drivers/gpu/drm/drm_crtc_helper.c

   1 /*
   2  * Copyright (c) 2006-2008 Intel Corporation
   3  * Copyright (c) 2007 Dave Airlie <[email protected]>
   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 <[email protected]>
  28  *      Dave Airlie <[email protected]>
  29  *      Jesse Barnes <[email protected]>
  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_crtc.h>
  40 #include <drm/drm_crtc_helper.h>
  41 #include <drm/drm_drv.h>
  42 #include <drm/drm_edid.h>
  43 #include <drm/drm_encoder.h>
  44 #include <drm/drm_fb_helper.h>
  45 #include <drm/drm_fourcc.h>
  46 #include <drm/drm_plane_helper.h>
  47 #include <drm/drm_print.h>
  48 #include <drm/drm_vblank.h>
  49
  50 /**
  51  * DOC: overview
  52  *
  53  * The CRTC modeset helper library provides a default set_config implementation
  54  * in drm_crtc_helper_set_config(). Plus a few other convenience functions using
  55  * the same callbacks which drivers can use to e.g. restore the modeset
  56  * configuration on resume with drm_helper_resume_force_mode().
  57  *
  58  * Note that this helper library doesn't track the current power state of CRTCs
  59  * and encoders. It can call callbacks like &drm_encoder_helper_funcs.dpms even
  60  * though the hardware is already in the desired state. This deficiency has been
  61  * fixed in the atomic helpers.
  62  *
  63  * The driver callbacks are mostly compatible with the atomic modeset helpers,
  64  * except for the handling of the primary plane: Atomic helpers require that the
  65  * primary plane is implemented as a real standalone plane and not directly tied
  66  * to the CRTC state. For easier transition this library provides functions to
  67  * implement the old semantics required by the CRTC helpers using the new plane
  68  * and atomic helper callbacks.
  69  *
  70  * Drivers are strongly urged to convert to the atomic helpers (by way of first
  71  * converting to the plane helpers). New drivers must not use these functions
  72  * but need to implement the atomic interface instead, potentially using the
  73  * atomic helpers for that.
  74  *
  75  * These legacy modeset helpers use the same function table structures as
  76  * all other modesetting helpers. See the documentation for struct
  77  * &drm_crtc_helper_funcs, &struct drm_encoder_helper_funcs and struct
  78  * &drm_connector_helper_funcs.
  79  */
  80
  81 /**
  82  * drm_helper_encoder_in_use - check if a given encoder is in use
  83  * @encoder: encoder to check
  84  *
  85  * Checks whether @encoder is with the current mode setting output configuration
  86  * in use by any connector. This doesn't mean that it is actually enabled since
  87  * the DPMS state is tracked separately.
  88  *
  89  * Returns:
  90  * True if @encoder is used, false otherwise.
  91  */
  92 bool drm_helper_encoder_in_use(struct drm_encoder *encoder)
  93 {
  94         struct drm_connector *connector;
  95         struct drm_connector_list_iter conn_iter;
  96         struct drm_device *dev = encoder->dev;
  97
  98         WARN_ON(drm_drv_uses_atomic_modeset(dev));
  99
 100         /*
 101          * We can expect this mutex to be locked if we are not panicking.
 102          * Locking is currently fubar in the panic handler.
 103          */
 104         if (!oops_in_progress) {
 105                 WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 106                 WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
 107         }
 108
 109
 110         drm_connector_list_iter_begin(dev, &conn_iter);
 111         drm_for_each_connector_iter(connector, &conn_iter) {
 112                 if (connector->encoder == encoder) {
 113                         drm_connector_list_iter_end(&conn_iter);
 114                         return true;
 115                 }
 116         }
 117         drm_connector_list_iter_end(&conn_iter);
 118         return false;
 119 }
 120 EXPORT_SYMBOL(drm_helper_encoder_in_use);
 121
 122 /**
 123  * drm_helper_crtc_in_use - check if a given CRTC is in a mode_config
 124  * @crtc: CRTC to check
 125  *
 126  * Checks whether @crtc is with the current mode setting output configuration
 127  * in use by any connector. This doesn't mean that it is actually enabled since
 128  * the DPMS state is tracked separately.
 129  *
 130  * Returns:
 131  * True if @crtc is used, false otherwise.
 132  */
 133 bool drm_helper_crtc_in_use(struct drm_crtc *crtc)
 134 {
 135         struct drm_encoder *encoder;
 136         struct drm_device *dev = crtc->dev;
 137
 138         WARN_ON(drm_drv_uses_atomic_modeset(dev));
 139
 140         /*
 141          * We can expect this mutex to be locked if we are not panicking.
 142          * Locking is currently fubar in the panic handler.
 143          */
 144         if (!oops_in_progress)
 145                 WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 146
 147         drm_for_each_encoder(encoder, dev)
 148                 if (encoder->crtc == crtc && drm_helper_encoder_in_use(encoder))
 149                         return true;
 150         return false;
 151 }
 152 EXPORT_SYMBOL(drm_helper_crtc_in_use);
 153
 154 static void
 155 drm_encoder_disable(struct drm_encoder *encoder)
 156 {
 157         const struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
 158
 159         if (!encoder_funcs)
 160                 return;
 161
 162         drm_bridge_disable(encoder->bridge);
 163
 164         if (encoder_funcs->disable)
 165                 (*encoder_funcs->disable)(encoder);
 166         else if (encoder_funcs->dpms)
 167                 (*encoder_funcs->dpms)(encoder, DRM_MODE_DPMS_OFF);
 168
 169         drm_bridge_post_disable(encoder->bridge);
 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                 crtc->enabled = drm_helper_crtc_in_use(crtc);
 190                 if (!crtc->enabled) {
 191                         if (crtc_funcs->disable)
 192                                 (*crtc_funcs->disable)(crtc);
 193                         else
 194                                 (*crtc_funcs->dpms)(crtc, DRM_MODE_DPMS_OFF);
 195                         crtc->primary->fb = NULL;
 196                 }
 197         }
 198 }
 199
 200 /**
 201  * drm_helper_disable_unused_functions - disable unused objects
 202  * @dev: DRM device
 203  *
 204  * This function walks through the entire mode setting configuration of @dev. It
 205  * will remove any CRTC links of unused encoders and encoder links of
 206  * disconnected connectors. Then it will disable all unused encoders and CRTCs
 207  * either by calling their disable callback if available or by calling their
 208  * dpms callback with DRM_MODE_DPMS_OFF.
 209  *
 210  * NOTE:
 211  *
 212  * This function is part of the legacy modeset helper library and will cause
 213  * major confusion with atomic drivers. This is because atomic helpers guarantee
 214  * to never call ->disable() hooks on a disabled function, or ->enable() hooks
 215  * on an enabled functions. drm_helper_disable_unused_functions() on the other
 216  * hand throws such guarantees into the wind and calls disable hooks
 217  * unconditionally on unused functions.
 218  */
 219 void drm_helper_disable_unused_functions(struct drm_device *dev)
 220 {
 221         WARN_ON(drm_drv_uses_atomic_modeset(dev));
 222
 223         drm_modeset_lock_all(dev);
 224         __drm_helper_disable_unused_functions(dev);
 225         drm_modeset_unlock_all(dev);
 226 }
 227 EXPORT_SYMBOL(drm_helper_disable_unused_functions);
 228
 229 /*
 230  * Check the CRTC we're going to map each output to vs. its current
 231  * CRTC.  If they don't match, we have to disable the output and the CRTC
 232  * since the driver will have to re-route things.
 233  */
 234 static void
 235 drm_crtc_prepare_encoders(struct drm_device *dev)
 236 {
 237         const struct drm_encoder_helper_funcs *encoder_funcs;
 238         struct drm_encoder *encoder;
 239
 240         drm_for_each_encoder(encoder, dev) {
 241                 encoder_funcs = encoder->helper_private;
 242                 if (!encoder_funcs)
 243                         continue;
 244
 245                 /* Disable unused encoders */
 246                 if (encoder->crtc == NULL)
 247                         drm_encoder_disable(encoder);
 248                 /* Disable encoders whose CRTC is about to change */
 249                 if (encoder_funcs->get_crtc &&
 250                     encoder->crtc != (*encoder_funcs->get_crtc)(encoder))
 251                         drm_encoder_disable(encoder);
 252         }
 253 }
 254
 255 /**
 256  * drm_crtc_helper_set_mode - internal helper to set a mode
 257  * @crtc: CRTC to program
 258  * @mode: mode to use
 259  * @x: horizontal offset into the surface
 260  * @y: vertical offset into the surface
 261  * @old_fb: old framebuffer, for cleanup
 262  *
 263  * Try to set @mode on @crtc.  Give @crtc and its associated connectors a chance
 264  * to fixup or reject the mode prior to trying to set it. This is an internal
 265  * helper that drivers could e.g. use to update properties that require the
 266  * entire output pipe to be disabled and re-enabled in a new configuration. For
 267  * example for changing whether audio is enabled on a hdmi link or for changing
 268  * panel fitter or dither attributes. It is also called by the
 269  * drm_crtc_helper_set_config() helper function to drive the mode setting
 270  * sequence.
 271  *
 272  * Returns:
 273  * True if the mode was set successfully, false otherwise.
 274  */
 275 bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
 276                               struct drm_display_mode *mode,
 277                               int x, int y,
 278                               struct drm_framebuffer *old_fb)
 279 {
 280         struct drm_device *dev = crtc->dev;
 281         struct drm_display_mode *adjusted_mode, saved_mode, saved_hwmode;
 282         const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 283         const struct drm_encoder_helper_funcs *encoder_funcs;
 284         int saved_x, saved_y;
 285         bool saved_enabled;
 286         struct drm_encoder *encoder;
 287         bool ret = true;
 288
 289         WARN_ON(drm_drv_uses_atomic_modeset(dev));
 290
 291         drm_warn_on_modeset_not_all_locked(dev);
 292
 293         saved_enabled = crtc->enabled;
 294         crtc->enabled = drm_helper_crtc_in_use(crtc);
 295         if (!crtc->enabled)
 296                 return true;
 297
 298         adjusted_mode = drm_mode_duplicate(dev, mode);
 299         if (!adjusted_mode) {
 300                 crtc->enabled = saved_enabled;
 301                 return false;
 302         }
 303
 304         saved_mode = crtc->mode;
 305         saved_hwmode = crtc->hwmode;
 306         saved_x = crtc->x;
 307         saved_y = crtc->y;
 308
 309         /* Update crtc values up front so the driver can rely on them for mode
 310          * setting.
 311          */
 312         crtc->mode = *mode;
 313         crtc->x = x;
 314         crtc->y = y;
 315
 316         /* Pass our mode to the connectors and the CRTC to give them a chance to
 317          * adjust it according to limitations or connector properties, and also
 318          * a chance to reject the mode entirely.
 319          */
 320         drm_for_each_encoder(encoder, dev) {
 321
 322                 if (encoder->crtc != crtc)
 323                         continue;
 324
 325                 encoder_funcs = encoder->helper_private;
 326                 if (!encoder_funcs)
 327                         continue;
 328
 329                 ret = drm_bridge_mode_fixup(encoder->bridge,
 330                         mode, adjusted_mode);
 331                 if (!ret) {
 332                         DRM_DEBUG_KMS("Bridge fixup failed\n");
 333                         goto done;
 334                 }
 335
 336                 encoder_funcs = encoder->helper_private;
 337                 if (encoder_funcs->mode_fixup) {
 338                         if (!(ret = encoder_funcs->mode_fixup(encoder, mode,
 339                                                               adjusted_mode))) {
 340                                 DRM_DEBUG_KMS("Encoder fixup failed\n");
 341                                 goto done;
 342                         }
 343                 }
 344         }
 345
 346         if (crtc_funcs->mode_fixup) {
 347                 if (!(ret = crtc_funcs->mode_fixup(crtc, mode,
 348                                                 adjusted_mode))) {
 349                         DRM_DEBUG_KMS("CRTC fixup failed\n");
 350                         goto done;
 351                 }
 352         }
 353         DRM_DEBUG_KMS("[CRTC:%d:%s]\n", crtc->base.id, crtc->name);
 354
 355         crtc->hwmode = *adjusted_mode;
 356
 357         /* Prepare the encoders and CRTCs before setting the mode. */
 358         drm_for_each_encoder(encoder, dev) {
 359
 360                 if (encoder->crtc != crtc)
 361                         continue;
 362
 363                 encoder_funcs = encoder->helper_private;
 364                 if (!encoder_funcs)
 365                         continue;
 366
 367                 drm_bridge_disable(encoder->bridge);
 368
 369                 /* Disable the encoders as the first thing we do. */
 370                 if (encoder_funcs->prepare)
 371                         encoder_funcs->prepare(encoder);
 372
 373                 drm_bridge_post_disable(encoder->bridge);
 374         }
 375
 376         drm_crtc_prepare_encoders(dev);
 377
 378         crtc_funcs->prepare(crtc);
 379
 380         /* Set up the DPLL and any encoders state that needs to adjust or depend
 381          * on the DPLL.
 382          */
 383         ret = !crtc_funcs->mode_set(crtc, mode, adjusted_mode, x, y, old_fb);
 384         if (!ret)
 385             goto done;
 386
 387         drm_for_each_encoder(encoder, dev) {
 388
 389                 if (encoder->crtc != crtc)
 390                         continue;
 391
 392                 encoder_funcs = encoder->helper_private;
 393                 if (!encoder_funcs)
 394                         continue;
 395
 396                 DRM_DEBUG_KMS("[ENCODER:%d:%s] set [MODE:%s]\n",
 397                         encoder->base.id, encoder->name, mode->name);
 398                 if (encoder_funcs->mode_set)
 399                         encoder_funcs->mode_set(encoder, mode, adjusted_mode);
 400
 401                 drm_bridge_mode_set(encoder->bridge, mode, adjusted_mode);
 402         }
 403
 404         /* Now enable the clocks, plane, pipe, and connectors that we set up. */
 405         crtc_funcs->commit(crtc);
 406
 407         drm_for_each_encoder(encoder, dev) {
 408
 409                 if (encoder->crtc != crtc)
 410                         continue;
 411
 412                 encoder_funcs = encoder->helper_private;
 413                 if (!encoder_funcs)
 414                         continue;
 415
 416                 drm_bridge_pre_enable(encoder->bridge);
 417
 418                 if (encoder_funcs->commit)
 419                         encoder_funcs->commit(encoder);
 420
 421                 drm_bridge_enable(encoder->bridge);
 422         }
 423
 424         /* Calculate and store various constants which
 425          * are later needed by vblank and swap-completion
 426          * timestamping. They are derived from true hwmode.
 427          */
 428         drm_calc_timestamping_constants(crtc, &crtc->hwmode);
 429
 430         /* FIXME: add subpixel order */
 431 done:
 432         drm_mode_destroy(dev, adjusted_mode);
 433         if (!ret) {
 434                 crtc->enabled = saved_enabled;
 435                 crtc->mode = saved_mode;
 436                 crtc->hwmode = saved_hwmode;
 437                 crtc->x = saved_x;
 438                 crtc->y = saved_y;
 439         }
 440
 441         return ret;
 442 }
 443 EXPORT_SYMBOL(drm_crtc_helper_set_mode);
 444
 445 static void
 446 drm_crtc_helper_disable(struct drm_crtc *crtc)
 447 {
 448         struct drm_device *dev = crtc->dev;
 449         struct drm_connector *connector;
 450         struct drm_encoder *encoder;
 451
 452         /* Decouple all encoders and their attached connectors from this crtc */
 453         drm_for_each_encoder(encoder, dev) {
 454                 struct drm_connector_list_iter conn_iter;
 455
 456                 if (encoder->crtc != crtc)
 457                         continue;
 458
 459                 drm_connector_list_iter_begin(dev, &conn_iter);
 460                 drm_for_each_connector_iter(connector, &conn_iter) {
 461                         if (connector->encoder != encoder)
 462                                 continue;
 463
 464                         connector->encoder = NULL;
 465
 466                         /*
 467                          * drm_helper_disable_unused_functions() ought to be
 468                          * doing this, but since we've decoupled the encoder
 469                          * from the connector above, the required connection
 470                          * between them is henceforth no longer available.
 471                          */
 472                         connector->dpms = DRM_MODE_DPMS_OFF;
 473
 474                         /* we keep a reference while the encoder is bound */
 475                         drm_connector_put(connector);
 476                 }
 477                 drm_connector_list_iter_end(&conn_iter);
 478         }
 479
 480         __drm_helper_disable_unused_functions(dev);
 481 }
 482
 483 /**
 484  * drm_crtc_helper_set_config - set a new config from userspace
 485  * @set: mode set configuration
 486  * @ctx: lock acquire context, not used here
 487  *
 488  * The drm_crtc_helper_set_config() helper function implements the of
 489  * &drm_crtc_funcs.set_config callback for drivers using the legacy CRTC
 490  * helpers.
 491  *
 492  * It first tries to locate the best encoder for each connector by calling the
 493  * connector @drm_connector_helper_funcs.best_encoder helper operation.
 494  *
 495  * After locating the appropriate encoders, the helper function will call the
 496  * mode_fixup encoder and CRTC helper operations to adjust the requested mode,
 497  * or reject it completely in which case an error will be returned to the
 498  * application. If the new configuration after mode adjustment is identical to
 499  * the current configuration the helper function will return without performing
 500  * any other operation.
 501  *
 502  * If the adjusted mode is identical to the current mode but changes to the
 503  * frame buffer need to be applied, the drm_crtc_helper_set_config() function
 504  * will call the CRTC &drm_crtc_helper_funcs.mode_set_base helper operation.
 505  *
 506  * If the adjusted mode differs from the current mode, or if the
 507  * ->mode_set_base() helper operation is not provided, the helper function
 508  * performs a full mode set sequence by calling the ->prepare(), ->mode_set()
 509  * and ->commit() CRTC and encoder helper operations, in that order.
 510  * Alternatively it can also use the dpms and disable helper operations. For
 511  * details see &struct drm_crtc_helper_funcs and struct
 512  * &drm_encoder_helper_funcs.
 513  *
 514  * This function is deprecated.  New drivers must implement atomic modeset
 515  * support, for which this function is unsuitable. Instead drivers should use
 516  * drm_atomic_helper_set_config().
 517  *
 518  * Returns:
 519  * Returns 0 on success, negative errno numbers on failure.
 520  */
 521 int drm_crtc_helper_set_config(struct drm_mode_set *set,
 522                                struct drm_modeset_acquire_ctx *ctx)
 523 {
 524         struct drm_device *dev;
 525         struct drm_crtc **save_encoder_crtcs, *new_crtc;
 526         struct drm_encoder **save_connector_encoders, *new_encoder, *encoder;
 527         bool mode_changed = false; /* if true do a full mode set */
 528         bool fb_changed = false; /* if true and !mode_changed just do a flip */
 529         struct drm_connector *connector;
 530         struct drm_connector_list_iter conn_iter;
 531         int count = 0, ro, fail = 0;
 532         const struct drm_crtc_helper_funcs *crtc_funcs;
 533         struct drm_mode_set save_set;
 534         int ret;
 535         int i;
 536
 537         DRM_DEBUG_KMS("\n");
 538
 539         BUG_ON(!set);
 540         BUG_ON(!set->crtc);
 541         BUG_ON(!set->crtc->helper_private);
 542
 543         /* Enforce sane interface api - has been abused by the fb helper. */
 544         BUG_ON(!set->mode && set->fb);
 545         BUG_ON(set->fb && set->num_connectors == 0);
 546
 547         crtc_funcs = set->crtc->helper_private;
 548
 549         dev = set->crtc->dev;
 550         WARN_ON(drm_drv_uses_atomic_modeset(dev));
 551
 552         if (!set->mode)
 553                 set->fb = NULL;
 554
 555         if (set->fb) {
 556                 DRM_DEBUG_KMS("[CRTC:%d:%s] [FB:%d] #connectors=%d (x y) (%i %i)\n",
 557                               set->crtc->base.id, set->crtc->name,
 558                               set->fb->base.id,
 559                               (int)set->num_connectors, set->x, set->y);
 560         } else {
 561                 DRM_DEBUG_KMS("[CRTC:%d:%s] [NOFB]\n",
 562                               set->crtc->base.id, set->crtc->name);
 563                 drm_crtc_helper_disable(set->crtc);
 564                 return 0;
 565         }
 566
 567         drm_warn_on_modeset_not_all_locked(dev);
 568
 569         /*
 570          * Allocate space for the backup of all (non-pointer) encoder and
 571          * connector data.
 572          */
 573         save_encoder_crtcs = kcalloc(dev->mode_config.num_encoder,
 574                                 sizeof(struct drm_crtc *), GFP_KERNEL);
 575         if (!save_encoder_crtcs)
 576                 return -ENOMEM;
 577
 578         save_connector_encoders = kcalloc(dev->mode_config.num_connector,
 579                                 sizeof(struct drm_encoder *), GFP_KERNEL);
 580         if (!save_connector_encoders) {
 581                 kfree(save_encoder_crtcs);
 582                 return -ENOMEM;
 583         }
 584
 585         /*
 586          * Copy data. Note that driver private data is not affected.
 587          * Should anything bad happen only the expected state is
 588          * restored, not the drivers personal bookkeeping.
 589          */
 590         count = 0;
 591         drm_for_each_encoder(encoder, dev) {
 592                 save_encoder_crtcs[count++] = encoder->crtc;
 593         }
 594
 595         count = 0;
 596         drm_connector_list_iter_begin(dev, &conn_iter);
 597         drm_for_each_connector_iter(connector, &conn_iter)
 598                 save_connector_encoders[count++] = connector->encoder;
 599         drm_connector_list_iter_end(&conn_iter);
 600
 601         save_set.crtc = set->crtc;
 602         save_set.mode = &set->crtc->mode;
 603         save_set.x = set->crtc->x;
 604         save_set.y = set->crtc->y;
 605         save_set.fb = set->crtc->primary->fb;
 606
 607         /* We should be able to check here if the fb has the same properties
 608          * and then just flip_or_move it */
 609         if (set->crtc->primary->fb != set->fb) {
 610                 /* If we have no fb then treat it as a full mode set */
 611                 if (set->crtc->primary->fb == NULL) {
 612                         DRM_DEBUG_KMS("crtc has no fb, full mode set\n");
 613                         mode_changed = true;
 614                 } else if (set->fb->format != set->crtc->primary->fb->format) {
 615                         mode_changed = true;
 616                 } else
 617                         fb_changed = true;
 618         }
 619
 620         if (set->x != set->crtc->x || set->y != set->crtc->y)
 621                 fb_changed = true;
 622
 623         if (!drm_mode_equal(set->mode, &set->crtc->mode)) {
 624                 DRM_DEBUG_KMS("modes are different, full mode set\n");
 625                 drm_mode_debug_printmodeline(&set->crtc->mode);
 626                 drm_mode_debug_printmodeline(set->mode);
 627                 mode_changed = true;
 628         }
 629
 630         /* take a reference on all unbound connectors in set, reuse the
 631          * already taken reference for bound connectors
 632          */
 633         for (ro = 0; ro < set->num_connectors; ro++) {
 634                 if (set->connectors[ro]->encoder)
 635                         continue;
 636                 drm_connector_get(set->connectors[ro]);
 637         }
 638
 639         /* a) traverse passed in connector list and get encoders for them */
 640         count = 0;
 641         drm_connector_list_iter_begin(dev, &conn_iter);
 642         drm_for_each_connector_iter(connector, &conn_iter) {
 643                 const struct drm_connector_helper_funcs *connector_funcs =
 644                         connector->helper_private;
 645                 new_encoder = connector->encoder;
 646                 for (ro = 0; ro < set->num_connectors; ro++) {
 647                         if (set->connectors[ro] == connector) {
 648                                 new_encoder = connector_funcs->best_encoder(connector);
 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         struct drm_bridge *bridge = encoder->bridge;
 821         const struct drm_encoder_helper_funcs *encoder_funcs;
 822
 823         encoder_funcs = encoder->helper_private;
 824         if (!encoder_funcs)
 825                 return;
 826
 827         if (mode == DRM_MODE_DPMS_ON)
 828                 drm_bridge_pre_enable(bridge);
 829         else
 830                 drm_bridge_disable(bridge);
 831
 832         if (encoder_funcs->dpms)
 833                 encoder_funcs->dpms(encoder, mode);
 834
 835         if (mode == DRM_MODE_DPMS_ON)
 836                 drm_bridge_enable(bridge);
 837         else
 838                 drm_bridge_post_disable(bridge);
 839 }
 840
 841 static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
 842 {
 843         int dpms = DRM_MODE_DPMS_OFF;
 844         struct drm_connector *connector;
 845         struct drm_connector_list_iter conn_iter;
 846         struct drm_device *dev = crtc->dev;
 847
 848         drm_connector_list_iter_begin(dev, &conn_iter);
 849         drm_for_each_connector_iter(connector, &conn_iter)
 850                 if (connector->encoder && connector->encoder->crtc == crtc)
 851                         if (connector->dpms < dpms)
 852                                 dpms = connector->dpms;
 853         drm_connector_list_iter_end(&conn_iter);
 854
 855         return dpms;
 856 }
 857
 858 /**
 859  * drm_helper_connector_dpms() - connector dpms helper implementation
 860  * @connector: affected connector
 861  * @mode: DPMS mode
 862  *
 863  * The drm_helper_connector_dpms() helper function implements the
 864  * &drm_connector_funcs.dpms callback for drivers using the legacy CRTC
 865  * helpers.
 866  *
 867  * This is the main helper function provided by the CRTC helper framework for
 868  * implementing the DPMS connector attribute. It computes the new desired DPMS
 869  * state for all encoders and CRTCs in the output mesh and calls the
 870  * &drm_crtc_helper_funcs.dpms and &drm_encoder_helper_funcs.dpms callbacks
 871  * provided by the driver.
 872  *
 873  * This function is deprecated.  New drivers must implement atomic modeset
 874  * support, where DPMS is handled in the DRM core.
 875  *
 876  * Returns:
 877  * Always returns 0.
 878  */
 879 int drm_helper_connector_dpms(struct drm_connector *connector, int mode)
 880 {
 881         struct drm_encoder *encoder = connector->encoder;
 882         struct drm_crtc *crtc = encoder ? encoder->crtc : NULL;
 883         int old_dpms, encoder_dpms = DRM_MODE_DPMS_OFF;
 884
 885         WARN_ON(drm_drv_uses_atomic_modeset(connector->dev));
 886
 887         if (mode == connector->dpms)
 888                 return 0;
 889
 890         old_dpms = connector->dpms;
 891         connector->dpms = mode;
 892
 893         if (encoder)
 894                 encoder_dpms = drm_helper_choose_encoder_dpms(encoder);
 895
 896         /* from off to on, do crtc then encoder */
 897         if (mode < old_dpms) {
 898                 if (crtc) {
 899                         const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 900                         if (crtc_funcs->dpms)
 901                                 (*crtc_funcs->dpms) (crtc,
 902                                                      drm_helper_choose_crtc_dpms(crtc));
 903                 }
 904                 if (encoder)
 905                         drm_helper_encoder_dpms(encoder, encoder_dpms);
 906         }
 907
 908         /* from on to off, do encoder then crtc */
 909         if (mode > old_dpms) {
 910                 if (encoder)
 911                         drm_helper_encoder_dpms(encoder, encoder_dpms);
 912                 if (crtc) {
 913                         const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 914                         if (crtc_funcs->dpms)
 915                                 (*crtc_funcs->dpms) (crtc,
 916                                                      drm_helper_choose_crtc_dpms(crtc));
 917                 }
 918         }
 919
 920         return 0;
 921 }
 922 EXPORT_SYMBOL(drm_helper_connector_dpms);
 923
 924 /**
 925  * drm_helper_resume_force_mode - force-restore mode setting configuration
 926  * @dev: drm_device which should be restored
 927  *
 928  * Drivers which use the mode setting helpers can use this function to
 929  * force-restore the mode setting configuration e.g. on resume or when something
 930  * else might have trampled over the hw state (like some overzealous old BIOSen
 931  * tended to do).
 932  *
 933  * This helper doesn't provide a error return value since restoring the old
 934  * config should never fail due to resource allocation issues since the driver
 935  * has successfully set the restored configuration already. Hence this should
 936  * boil down to the equivalent of a few dpms on calls, which also don't provide
 937  * an error code.
 938  *
 939  * Drivers where simply restoring an old configuration again might fail (e.g.
 940  * due to slight differences in allocating shared resources when the
 941  * configuration is restored in a different order than when userspace set it up)
 942  * need to use their own restore logic.
 943  *
 944  * This function is deprecated. New drivers should implement atomic mode-
 945  * setting and use the atomic suspend/resume helpers.
 946  *
 947  * See also:
 948  * drm_atomic_helper_suspend(), drm_atomic_helper_resume()
 949  */
 950 void drm_helper_resume_force_mode(struct drm_device *dev)
 951 {
 952         struct drm_crtc *crtc;
 953         struct drm_encoder *encoder;
 954         const struct drm_crtc_helper_funcs *crtc_funcs;
 955         int encoder_dpms;
 956         bool ret;
 957
 958         WARN_ON(drm_drv_uses_atomic_modeset(dev));
 959
 960         drm_modeset_lock_all(dev);
 961         drm_for_each_crtc(crtc, dev) {
 962
 963                 if (!crtc->enabled)
 964                         continue;
 965
 966                 ret = drm_crtc_helper_set_mode(crtc, &crtc->mode,
 967                                                crtc->x, crtc->y, crtc->primary->fb);
 968
 969                 /* Restoring the old config should never fail! */
 970                 if (ret == false)
 971                         DRM_ERROR("failed to set mode on crtc %p\n", crtc);
 972
 973                 /* Turn off outputs that were already powered off */
 974                 if (drm_helper_choose_crtc_dpms(crtc)) {
 975                         drm_for_each_encoder(encoder, dev) {
 976
 977                                 if(encoder->crtc != crtc)
 978                                         continue;
 979
 980                                 encoder_dpms = drm_helper_choose_encoder_dpms(
 981                                                         encoder);
 982
 983                                 drm_helper_encoder_dpms(encoder, encoder_dpms);
 984                         }
 985
 986                         crtc_funcs = crtc->helper_private;
 987                         if (crtc_funcs->dpms)
 988                                 (*crtc_funcs->dpms) (crtc,
 989                                                      drm_helper_choose_crtc_dpms(crtc));
 990                 }
 991         }
 992
 993         /* disable the unused connectors while restoring the modesetting */
 994         __drm_helper_disable_unused_functions(dev);
 995         drm_modeset_unlock_all(dev);
 996 }
 997 EXPORT_SYMBOL(drm_helper_resume_force_mode);
 998
 999 /**
1000  * drm_helper_force_disable_all - Forcibly turn off all enabled CRTCs
1001  * @dev: DRM device whose CRTCs to turn off
1002  *
1003  * Drivers may want to call this on unload to ensure that all displays are
1004  * unlit and the GPU is in a consistent, low power state. Takes modeset locks.
1005  *
1006  * Note: This should only be used by non-atomic legacy drivers. For an atomic
1007  * version look at drm_atomic_helper_shutdown().
1008  *
1009  * Returns:
1010  * Zero on success, error code on failure.
1011  */
1012 int drm_helper_force_disable_all(struct drm_device *dev)
1013 {
1014         struct drm_crtc *crtc;
1015         int ret = 0;
1016
1017         drm_modeset_lock_all(dev);
1018         drm_for_each_crtc(crtc, dev)
1019                 if (crtc->enabled) {
1020                         struct drm_mode_set set = {
1021                                 .crtc = crtc,
1022                         };
1023
1024                         ret = drm_mode_set_config_internal(&set);
1025                         if (ret)
1026                                 goto out;
1027                 }
1028 out:
1029         drm_modeset_unlock_all(dev);
1030         return ret;
1031 }
1032 EXPORT_SYMBOL(drm_helper_force_disable_all);