  * @encoder: encoder to check
88  *
89  * Checks whether @encoder is with the current mode setting output configuration
90  * in use by any connector. This doesn't mean that it is actually enabled since
91  * the DPMS state is tracked separately.
92  *
93  * Returns:
94  * True if @encoder is used, false otherwise.
95  */
96 bool drm_helper_encoder_in_use(struct drm_encoder *encoder)
97 {
98 	struct drm_connector *connector;
99 	struct drm_connector_list_iter conn_iter;
100 	struct drm_device *dev = encoder->dev;
101 
102 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
103 
104 	/*
105 	 * We can expect this mutex to be locked if we are not panicking.
106 	 * Locking is currently fubar in the panic handler.
107 	 */
108 	if (!oops_in_progress) {
109 		WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
110 		WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
111 	}
112 
113 
114 	drm_connector_list_iter_begin(dev, &conn_iter);
115 	drm_for_each_connector_iter(connector, &conn_iter) {
116 		if (connector->encoder == encoder) {
117 			drm_connector_list_iter_end(&conn_iter);
118 			return true;
119 		}
120 	}
121 	drm_connector_list_iter_end(&conn_iter);
122 	return false;
123 }
124 EXPORT_SYMBOL(drm_helper_encoder_in_use);
125 
126 /**
127  * drm_helper_crtc_in_use - check if a given CRTC is in a mode_config
128  * @crtc: CRTC to check
129  *
130  * Checks whether @crtc is with the current mode setting output configuration
131  * in use by any connector. This doesn't mean that it is actually enabled since
132  * the DPMS state is tracked separately.
133  *
134  * Returns:
135  * True if @crtc is used, false otherwise.
136  */
137 bool drm_helper_crtc_in_use(struct drm_crtc *crtc)
138 {
139 	struct drm_encoder *encoder;
140 	struct drm_device *dev = crtc->dev;
141 
142 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
143 
144 	/*
145 	 * We can expect this mutex to be locked if we are not panicking.
146 	 * Locking is currently fubar in the panic handler.
147 	 */
148 	if (!oops_in_progress)
149 		WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
150 
151 	drm_for_each_encoder(encoder, dev)
152 		if (encoder->crtc == crtc && drm_helper_encoder_in_use(encoder))
153 			return true;
154 	return false;
155 }
156 EXPORT_SYMBOL(drm_helper_crtc_in_use);
157 
158 static void
159 drm_encoder_disable(struct drm_encoder *encoder)
160 {
161 	const struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
162 
163 	if (!encoder_funcs)
164 		return;
165 
166 	if (encoder_funcs->disable)
167 		(*encoder_funcs->disable)(encoder);
168 	else if (encoder_funcs->dpms)
169 		(*encoder_funcs->dpms)(encoder, DRM_MODE_DPMS_OFF);
170 }
171 
172 static void __drm_helper_disable_unused_functions(struct drm_device *dev)
173 {
174 	struct drm_encoder *encoder;
175 	struct drm_crtc *crtc;
176 
177 	drm_warn_on_modeset_not_all_locked(dev);
178 
179 	drm_for_each_encoder(encoder, dev) {
180 		if (!drm_helper_encoder_in_use(encoder)) {
181 			drm_encoder_disable(encoder);
182 			/* disconnect encoder from any connector */
183 			encoder->crtc = NULL;
184 		}
185 	}
186 
187 	drm_for_each_crtc(crtc, dev) {
188 		const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
189 
190 		crtc->enabled = drm_helper_crtc_in_use(crtc);
191 		if (!crtc->enabled) {
192 			if (crtc_funcs->disable)
193 				(*crtc_funcs->disable)(crtc);
194 			else
195 				(*crtc_funcs->dpms)(crtc, DRM_MODE_DPMS_OFF);
196 			crtc->primary->fb = NULL;
197 		}
198 	}
199 }
200 
201 /**
202  * drm_helper_disable_unused_functions - disable unused objects
203  * @dev: DRM device
204  *
205  * This function walks through the entire mode setting configuration of @dev. It
206  * will remove any CRTC links of unused encoders and encoder links of
207  * disconnected connectors. Then it will disable all unused encoders and CRTCs
208  * either by calling their disable callback if available or by calling their
209  * dpms callback with DRM_MODE_DPMS_OFF.
210  *
211  * NOTE:
212  *
213  * This function is part of the legacy modeset helper library and will cause
214  * major confusion with atomic drivers. This is because atomic helpers guarantee
215  * to never call ->disable() hooks on a disabled function, or ->enable() hooks
216  * on an enabled functions. drm_helper_disable_unused_functions() on the other
217  * hand throws such guarantees into the wind and calls disable hooks
218  * unconditionally on unused functions.
219  */
220 void drm_helper_disable_unused_functions(struct drm_device *dev)
221 {
222 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
223 
224 	drm_modeset_lock_all(dev);
225 	__drm_helper_disable_unused_functions(dev);
226 	drm_modeset_unlock_all(dev);
227 }
228 EXPORT_SYMBOL(drm_helper_disable_unused_functions);
229 
230 /*
231  * Check the CRTC we're going to map each output to vs. its current
232  * CRTC.  If they don't match, we have to disable the output and the CRTC
233  * since the driver will have to re-route things.
234  */
235 static void
236 drm_crtc_prepare_encoders(struct drm_device *dev)
237 {
238 	const struct drm_encoder_helper_funcs *encoder_funcs;
239 	struct drm_encoder *encoder;
240 
241 	drm_for_each_encoder(encoder, dev) {
242 		encoder_funcs = encoder->helper_private;
243 		if (!encoder_funcs)
244 			continue;
245 
246 		/* Disable unused encoders */
247 		if (encoder->crtc == NULL)
248 			drm_encoder_disable(encoder);
249 	}
250 }
251 
252 /**
253  * drm_crtc_helper_set_mode - internal helper to set a mode
254  * @crtc: CRTC to program
255  * @mode: mode to use
256  * @x: horizontal offset into the surface
257  * @y: vertical offset into the surface
258  * @old_fb: old framebuffer, for cleanup
259  *
260  * Try to set @mode on @crtc.  Give @crtc and its associated connectors a chance
261  * to fixup or reject the mode prior to trying to set it. This is an internal
262  * helper that drivers could e.g. use to update properties that require the
263  * entire output pipe to be disabled and re-enabled in a new configuration. For
264  * example for changing whether audio is enabled on a hdmi link or for changing
265  * panel fitter or dither attributes. It is also called by the
266  * drm_crtc_helper_set_config() helper function to drive the mode setting
267  * sequence.
268  *
269  * Returns:
270  * True if the mode was set successfully, false otherwise.
271  */
272 bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
273 			      struct drm_display_mode *mode,
274 			      int x, int y,
275 			      struct drm_framebuffer *old_fb)
276 {
277 	struct drm_device *dev = crtc->dev;
278 	struct drm_display_mode *adjusted_mode, saved_mode, saved_hwmode;
279 	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
280 	const struct drm_encoder_helper_funcs *encoder_funcs;
281 	int saved_x, saved_y;
282 	bool saved_enabled;
283 	struct drm_encoder *encoder;
284 	bool ret = true;
285 
286 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
287 
288 	drm_warn_on_modeset_not_all_locked(dev);
289 
290 	saved_enabled = crtc->enabled;
291 	crtc->enabled = drm_helper_crtc_in_use(crtc);
292 	if (!crtc->enabled)
293 		return true;
294 
295 	adjusted_mode = drm_mode_duplicate(dev, mode);
296 	if (!adjusted_mode) {
297 		crtc->enabled = saved_enabled;
298 		return false;
299 	}
300 
301 	drm_mode_init(&saved_mode, &crtc->mode);
302 	drm_mode_init(&saved_hwmode, &crtc->hwmode);
303 	saved_x = crtc->x;
304 	saved_y = crtc->y;
305 
306 	/* Update crtc values up front so the driver can rely on them for mode
307 	 * setting.
308 	 */
309 	drm_mode_copy(&crtc->mode, mode);
310 	crtc->x = x;
311 	crtc->y = y;
312 
313 	/* Pass our mode to the connectors and the CRTC to give them a chance to
314 	 * adjust it according to limitations or connector properties, and also
315 	 * a chance to reject the mode entirely.
316 	 */
317 	drm_for_each_encoder(encoder, dev) {
318 
319 		if (encoder->crtc != crtc)
320 			continue;
321 
322 		encoder_funcs = encoder->helper_private;
323 		if (!encoder_funcs)
324 			continue;
325 
326 		encoder_funcs = encoder->helper_private;
327 		if (encoder_funcs->mode_fixup) {
328 			if (!(ret = encoder_funcs->mode_fixup(encoder, mode,
329 							      adjusted_mode))) {
330 				DRM_DEBUG_KMS("Encoder fixup failed\n");
331 				goto done;
332 			}
333 		}
334 	}
335 
336 	if (crtc_funcs->mode_fixup) {
337 		if (!(ret = crtc_funcs->mode_fixup(crtc, mode,
338 						adjusted_mode))) {
339 			DRM_DEBUG_KMS("CRTC fixup failed\n");
340 			goto done;
341 		}
342 	}
343 	DRM_DEBUG_KMS("[CRTC:%d:%s]\n", crtc->base.id, crtc->name);
344 
345 	drm_mode_copy(&crtc->hwmode, adjusted_mode);
346 
347 	/* Prepare the encoders and CRTCs before setting the mode. */
348 	drm_for_each_encoder(encoder, dev) {
349 
350 		if (encoder->crtc != crtc)
351 			continue;
352 
353 		encoder_funcs = encoder->helper_private;
354 		if (!encoder_funcs)
355 			continue;
356 
357 		/* Disable the encoders as the first thing we do. */
358 		if (encoder_funcs->prepare)
359 			encoder_funcs->prepare(encoder);
360 	}
361 
362 	drm_crtc_prepare_encoders(dev);
363 
364 	crtc_funcs->prepare(crtc);
365 
366 	/* Set up the DPLL and any encoders state that needs to adjust or depend
367 	 * on the DPLL.
368 	 */
369 	ret = !crtc_funcs->mode_set(crtc, mode, adjusted_mode, x, y, old_fb);
370 	if (!ret)
371 	    goto done;
372 
373 	drm_for_each_encoder(encoder, dev) {
374 
375 		if (encoder->crtc != crtc)
376 			continue;
377 
378 		encoder_funcs = encoder->helper_private;
379 		if (!encoder_funcs)
380 			continue;
381 
382 		DRM_DEBUG_KMS("[ENCODER:%d:%s] set [MODE:%s]\n",
383 			encoder->base.id, encoder->name, mode->name);
384 		if (encoder_funcs->mode_set)
385 			encoder_funcs->mode_set(encoder, mode, adjusted_mode);
386 	}
387 
388 	/* Now enable the clocks, plane, pipe, and connectors that we set up. */
389 	crtc_funcs->commit(crtc);
390 
391 	drm_for_each_encoder(encoder, dev) {
392 
393 		if (encoder->crtc != crtc)
394 			continue;
395 
396 		encoder_funcs = encoder->helper_private;
397 		if (!encoder_funcs)
398 			continue;
399 
400 		if (encoder_funcs->commit)
401 			encoder_funcs->commit(encoder);
402 	}
403 
404 	/* Calculate and store various constants which
405 	 * are later needed by vblank and swap-completion
406 	 * timestamping. They are derived from true hwmode.
407 	 */
408 	drm_calc_timestamping_constants(crtc, &crtc->hwmode);
409 
410 	/* FIXME: add subpixel order */
411 done:
412 	drm_mode_destroy(dev, adjusted_mode);
413 	if (!ret) {
414 		crtc->enabled = saved_enabled;
415 		drm_mode_copy(&crtc->mode, &saved_mode);
416 		drm_mode_copy(&crtc->hwmode, &saved_hwmode);
417 		crtc->x = saved_x;
418 		crtc->y = saved_y;
419 	}
420 
421 	return ret;
422 }
423 EXPORT_SYMBOL(drm_crtc_helper_set_mode);
424 
425 static void
426 drm_crtc_helper_disable(struct drm_crtc *crtc)
427 {
428 	struct drm_device *dev = crtc->dev;
429 	struct drm_connector *connector;
430 	struct drm_encoder *encoder;
431 
432 	/* Decouple all encoders and their attached connectors from this crtc */
433 	drm_for_each_encoder(encoder, dev) {
434 		struct drm_connector_list_iter conn_iter;
435 
436 		if (encoder->crtc != crtc)
437 			continue;
438 
439 		drm_connector_list_iter_begin(dev, &conn_iter);
440 		drm_for_each_connector_iter(connector, &conn_iter) {
441 			if (connector->encoder != encoder)
442 				continue;
443 
444 			connector->encoder = NULL;
445 
446 			/*
447 			 * drm_helper_disable_unused_functions() ought to be
448 			 * doing this, but since we've decoupled the encoder
449 			 * from the connector above, the required connection
450 			 * between them is henceforth no longer available.
451 			 */
452 			connector->dpms = DRM_MODE_DPMS_OFF;
453 
454 			/* we keep a reference while the encoder is bound */
455 			drm_connector_put(connector);
456 		}
457 		drm_connector_list_iter_end(&conn_iter);
458 	}
459 
460 	__drm_helper_disable_unused_functions(dev);
461 }
462 
463 /*
464  * For connectors that support multiple encoders, either the
465  * .atomic_best_encoder() or .best_encoder() operation must be implemented.
466  */
467 struct drm_encoder *
468 drm_connector_get_single_encoder(struct drm_connector *connector)
469 {
470 	struct drm_encoder *encoder;
471 
472 	WARN_ON(hweight32(connector->possible_encoders) > 1);
473 	drm_connector_for_each_possible_encoder(connector, encoder)
474 		return encoder;
475 
476 	return NULL;
477 }
478 
479 /**
480  * drm_crtc_helper_set_config - set a new config from userspace
481  * @set: mode set configuration
482  * @ctx: lock acquire context, not used here
483  *
484  * The drm_crtc_helper_set_config() helper function implements the of
485  * &drm_crtc_funcs.set_config callback for drivers using the legacy CRTC
486  * helpers.
487  *
488  * It first tries to locate the best encoder for each connector by calling the
489  * connector @drm_connector_helper_funcs.best_encoder helper operation.
490  *
491  * After locating the appropriate encoders, the helper function will call the
492  * mode_fixup encoder and CRTC helper operations to adjust the requested mode,
493  * or reject it completely in which case an error will be returned to the
494  * application. If the new configuration after mode adjustment is identical to
495  * the current configuration the helper function will return without performing
496  * any other operation.
497  *
498  * If the adjusted mode is identical to the current mode but changes to the
499  * frame buffer need to be applied, the drm_crtc_helper_set_config() function
500  * will call the CRTC &drm_crtc_helper_funcs.mode_set_base helper operation.
501  *
502  * If the adjusted mode differs from the current mode, or if the
503  * ->mode_set_base() helper operation is not provided, the helper function
504  * performs a full mode set sequence by calling the ->prepare(), ->mode_set()
505  * and ->commit() CRTC and encoder helper operations, in that order.
506  * Alternatively it can also use the dpms and disable helper operations. For
507  * details see &struct drm_crtc_helper_funcs and struct
508  * &drm_encoder_helper_funcs.
509  *
510  * This function is deprecated.  New drivers must implement atomic modeset
511  * support, for which this function is unsuitable. Instead drivers should use
512  * drm_atomic_helper_set_config().
513  *
514  * Returns:
515  * Returns 0 on success, negative errno numbers on failure.
516  */
517 int drm_crtc_helper_set_config(struct drm_mode_set *set,
518 			       struct drm_modeset_acquire_ctx *ctx)
519 {
520 	struct drm_device *dev;
521 	struct drm_crtc **save_encoder_crtcs, *new_crtc;
522 	struct drm_encoder **save_connector_encoders, *new_encoder, *encoder;
523 	bool mode_changed = false; /* if true do a full mode set */
524 	bool fb_changed = false; /* if true and !mode_changed just do a flip */
525 	struct drm_connector *connector;
526 	struct drm_connector_list_iter conn_iter;
527 	int count = 0, ro, fail = 0;
528 	const struct drm_crtc_helper_funcs *crtc_funcs;
529 	struct drm_mode_set save_set;
530 	int ret;
531 	int i;
532 
533 	DRM_DEBUG_KMS("\n");
534 
535 	BUG_ON(!set);
536 	BUG_ON(!set->crtc);
537 	BUG_ON(!set->crtc->helper_private);
538 
539 	/* Enforce sane interface api - has been abused by the fb helper. */
540 	BUG_ON(!set->mode && set->fb);
541 	BUG_ON(set->fb && set->num_connectors == 0);
542 
543 	crtc_funcs = set->crtc->helper_private;
544 
545 	dev = set->crtc->dev;
546 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
547 
548 	if (!set->mode)
549 		set->fb = NULL;
550 
551 	if (set->fb) {
552 		DRM_DEBUG_KMS("[CRTC:%d:%s] [FB:%d] #connectors=%d (x y) (%i %i)\n",
553 			      set->crtc->base.id, set->crtc->name,
554 			      set->fb->base.id,
555 			      (int)set->num_connectors, set->x, set->y);
556 	} else {
557 		DRM_DEBUG_KMS("[CRTC:%d:%s] [NOFB]\n",
558 			      set->crtc->base.id, set->crtc->name);
559 		drm_crtc_helper_disable(set->crtc);
560 		return 0;
561 	}
562 
563 	drm_warn_on_modeset_not_all_locked(dev);
564 
565 	/*
566 	 * Allocate space for the backup of all (non-pointer) encoder and
567 	 * connector data.
568 	 */
569 	save_encoder_crtcs = kcalloc(dev->mode_config.num_encoder,
570 				sizeof(struct drm_crtc *), GFP_KERNEL);
571 	if (!save_encoder_crtcs)
572 		return -ENOMEM;
573 
574 	save_connector_encoders = kcalloc(dev->mode_config.num_connector,
575 				sizeof(struct drm_encoder *), GFP_KERNEL);
576 	if (!save_connector_encoders) {
577 		kfree(save_encoder_crtcs);
578 		return -ENOMEM;
579 	}
580 
581 	/*
582 	 * Copy data. Note that driver private data is not affected.
583 	 * Should anything bad happen only the expected state is
584 	 * restored, not the drivers personal bookkeeping.
585 	 */
586 	count = 0;
587 	drm_for_each_encoder(encoder, dev) {
588 		save_encoder_crtcs[count++] = encoder->crtc;
589 	}
590 
591 	count = 0;
592 	drm_connector_list_iter_begin(dev, &conn_iter);
593 	drm_for_each_connector_iter(connector, &conn_iter)
594 		save_connector_encoders[count++] = connector->encoder;
595 	drm_connector_list_iter_end(&conn_iter);
596 
597 	save_set.crtc = set->crtc;
598 	save_set.mode = &set->crtc->mode;
599 	save_set.x = set->crtc->x;
600 	save_set.y = set->crtc->y;
601 	save_set.fb = set->crtc->primary->fb;
602 
603 	/* We should be able to check here if the fb has the same properties
604 	 * and then just flip_or_move it */
605 	if (set->crtc->primary->fb != set->fb) {
606 		/* If we have no fb then treat it as a full mode set */
607 		if (set->crtc->primary->fb == NULL) {
608 			DRM_DEBUG_KMS("crtc has no fb, full mode set\n");
609 			mode_changed = true;
610 		} else if (set->fb->format != set->crtc->primary->fb->format) {
611 			mode_changed = true;
612 		} else
613 			fb_changed = true;
614 	}
615 
616 	if (set->x != set->crtc->x || set->y != set->crtc->y)
617 		fb_changed = true;
618 
619 	if (!drm_mode_equal(set->mode, &set->crtc->mode)) {
620 		DRM_DEBUG_KMS("modes are different, full mode set\n");
621 		drm_mode_debug_printmodeline(&set->crtc->mode);
622 		drm_mode_debug_printmodeline(set->mode);
623 		mode_changed = true;
624 	}
625 
626 	/* take a reference on all unbound connectors in set, reuse the
627 	 * already taken reference for bound connectors
628 	 */
629 	for (ro = 0; ro < set->num_connectors; ro++) {
630 		if (set->connectors[ro]->encoder)
631 			continue;
632 		drm_connector_get(set->connectors[ro]);
633 	}
634 
635 	/* a) traverse passed in connector list and get encoders for them */
636 	count = 0;
637 	drm_connector_list_iter_begin(dev, &conn_iter);
638 	drm_for_each_connector_iter(connector, &conn_iter) {
639 		const struct drm_connector_helper_funcs *connector_funcs =
640 			connector->helper_private;
641 		new_encoder = connector->encoder;
642 		for (ro = 0; ro < set->num_connectors; ro++) {
643 			if (set->connectors[ro] == connector) {
644 				if (connector_funcs->best_encoder)
645 					new_encoder = connector_funcs->best_encoder(connector);
646 				else
647 					new_encoder = drm_connector_get_single_encoder(connector);
648 
649 				/* if we can't get an encoder for a connector
650 				   we are setting now - then fail */
651 				if (new_encoder == NULL)
652 					/* don't break so fail path works correct */
653 					fail = 1;
654 
655 				if (connector->dpms != DRM_MODE_DPMS_ON) {
656 					DRM_DEBUG_KMS("connector dpms not on, full mode switch\n");
657 					mode_changed = true;
658 				}
659 
660 				break;
661 			}
662 		}
663 
664 		if (new_encoder != connector->encoder) {
665 			DRM_DEBUG_KMS("encoder changed, full mode switch\n");
666 			mode_changed = true;
667 			/* If the encoder is reused for another connector, then
668 			 * the appropriate crtc will be set later.
669 			 */
670 			if (connector->encoder)
671 				connector->encoder->crtc = NULL;
672 			connector->encoder = new_encoder;
673 		}
674 	}
675 	drm_connector_list_iter_end(&conn_iter);
676 
677 	if (fail) {
678 		ret = -EINVAL;
679 		goto fail;
680 	}
681 
682 	count = 0;
683 	drm_connector_list_iter_begin(dev, &conn_iter);
684 	drm_for_each_connector_iter(connector, &conn_iter) {
685 		if (!connector->encoder)
686 			continue;
687 
688 		if (connector->encoder->crtc == set->crtc)
689 			new_crtc = NULL;
690 		else
691 			new_crtc = connector->encoder->crtc;
692 
693 		for (ro = 0; ro < set->num_connectors; ro++) {
694 			if (set->connectors[ro] == connector)
695 				new_crtc = set->crtc;
696 		}
697 
698 		/* Make sure the new CRTC will work with the encoder */
699 		if (new_crtc &&
700 		    !drm_encoder_crtc_ok(connector->encoder, new_crtc)) {
701 			ret = -EINVAL;
702 			drm_connector_list_iter_end(&conn_iter);
703 			goto fail;
704 		}
705 		if (new_crtc != connector->encoder->crtc) {
706 			DRM_DEBUG_KMS("crtc changed, full mode switch\n");
707 			mode_changed = true;
708 			connector->encoder->crtc = new_crtc;
709 		}
710 		if (new_crtc) {
711 			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [CRTC:%d:%s]\n",
712 				      connector->base.id, connector->name,
713 				      new_crtc->base.id, new_crtc->name);
714 		} else {
715 			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [NOCRTC]\n",
716 				      connector->base.id, connector->name);
717 		}
718 	}
719 	drm_connector_list_iter_end(&conn_iter);
720 
721 	/* mode_set_base is not a required function */
722 	if (fb_changed && !crtc_funcs->mode_set_base)
723 		mode_changed = true;
724 
725 	if (mode_changed) {
726 		if (drm_helper_crtc_in_use(set->crtc)) {
727 			DRM_DEBUG_KMS("attempting to set mode from"
728 					" userspace\n");
729 			drm_mode_debug_printmodeline(set->mode);
730 			set->crtc->primary->fb = set->fb;
731 			if (!drm_crtc_helper_set_mode(set->crtc, set->mode,
732 						      set->x, set->y,
733 						      save_set.fb)) {
734 				DRM_ERROR("failed to set mode on [CRTC:%d:%s]\n",
735 					  set->crtc->base.id, set->crtc->name);
736 				set->crtc->primary->fb = save_set.fb;
737 				ret = -EINVAL;
738 				goto fail;
739 			}
740 			DRM_DEBUG_KMS("Setting connector DPMS state to on\n");
741 			for (i = 0; i < set->num_connectors; i++) {
742 				DRM_DEBUG_KMS("\t[CONNECTOR:%d:%s] set DPMS on\n", set->connectors[i]->base.id,
743 					      set->connectors[i]->name);
744 				set->connectors[i]->funcs->dpms(set->connectors[i], DRM_MODE_DPMS_ON);
745 			}
746 		}
747 		__drm_helper_disable_unused_functions(dev);
748 	} else if (fb_changed) {
749 		set->crtc->x = set->x;
750 		set->crtc->y = set->y;
751 		set->crtc->primary->fb = set->fb;
752 		ret = crtc_funcs->mode_set_base(set->crtc,
753 						set->x, set->y, save_set.fb);
754 		if (ret != 0) {
755 			set->crtc->x = save_set.x;
756 			set->crtc->y = save_set.y;
757 			set->crtc->primary->fb = save_set.fb;
758 			goto fail;
759 		}
760 	}
761 
762 	kfree(save_connector_encoders);
763 	kfree(save_encoder_crtcs);
764 	return 0;
765 
766 fail:
767 	/* Restore all previous data. */
768 	count = 0;
769 	drm_for_each_encoder(encoder, dev) {
770 		encoder->crtc = save_encoder_crtcs[count++];
771 	}
772 
773 	count = 0;
774 	drm_connector_list_iter_begin(dev, &conn_iter);
775 	drm_for_each_connector_iter(connector, &conn_iter)
776 		connector->encoder = save_connector_encoders[count++];
777 	drm_connector_list_iter_end(&conn_iter);
778 
779 	/* after fail drop reference on all unbound connectors in set, let
780 	 * bound connectors keep their reference
781 	 */
782 	for (ro = 0; ro < set->num_connectors; ro++) {
783 		if (set->connectors[ro]->encoder)
784 			continue;
785 		drm_connector_put(set->connectors[ro]);
786 	}
787 
788 	/* Try to restore the config */
789 	if (mode_changed &&
790 	    !drm_crtc_helper_set_mode(save_set.crtc, save_set.mode, save_set.x,
791 				      save_set.y, save_set.fb))
792 		DRM_ERROR("failed to restore config after modeset failure\n");
793 
794 	kfree(save_connector_encoders);
795 	kfree(save_encoder_crtcs);
796 	return ret;
797 }
798 EXPORT_SYMBOL(drm_crtc_helper_set_config);
799 
800 static int drm_helper_choose_encoder_dpms(struct drm_encoder *encoder)
801 {
802 	int dpms = DRM_MODE_DPMS_OFF;
803 	struct drm_connector *connector;
804 	struct drm_connector_list_iter conn_iter;
805 	struct drm_device *dev = encoder->dev;
806 
807 	drm_connector_list_iter_begin(dev, &conn_iter);
808 	drm_for_each_connector_iter(connector, &conn_iter)
809 		if (connector->encoder == encoder)
810 			if (connector->dpms < dpms)
811 				dpms = connector->dpms;
812 	drm_connector_list_iter_end(&conn_iter);
813 
814 	return dpms;
815 }
816 
817 /* Helper which handles bridge ordering around encoder dpms */
818 static void drm_helper_encoder_dpms(struct drm_encoder *encoder, int mode)
819 {
820 	const struct drm_encoder_helper_funcs *encoder_funcs;
821 
822 	encoder_funcs = encoder->helper_private;
823 	if (!encoder_funcs)
824 		return;
825 
826 	if (encoder_funcs->dpms)
827 		encoder_funcs->dpms(encoder, mode);
828 }
829 
830 static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
831 {
832 	int dpms = DRM_MODE_DPMS_OFF;
833 	struct drm_connector *connector;
834 	struct drm_connector_list_iter conn_iter;
835 	struct drm_device *dev = crtc->dev;
836 
837 	drm_connector_list_iter_begin(dev, &conn_iter);
838 	drm_for_each_connector_iter(connector, &conn_iter)
839 		if (connector->encoder && connector->encoder->crtc == crtc)
840 			if (connector->dpms < dpms)
841 				dpms = connector->dpms;
842 	drm_connector_list_iter_end(&conn_iter);
843 
844 	return dpms;
845 }
846 
847 /**
848  * drm_helper_connector_dpms() - connector dpms helper implementation
849  * @connector: affected connector
850  * @mode: DPMS mode
851  *
852  * The drm_helper_connector_dpms() helper function implements the
853  * &drm_connector_funcs.dpms callback for drivers using the legacy CRTC
854  * helpers.
855  *
856  * This is the main helper function provided by the CRTC helper framework for
857  * implementing the DPMS connector attribute. It computes the new desired DPMS
858  * state for all encoders and CRTCs in the output mesh and calls the
859  * &drm_crtc_helper_funcs.dpms and &drm_encoder_helper_funcs.dpms callbacks
860  * provided by the driver.
861  *
862  * This function is deprecated.  New drivers must implement atomic modeset
863  * support, where DPMS is handled in the DRM core.
864  *
865  * Returns:
866  * Always returns 0.
867  */
868 int drm_helper_connector_dpms(struct drm_connector *connector, int mode)
869 {
870 	struct drm_encoder *encoder = connector->encoder;
871 	struct drm_crtc *crtc = encoder ? encoder->crtc : NULL;
872 	int old_dpms, encoder_dpms = DRM_MODE_DPMS_OFF;
873 
874 	WARN_ON(drm_drv_uses_atomic_modeset(connector->dev));
875 
876 	if (mode == connector->dpms)
877 		return 0;
878 
879 	old_dpms = connector->dpms;
880 	connector->dpms = mode;
881 
882 	if (encoder)
883 		encoder_dpms = drm_helper_choose_encoder_dpms(encoder);
884 
885 	/* from off to on, do crtc then encoder */
886 	if (mode < old_dpms) {
887 		if (crtc) {
888 			const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
889 
890 			if (crtc_funcs->dpms)
891 				(*crtc_funcs->dpms) (crtc,
892 						     drm_helper_choose_crtc_dpms(crtc));
893 		}
894 		if (encoder)
895 			drm_helper_encoder_dpms(encoder, encoder_dpms);
896 	}
897 
898 	/* from on to off, do encoder then crtc */
899 	if (mode > old_dpms) {
900 		if (encoder)
901 			drm_helper_encoder_dpms(encoder, encoder_dpms);
902 		if (crtc) {
903 			const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
904 
905 			if (crtc_funcs->dpms)
906 				(*crtc_funcs->dpms) (crtc,
907 						     drm_helper_choose_crtc_dpms(crtc));
908 		}
909 	}
910 
911 	return 0;
912 }
913 EXPORT_SYMBOL(drm_helper_connector_dpms);
914 
915 /**
916  * drm_helper_resume_force_mode - force-restore mode setting configuration
917  * @dev: drm_device which should be restored
918  *
919  * Drivers which use the mode setting helpers can use this function to
920  * force-restore the mode setting configuration e.g. on resume or when something
921  * else might have trampled over the hw state (like some overzealous old BIOSen
922  * tended to do).
923  *
924  * This helper doesn't provide a error return value since restoring the old
925  * config should never fail due to resource allocation issues since the driver
926  * has successfully set the restored configuration already. Hence this should
927  * boil down to the equivalent of a few dpms on calls, which also don't provide
928  * an error code.
929  *
930  * Drivers where simply restoring an old configuration again might fail (e.g.
931  * due to slight differences in allocating shared resources when the
932  * configuration is restored in a different order than when userspace set it up)
933  * need to use their own restore logic.
934  *
935  * This function is deprecated. New drivers should implement atomic mode-
936  * setting and use the atomic suspend/resume helpers.
937  *
938  * See also:
939  * drm_atomic_helper_suspend(), drm_atomic_helper_resume()
940  */
941 void drm_helper_resume_force_mode(struct drm_device *dev)
942 {
943 	struct drm_crtc *crtc;
944 	struct drm_encoder *encoder;
945 	const struct drm_crtc_helper_funcs *crtc_funcs;
946 	int encoder_dpms;
947 	bool ret;
948 
949 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
950 
951 	drm_modeset_lock_all(dev);
952 	drm_for_each_crtc(crtc, dev) {
953 
954 		if (!crtc->enabled)
955 			continue;
956 
957 		ret = drm_crtc_helper_set_mode(crtc, &crtc->mode,
958 					       crtc->x, crtc->y, crtc->primary->fb);
959 
960 		/* Restoring the old config should never fail! */
961 		if (ret == false)
962 			DRM_ERROR("failed to set mode on crtc %p\n", crtc);
963 
964 		/* Turn off outputs that were already powered off */
965 		if (drm_helper_choose_crtc_dpms(crtc)) {
966 			drm_for_each_encoder(encoder, dev) {
967 
968 				if(encoder->crtc != crtc)
969 					continue;
970 
971 				encoder_dpms = drm_helper_choose_encoder_dpms(
972 							encoder);
973 
974 				drm_helper_encoder_dpms(encoder, encoder_dpms);
975 			}
976 
977 			crtc_funcs = crtc->helper_private;
978 			if (crtc_funcs->dpms)
979 				(*crtc_funcs->dpms) (crtc,
980 						     drm_helper_choose_crtc_dpms(crtc));
981 		}
982 	}
983 
984 	/* disable the unused connectors while restoring the modesetting */
985 	__drm_helper_disable_unused_functions(dev);
986 	drm_modeset_unlock_all(dev);
987 }
988 EXPORT_SYMBOL(drm_helper_resume_force_mode);
989 
990 /**
991  * drm_helper_force_disable_all - Forcibly turn off all enabled CRTCs
992  * @dev: DRM device whose CRTCs to turn off
993  *
994  * Drivers may want to call this on unload to ensure that all displays are
995  * unlit and the GPU is in a consistent, low power state. Takes modeset locks.
996  *
997  * Note: This should only be used by non-atomic legacy drivers. For an atomic
998  * version look at drm_atomic_helper_shutdown().
999  *
1000  * Returns:
1001  * Zero on success, error code on failure.
1002  */
1003 int drm_helper_force_disable_all(struct drm_device *dev)
1004 {
1005 	struct drm_crtc *crtc;
1006 	int ret = 0;
1007 
1008 	drm_modeset_lock_all(dev);
1009 	drm_for_each_crtc(crtc, dev)
1010 		if (crtc->enabled) {
1011 			struct drm_mode_set set = {
1012 				.crtc = crtc,
1013 			};
1014 
1015 			ret = drm_mode_set_config_internal(&set);
1016 			if (ret)
1017 				goto out;
1018 		}
1019 out:
1020 	drm_modeset_unlock_all(dev);
1021 	return ret;
1022 }
1023 EXPORT_SYMBOL(drm_helper_force_disable_all);
1024