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 #include <linux/dynamic_debug.h>
36 
37 #include <drm/drm_atomic.h>
38 #include <drm/drm_atomic_helper.h>
39 #include <drm/drm_atomic_uapi.h>
40 #include <drm/drm_bridge.h>
41 #include <drm/drm_crtc.h>
42 #include <drm/drm_crtc_helper.h>
43 #include <drm/drm_drv.h>
44 #include <drm/drm_edid.h>
45 #include <drm/drm_encoder.h>
46 #include <drm/drm_fb_helper.h>
47 #include <drm/drm_fourcc.h>
48 #include <drm/drm_framebuffer.h>
49 #include <drm/drm_print.h>
50 #include <drm/drm_vblank.h>
51 
52 #include "drm_crtc_helper_internal.h"
53 
54 DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
55 			"DRM_UT_CORE",
56 			"DRM_UT_DRIVER",
57 			"DRM_UT_KMS",
58 			"DRM_UT_PRIME",
59 			"DRM_UT_ATOMIC",
60 			"DRM_UT_VBL",
61 			"DRM_UT_STATE",
62 			"DRM_UT_LEASE",
63 			"DRM_UT_DP",
64 			"DRM_UT_DRMRES");
65 
66 /**
67  * DOC: overview
68  *
69  * The CRTC modeset helper library provides a default set_config implementation
70  * in drm_crtc_helper_set_config(). Plus a few other convenience functions using
71  * the same callbacks which drivers can use to e.g. restore the modeset
72  * configuration on resume with drm_helper_resume_force_mode().
73  *
74  * Note that this helper library doesn't track the current power state of CRTCs
75  * and encoders. It can call callbacks like &drm_encoder_helper_funcs.dpms even
76  * though the hardware is already in the desired state. This deficiency has been
77  * fixed in the atomic helpers.
78  *
79  * The driver callbacks are mostly compatible with the atomic modeset helpers,
80  * except for the handling of the primary plane: Atomic helpers require that the
81  * primary plane is implemented as a real standalone plane and not directly tied
82  * to the CRTC state. For easier transition this library provides functions to
83  * implement the old semantics required by the CRTC helpers using the new plane
84  * and atomic helper callbacks.
85  *
86  * Drivers are strongly urged to convert to the atomic helpers (by way of first
87  * converting to the plane helpers). New drivers must not use these functions
88  * but need to implement the atomic interface instead, potentially using the
89  * atomic helpers for that.
90  *
91  * These legacy modeset helpers use the same function table structures as
92  * all other modesetting helpers. See the documentation for struct
93  * &drm_crtc_helper_funcs, &struct drm_encoder_helper_funcs and struct
94  * &drm_connector_helper_funcs.
95  */
96 
97 /**
98  * drm_helper_encoder_in_use - check if a given encoder is in use
99  * @encoder: encoder to check
100  *
101  * Checks whether @encoder is with the current mode setting output configuration
102  * in use by any connector. This doesn't mean that it is actually enabled since
103  * the DPMS state is tracked separately.
104  *
105  * Returns:
106  * True if @encoder is used, false otherwise.
107  */
108 bool drm_helper_encoder_in_use(struct drm_encoder *encoder)
109 {
110 	struct drm_connector *connector;
111 	struct drm_connector_list_iter conn_iter;
112 	struct drm_device *dev = encoder->dev;
113 
114 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
115 
116 	/*
117 	 * We can expect this mutex to be locked if we are not panicking.
118 	 * Locking is currently fubar in the panic handler.
119 	 */
120 	if (!oops_in_progress) {
121 		WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
122 		WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
123 	}
124 
125 
126 	drm_connector_list_iter_begin(dev, &conn_iter);
127 	drm_for_each_connector_iter(connector, &conn_iter) {
128 		if (connector->encoder == encoder) {
129 			drm_connector_list_iter_end(&conn_iter);
130 			return true;
131 		}
132 	}
133 	drm_connector_list_iter_end(&conn_iter);
134 	return false;
135 }
136 EXPORT_SYMBOL(drm_helper_encoder_in_use);
137 
138 /**
139  * drm_helper_crtc_in_use - check if a given CRTC is in a mode_config
140  * @crtc: CRTC to check
141  *
142  * Checks whether @crtc is with the current mode setting output configuration
143  * in use by any connector. This doesn't mean that it is actually enabled since
144  * the DPMS state is tracked separately.
145  *
146  * Returns:
147  * True if @crtc is used, false otherwise.
148  */
149 bool drm_helper_crtc_in_use(struct drm_crtc *crtc)
150 {
151 	struct drm_encoder *encoder;
152 	struct drm_device *dev = crtc->dev;
153 
154 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
155 
156 	/*
157 	 * We can expect this mutex to be locked if we are not panicking.
158 	 * Locking is currently fubar in the panic handler.
159 	 */
160 	if (!oops_in_progress)
161 		WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
162 
163 	drm_for_each_encoder(encoder, dev)
164 		if (encoder->crtc == crtc && drm_helper_encoder_in_use(encoder))
165 			return true;
166 	return false;
167 }
168 EXPORT_SYMBOL(drm_helper_crtc_in_use);
169 
170 static void
171 drm_encoder_disable(struct drm_encoder *encoder)
172 {
173 	const struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
174 
175 	if (!encoder_funcs)
176 		return;
177 
178 	if (encoder_funcs->disable)
179 		(*encoder_funcs->disable)(encoder);
180 	else if (encoder_funcs->dpms)
181 		(*encoder_funcs->dpms)(encoder, DRM_MODE_DPMS_OFF);
182 }
183 
184 static void __drm_helper_disable_unused_functions(struct drm_device *dev)
185 {
186 	struct drm_encoder *encoder;
187 	struct drm_crtc *crtc;
188 
189 	drm_warn_on_modeset_not_all_locked(dev);
190 
191 	drm_for_each_encoder(encoder, dev) {
192 		if (!drm_helper_encoder_in_use(encoder)) {
193 			drm_encoder_disable(encoder);
194 			/* disconnect encoder from any connector */
195 			encoder->crtc = NULL;
196 		}
197 	}
198 
199 	drm_for_each_crtc(crtc, dev) {
200 		const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
201 
202 		crtc->enabled = drm_helper_crtc_in_use(crtc);
203 		if (!crtc->enabled) {
204 			if (crtc_funcs->disable)
205 				(*crtc_funcs->disable)(crtc);
206 			else
207 				(*crtc_funcs->dpms)(crtc, DRM_MODE_DPMS_OFF);
208 			crtc->primary->fb = NULL;
209 		}
210 	}
211 }
212 
213 /**
214  * drm_helper_disable_unused_functions - disable unused objects
215  * @dev: DRM device
216  *
217  * This function walks through the entire mode setting configuration of @dev. It
218  * will remove any CRTC links of unused encoders and encoder links of
219  * disconnected connectors. Then it will disable all unused encoders and CRTCs
220  * either by calling their disable callback if available or by calling their
221  * dpms callback with DRM_MODE_DPMS_OFF.
222  *
223  * NOTE:
224  *
225  * This function is part of the legacy modeset helper library and will cause
226  * major confusion with atomic drivers. This is because atomic helpers guarantee
227  * to never call ->disable() hooks on a disabled function, or ->enable() hooks
228  * on an enabled functions. drm_helper_disable_unused_functions() on the other
229  * hand throws such guarantees into the wind and calls disable hooks
230  * unconditionally on unused functions.
231  */
232 void drm_helper_disable_unused_functions(struct drm_device *dev)
233 {
234 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
235 
236 	drm_modeset_lock_all(dev);
237 	__drm_helper_disable_unused_functions(dev);
238 	drm_modeset_unlock_all(dev);
239 }
240 EXPORT_SYMBOL(drm_helper_disable_unused_functions);
241 
242 /*
243  * Check the CRTC we're going to map each output to vs. its current
244  * CRTC.  If they don't match, we have to disable the output and the CRTC
245  * since the driver will have to re-route things.
246  */
247 static void
248 drm_crtc_prepare_encoders(struct drm_device *dev)
249 {
250 	const struct drm_encoder_helper_funcs *encoder_funcs;
251 	struct drm_encoder *encoder;
252 
253 	drm_for_each_encoder(encoder, dev) {
254 		encoder_funcs = encoder->helper_private;
255 		if (!encoder_funcs)
256 			continue;
257 
258 		/* Disable unused encoders */
259 		if (encoder->crtc == NULL)
260 			drm_encoder_disable(encoder);
261 	}
262 }
263 
264 /**
265  * drm_crtc_helper_set_mode - internal helper to set a mode
266  * @crtc: CRTC to program
267  * @mode: mode to use
268  * @x: horizontal offset into the surface
269  * @y: vertical offset into the surface
270  * @old_fb: old framebuffer, for cleanup
271  *
272  * Try to set @mode on @crtc.  Give @crtc and its associated connectors a chance
273  * to fixup or reject the mode prior to trying to set it. This is an internal
274  * helper that drivers could e.g. use to update properties that require the
275  * entire output pipe to be disabled and re-enabled in a new configuration. For
276  * example for changing whether audio is enabled on a hdmi link or for changing
277  * panel fitter or dither attributes. It is also called by the
278  * drm_crtc_helper_set_config() helper function to drive the mode setting
279  * sequence.
280  *
281  * Returns:
282  * True if the mode was set successfully, false otherwise.
283  */
284 bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
285 			      struct drm_display_mode *mode,
286 			      int x, int y,
287 			      struct drm_framebuffer *old_fb)
288 {
289 	struct drm_device *dev = crtc->dev;
290 	struct drm_display_mode *adjusted_mode, saved_mode, saved_hwmode;
291 	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
292 	const struct drm_encoder_helper_funcs *encoder_funcs;
293 	int saved_x, saved_y;
294 	bool saved_enabled;
295 	struct drm_encoder *encoder;
296 	bool ret = true;
297 
298 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
299 
300 	drm_warn_on_modeset_not_all_locked(dev);
301 
302 	saved_enabled = crtc->enabled;
303 	crtc->enabled = drm_helper_crtc_in_use(crtc);
304 	if (!crtc->enabled)
305 		return true;
306 
307 	adjusted_mode = drm_mode_duplicate(dev, mode);
308 	if (!adjusted_mode) {
309 		crtc->enabled = saved_enabled;
310 		return false;
311 	}
312 
313 	drm_mode_init(&saved_mode, &crtc->mode);
314 	drm_mode_init(&saved_hwmode, &crtc->hwmode);
315 	saved_x = crtc->x;
316 	saved_y = crtc->y;
317 
318 	/* Update crtc values up front so the driver can rely on them for mode
319 	 * setting.
320 	 */
321 	drm_mode_copy(&crtc->mode, mode);
322 	crtc->x = x;
323 	crtc->y = y;
324 
325 	/* Pass our mode to the connectors and the CRTC to give them a chance to
326 	 * adjust it according to limitations or connector properties, and also
327 	 * a chance to reject the mode entirely.
328 	 */
329 	drm_for_each_encoder(encoder, dev) {
330 
331 		if (encoder->crtc != crtc)
332 			continue;
333 
334 		encoder_funcs = encoder->helper_private;
335 		if (!encoder_funcs)
336 			continue;
337 
338 		encoder_funcs = encoder->helper_private;
339 		if (encoder_funcs->mode_fixup) {
340 			if (!(ret = encoder_funcs->mode_fixup(encoder, mode,
341 							      adjusted_mode))) {
342 				DRM_DEBUG_KMS("Encoder fixup failed\n");
343 				goto done;
344 			}
345 		}
346 	}
347 
348 	if (crtc_funcs->mode_fixup) {
349 		if (!(ret = crtc_funcs->mode_fixup(crtc, mode,
350 						adjusted_mode))) {
351 			DRM_DEBUG_KMS("CRTC fixup failed\n");
352 			goto done;
353 		}
354 	}
355 	DRM_DEBUG_KMS("[CRTC:%d:%s]\n", crtc->base.id, crtc->name);
356 
357 	drm_mode_copy(&crtc->hwmode, adjusted_mode);
358 
359 	/* Prepare the encoders and CRTCs before setting the mode. */
360 	drm_for_each_encoder(encoder, dev) {
361 
362 		if (encoder->crtc != crtc)
363 			continue;
364 
365 		encoder_funcs = encoder->helper_private;
366 		if (!encoder_funcs)
367 			continue;
368 
369 		/* Disable the encoders as the first thing we do. */
370 		if (encoder_funcs->prepare)
371 			encoder_funcs->prepare(encoder);
372 	}
373 
374 	drm_crtc_prepare_encoders(dev);
375 
376 	crtc_funcs->prepare(crtc);
377 
378 	/* Set up the DPLL and any encoders state that needs to adjust or depend
379 	 * on the DPLL.
380 	 */
381 	ret = !crtc_funcs->mode_set(crtc, mode, adjusted_mode, x, y, old_fb);
382 	if (!ret)
383 	    goto done;
384 
385 	drm_for_each_encoder(encoder, dev) {
386 
387 		if (encoder->crtc != crtc)
388 			continue;
389 
390 		encoder_funcs = encoder->helper_private;
391 		if (!encoder_funcs)
392 			continue;
393 
394 		DRM_DEBUG_KMS("[ENCODER:%d:%s] set [MODE:%s]\n",
395 			encoder->base.id, encoder->name, mode->name);
396 		if (encoder_funcs->mode_set)
397 			encoder_funcs->mode_set(encoder, mode, adjusted_mode);
398 	}
399 
400 	/* Now enable the clocks, plane, pipe, and connectors that we set up. */
401 	crtc_funcs->commit(crtc);
402 
403 	drm_for_each_encoder(encoder, dev) {
404 
405 		if (encoder->crtc != crtc)
406 			continue;
407 
408 		encoder_funcs = encoder->helper_private;
409 		if (!encoder_funcs)
410 			continue;
411 
412 		if (encoder_funcs->commit)
413 			encoder_funcs->commit(encoder);
414 	}
415 
416 	/* Calculate and store various constants which
417 	 * are later needed by vblank and swap-completion
418 	 * timestamping. They are derived from true hwmode.
419 	 */
420 	drm_calc_timestamping_constants(crtc, &crtc->hwmode);
421 
422 	/* FIXME: add subpixel order */
423 done:
424 	drm_mode_destroy(dev, adjusted_mode);
425 	if (!ret) {
426 		crtc->enabled = saved_enabled;
427 		drm_mode_copy(&crtc->mode, &saved_mode);
428 		drm_mode_copy(&crtc->hwmode, &saved_hwmode);
429 		crtc->x = saved_x;
430 		crtc->y = saved_y;
431 	}
432 
433 	return ret;
434 }
435 EXPORT_SYMBOL(drm_crtc_helper_set_mode);
436 
437 static void
438 drm_crtc_helper_disable(struct drm_crtc *crtc)
439 {
440 	struct drm_device *dev = crtc->dev;
441 	struct drm_connector *connector;
442 	struct drm_encoder *encoder;
443 
444 	/* Decouple all encoders and their attached connectors from this crtc */
445 	drm_for_each_encoder(encoder, dev) {
446 		struct drm_connector_list_iter conn_iter;
447 
448 		if (encoder->crtc != crtc)
449 			continue;
450 
451 		drm_connector_list_iter_begin(dev, &conn_iter);
452 		drm_for_each_connector_iter(connector, &conn_iter) {
453 			if (connector->encoder != encoder)
454 				continue;
455 
456 			connector->encoder = NULL;
457 
458 			/*
459 			 * drm_helper_disable_unused_functions() ought to be
460 			 * doing this, but since we've decoupled the encoder
461 			 * from the connector above, the required connection
462 			 * between them is henceforth no longer available.
463 			 */
464 			connector->dpms = DRM_MODE_DPMS_OFF;
465 
466 			/* we keep a reference while the encoder is bound */
467 			drm_connector_put(connector);
468 		}
469 		drm_connector_list_iter_end(&conn_iter);
470 	}
471 
472 	__drm_helper_disable_unused_functions(dev);
473 }
474 
475 /*
476  * For connectors that support multiple encoders, either the
477  * .atomic_best_encoder() or .best_encoder() operation must be implemented.
478  */
479 struct drm_encoder *
480 drm_connector_get_single_encoder(struct drm_connector *connector)
481 {
482 	struct drm_encoder *encoder;
483 
484 	WARN_ON(hweight32(connector->possible_encoders) > 1);
485 	drm_connector_for_each_possible_encoder(connector, encoder)
486 		return encoder;
487 
488 	return NULL;
489 }
490 
491 /**
492  * drm_crtc_helper_set_config - set a new config from userspace
493  * @set: mode set configuration
494  * @ctx: lock acquire context, not used here
495  *
496  * The drm_crtc_helper_set_config() helper function implements the of
497  * &drm_crtc_funcs.set_config callback for drivers using the legacy CRTC
498  * helpers.
499  *
500  * It first tries to locate the best encoder for each connector by calling the
501  * connector @drm_connector_helper_funcs.best_encoder helper operation.
502  *
503  * After locating the appropriate encoders, the helper function will call the
504  * mode_fixup encoder and CRTC helper operations to adjust the requested mode,
505  * or reject it completely in which case an error will be returned to the
506  * application. If the new configuration after mode adjustment is identical to
507  * the current configuration the helper function will return without performing
508  * any other operation.
509  *
510  * If the adjusted mode is identical to the current mode but changes to the
511  * frame buffer need to be applied, the drm_crtc_helper_set_config() function
512  * will call the CRTC &drm_crtc_helper_funcs.mode_set_base helper operation.
513  *
514  * If the adjusted mode differs from the current mode, or if the
515  * ->mode_set_base() helper operation is not provided, the helper function
516  * performs a full mode set sequence by calling the ->prepare(), ->mode_set()
517  * and ->commit() CRTC and encoder helper operations, in that order.
518  * Alternatively it can also use the dpms and disable helper operations. For
519  * details see &struct drm_crtc_helper_funcs and struct
520  * &drm_encoder_helper_funcs.
521  *
522  * This function is deprecated.  New drivers must implement atomic modeset
523  * support, for which this function is unsuitable. Instead drivers should use
524  * drm_atomic_helper_set_config().
525  *
526  * Returns:
527  * Returns 0 on success, negative errno numbers on failure.
528  */
529 int drm_crtc_helper_set_config(struct drm_mode_set *set,
530 			       struct drm_modeset_acquire_ctx *ctx)
531 {
532 	struct drm_device *dev;
533 	struct drm_crtc **save_encoder_crtcs, *new_crtc;
534 	struct drm_encoder **save_connector_encoders, *new_encoder, *encoder;
535 	bool mode_changed = false; /* if true do a full mode set */
536 	bool fb_changed = false; /* if true and !mode_changed just do a flip */
537 	struct drm_connector *connector;
538 	struct drm_connector_list_iter conn_iter;
539 	int count = 0, ro, fail = 0;
540 	const struct drm_crtc_helper_funcs *crtc_funcs;
541 	struct drm_mode_set save_set;
542 	int ret;
543 	int i;
544 
545 	DRM_DEBUG_KMS("\n");
546 
547 	BUG_ON(!set);
548 	BUG_ON(!set->crtc);
549 	BUG_ON(!set->crtc->helper_private);
550 
551 	/* Enforce sane interface api - has been abused by the fb helper. */
552 	BUG_ON(!set->mode && set->fb);
553 	BUG_ON(set->fb && set->num_connectors == 0);
554 
555 	crtc_funcs = set->crtc->helper_private;
556 
557 	dev = set->crtc->dev;
558 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
559 
560 	if (!set->mode)
561 		set->fb = NULL;
562 
563 	if (set->fb) {
564 		DRM_DEBUG_KMS("[CRTC:%d:%s] [FB:%d] #connectors=%d (x y) (%i %i)\n",
565 			      set->crtc->base.id, set->crtc->name,
566 			      set->fb->base.id,
567 			      (int)set->num_connectors, set->x, set->y);
568 	} else {
569 		DRM_DEBUG_KMS("[CRTC:%d:%s] [NOFB]\n",
570 			      set->crtc->base.id, set->crtc->name);
571 		drm_crtc_helper_disable(set->crtc);
572 		return 0;
573 	}
574 
575 	drm_warn_on_modeset_not_all_locked(dev);
576 
577 	/*
578 	 * Allocate space for the backup of all (non-pointer) encoder and
579 	 * connector data.
580 	 */
581 	save_encoder_crtcs = kcalloc(dev->mode_config.num_encoder,
582 				sizeof(struct drm_crtc *), GFP_KERNEL);
583 	if (!save_encoder_crtcs)
584 		return -ENOMEM;
585 
586 	save_connector_encoders = kcalloc(dev->mode_config.num_connector,
587 				sizeof(struct drm_encoder *), GFP_KERNEL);
588 	if (!save_connector_encoders) {
589 		kfree(save_encoder_crtcs);
590 		return -ENOMEM;
591 	}
592 
593 	/*
594 	 * Copy data. Note that driver private data is not affected.
595 	 * Should anything bad happen only the expected state is
596 	 * restored, not the drivers personal bookkeeping.
597 	 */
598 	count = 0;
599 	drm_for_each_encoder(encoder, dev) {
600 		save_encoder_crtcs[count++] = encoder->crtc;
601 	}
602 
603 	count = 0;
604 	drm_connector_list_iter_begin(dev, &conn_iter);
605 	drm_for_each_connector_iter(connector, &conn_iter)
606 		save_connector_encoders[count++] = connector->encoder;
607 	drm_connector_list_iter_end(&conn_iter);
608 
609 	save_set.crtc = set->crtc;
610 	save_set.mode = &set->crtc->mode;
611 	save_set.x = set->crtc->x;
612 	save_set.y = set->crtc->y;
613 	save_set.fb = set->crtc->primary->fb;
614 
615 	/* We should be able to check here if the fb has the same properties
616 	 * and then just flip_or_move it */
617 	if (set->crtc->primary->fb != set->fb) {
618 		/* If we have no fb then treat it as a full mode set */
619 		if (set->crtc->primary->fb == NULL) {
620 			DRM_DEBUG_KMS("crtc has no fb, full mode set\n");
621 			mode_changed = true;
622 		} else if (set->fb->format != set->crtc->primary->fb->format) {
623 			mode_changed = true;
624 		} else
625 			fb_changed = true;
626 	}
627 
628 	if (set->x != set->crtc->x || set->y != set->crtc->y)
629 		fb_changed = true;
630 
631 	if (!drm_mode_equal(set->mode, &set->crtc->mode)) {
632 		DRM_DEBUG_KMS("modes are different, full mode set\n");
633 		drm_mode_debug_printmodeline(&set->crtc->mode);
634 		drm_mode_debug_printmodeline(set->mode);
635 		mode_changed = true;
636 	}
637 
638 	/* take a reference on all unbound connectors in set, reuse the
639 	 * already taken reference for bound connectors
640 	 */
641 	for (ro = 0; ro < set->num_connectors; ro++) {
642 		if (set->connectors[ro]->encoder)
643 			continue;
644 		drm_connector_get(set->connectors[ro]);
645 	}
646 
647 	/* a) traverse passed in connector list and get encoders for them */
648 	count = 0;
649 	drm_connector_list_iter_begin(dev, &conn_iter);
650 	drm_for_each_connector_iter(connector, &conn_iter) {
651 		const struct drm_connector_helper_funcs *connector_funcs =
652 			connector->helper_private;
653 		new_encoder = connector->encoder;
654 		for (ro = 0; ro < set->num_connectors; ro++) {
655 			if (set->connectors[ro] == connector) {
656 				if (connector_funcs->best_encoder)
657 					new_encoder = connector_funcs->best_encoder(connector);
658 				else
659 					new_encoder = drm_connector_get_single_encoder(connector);
660 
661 				/* if we can't get an encoder for a connector
662 				   we are setting now - then fail */
663 				if (new_encoder == NULL)
664 					/* don't break so fail path works correct */
665 					fail = 1;
666 
667 				if (connector->dpms != DRM_MODE_DPMS_ON) {
668 					DRM_DEBUG_KMS("connector dpms not on, full mode switch\n");
669 					mode_changed = true;
670 				}
671 
672 				break;
673 			}
674 		}
675 
676 		if (new_encoder != connector->encoder) {
677 			DRM_DEBUG_KMS("encoder changed, full mode switch\n");
678 			mode_changed = true;
679 			/* If the encoder is reused for another connector, then
680 			 * the appropriate crtc will be set later.
681 			 */
682 			if (connector->encoder)
683 				connector->encoder->crtc = NULL;
684 			connector->encoder = new_encoder;
685 		}
686 	}
687 	drm_connector_list_iter_end(&conn_iter);
688 
689 	if (fail) {
690 		ret = -EINVAL;
691 		goto fail;
692 	}
693 
694 	count = 0;
695 	drm_connector_list_iter_begin(dev, &conn_iter);
696 	drm_for_each_connector_iter(connector, &conn_iter) {
697 		if (!connector->encoder)
698 			continue;
699 
700 		if (connector->encoder->crtc == set->crtc)
701 			new_crtc = NULL;
702 		else
703 			new_crtc = connector->encoder->crtc;
704 
705 		for (ro = 0; ro < set->num_connectors; ro++) {
706 			if (set->connectors[ro] == connector)
707 				new_crtc = set->crtc;
708 		}
709 
710 		/* Make sure the new CRTC will work with the encoder */
711 		if (new_crtc &&
712 		    !drm_encoder_crtc_ok(connector->encoder, new_crtc)) {
713 			ret = -EINVAL;
714 			drm_connector_list_iter_end(&conn_iter);
715 			goto fail;
716 		}
717 		if (new_crtc != connector->encoder->crtc) {
718 			DRM_DEBUG_KMS("crtc changed, full mode switch\n");
719 			mode_changed = true;
720 			connector->encoder->crtc = new_crtc;
721 		}
722 		if (new_crtc) {
723 			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [CRTC:%d:%s]\n",
724 				      connector->base.id, connector->name,
725 				      new_crtc->base.id, new_crtc->name);
726 		} else {
727 			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [NOCRTC]\n",
728 				      connector->base.id, connector->name);
729 		}
730 	}
731 	drm_connector_list_iter_end(&conn_iter);
732 
733 	/* mode_set_base is not a required function */
734 	if (fb_changed && !crtc_funcs->mode_set_base)
735 		mode_changed = true;
736 
737 	if (mode_changed) {
738 		if (drm_helper_crtc_in_use(set->crtc)) {
739 			DRM_DEBUG_KMS("attempting to set mode from"
740 					" userspace\n");
741 			drm_mode_debug_printmodeline(set->mode);
742 			set->crtc->primary->fb = set->fb;
743 			if (!drm_crtc_helper_set_mode(set->crtc, set->mode,
744 						      set->x, set->y,
745 						      save_set.fb)) {
746 				DRM_ERROR("failed to set mode on [CRTC:%d:%s]\n",
747 					  set->crtc->base.id, set->crtc->name);
748 				set->crtc->primary->fb = save_set.fb;
749 				ret = -EINVAL;
750 				goto fail;
751 			}
752 			DRM_DEBUG_KMS("Setting connector DPMS state to on\n");
753 			for (i = 0; i < set->num_connectors; i++) {
754 				DRM_DEBUG_KMS("\t[CONNECTOR:%d:%s] set DPMS on\n", set->connectors[i]->base.id,
755 					      set->connectors[i]->name);
756 				set->connectors[i]->funcs->dpms(set->connectors[i], DRM_MODE_DPMS_ON);
757 			}
758 		}
759 		__drm_helper_disable_unused_functions(dev);
760 	} else if (fb_changed) {
761 		set->crtc->x = set->x;
762 		set->crtc->y = set->y;
763 		set->crtc->primary->fb = set->fb;
764 		ret = crtc_funcs->mode_set_base(set->crtc,
765 						set->x, set->y, save_set.fb);
766 		if (ret != 0) {
767 			set->crtc->x = save_set.x;
768 			set->crtc->y = save_set.y;
769 			set->crtc->primary->fb = save_set.fb;
770 			goto fail;
771 		}
772 	}
773 
774 	kfree(save_connector_encoders);
775 	kfree(save_encoder_crtcs);
776 	return 0;
777 
778 fail:
779 	/* Restore all previous data. */
780 	count = 0;
781 	drm_for_each_encoder(encoder, dev) {
782 		encoder->crtc = save_encoder_crtcs[count++];
783 	}
784 
785 	count = 0;
786 	drm_connector_list_iter_begin(dev, &conn_iter);
787 	drm_for_each_connector_iter(connector, &conn_iter)
788 		connector->encoder = save_connector_encoders[count++];
789 	drm_connector_list_iter_end(&conn_iter);
790 
791 	/* after fail drop reference on all unbound connectors in set, let
792 	 * bound connectors keep their reference
793 	 */
794 	for (ro = 0; ro < set->num_connectors; ro++) {
795 		if (set->connectors[ro]->encoder)
796 			continue;
797 		drm_connector_put(set->connectors[ro]);
798 	}
799 
800 	/* Try to restore the config */
801 	if (mode_changed &&
802 	    !drm_crtc_helper_set_mode(save_set.crtc, save_set.mode, save_set.x,
803 				      save_set.y, save_set.fb))
804 		DRM_ERROR("failed to restore config after modeset failure\n");
805 
806 	kfree(save_connector_encoders);
807 	kfree(save_encoder_crtcs);
808 	return ret;
809 }
810 EXPORT_SYMBOL(drm_crtc_helper_set_config);
811 
812 static int drm_helper_choose_encoder_dpms(struct drm_encoder *encoder)
813 {
814 	int dpms = DRM_MODE_DPMS_OFF;
815 	struct drm_connector *connector;
816 	struct drm_connector_list_iter conn_iter;
817 	struct drm_device *dev = encoder->dev;
818 
819 	drm_connector_list_iter_begin(dev, &conn_iter);
820 	drm_for_each_connector_iter(connector, &conn_iter)
821 		if (connector->encoder == encoder)
822 			if (connector->dpms < dpms)
823 				dpms = connector->dpms;
824 	drm_connector_list_iter_end(&conn_iter);
825 
826 	return dpms;
827 }
828 
829 /* Helper which handles bridge ordering around encoder dpms */
830 static void drm_helper_encoder_dpms(struct drm_encoder *encoder, int mode)
831 {
832 	const struct drm_encoder_helper_funcs *encoder_funcs;
833 
834 	encoder_funcs = encoder->helper_private;
835 	if (!encoder_funcs)
836 		return;
837 
838 	if (encoder_funcs->dpms)
839 		encoder_funcs->dpms(encoder, mode);
840 }
841 
842 static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
843 {
844 	int dpms = DRM_MODE_DPMS_OFF;
845 	struct drm_connector *connector;
846 	struct drm_connector_list_iter conn_iter;
847 	struct drm_device *dev = crtc->dev;
848 
849 	drm_connector_list_iter_begin(dev, &conn_iter);
850 	drm_for_each_connector_iter(connector, &conn_iter)
851 		if (connector->encoder && connector->encoder->crtc == crtc)
852 			if (connector->dpms < dpms)
853 				dpms = connector->dpms;
854 	drm_connector_list_iter_end(&conn_iter);
855 
856 	return dpms;
857 }
858 
859 /**
860  * drm_helper_connector_dpms() - connector dpms helper implementation
861  * @connector: affected connector
862  * @mode: DPMS mode
863  *
864  * The drm_helper_connector_dpms() helper function implements the
865  * &drm_connector_funcs.dpms callback for drivers using the legacy CRTC
866  * helpers.
867  *
868  * This is the main helper function provided by the CRTC helper framework for
869  * implementing the DPMS connector attribute. It computes the new desired DPMS
870  * state for all encoders and CRTCs in the output mesh and calls the
871  * &drm_crtc_helper_funcs.dpms and &drm_encoder_helper_funcs.dpms callbacks
872  * provided by the driver.
873  *
874  * This function is deprecated.  New drivers must implement atomic modeset
875  * support, where DPMS is handled in the DRM core.
876  *
877  * Returns:
878  * Always returns 0.
879  */
880 int drm_helper_connector_dpms(struct drm_connector *connector, int mode)
881 {
882 	struct drm_encoder *encoder = connector->encoder;
883 	struct drm_crtc *crtc = encoder ? encoder->crtc : NULL;
884 	int old_dpms, encoder_dpms = DRM_MODE_DPMS_OFF;
885 
886 	WARN_ON(drm_drv_uses_atomic_modeset(connector->dev));
887 
888 	if (mode == connector->dpms)
889 		return 0;
890 
891 	old_dpms = connector->dpms;
892 	connector->dpms = mode;
893 
894 	if (encoder)
895 		encoder_dpms = drm_helper_choose_encoder_dpms(encoder);
896 
897 	/* from off to on, do crtc then encoder */
898 	if (mode < old_dpms) {
899 		if (crtc) {
900 			const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
901 
902 			if (crtc_funcs->dpms)
903 				(*crtc_funcs->dpms) (crtc,
904 						     drm_helper_choose_crtc_dpms(crtc));
905 		}
906 		if (encoder)
907 			drm_helper_encoder_dpms(encoder, encoder_dpms);
908 	}
909 
910 	/* from on to off, do encoder then crtc */
911 	if (mode > old_dpms) {
912 		if (encoder)
913 			drm_helper_encoder_dpms(encoder, encoder_dpms);
914 		if (crtc) {
915 			const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
916 
917 			if (crtc_funcs->dpms)
918 				(*crtc_funcs->dpms) (crtc,
919 						     drm_helper_choose_crtc_dpms(crtc));
920 		}
921 	}
922 
923 	return 0;
924 }
925 EXPORT_SYMBOL(drm_helper_connector_dpms);
926 
927 /**
928  * drm_helper_resume_force_mode - force-restore mode setting configuration
929  * @dev: drm_device which should be restored
930  *
931  * Drivers which use the mode setting helpers can use this function to
932  * force-restore the mode setting configuration e.g. on resume or when something
933  * else might have trampled over the hw state (like some overzealous old BIOSen
934  * tended to do).
935  *
936  * This helper doesn't provide a error return value since restoring the old
937  * config should never fail due to resource allocation issues since the driver
938  * has successfully set the restored configuration already. Hence this should
939  * boil down to the equivalent of a few dpms on calls, which also don't provide
940  * an error code.
941  *
942  * Drivers where simply restoring an old configuration again might fail (e.g.
943  * due to slight differences in allocating shared resources when the
944  * configuration is restored in a different order than when userspace set it up)
945  * need to use their own restore logic.
946  *
947  * This function is deprecated. New drivers should implement atomic mode-
948  * setting and use the atomic suspend/resume helpers.
949  *
950  * See also:
951  * drm_atomic_helper_suspend(), drm_atomic_helper_resume()
952  */
953 void drm_helper_resume_force_mode(struct drm_device *dev)
954 {
955 	struct drm_crtc *crtc;
956 	struct drm_encoder *encoder;
957 	const struct drm_crtc_helper_funcs *crtc_funcs;
958 	int encoder_dpms;
959 	bool ret;
960 
961 	WARN_ON(drm_drv_uses_atomic_modeset(dev));
962 
963 	drm_modeset_lock_all(dev);
964 	drm_for_each_crtc(crtc, dev) {
965 
966 		if (!crtc->enabled)
967 			continue;
968 
969 		ret = drm_crtc_helper_set_mode(crtc, &crtc->mode,
970 					       crtc->x, crtc->y, crtc->primary->fb);
971 
972 		/* Restoring the old config should never fail! */
973 		if (ret == false)
974 			DRM_ERROR("failed to set mode on crtc %p\n", crtc);
975 
976 		/* Turn off outputs that were already powered off */
977 		if (drm_helper_choose_crtc_dpms(crtc)) {
978 			drm_for_each_encoder(encoder, dev) {
979 
980 				if(encoder->crtc != crtc)
981 					continue;
982 
983 				encoder_dpms = drm_helper_choose_encoder_dpms(
984 							encoder);
985 
986 				drm_helper_encoder_dpms(encoder, encoder_dpms);
987 			}
988 
989 			crtc_funcs = crtc->helper_private;
990 			if (crtc_funcs->dpms)
991 				(*crtc_funcs->dpms) (crtc,
992 						     drm_helper_choose_crtc_dpms(crtc));
993 		}
994 	}
995 
996 	/* disable the unused connectors while restoring the modesetting */
997 	__drm_helper_disable_unused_functions(dev);
998 	drm_modeset_unlock_all(dev);
999 }
1000 EXPORT_SYMBOL(drm_helper_resume_force_mode);
1001 
1002 /**
1003  * drm_helper_force_disable_all - Forcibly turn off all enabled CRTCs
1004  * @dev: DRM device whose CRTCs to turn off
1005  *
1006  * Drivers may want to call this on unload to ensure that all displays are
1007  * unlit and the GPU is in a consistent, low power state. Takes modeset locks.
1008  *
1009  * Note: This should only be used by non-atomic legacy drivers. For an atomic
1010  * version look at drm_atomic_helper_shutdown().
1011  *
1012  * Returns:
1013  * Zero on success, error code on failure.
1014  */
1015 int drm_helper_force_disable_all(struct drm_device *dev)
1016 {
1017 	struct drm_crtc *crtc;
1018 	int ret = 0;
1019 
1020 	drm_modeset_lock_all(dev);
1021 	drm_for_each_crtc(crtc, dev)
1022 		if (crtc->enabled) {
1023 			struct drm_mode_set set = {
1024 				.crtc = crtc,
1025 			};
1026 
1027 			ret = drm_mode_set_config_internal(&set);
1028 			if (ret)
1029 				goto out;
1030 		}
1031 out:
1032 	drm_modeset_unlock_all(dev);
1033 	return ret;
1034 }
1035 EXPORT_SYMBOL(drm_helper_force_disable_all);
1036