linux/drivers/gpu/drm/drm_atomic_state_helper.c
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   1/*
   2 * Copyright (C) 2018 Intel Corp.
   3 *
   4 * Permission is hereby granted, free of charge, to any person obtaining a
   5 * copy of this software and associated documentation files (the "Software"),
   6 * to deal in the Software without restriction, including without limitation
   7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8 * and/or sell copies of the Software, and to permit persons to whom the
   9 * Software is furnished to do so, subject to the following conditions:
  10 *
  11 * The above copyright notice and this permission notice shall be included in
  12 * all copies or substantial portions of the Software.
  13 *
  14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20 * OTHER DEALINGS IN THE SOFTWARE.
  21 *
  22 * Authors:
  23 * Rob Clark <robdclark@gmail.com>
  24 * Daniel Vetter <daniel.vetter@ffwll.ch>
  25 */
  26
  27#include <drm/drm_atomic.h>
  28#include <drm/drm_atomic_state_helper.h>
  29#include <drm/drm_bridge.h>
  30#include <drm/drm_connector.h>
  31#include <drm/drm_crtc.h>
  32#include <drm/drm_device.h>
  33#include <drm/drm_plane.h>
  34#include <drm/drm_print.h>
  35#include <drm/drm_vblank.h>
  36#include <drm/drm_writeback.h>
  37
  38#include <linux/slab.h>
  39#include <linux/dma-fence.h>
  40
  41/**
  42 * DOC: atomic state reset and initialization
  43 *
  44 * Both the drm core and the atomic helpers assume that there is always the full
  45 * and correct atomic software state for all connectors, CRTCs and planes
  46 * available. Which is a bit a problem on driver load and also after system
  47 * suspend. One way to solve this is to have a hardware state read-out
  48 * infrastructure which reconstructs the full software state (e.g. the i915
  49 * driver).
  50 *
  51 * The simpler solution is to just reset the software state to everything off,
  52 * which is easiest to do by calling drm_mode_config_reset(). To facilitate this
  53 * the atomic helpers provide default reset implementations for all hooks.
  54 *
  55 * On the upside the precise state tracking of atomic simplifies system suspend
  56 * and resume a lot. For drivers using drm_mode_config_reset() a complete recipe
  57 * is implemented in drm_atomic_helper_suspend() and drm_atomic_helper_resume().
  58 * For other drivers the building blocks are split out, see the documentation
  59 * for these functions.
  60 */
  61
  62/**
  63 * __drm_atomic_helper_crtc_state_reset - reset the CRTC state
  64 * @crtc_state: atomic CRTC state, must not be NULL
  65 * @crtc: CRTC object, must not be NULL
  66 *
  67 * Initializes the newly allocated @crtc_state with default
  68 * values. This is useful for drivers that subclass the CRTC state.
  69 */
  70void
  71__drm_atomic_helper_crtc_state_reset(struct drm_crtc_state *crtc_state,
  72                                     struct drm_crtc *crtc)
  73{
  74        crtc_state->crtc = crtc;
  75}
  76EXPORT_SYMBOL(__drm_atomic_helper_crtc_state_reset);
  77
  78/**
  79 * __drm_atomic_helper_crtc_reset - reset state on CRTC
  80 * @crtc: drm CRTC
  81 * @crtc_state: CRTC state to assign
  82 *
  83 * Initializes the newly allocated @crtc_state and assigns it to
  84 * the &drm_crtc->state pointer of @crtc, usually required when
  85 * initializing the drivers or when called from the &drm_crtc_funcs.reset
  86 * hook.
  87 *
  88 * This is useful for drivers that subclass the CRTC state.
  89 */
  90void
  91__drm_atomic_helper_crtc_reset(struct drm_crtc *crtc,
  92                               struct drm_crtc_state *crtc_state)
  93{
  94        if (crtc_state)
  95                __drm_atomic_helper_crtc_state_reset(crtc_state, crtc);
  96
  97        if (drm_dev_has_vblank(crtc->dev))
  98                drm_crtc_vblank_reset(crtc);
  99
 100        crtc->state = crtc_state;
 101}
 102EXPORT_SYMBOL(__drm_atomic_helper_crtc_reset);
 103
 104/**
 105 * drm_atomic_helper_crtc_reset - default &drm_crtc_funcs.reset hook for CRTCs
 106 * @crtc: drm CRTC
 107 *
 108 * Resets the atomic state for @crtc by freeing the state pointer (which might
 109 * be NULL, e.g. at driver load time) and allocating a new empty state object.
 110 */
 111void drm_atomic_helper_crtc_reset(struct drm_crtc *crtc)
 112{
 113        struct drm_crtc_state *crtc_state =
 114                kzalloc(sizeof(*crtc->state), GFP_KERNEL);
 115
 116        if (crtc->state)
 117                crtc->funcs->atomic_destroy_state(crtc, crtc->state);
 118
 119        __drm_atomic_helper_crtc_reset(crtc, crtc_state);
 120}
 121EXPORT_SYMBOL(drm_atomic_helper_crtc_reset);
 122
 123/**
 124 * __drm_atomic_helper_crtc_duplicate_state - copy atomic CRTC state
 125 * @crtc: CRTC object
 126 * @state: atomic CRTC state
 127 *
 128 * Copies atomic state from a CRTC's current state and resets inferred values.
 129 * This is useful for drivers that subclass the CRTC state.
 130 */
 131void __drm_atomic_helper_crtc_duplicate_state(struct drm_crtc *crtc,
 132                                              struct drm_crtc_state *state)
 133{
 134        memcpy(state, crtc->state, sizeof(*state));
 135
 136        if (state->mode_blob)
 137                drm_property_blob_get(state->mode_blob);
 138        if (state->degamma_lut)
 139                drm_property_blob_get(state->degamma_lut);
 140        if (state->ctm)
 141                drm_property_blob_get(state->ctm);
 142        if (state->gamma_lut)
 143                drm_property_blob_get(state->gamma_lut);
 144        state->mode_changed = false;
 145        state->active_changed = false;
 146        state->planes_changed = false;
 147        state->connectors_changed = false;
 148        state->color_mgmt_changed = false;
 149        state->zpos_changed = false;
 150        state->commit = NULL;
 151        state->event = NULL;
 152        state->async_flip = false;
 153
 154        /* Self refresh should be canceled when a new update is available */
 155        state->active = drm_atomic_crtc_effectively_active(state);
 156        state->self_refresh_active = false;
 157}
 158EXPORT_SYMBOL(__drm_atomic_helper_crtc_duplicate_state);
 159
 160/**
 161 * drm_atomic_helper_crtc_duplicate_state - default state duplicate hook
 162 * @crtc: drm CRTC
 163 *
 164 * Default CRTC state duplicate hook for drivers which don't have their own
 165 * subclassed CRTC state structure.
 166 */
 167struct drm_crtc_state *
 168drm_atomic_helper_crtc_duplicate_state(struct drm_crtc *crtc)
 169{
 170        struct drm_crtc_state *state;
 171
 172        if (WARN_ON(!crtc->state))
 173                return NULL;
 174
 175        state = kmalloc(sizeof(*state), GFP_KERNEL);
 176        if (state)
 177                __drm_atomic_helper_crtc_duplicate_state(crtc, state);
 178
 179        return state;
 180}
 181EXPORT_SYMBOL(drm_atomic_helper_crtc_duplicate_state);
 182
 183/**
 184 * __drm_atomic_helper_crtc_destroy_state - release CRTC state
 185 * @state: CRTC state object to release
 186 *
 187 * Releases all resources stored in the CRTC state without actually freeing
 188 * the memory of the CRTC state. This is useful for drivers that subclass the
 189 * CRTC state.
 190 */
 191void __drm_atomic_helper_crtc_destroy_state(struct drm_crtc_state *state)
 192{
 193        if (state->commit) {
 194                /*
 195                 * In the event that a non-blocking commit returns
 196                 * -ERESTARTSYS before the commit_tail work is queued, we will
 197                 * have an extra reference to the commit object. Release it, if
 198                 * the event has not been consumed by the worker.
 199                 *
 200                 * state->event may be freed, so we can't directly look at
 201                 * state->event->base.completion.
 202                 */
 203                if (state->event && state->commit->abort_completion)
 204                        drm_crtc_commit_put(state->commit);
 205
 206                kfree(state->commit->event);
 207                state->commit->event = NULL;
 208
 209                drm_crtc_commit_put(state->commit);
 210        }
 211
 212        drm_property_blob_put(state->mode_blob);
 213        drm_property_blob_put(state->degamma_lut);
 214        drm_property_blob_put(state->ctm);
 215        drm_property_blob_put(state->gamma_lut);
 216}
 217EXPORT_SYMBOL(__drm_atomic_helper_crtc_destroy_state);
 218
 219/**
 220 * drm_atomic_helper_crtc_destroy_state - default state destroy hook
 221 * @crtc: drm CRTC
 222 * @state: CRTC state object to release
 223 *
 224 * Default CRTC state destroy hook for drivers which don't have their own
 225 * subclassed CRTC state structure.
 226 */
 227void drm_atomic_helper_crtc_destroy_state(struct drm_crtc *crtc,
 228                                          struct drm_crtc_state *state)
 229{
 230        __drm_atomic_helper_crtc_destroy_state(state);
 231        kfree(state);
 232}
 233EXPORT_SYMBOL(drm_atomic_helper_crtc_destroy_state);
 234
 235/**
 236 * __drm_atomic_helper_plane_state_reset - resets plane state to default values
 237 * @plane_state: atomic plane state, must not be NULL
 238 * @plane: plane object, must not be NULL
 239 *
 240 * Initializes the newly allocated @plane_state with default
 241 * values. This is useful for drivers that subclass the CRTC state.
 242 */
 243void __drm_atomic_helper_plane_state_reset(struct drm_plane_state *plane_state,
 244                                           struct drm_plane *plane)
 245{
 246        plane_state->plane = plane;
 247        plane_state->rotation = DRM_MODE_ROTATE_0;
 248
 249        plane_state->alpha = DRM_BLEND_ALPHA_OPAQUE;
 250        plane_state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
 251}
 252EXPORT_SYMBOL(__drm_atomic_helper_plane_state_reset);
 253
 254/**
 255 * __drm_atomic_helper_plane_reset - reset state on plane
 256 * @plane: drm plane
 257 * @plane_state: plane state to assign
 258 *
 259 * Initializes the newly allocated @plane_state and assigns it to
 260 * the &drm_crtc->state pointer of @plane, usually required when
 261 * initializing the drivers or when called from the &drm_plane_funcs.reset
 262 * hook.
 263 *
 264 * This is useful for drivers that subclass the plane state.
 265 */
 266void __drm_atomic_helper_plane_reset(struct drm_plane *plane,
 267                                     struct drm_plane_state *plane_state)
 268{
 269        if (plane_state)
 270                __drm_atomic_helper_plane_state_reset(plane_state, plane);
 271
 272        plane->state = plane_state;
 273}
 274EXPORT_SYMBOL(__drm_atomic_helper_plane_reset);
 275
 276/**
 277 * drm_atomic_helper_plane_reset - default &drm_plane_funcs.reset hook for planes
 278 * @plane: drm plane
 279 *
 280 * Resets the atomic state for @plane by freeing the state pointer (which might
 281 * be NULL, e.g. at driver load time) and allocating a new empty state object.
 282 */
 283void drm_atomic_helper_plane_reset(struct drm_plane *plane)
 284{
 285        if (plane->state)
 286                __drm_atomic_helper_plane_destroy_state(plane->state);
 287
 288        kfree(plane->state);
 289        plane->state = kzalloc(sizeof(*plane->state), GFP_KERNEL);
 290        if (plane->state)
 291                __drm_atomic_helper_plane_reset(plane, plane->state);
 292}
 293EXPORT_SYMBOL(drm_atomic_helper_plane_reset);
 294
 295/**
 296 * __drm_atomic_helper_plane_duplicate_state - copy atomic plane state
 297 * @plane: plane object
 298 * @state: atomic plane state
 299 *
 300 * Copies atomic state from a plane's current state. This is useful for
 301 * drivers that subclass the plane state.
 302 */
 303void __drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane,
 304                                               struct drm_plane_state *state)
 305{
 306        memcpy(state, plane->state, sizeof(*state));
 307
 308        if (state->fb)
 309                drm_framebuffer_get(state->fb);
 310
 311        state->fence = NULL;
 312        state->commit = NULL;
 313        state->fb_damage_clips = NULL;
 314}
 315EXPORT_SYMBOL(__drm_atomic_helper_plane_duplicate_state);
 316
 317/**
 318 * drm_atomic_helper_plane_duplicate_state - default state duplicate hook
 319 * @plane: drm plane
 320 *
 321 * Default plane state duplicate hook for drivers which don't have their own
 322 * subclassed plane state structure.
 323 */
 324struct drm_plane_state *
 325drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane)
 326{
 327        struct drm_plane_state *state;
 328
 329        if (WARN_ON(!plane->state))
 330                return NULL;
 331
 332        state = kmalloc(sizeof(*state), GFP_KERNEL);
 333        if (state)
 334                __drm_atomic_helper_plane_duplicate_state(plane, state);
 335
 336        return state;
 337}
 338EXPORT_SYMBOL(drm_atomic_helper_plane_duplicate_state);
 339
 340/**
 341 * __drm_atomic_helper_plane_destroy_state - release plane state
 342 * @state: plane state object to release
 343 *
 344 * Releases all resources stored in the plane state without actually freeing
 345 * the memory of the plane state. This is useful for drivers that subclass the
 346 * plane state.
 347 */
 348void __drm_atomic_helper_plane_destroy_state(struct drm_plane_state *state)
 349{
 350        if (state->fb)
 351                drm_framebuffer_put(state->fb);
 352
 353        if (state->fence)
 354                dma_fence_put(state->fence);
 355
 356        if (state->commit)
 357                drm_crtc_commit_put(state->commit);
 358
 359        drm_property_blob_put(state->fb_damage_clips);
 360}
 361EXPORT_SYMBOL(__drm_atomic_helper_plane_destroy_state);
 362
 363/**
 364 * drm_atomic_helper_plane_destroy_state - default state destroy hook
 365 * @plane: drm plane
 366 * @state: plane state object to release
 367 *
 368 * Default plane state destroy hook for drivers which don't have their own
 369 * subclassed plane state structure.
 370 */
 371void drm_atomic_helper_plane_destroy_state(struct drm_plane *plane,
 372                                           struct drm_plane_state *state)
 373{
 374        __drm_atomic_helper_plane_destroy_state(state);
 375        kfree(state);
 376}
 377EXPORT_SYMBOL(drm_atomic_helper_plane_destroy_state);
 378
 379/**
 380 * __drm_atomic_helper_connector_state_reset - reset the connector state
 381 * @conn_state: atomic connector state, must not be NULL
 382 * @connector: connectotr object, must not be NULL
 383 *
 384 * Initializes the newly allocated @conn_state with default
 385 * values. This is useful for drivers that subclass the connector state.
 386 */
 387void
 388__drm_atomic_helper_connector_state_reset(struct drm_connector_state *conn_state,
 389                                          struct drm_connector *connector)
 390{
 391        conn_state->connector = connector;
 392}
 393EXPORT_SYMBOL(__drm_atomic_helper_connector_state_reset);
 394
 395/**
 396 * __drm_atomic_helper_connector_reset - reset state on connector
 397 * @connector: drm connector
 398 * @conn_state: connector state to assign
 399 *
 400 * Initializes the newly allocated @conn_state and assigns it to
 401 * the &drm_connector->state pointer of @connector, usually required when
 402 * initializing the drivers or when called from the &drm_connector_funcs.reset
 403 * hook.
 404 *
 405 * This is useful for drivers that subclass the connector state.
 406 */
 407void
 408__drm_atomic_helper_connector_reset(struct drm_connector *connector,
 409                                    struct drm_connector_state *conn_state)
 410{
 411        if (conn_state)
 412                __drm_atomic_helper_connector_state_reset(conn_state, connector);
 413
 414        connector->state = conn_state;
 415}
 416EXPORT_SYMBOL(__drm_atomic_helper_connector_reset);
 417
 418/**
 419 * drm_atomic_helper_connector_reset - default &drm_connector_funcs.reset hook for connectors
 420 * @connector: drm connector
 421 *
 422 * Resets the atomic state for @connector by freeing the state pointer (which
 423 * might be NULL, e.g. at driver load time) and allocating a new empty state
 424 * object.
 425 */
 426void drm_atomic_helper_connector_reset(struct drm_connector *connector)
 427{
 428        struct drm_connector_state *conn_state =
 429                kzalloc(sizeof(*conn_state), GFP_KERNEL);
 430
 431        if (connector->state)
 432                __drm_atomic_helper_connector_destroy_state(connector->state);
 433
 434        kfree(connector->state);
 435        __drm_atomic_helper_connector_reset(connector, conn_state);
 436}
 437EXPORT_SYMBOL(drm_atomic_helper_connector_reset);
 438
 439/**
 440 * drm_atomic_helper_connector_tv_reset - Resets TV connector properties
 441 * @connector: DRM connector
 442 *
 443 * Resets the TV-related properties attached to a connector.
 444 */
 445void drm_atomic_helper_connector_tv_reset(struct drm_connector *connector)
 446{
 447        struct drm_cmdline_mode *cmdline = &connector->cmdline_mode;
 448        struct drm_connector_state *state = connector->state;
 449
 450        state->tv.margins.left = cmdline->tv_margins.left;
 451        state->tv.margins.right = cmdline->tv_margins.right;
 452        state->tv.margins.top = cmdline->tv_margins.top;
 453        state->tv.margins.bottom = cmdline->tv_margins.bottom;
 454}
 455EXPORT_SYMBOL(drm_atomic_helper_connector_tv_reset);
 456
 457/**
 458 * __drm_atomic_helper_connector_duplicate_state - copy atomic connector state
 459 * @connector: connector object
 460 * @state: atomic connector state
 461 *
 462 * Copies atomic state from a connector's current state. This is useful for
 463 * drivers that subclass the connector state.
 464 */
 465void
 466__drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector,
 467                                            struct drm_connector_state *state)
 468{
 469        memcpy(state, connector->state, sizeof(*state));
 470        if (state->crtc)
 471                drm_connector_get(connector);
 472        state->commit = NULL;
 473
 474        if (state->hdr_output_metadata)
 475                drm_property_blob_get(state->hdr_output_metadata);
 476
 477        /* Don't copy over a writeback job, they are used only once */
 478        state->writeback_job = NULL;
 479}
 480EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);
 481
 482/**
 483 * drm_atomic_helper_connector_duplicate_state - default state duplicate hook
 484 * @connector: drm connector
 485 *
 486 * Default connector state duplicate hook for drivers which don't have their own
 487 * subclassed connector state structure.
 488 */
 489struct drm_connector_state *
 490drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector)
 491{
 492        struct drm_connector_state *state;
 493
 494        if (WARN_ON(!connector->state))
 495                return NULL;
 496
 497        state = kmalloc(sizeof(*state), GFP_KERNEL);
 498        if (state)
 499                __drm_atomic_helper_connector_duplicate_state(connector, state);
 500
 501        return state;
 502}
 503EXPORT_SYMBOL(drm_atomic_helper_connector_duplicate_state);
 504
 505/**
 506 * __drm_atomic_helper_connector_destroy_state - release connector state
 507 * @state: connector state object to release
 508 *
 509 * Releases all resources stored in the connector state without actually
 510 * freeing the memory of the connector state. This is useful for drivers that
 511 * subclass the connector state.
 512 */
 513void
 514__drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state)
 515{
 516        if (state->crtc)
 517                drm_connector_put(state->connector);
 518
 519        if (state->commit)
 520                drm_crtc_commit_put(state->commit);
 521
 522        if (state->writeback_job)
 523                drm_writeback_cleanup_job(state->writeback_job);
 524
 525        drm_property_blob_put(state->hdr_output_metadata);
 526}
 527EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state);
 528
 529/**
 530 * drm_atomic_helper_connector_destroy_state - default state destroy hook
 531 * @connector: drm connector
 532 * @state: connector state object to release
 533 *
 534 * Default connector state destroy hook for drivers which don't have their own
 535 * subclassed connector state structure.
 536 */
 537void drm_atomic_helper_connector_destroy_state(struct drm_connector *connector,
 538                                          struct drm_connector_state *state)
 539{
 540        __drm_atomic_helper_connector_destroy_state(state);
 541        kfree(state);
 542}
 543EXPORT_SYMBOL(drm_atomic_helper_connector_destroy_state);
 544
 545/**
 546 * __drm_atomic_helper_private_obj_duplicate_state - copy atomic private state
 547 * @obj: CRTC object
 548 * @state: new private object state
 549 *
 550 * Copies atomic state from a private objects's current state and resets inferred values.
 551 * This is useful for drivers that subclass the private state.
 552 */
 553void __drm_atomic_helper_private_obj_duplicate_state(struct drm_private_obj *obj,
 554                                                     struct drm_private_state *state)
 555{
 556        memcpy(state, obj->state, sizeof(*state));
 557}
 558EXPORT_SYMBOL(__drm_atomic_helper_private_obj_duplicate_state);
 559
 560/**
 561 * __drm_atomic_helper_bridge_duplicate_state() - Copy atomic bridge state
 562 * @bridge: bridge object
 563 * @state: atomic bridge state
 564 *
 565 * Copies atomic state from a bridge's current state and resets inferred values.
 566 * This is useful for drivers that subclass the bridge state.
 567 */
 568void __drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge,
 569                                                struct drm_bridge_state *state)
 570{
 571        __drm_atomic_helper_private_obj_duplicate_state(&bridge->base,
 572                                                        &state->base);
 573        state->bridge = bridge;
 574}
 575EXPORT_SYMBOL(__drm_atomic_helper_bridge_duplicate_state);
 576
 577/**
 578 * drm_atomic_helper_bridge_duplicate_state() - Duplicate a bridge state object
 579 * @bridge: bridge object
 580 *
 581 * Allocates a new bridge state and initializes it with the current bridge
 582 * state values. This helper is meant to be used as a bridge
 583 * &drm_bridge_funcs.atomic_duplicate_state hook for bridges that don't
 584 * subclass the bridge state.
 585 */
 586struct drm_bridge_state *
 587drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge)
 588{
 589        struct drm_bridge_state *new;
 590
 591        if (WARN_ON(!bridge->base.state))
 592                return NULL;
 593
 594        new = kzalloc(sizeof(*new), GFP_KERNEL);
 595        if (new)
 596                __drm_atomic_helper_bridge_duplicate_state(bridge, new);
 597
 598        return new;
 599}
 600EXPORT_SYMBOL(drm_atomic_helper_bridge_duplicate_state);
 601
 602/**
 603 * drm_atomic_helper_bridge_destroy_state() - Destroy a bridge state object
 604 * @bridge: the bridge this state refers to
 605 * @state: bridge state to destroy
 606 *
 607 * Destroys a bridge state previously created by
 608 * &drm_atomic_helper_bridge_reset() or
 609 * &drm_atomic_helper_bridge_duplicate_state(). This helper is meant to be
 610 * used as a bridge &drm_bridge_funcs.atomic_destroy_state hook for bridges
 611 * that don't subclass the bridge state.
 612 */
 613void drm_atomic_helper_bridge_destroy_state(struct drm_bridge *bridge,
 614                                            struct drm_bridge_state *state)
 615{
 616        kfree(state);
 617}
 618EXPORT_SYMBOL(drm_atomic_helper_bridge_destroy_state);
 619
 620/**
 621 * __drm_atomic_helper_bridge_reset() - Initialize a bridge state to its
 622 *                                      default
 623 * @bridge: the bridge this state refers to
 624 * @state: bridge state to initialize
 625 *
 626 * Initializes the bridge state to default values. This is meant to be called
 627 * by the bridge &drm_bridge_funcs.atomic_reset hook for bridges that subclass
 628 * the bridge state.
 629 */
 630void __drm_atomic_helper_bridge_reset(struct drm_bridge *bridge,
 631                                      struct drm_bridge_state *state)
 632{
 633        memset(state, 0, sizeof(*state));
 634        state->bridge = bridge;
 635}
 636EXPORT_SYMBOL(__drm_atomic_helper_bridge_reset);
 637
 638/**
 639 * drm_atomic_helper_bridge_reset() - Allocate and initialize a bridge state
 640 *                                    to its default
 641 * @bridge: the bridge this state refers to
 642 *
 643 * Allocates the bridge state and initializes it to default values. This helper
 644 * is meant to be used as a bridge &drm_bridge_funcs.atomic_reset hook for
 645 * bridges that don't subclass the bridge state.
 646 */
 647struct drm_bridge_state *
 648drm_atomic_helper_bridge_reset(struct drm_bridge *bridge)
 649{
 650        struct drm_bridge_state *bridge_state;
 651
 652        bridge_state = kzalloc(sizeof(*bridge_state), GFP_KERNEL);
 653        if (!bridge_state)
 654                return ERR_PTR(-ENOMEM);
 655
 656        __drm_atomic_helper_bridge_reset(bridge, bridge_state);
 657        return bridge_state;
 658}
 659EXPORT_SYMBOL(drm_atomic_helper_bridge_reset);
 660