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_fourcc.h>
  47#include <drm/drm_framebuffer.h>
  48#include <drm/drm_print.h>
  49#include <drm/drm_vblank.h>
  50
  51#include "drm_crtc_helper_internal.h"
  52
  53DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
  54			"DRM_UT_CORE",
  55			"DRM_UT_DRIVER",
  56			"DRM_UT_KMS",
  57			"DRM_UT_PRIME",
  58			"DRM_UT_ATOMIC",
  59			"DRM_UT_VBL",
  60			"DRM_UT_STATE",
  61			"DRM_UT_LEASE",
  62			"DRM_UT_DP",
  63			"DRM_UT_DRMRES");
  64
  65/**
  66 * DOC: overview
  67 *
  68 * The CRTC modeset helper library provides a default set_config implementation
  69 * in drm_crtc_helper_set_config(). Plus a few other convenience functions using
  70 * the same callbacks which drivers can use to e.g. restore the modeset
  71 * configuration on resume with drm_helper_resume_force_mode().
  72 *
  73 * Note that this helper library doesn't track the current power state of CRTCs
  74 * and encoders. It can call callbacks like &drm_encoder_helper_funcs.dpms even
  75 * though the hardware is already in the desired state. This deficiency has been
  76 * fixed in the atomic helpers.
  77 *
  78 * The driver callbacks are mostly compatible with the atomic modeset helpers,
  79 * except for the handling of the primary plane: Atomic helpers require that the
  80 * primary plane is implemented as a real standalone plane and not directly tied
  81 * to the CRTC state. For easier transition this library provides functions to
  82 * implement the old semantics required by the CRTC helpers using the new plane
  83 * and atomic helper callbacks.
  84 *
  85 * Drivers are strongly urged to convert to the atomic helpers (by way of first
  86 * converting to the plane helpers). New drivers must not use these functions
  87 * but need to implement the atomic interface instead, potentially using the
  88 * atomic helpers for that.
  89 *
  90 * These legacy modeset helpers use the same function table structures as
  91 * all other modesetting helpers. See the documentation for struct
  92 * &drm_crtc_helper_funcs, &struct drm_encoder_helper_funcs and struct
  93 * &drm_connector_helper_funcs.
  94 */
  95
  96/**
  97 * drm_helper_encoder_in_use - check if a given encoder is in use
  98 * @encoder: encoder to check
  99 *
 100 * Checks whether @encoder is with the current mode setting output configuration
 101 * in use by any connector. This doesn't mean that it is actually enabled since
 102 * the DPMS state is tracked separately.
 103 *
 104 * Returns:
 105 * True if @encoder is used, false otherwise.
 106 */
 107bool drm_helper_encoder_in_use(struct drm_encoder *encoder)
 108{
 109	struct drm_connector *connector;
 110	struct drm_connector_list_iter conn_iter;
 111	struct drm_device *dev = encoder->dev;
 112
 113	drm_WARN_ON(dev, drm_drv_uses_atomic_modeset(dev));
 114
 115	/*
 116	 * We can expect this mutex to be locked if we are not panicking.
 117	 * Locking is currently fubar in the panic handler.
 118	 */
 119	if (!oops_in_progress) {
 120		drm_WARN_ON(dev, !mutex_is_locked(&dev->mode_config.mutex));
 121		drm_WARN_ON(dev, !drm_modeset_is_locked(&dev->mode_config.connection_mutex));
 122	}
 123
 124
 125	drm_connector_list_iter_begin(dev, &conn_iter);
 126	drm_for_each_connector_iter(connector, &conn_iter) {
 127		if (connector->encoder == encoder) {
 128			drm_connector_list_iter_end(&conn_iter);
 129			return true;
 130		}
 131	}
 132	drm_connector_list_iter_end(&conn_iter);
 133	return false;
 134}
 135EXPORT_SYMBOL(drm_helper_encoder_in_use);
 136
 137/**
 138 * drm_helper_crtc_in_use - check if a given CRTC is in a mode_config
 139 * @crtc: CRTC to check
 140 *
 141 * Checks whether @crtc is with the current mode setting output configuration
 142 * in use by any connector. This doesn't mean that it is actually enabled since
 143 * the DPMS state is tracked separately.
 144 *
 145 * Returns:
 146 * True if @crtc is used, false otherwise.
 147 */
 148bool drm_helper_crtc_in_use(struct drm_crtc *crtc)
 149{
 150	struct drm_encoder *encoder;
 151	struct drm_device *dev = crtc->dev;
 152
 153	drm_WARN_ON(dev, drm_drv_uses_atomic_modeset(dev));
 154
 155	/*
 156	 * We can expect this mutex to be locked if we are not panicking.
 157	 * Locking is currently fubar in the panic handler.
 158	 */
 159	if (!oops_in_progress)
 160		drm_WARN_ON(dev, !mutex_is_locked(&dev->mode_config.mutex));
 161
 162	drm_for_each_encoder(encoder, dev)
 163		if (encoder->crtc == crtc && drm_helper_encoder_in_use(encoder))
 164			return true;
 165	return false;
 166}
 167EXPORT_SYMBOL(drm_helper_crtc_in_use);
 168
 169static void
 170drm_encoder_disable(struct drm_encoder *encoder)
 171{
 172	const struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
 173
 174	if (!encoder_funcs)
 175		return;
 176
 177	if (encoder_funcs->disable)
 178		(*encoder_funcs->disable)(encoder);
 179	else if (encoder_funcs->dpms)
 180		(*encoder_funcs->dpms)(encoder, DRM_MODE_DPMS_OFF);
 181}
 182
 183static void __drm_helper_disable_unused_functions(struct drm_device *dev)
 184{
 185	struct drm_encoder *encoder;
 186	struct drm_crtc *crtc;
 187
 188	drm_warn_on_modeset_not_all_locked(dev);
 189
 190	drm_for_each_encoder(encoder, dev) {
 191		if (!drm_helper_encoder_in_use(encoder)) {
 192			drm_encoder_disable(encoder);
 193			/* disconnect encoder from any connector */
 194			encoder->crtc = NULL;
 195		}
 196	}
 197
 198	drm_for_each_crtc(crtc, dev) {
 199		const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 200
 201		crtc->enabled = drm_helper_crtc_in_use(crtc);
 202		if (!crtc->enabled) {
 203			if (crtc_funcs->disable)
 204				(*crtc_funcs->disable)(crtc);
 205			else
 206				(*crtc_funcs->dpms)(crtc, DRM_MODE_DPMS_OFF);
 207			crtc->primary->fb = NULL;
 208		}
 209	}
 210}
 211
 212/**
 213 * drm_helper_disable_unused_functions - disable unused objects
 214 * @dev: DRM device
 215 *
 216 * This function walks through the entire mode setting configuration of @dev. It
 217 * will remove any CRTC links of unused encoders and encoder links of
 218 * disconnected connectors. Then it will disable all unused encoders and CRTCs
 219 * either by calling their disable callback if available or by calling their
 220 * dpms callback with DRM_MODE_DPMS_OFF.
 221 *
 222 * NOTE:
 223 *
 224 * This function is part of the legacy modeset helper library and will cause
 225 * major confusion with atomic drivers. This is because atomic helpers guarantee
 226 * to never call ->disable() hooks on a disabled function, or ->enable() hooks
 227 * on an enabled functions. drm_helper_disable_unused_functions() on the other
 228 * hand throws such guarantees into the wind and calls disable hooks
 229 * unconditionally on unused functions.
 230 */
 231void drm_helper_disable_unused_functions(struct drm_device *dev)
 232{
 233	drm_WARN_ON(dev, drm_drv_uses_atomic_modeset(dev));
 234
 235	drm_modeset_lock_all(dev);
 236	__drm_helper_disable_unused_functions(dev);
 237	drm_modeset_unlock_all(dev);
 238}
 239EXPORT_SYMBOL(drm_helper_disable_unused_functions);
 240
 241/*
 242 * Check the CRTC we're going to map each output to vs. its current
 243 * CRTC.  If they don't match, we have to disable the output and the CRTC
 244 * since the driver will have to re-route things.
 245 */
 246static void
 247drm_crtc_prepare_encoders(struct drm_device *dev)
 248{
 249	const struct drm_encoder_helper_funcs *encoder_funcs;
 250	struct drm_encoder *encoder;
 251
 252	drm_for_each_encoder(encoder, dev) {
 253		encoder_funcs = encoder->helper_private;
 254		if (!encoder_funcs)
 255			continue;
 256
 257		/* Disable unused encoders */
 258		if (encoder->crtc == NULL)
 259			drm_encoder_disable(encoder);
 260	}
 261}
 262
 263/**
 264 * drm_crtc_helper_set_mode - internal helper to set a mode
 265 * @crtc: CRTC to program
 266 * @mode: mode to use
 267 * @x: horizontal offset into the surface
 268 * @y: vertical offset into the surface
 269 * @old_fb: old framebuffer, for cleanup
 270 *
 271 * Try to set @mode on @crtc.  Give @crtc and its associated connectors a chance
 272 * to fixup or reject the mode prior to trying to set it. This is an internal
 273 * helper that drivers could e.g. use to update properties that require the
 274 * entire output pipe to be disabled and re-enabled in a new configuration. For
 275 * example for changing whether audio is enabled on a hdmi link or for changing
 276 * panel fitter or dither attributes. It is also called by the
 277 * drm_crtc_helper_set_config() helper function to drive the mode setting
 278 * sequence.
 279 *
 280 * Returns:
 281 * True if the mode was set successfully, false otherwise.
 282 */
 283bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
 284			      struct drm_display_mode *mode,
 285			      int x, int y,
 286			      struct drm_framebuffer *old_fb)
 287{
 288	struct drm_device *dev = crtc->dev;
 289	struct drm_display_mode *adjusted_mode, saved_mode, saved_hwmode;
 290	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 291	const struct drm_encoder_helper_funcs *encoder_funcs;
 292	int saved_x, saved_y;
 293	bool saved_enabled;
 294	struct drm_encoder *encoder;
 295	bool ret = true;
 296
 297	drm_WARN_ON(dev, drm_drv_uses_atomic_modeset(dev));
 298
 299	drm_warn_on_modeset_not_all_locked(dev);
 300
 301	saved_enabled = crtc->enabled;
 302	crtc->enabled = drm_helper_crtc_in_use(crtc);
 303	if (!crtc->enabled)
 304		return true;
 305
 306	adjusted_mode = drm_mode_duplicate(dev, mode);
 307	if (!adjusted_mode) {
 308		crtc->enabled = saved_enabled;
 309		return false;
 310	}
 311
 312	drm_mode_init(&saved_mode, &crtc->mode);
 313	drm_mode_init(&saved_hwmode, &crtc->hwmode);
 314	saved_x = crtc->x;
 315	saved_y = crtc->y;
 316
 317	/* Update crtc values up front so the driver can rely on them for mode
 318	 * setting.
 319	 */
 320	drm_mode_copy(&crtc->mode, mode);
 321	crtc->x = x;
 322	crtc->y = y;
 323
 324	/* Pass our mode to the connectors and the CRTC to give them a chance to
 325	 * adjust it according to limitations or connector properties, and also
 326	 * a chance to reject the mode entirely.
 327	 */
 328	drm_for_each_encoder(encoder, dev) {
 329
 330		if (encoder->crtc != crtc)
 331			continue;
 332
 333		encoder_funcs = encoder->helper_private;
 334		if (!encoder_funcs)
 335			continue;
 336
 337		encoder_funcs = encoder->helper_private;
 338		if (encoder_funcs->mode_fixup) {
 339			if (!(ret = encoder_funcs->mode_fixup(encoder, mode,
 340							      adjusted_mode))) {
 341				drm_dbg_kms(dev, "[ENCODER:%d:%s] mode fixup failed\n",
 342					    encoder->base.id, encoder->name);
 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_dbg_kms(dev, "[CRTC:%d:%s] mode fixup failed\n",
 352				    crtc->base.id, crtc->name);
 353			goto done;
 354		}
 355	}
 356	drm_dbg_kms(dev, "[CRTC:%d:%s]\n", crtc->base.id, crtc->name);
 357
 358	drm_mode_copy(&crtc->hwmode, adjusted_mode);
 359
 360	/* Prepare the encoders and CRTCs before setting the mode. */
 361	drm_for_each_encoder(encoder, dev) {
 362
 363		if (encoder->crtc != crtc)
 364			continue;
 365
 366		encoder_funcs = encoder->helper_private;
 367		if (!encoder_funcs)
 368			continue;
 369
 370		/* Disable the encoders as the first thing we do. */
 371		if (encoder_funcs->prepare)
 372			encoder_funcs->prepare(encoder);
 373	}
 374
 375	drm_crtc_prepare_encoders(dev);
 376
 377	crtc_funcs->prepare(crtc);
 378
 379	/* Set up the DPLL and any encoders state that needs to adjust or depend
 380	 * on the DPLL.
 381	 */
 382	ret = !crtc_funcs->mode_set(crtc, mode, adjusted_mode, x, y, old_fb);
 383	if (!ret)
 384	    goto done;
 385
 386	drm_for_each_encoder(encoder, dev) {
 387
 388		if (encoder->crtc != crtc)
 389			continue;
 390
 391		encoder_funcs = encoder->helper_private;
 392		if (!encoder_funcs)
 393			continue;
 394
 395		drm_dbg_kms(dev, "[ENCODER:%d:%s] set [MODE:%s]\n",
 396			    encoder->base.id, encoder->name, mode->name);
 397		if (encoder_funcs->mode_set)
 398			encoder_funcs->mode_set(encoder, mode, adjusted_mode);
 399	}
 400
 401	/* Now enable the clocks, plane, pipe, and connectors that we set up. */
 402	crtc_funcs->commit(crtc);
 403
 404	drm_for_each_encoder(encoder, dev) {
 405
 406		if (encoder->crtc != crtc)
 407			continue;
 408
 409		encoder_funcs = encoder->helper_private;
 410		if (!encoder_funcs)
 411			continue;
 412
 413		if (encoder_funcs->commit)
 414			encoder_funcs->commit(encoder);
 415	}
 416
 417	/* Calculate and store various constants which
 418	 * are later needed by vblank and swap-completion
 419	 * timestamping. They are derived from true hwmode.
 420	 */
 421	drm_calc_timestamping_constants(crtc, &crtc->hwmode);
 422
 423	/* FIXME: add subpixel order */
 424done:
 425	drm_mode_destroy(dev, adjusted_mode);
 426	if (!ret) {
 427		crtc->enabled = saved_enabled;
 428		drm_mode_copy(&crtc->mode, &saved_mode);
 429		drm_mode_copy(&crtc->hwmode, &saved_hwmode);
 430		crtc->x = saved_x;
 431		crtc->y = saved_y;
 432	}
 433
 434	return ret;
 435}
 436EXPORT_SYMBOL(drm_crtc_helper_set_mode);
 437
 438/**
 439 * drm_crtc_helper_atomic_check() - Helper to check CRTC atomic-state
 440 * @crtc: CRTC to check
 441 * @state: atomic state object
 442 *
 443 * Provides a default CRTC-state check handler for CRTCs that only have
 444 * one primary plane attached to it. This is often the case for the CRTC
 445 * of simple framebuffers.
 
 
 
 446 *
 447 * RETURNS:
 448 * Zero on success, or an errno code otherwise.
 449 */
 450int drm_crtc_helper_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *state)
 451{
 452	struct drm_crtc_state *new_crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
 453
 454	if (!new_crtc_state->enable)
 455		return 0;
 456
 457	return drm_atomic_helper_check_crtc_primary_plane(new_crtc_state);
 458}
 459EXPORT_SYMBOL(drm_crtc_helper_atomic_check);
 460
 461static void
 462drm_crtc_helper_disable(struct drm_crtc *crtc)
 463{
 464	struct drm_device *dev = crtc->dev;
 465	struct drm_connector *connector;
 466	struct drm_encoder *encoder;
 467
 468	/* Decouple all encoders and their attached connectors from this crtc */
 469	drm_for_each_encoder(encoder, dev) {
 470		struct drm_connector_list_iter conn_iter;
 471
 472		if (encoder->crtc != crtc)
 473			continue;
 474
 475		drm_connector_list_iter_begin(dev, &conn_iter);
 476		drm_for_each_connector_iter(connector, &conn_iter) {
 477			if (connector->encoder != encoder)
 478				continue;
 479
 480			connector->encoder = NULL;
 481
 482			/*
 483			 * drm_helper_disable_unused_functions() ought to be
 484			 * doing this, but since we've decoupled the encoder
 485			 * from the connector above, the required connection
 486			 * between them is henceforth no longer available.
 487			 */
 488			connector->dpms = DRM_MODE_DPMS_OFF;
 489
 490			/* we keep a reference while the encoder is bound */
 491			drm_connector_put(connector);
 492		}
 493		drm_connector_list_iter_end(&conn_iter);
 494	}
 495
 496	__drm_helper_disable_unused_functions(dev);
 497}
 498
 499/*
 500 * For connectors that support multiple encoders, either the
 501 * .atomic_best_encoder() or .best_encoder() operation must be implemented.
 502 */
 503struct drm_encoder *
 504drm_connector_get_single_encoder(struct drm_connector *connector)
 505{
 506	struct drm_encoder *encoder;
 507
 508	drm_WARN_ON(connector->dev, hweight32(connector->possible_encoders) > 1);
 509	drm_connector_for_each_possible_encoder(connector, encoder)
 510		return encoder;
 511
 512	return NULL;
 513}
 514
 515/**
 516 * drm_crtc_helper_set_config - set a new config from userspace
 517 * @set: mode set configuration
 518 * @ctx: lock acquire context, not used here
 519 *
 520 * The drm_crtc_helper_set_config() helper function implements the of
 521 * &drm_crtc_funcs.set_config callback for drivers using the legacy CRTC
 522 * helpers.
 523 *
 524 * It first tries to locate the best encoder for each connector by calling the
 525 * connector @drm_connector_helper_funcs.best_encoder helper operation.
 526 *
 527 * After locating the appropriate encoders, the helper function will call the
 528 * mode_fixup encoder and CRTC helper operations to adjust the requested mode,
 529 * or reject it completely in which case an error will be returned to the
 530 * application. If the new configuration after mode adjustment is identical to
 531 * the current configuration the helper function will return without performing
 532 * any other operation.
 533 *
 534 * If the adjusted mode is identical to the current mode but changes to the
 535 * frame buffer need to be applied, the drm_crtc_helper_set_config() function
 536 * will call the CRTC &drm_crtc_helper_funcs.mode_set_base helper operation.
 537 *
 538 * If the adjusted mode differs from the current mode, or if the
 539 * ->mode_set_base() helper operation is not provided, the helper function
 540 * performs a full mode set sequence by calling the ->prepare(), ->mode_set()
 541 * and ->commit() CRTC and encoder helper operations, in that order.
 542 * Alternatively it can also use the dpms and disable helper operations. For
 543 * details see &struct drm_crtc_helper_funcs and struct
 544 * &drm_encoder_helper_funcs.
 545 *
 546 * This function is deprecated.  New drivers must implement atomic modeset
 547 * support, for which this function is unsuitable. Instead drivers should use
 548 * drm_atomic_helper_set_config().
 549 *
 550 * Returns:
 551 * Returns 0 on success, negative errno numbers on failure.
 552 */
 553int drm_crtc_helper_set_config(struct drm_mode_set *set,
 554			       struct drm_modeset_acquire_ctx *ctx)
 555{
 556	struct drm_device *dev;
 557	struct drm_crtc **save_encoder_crtcs, *new_crtc;
 558	struct drm_encoder **save_connector_encoders, *new_encoder, *encoder;
 559	bool mode_changed = false; /* if true do a full mode set */
 560	bool fb_changed = false; /* if true and !mode_changed just do a flip */
 561	struct drm_connector *connector;
 562	struct drm_connector_list_iter conn_iter;
 563	int count = 0, ro, fail = 0;
 564	const struct drm_crtc_helper_funcs *crtc_funcs;
 565	struct drm_mode_set save_set;
 566	int ret;
 567	int i;
 568
 
 
 569	BUG_ON(!set);
 570	BUG_ON(!set->crtc);
 571	BUG_ON(!set->crtc->helper_private);
 572
 573	/* Enforce sane interface api - has been abused by the fb helper. */
 574	BUG_ON(!set->mode && set->fb);
 575	BUG_ON(set->fb && set->num_connectors == 0);
 576
 577	crtc_funcs = set->crtc->helper_private;
 578
 579	dev = set->crtc->dev;
 580
 581	drm_dbg_kms(dev, "\n");
 582
 583	drm_WARN_ON(dev, drm_drv_uses_atomic_modeset(dev));
 584
 585	if (!set->mode)
 586		set->fb = NULL;
 587
 588	if (set->fb) {
 589		drm_dbg_kms(dev, "[CRTC:%d:%s] [FB:%d] #connectors=%d (x y) (%i %i)\n",
 590			    set->crtc->base.id, set->crtc->name,
 591			    set->fb->base.id,
 592			    (int)set->num_connectors, set->x, set->y);
 593	} else {
 594		drm_dbg_kms(dev, "[CRTC:%d:%s] [NOFB]\n",
 595			    set->crtc->base.id, set->crtc->name);
 596		drm_crtc_helper_disable(set->crtc);
 597		return 0;
 598	}
 599
 600	drm_warn_on_modeset_not_all_locked(dev);
 601
 602	/*
 603	 * Allocate space for the backup of all (non-pointer) encoder and
 604	 * connector data.
 605	 */
 606	save_encoder_crtcs = kcalloc(dev->mode_config.num_encoder,
 607				sizeof(struct drm_crtc *), GFP_KERNEL);
 608	if (!save_encoder_crtcs)
 609		return -ENOMEM;
 610
 611	save_connector_encoders = kcalloc(dev->mode_config.num_connector,
 612				sizeof(struct drm_encoder *), GFP_KERNEL);
 613	if (!save_connector_encoders) {
 614		kfree(save_encoder_crtcs);
 615		return -ENOMEM;
 616	}
 617
 618	/*
 619	 * Copy data. Note that driver private data is not affected.
 620	 * Should anything bad happen only the expected state is
 621	 * restored, not the drivers personal bookkeeping.
 622	 */
 623	count = 0;
 624	drm_for_each_encoder(encoder, dev) {
 625		save_encoder_crtcs[count++] = encoder->crtc;
 626	}
 627
 628	count = 0;
 629	drm_connector_list_iter_begin(dev, &conn_iter);
 630	drm_for_each_connector_iter(connector, &conn_iter)
 631		save_connector_encoders[count++] = connector->encoder;
 632	drm_connector_list_iter_end(&conn_iter);
 633
 634	save_set.crtc = set->crtc;
 635	save_set.mode = &set->crtc->mode;
 636	save_set.x = set->crtc->x;
 637	save_set.y = set->crtc->y;
 638	save_set.fb = set->crtc->primary->fb;
 639
 640	/* We should be able to check here if the fb has the same properties
 641	 * and then just flip_or_move it */
 642	if (set->crtc->primary->fb != set->fb) {
 643		/* If we have no fb then treat it as a full mode set */
 644		if (set->crtc->primary->fb == NULL) {
 645			drm_dbg_kms(dev, "[CRTC:%d:%s] no fb, full mode set\n",
 646				    set->crtc->base.id, set->crtc->name);
 647			mode_changed = true;
 648		} else if (set->fb->format != set->crtc->primary->fb->format) {
 649			mode_changed = true;
 650		} else
 651			fb_changed = true;
 652	}
 653
 654	if (set->x != set->crtc->x || set->y != set->crtc->y)
 655		fb_changed = true;
 656
 657	if (!drm_mode_equal(set->mode, &set->crtc->mode)) {
 658		drm_dbg_kms(dev, "[CRTC:%d:%s] modes are different, full mode set:\n",
 659			    set->crtc->base.id, set->crtc->name);
 660		drm_dbg_kms(dev, DRM_MODE_FMT "\n", DRM_MODE_ARG(&set->crtc->mode));
 661		drm_dbg_kms(dev, DRM_MODE_FMT "\n", DRM_MODE_ARG(set->mode));
 662		mode_changed = true;
 663	}
 664
 665	/* take a reference on all unbound connectors in set, reuse the
 666	 * already taken reference for bound connectors
 667	 */
 668	for (ro = 0; ro < set->num_connectors; ro++) {
 669		if (set->connectors[ro]->encoder)
 670			continue;
 671		drm_connector_get(set->connectors[ro]);
 672	}
 673
 674	/* a) traverse passed in connector list and get encoders for them */
 675	count = 0;
 676	drm_connector_list_iter_begin(dev, &conn_iter);
 677	drm_for_each_connector_iter(connector, &conn_iter) {
 678		const struct drm_connector_helper_funcs *connector_funcs =
 679			connector->helper_private;
 680		new_encoder = connector->encoder;
 681		for (ro = 0; ro < set->num_connectors; ro++) {
 682			if (set->connectors[ro] == connector) {
 683				if (connector_funcs->best_encoder)
 684					new_encoder = connector_funcs->best_encoder(connector);
 685				else
 686					new_encoder = drm_connector_get_single_encoder(connector);
 687
 688				/* if we can't get an encoder for a connector
 689				   we are setting now - then fail */
 690				if (new_encoder == NULL)
 691					/* don't break so fail path works correct */
 692					fail = 1;
 693
 694				if (connector->dpms != DRM_MODE_DPMS_ON) {
 695					drm_dbg_kms(dev, "[CONNECTOR:%d:%s] DPMS not on, full mode switch\n",
 696						    connector->base.id, connector->name);
 697					mode_changed = true;
 698				}
 699
 700				break;
 701			}
 702		}
 703
 704		if (new_encoder != connector->encoder) {
 705			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] encoder changed, full mode switch\n",
 706				    connector->base.id, connector->name);
 707			mode_changed = true;
 708			/* If the encoder is reused for another connector, then
 709			 * the appropriate crtc will be set later.
 710			 */
 711			if (connector->encoder)
 712				connector->encoder->crtc = NULL;
 713			connector->encoder = new_encoder;
 714		}
 715	}
 716	drm_connector_list_iter_end(&conn_iter);
 717
 718	if (fail) {
 719		ret = -EINVAL;
 720		goto fail;
 721	}
 722
 723	count = 0;
 724	drm_connector_list_iter_begin(dev, &conn_iter);
 725	drm_for_each_connector_iter(connector, &conn_iter) {
 726		if (!connector->encoder)
 727			continue;
 728
 729		if (connector->encoder->crtc == set->crtc)
 730			new_crtc = NULL;
 731		else
 732			new_crtc = connector->encoder->crtc;
 733
 734		for (ro = 0; ro < set->num_connectors; ro++) {
 735			if (set->connectors[ro] == connector)
 736				new_crtc = set->crtc;
 737		}
 738
 739		/* Make sure the new CRTC will work with the encoder */
 740		if (new_crtc &&
 741		    !drm_encoder_crtc_ok(connector->encoder, new_crtc)) {
 742			ret = -EINVAL;
 743			drm_connector_list_iter_end(&conn_iter);
 744			goto fail;
 745		}
 746		if (new_crtc != connector->encoder->crtc) {
 747			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] CRTC changed, full mode switch\n",
 748				    connector->base.id, connector->name);
 749			mode_changed = true;
 750			connector->encoder->crtc = new_crtc;
 751		}
 752		if (new_crtc) {
 753			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] to [CRTC:%d:%s]\n",
 754				    connector->base.id, connector->name,
 755				    new_crtc->base.id, new_crtc->name);
 756		} else {
 757			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] to [NOCRTC]\n",
 758				    connector->base.id, connector->name);
 759		}
 760	}
 761	drm_connector_list_iter_end(&conn_iter);
 762
 763	/* mode_set_base is not a required function */
 764	if (fb_changed && !crtc_funcs->mode_set_base)
 765		mode_changed = true;
 766
 767	if (mode_changed) {
 768		if (drm_helper_crtc_in_use(set->crtc)) {
 769			drm_dbg_kms(dev, "[CRTC:%d:%s] attempting to set mode from userspace: " DRM_MODE_FMT "\n",
 770				    set->crtc->base.id, set->crtc->name, DRM_MODE_ARG(set->mode));
 
 771			set->crtc->primary->fb = set->fb;
 772			if (!drm_crtc_helper_set_mode(set->crtc, set->mode,
 773						      set->x, set->y,
 774						      save_set.fb)) {
 775				drm_err(dev, "[CRTC:%d:%s] failed to set mode\n",
 776					set->crtc->base.id, set->crtc->name);
 777				set->crtc->primary->fb = save_set.fb;
 778				ret = -EINVAL;
 779				goto fail;
 780			}
 781			drm_dbg_kms(dev, "[CRTC:%d:%s] Setting connector DPMS state to on\n",
 782				    set->crtc->base.id, set->crtc->name);
 783			for (i = 0; i < set->num_connectors; i++) {
 784				drm_dbg_kms(dev, "\t[CONNECTOR:%d:%s] set DPMS on\n", set->connectors[i]->base.id,
 785					    set->connectors[i]->name);
 786				set->connectors[i]->funcs->dpms(set->connectors[i], DRM_MODE_DPMS_ON);
 787			}
 788		}
 789		__drm_helper_disable_unused_functions(dev);
 790	} else if (fb_changed) {
 791		set->crtc->x = set->x;
 792		set->crtc->y = set->y;
 793		set->crtc->primary->fb = set->fb;
 794		ret = crtc_funcs->mode_set_base(set->crtc,
 795						set->x, set->y, save_set.fb);
 796		if (ret != 0) {
 797			set->crtc->x = save_set.x;
 798			set->crtc->y = save_set.y;
 799			set->crtc->primary->fb = save_set.fb;
 800			goto fail;
 801		}
 802	}
 803
 804	kfree(save_connector_encoders);
 805	kfree(save_encoder_crtcs);
 806	return 0;
 807
 808fail:
 809	/* Restore all previous data. */
 810	count = 0;
 811	drm_for_each_encoder(encoder, dev) {
 812		encoder->crtc = save_encoder_crtcs[count++];
 813	}
 814
 815	count = 0;
 816	drm_connector_list_iter_begin(dev, &conn_iter);
 817	drm_for_each_connector_iter(connector, &conn_iter)
 818		connector->encoder = save_connector_encoders[count++];
 819	drm_connector_list_iter_end(&conn_iter);
 820
 821	/* after fail drop reference on all unbound connectors in set, let
 822	 * bound connectors keep their reference
 823	 */
 824	for (ro = 0; ro < set->num_connectors; ro++) {
 825		if (set->connectors[ro]->encoder)
 826			continue;
 827		drm_connector_put(set->connectors[ro]);
 828	}
 829
 830	/* Try to restore the config */
 831	if (mode_changed &&
 832	    !drm_crtc_helper_set_mode(save_set.crtc, save_set.mode, save_set.x,
 833				      save_set.y, save_set.fb))
 834		drm_err(dev, "failed to restore config after modeset failure\n");
 835
 836	kfree(save_connector_encoders);
 837	kfree(save_encoder_crtcs);
 838	return ret;
 839}
 840EXPORT_SYMBOL(drm_crtc_helper_set_config);
 841
 842static int drm_helper_choose_encoder_dpms(struct drm_encoder *encoder)
 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 = encoder->dev;
 848
 849	drm_connector_list_iter_begin(dev, &conn_iter);
 850	drm_for_each_connector_iter(connector, &conn_iter)
 851		if (connector->encoder == encoder)
 852			if (connector->dpms < dpms)
 853				dpms = connector->dpms;
 854	drm_connector_list_iter_end(&conn_iter);
 855
 856	return dpms;
 857}
 858
 859/* Helper which handles bridge ordering around encoder dpms */
 860static void drm_helper_encoder_dpms(struct drm_encoder *encoder, int mode)
 861{
 862	const struct drm_encoder_helper_funcs *encoder_funcs;
 863
 864	encoder_funcs = encoder->helper_private;
 865	if (!encoder_funcs)
 866		return;
 867
 868	if (encoder_funcs->dpms)
 869		encoder_funcs->dpms(encoder, mode);
 870}
 871
 872static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
 873{
 874	int dpms = DRM_MODE_DPMS_OFF;
 875	struct drm_connector *connector;
 876	struct drm_connector_list_iter conn_iter;
 877	struct drm_device *dev = crtc->dev;
 878
 879	drm_connector_list_iter_begin(dev, &conn_iter);
 880	drm_for_each_connector_iter(connector, &conn_iter)
 881		if (connector->encoder && connector->encoder->crtc == crtc)
 882			if (connector->dpms < dpms)
 883				dpms = connector->dpms;
 884	drm_connector_list_iter_end(&conn_iter);
 885
 886	return dpms;
 887}
 888
 889/**
 890 * drm_helper_connector_dpms() - connector dpms helper implementation
 891 * @connector: affected connector
 892 * @mode: DPMS mode
 893 *
 894 * The drm_helper_connector_dpms() helper function implements the
 895 * &drm_connector_funcs.dpms callback for drivers using the legacy CRTC
 896 * helpers.
 897 *
 898 * This is the main helper function provided by the CRTC helper framework for
 899 * implementing the DPMS connector attribute. It computes the new desired DPMS
 900 * state for all encoders and CRTCs in the output mesh and calls the
 901 * &drm_crtc_helper_funcs.dpms and &drm_encoder_helper_funcs.dpms callbacks
 902 * provided by the driver.
 903 *
 904 * This function is deprecated.  New drivers must implement atomic modeset
 905 * support, where DPMS is handled in the DRM core.
 906 *
 907 * Returns:
 908 * Always returns 0.
 909 */
 910int drm_helper_connector_dpms(struct drm_connector *connector, int mode)
 911{
 912	struct drm_encoder *encoder = connector->encoder;
 913	struct drm_crtc *crtc = encoder ? encoder->crtc : NULL;
 914	int old_dpms, encoder_dpms = DRM_MODE_DPMS_OFF;
 915
 916	drm_WARN_ON(connector->dev, drm_drv_uses_atomic_modeset(connector->dev));
 917
 918	if (mode == connector->dpms)
 919		return 0;
 920
 921	old_dpms = connector->dpms;
 922	connector->dpms = mode;
 923
 924	if (encoder)
 925		encoder_dpms = drm_helper_choose_encoder_dpms(encoder);
 926
 927	/* from off to on, do crtc then encoder */
 928	if (mode < old_dpms) {
 929		if (crtc) {
 930			const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 931
 932			if (crtc_funcs->dpms)
 933				(*crtc_funcs->dpms) (crtc,
 934						     drm_helper_choose_crtc_dpms(crtc));
 935		}
 936		if (encoder)
 937			drm_helper_encoder_dpms(encoder, encoder_dpms);
 938	}
 939
 940	/* from on to off, do encoder then crtc */
 941	if (mode > old_dpms) {
 942		if (encoder)
 943			drm_helper_encoder_dpms(encoder, encoder_dpms);
 944		if (crtc) {
 945			const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 946
 947			if (crtc_funcs->dpms)
 948				(*crtc_funcs->dpms) (crtc,
 949						     drm_helper_choose_crtc_dpms(crtc));
 950		}
 951	}
 952
 953	return 0;
 954}
 955EXPORT_SYMBOL(drm_helper_connector_dpms);
 956
 957/**
 958 * drm_helper_resume_force_mode - force-restore mode setting configuration
 959 * @dev: drm_device which should be restored
 960 *
 961 * Drivers which use the mode setting helpers can use this function to
 962 * force-restore the mode setting configuration e.g. on resume or when something
 963 * else might have trampled over the hw state (like some overzealous old BIOSen
 964 * tended to do).
 965 *
 966 * This helper doesn't provide a error return value since restoring the old
 967 * config should never fail due to resource allocation issues since the driver
 968 * has successfully set the restored configuration already. Hence this should
 969 * boil down to the equivalent of a few dpms on calls, which also don't provide
 970 * an error code.
 971 *
 972 * Drivers where simply restoring an old configuration again might fail (e.g.
 973 * due to slight differences in allocating shared resources when the
 974 * configuration is restored in a different order than when userspace set it up)
 975 * need to use their own restore logic.
 976 *
 977 * This function is deprecated. New drivers should implement atomic mode-
 978 * setting and use the atomic suspend/resume helpers.
 979 *
 980 * See also:
 981 * drm_atomic_helper_suspend(), drm_atomic_helper_resume()
 982 */
 983void drm_helper_resume_force_mode(struct drm_device *dev)
 984{
 985	struct drm_crtc *crtc;
 986	struct drm_encoder *encoder;
 987	const struct drm_crtc_helper_funcs *crtc_funcs;
 988	int encoder_dpms;
 989	bool ret;
 990
 991	drm_WARN_ON(dev, drm_drv_uses_atomic_modeset(dev));
 992
 993	drm_modeset_lock_all(dev);
 994	drm_for_each_crtc(crtc, dev) {
 995
 996		if (!crtc->enabled)
 997			continue;
 998
 999		ret = drm_crtc_helper_set_mode(crtc, &crtc->mode,
1000					       crtc->x, crtc->y, crtc->primary->fb);
1001
1002		/* Restoring the old config should never fail! */
1003		if (ret == false)
1004			drm_err(dev, "failed to set mode on crtc %p\n", crtc);
1005
1006		/* Turn off outputs that were already powered off */
1007		if (drm_helper_choose_crtc_dpms(crtc)) {
1008			drm_for_each_encoder(encoder, dev) {
1009
1010				if(encoder->crtc != crtc)
1011					continue;
1012
1013				encoder_dpms = drm_helper_choose_encoder_dpms(
1014							encoder);
1015
1016				drm_helper_encoder_dpms(encoder, encoder_dpms);
1017			}
1018
1019			crtc_funcs = crtc->helper_private;
1020			if (crtc_funcs->dpms)
1021				(*crtc_funcs->dpms) (crtc,
1022						     drm_helper_choose_crtc_dpms(crtc));
1023		}
1024	}
1025
1026	/* disable the unused connectors while restoring the modesetting */
1027	__drm_helper_disable_unused_functions(dev);
1028	drm_modeset_unlock_all(dev);
1029}
1030EXPORT_SYMBOL(drm_helper_resume_force_mode);
1031
1032/**
1033 * drm_helper_force_disable_all - Forcibly turn off all enabled CRTCs
1034 * @dev: DRM device whose CRTCs to turn off
1035 *
1036 * Drivers may want to call this on unload to ensure that all displays are
1037 * unlit and the GPU is in a consistent, low power state. Takes modeset locks.
1038 *
1039 * Note: This should only be used by non-atomic legacy drivers. For an atomic
1040 * version look at drm_atomic_helper_shutdown().
1041 *
1042 * Returns:
1043 * Zero on success, error code on failure.
1044 */
1045int drm_helper_force_disable_all(struct drm_device *dev)
1046{
1047	struct drm_crtc *crtc;
1048	int ret = 0;
1049
1050	drm_modeset_lock_all(dev);
1051	drm_for_each_crtc(crtc, dev)
1052		if (crtc->enabled) {
1053			struct drm_mode_set set = {
1054				.crtc = crtc,
1055			};
1056
1057			ret = drm_mode_set_config_internal(&set);
1058			if (ret)
1059				goto out;
1060		}
1061out:
1062	drm_modeset_unlock_all(dev);
1063	return ret;
1064}
1065EXPORT_SYMBOL(drm_helper_force_disable_all);