drivers/gpu/drm/rcar-du/rcar_du_kms.c

   1 /*
   2  * rcar_du_kms.c  --  R-Car Display Unit Mode Setting
   3  *
   4  * Copyright (C) 2013-2015 Renesas Electronics Corporation
   5  *
   6  * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  */
  13
  14 #include <drm/drmP.h>
  15 #include <drm/drm_atomic.h>
  16 #include <drm/drm_atomic_helper.h>
  17 #include <drm/drm_crtc.h>
  18 #include <drm/drm_crtc_helper.h>
  19 #include <drm/drm_fb_cma_helper.h>
  20 #include <drm/drm_gem_cma_helper.h>
  21
  22 #include <linux/of_graph.h>
  23 #include <linux/wait.h>
  24
  25 #include "rcar_du_crtc.h"
  26 #include "rcar_du_drv.h"
  27 #include "rcar_du_encoder.h"
  28 #include "rcar_du_kms.h"
  29 #include "rcar_du_lvdsenc.h"
  30 #include "rcar_du_regs.h"
  31 #include "rcar_du_vsp.h"
  32
  33 /* -----------------------------------------------------------------------------
  34  * Format helpers
  35  */
  36
  37 static const struct rcar_du_format_info rcar_du_format_infos[] = {
  38         {
  39                 .fourcc = DRM_FORMAT_RGB565,
  40                 .bpp = 16,
  41                 .planes = 1,
  42                 .pnmr = PnMR_SPIM_TP | PnMR_DDDF_16BPP,
  43                 .edf = PnDDCR4_EDF_NONE,
  44         }, {
  45                 .fourcc = DRM_FORMAT_ARGB1555,
  46                 .bpp = 16,
  47                 .planes = 1,
  48                 .pnmr = PnMR_SPIM_ALP | PnMR_DDDF_ARGB,
  49                 .edf = PnDDCR4_EDF_NONE,
  50         }, {
  51                 .fourcc = DRM_FORMAT_XRGB1555,
  52                 .bpp = 16,
  53                 .planes = 1,
  54                 .pnmr = PnMR_SPIM_ALP | PnMR_DDDF_ARGB,
  55                 .edf = PnDDCR4_EDF_NONE,
  56         }, {
  57                 .fourcc = DRM_FORMAT_XRGB8888,
  58                 .bpp = 32,
  59                 .planes = 1,
  60                 .pnmr = PnMR_SPIM_TP | PnMR_DDDF_16BPP,
  61                 .edf = PnDDCR4_EDF_RGB888,
  62         }, {
  63                 .fourcc = DRM_FORMAT_ARGB8888,
  64                 .bpp = 32,
  65                 .planes = 1,
  66                 .pnmr = PnMR_SPIM_ALP | PnMR_DDDF_16BPP,
  67                 .edf = PnDDCR4_EDF_ARGB8888,
  68         }, {
  69                 .fourcc = DRM_FORMAT_UYVY,
  70                 .bpp = 16,
  71                 .planes = 1,
  72                 .pnmr = PnMR_SPIM_TP_OFF | PnMR_DDDF_YC,
  73                 .edf = PnDDCR4_EDF_NONE,
  74         }, {
  75                 .fourcc = DRM_FORMAT_YUYV,
  76                 .bpp = 16,
  77                 .planes = 1,
  78                 .pnmr = PnMR_SPIM_TP_OFF | PnMR_DDDF_YC,
  79                 .edf = PnDDCR4_EDF_NONE,
  80         }, {
  81                 .fourcc = DRM_FORMAT_NV12,
  82                 .bpp = 12,
  83                 .planes = 2,
  84                 .pnmr = PnMR_SPIM_TP_OFF | PnMR_DDDF_YC,
  85                 .edf = PnDDCR4_EDF_NONE,
  86         }, {
  87                 .fourcc = DRM_FORMAT_NV21,
  88                 .bpp = 12,
  89                 .planes = 2,
  90                 .pnmr = PnMR_SPIM_TP_OFF | PnMR_DDDF_YC,
  91                 .edf = PnDDCR4_EDF_NONE,
  92         }, {
  93                 .fourcc = DRM_FORMAT_NV16,
  94                 .bpp = 16,
  95                 .planes = 2,
  96                 .pnmr = PnMR_SPIM_TP_OFF | PnMR_DDDF_YC,
  97                 .edf = PnDDCR4_EDF_NONE,
  98         },
  99         /* The following formats are not supported on Gen2 and thus have no
 100          * associated .pnmr or .edf settings.
 101          */
 102         {
 103                 .fourcc = DRM_FORMAT_NV61,
 104                 .bpp = 16,
 105                 .planes = 2,
 106         }, {
 107                 .fourcc = DRM_FORMAT_YUV420,
 108                 .bpp = 12,
 109                 .planes = 3,
 110         }, {
 111                 .fourcc = DRM_FORMAT_YVU420,
 112                 .bpp = 12,
 113                 .planes = 3,
 114         }, {
 115                 .fourcc = DRM_FORMAT_YUV422,
 116                 .bpp = 16,
 117                 .planes = 3,
 118         }, {
 119                 .fourcc = DRM_FORMAT_YVU422,
 120                 .bpp = 16,
 121                 .planes = 3,
 122         }, {
 123                 .fourcc = DRM_FORMAT_YUV444,
 124                 .bpp = 24,
 125                 .planes = 3,
 126         }, {
 127                 .fourcc = DRM_FORMAT_YVU444,
 128                 .bpp = 24,
 129                 .planes = 3,
 130         },
 131 };
 132
 133 const struct rcar_du_format_info *rcar_du_format_info(u32 fourcc)
 134 {
 135         unsigned int i;
 136
 137         for (i = 0; i < ARRAY_SIZE(rcar_du_format_infos); ++i) {
 138                 if (rcar_du_format_infos[i].fourcc == fourcc)
 139                         return &rcar_du_format_infos[i];
 140         }
 141
 142         return NULL;
 143 }
 144
 145 /* -----------------------------------------------------------------------------
 146  * Frame buffer
 147  */
 148
 149 int rcar_du_dumb_create(struct drm_file *file, struct drm_device *dev,
 150                         struct drm_mode_create_dumb *args)
 151 {
 152         struct rcar_du_device *rcdu = dev->dev_private;
 153         unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 154         unsigned int align;
 155
 156         /* The R8A7779 DU requires a 16 pixels pitch alignment as documented,
 157          * but the R8A7790 DU seems to require a 128 bytes pitch alignment.
 158          */
 159         if (rcar_du_needs(rcdu, RCAR_DU_QUIRK_ALIGN_128B))
 160                 align = 128;
 161         else
 162                 align = 16 * args->bpp / 8;
 163
 164         args->pitch = roundup(min_pitch, align);
 165
 166         return drm_gem_cma_dumb_create_internal(file, dev, args);
 167 }
 168
 169 static struct drm_framebuffer *
 170 rcar_du_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 171                   const struct drm_mode_fb_cmd2 *mode_cmd)
 172 {
 173         struct rcar_du_device *rcdu = dev->dev_private;
 174         const struct rcar_du_format_info *format;
 175         unsigned int max_pitch;
 176         unsigned int align;
 177         unsigned int bpp;
 178         unsigned int i;
 179
 180         format = rcar_du_format_info(mode_cmd->pixel_format);
 181         if (format == NULL) {
 182                 dev_dbg(dev->dev, "unsupported pixel format %08x\n",
 183                         mode_cmd->pixel_format);
 184                 return ERR_PTR(-EINVAL);
 185         }
 186
 187         /*
 188          * The pitch and alignment constraints are expressed in pixels on the
 189          * hardware side and in bytes in the DRM API.
 190          */
 191         bpp = format->planes == 1 ? format->bpp / 8 : 1;
 192         max_pitch =  4096 * bpp;
 193
 194         if (rcar_du_needs(rcdu, RCAR_DU_QUIRK_ALIGN_128B))
 195                 align = 128;
 196         else
 197                 align = 16 * bpp;
 198
 199         if (mode_cmd->pitches[0] & (align - 1) ||
 200             mode_cmd->pitches[0] >= max_pitch) {
 201                 dev_dbg(dev->dev, "invalid pitch value %u\n",
 202                         mode_cmd->pitches[0]);
 203                 return ERR_PTR(-EINVAL);
 204         }
 205
 206         for (i = 1; i < format->planes; ++i) {
 207                 if (mode_cmd->pitches[i] != mode_cmd->pitches[0]) {
 208                         dev_dbg(dev->dev,
 209                                 "luma and chroma pitches do not match\n");
 210                         return ERR_PTR(-EINVAL);
 211                 }
 212         }
 213
 214         return drm_fb_cma_create(dev, file_priv, mode_cmd);
 215 }
 216
 217 static void rcar_du_output_poll_changed(struct drm_device *dev)
 218 {
 219         struct rcar_du_device *rcdu = dev->dev_private;
 220
 221         drm_fbdev_cma_hotplug_event(rcdu->fbdev);
 222 }
 223
 224 /* -----------------------------------------------------------------------------
 225  * Atomic Check and Update
 226  */
 227
 228 static int rcar_du_atomic_check(struct drm_device *dev,
 229                                 struct drm_atomic_state *state)
 230 {
 231         struct rcar_du_device *rcdu = dev->dev_private;
 232         int ret;
 233
 234         ret = drm_atomic_helper_check(dev, state);
 235         if (ret < 0)
 236                 return ret;
 237
 238         if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE))
 239                 return 0;
 240
 241         return rcar_du_atomic_check_planes(dev, state);
 242 }
 243
 244 struct rcar_du_commit {
 245         struct work_struct work;
 246         struct drm_device *dev;
 247         struct drm_atomic_state *state;
 248         u32 crtcs;
 249 };
 250
 251 static void rcar_du_atomic_complete(struct rcar_du_commit *commit)
 252 {
 253         struct drm_device *dev = commit->dev;
 254         struct rcar_du_device *rcdu = dev->dev_private;
 255         struct drm_atomic_state *old_state = commit->state;
 256
 257         /* Apply the atomic update. */
 258         drm_atomic_helper_commit_modeset_disables(dev, old_state);
 259         drm_atomic_helper_commit_modeset_enables(dev, old_state);
 260         drm_atomic_helper_commit_planes(dev, old_state, true);
 261
 262         drm_atomic_helper_wait_for_vblanks(dev, old_state);
 263
 264         drm_atomic_helper_cleanup_planes(dev, old_state);
 265
 266         drm_atomic_state_free(old_state);
 267
 268         /* Complete the commit, wake up any waiter. */
 269         spin_lock(&rcdu->commit.wait.lock);
 270         rcdu->commit.pending &= ~commit->crtcs;
 271         wake_up_all_locked(&rcdu->commit.wait);
 272         spin_unlock(&rcdu->commit.wait.lock);
 273
 274         kfree(commit);
 275 }
 276
 277 static void rcar_du_atomic_work(struct work_struct *work)
 278 {
 279         struct rcar_du_commit *commit =
 280                 container_of(work, struct rcar_du_commit, work);
 281
 282         rcar_du_atomic_complete(commit);
 283 }
 284
 285 static int rcar_du_atomic_commit(struct drm_device *dev,
 286                                  struct drm_atomic_state *state, bool async)
 287 {
 288         struct rcar_du_device *rcdu = dev->dev_private;
 289         struct rcar_du_commit *commit;
 290         unsigned int i;
 291         int ret;
 292
 293         ret = drm_atomic_helper_prepare_planes(dev, state);
 294         if (ret)
 295                 return ret;
 296
 297         /* Allocate the commit object. */
 298         commit = kzalloc(sizeof(*commit), GFP_KERNEL);
 299         if (commit == NULL) {
 300                 ret = -ENOMEM;
 301                 goto error;
 302         }
 303
 304         INIT_WORK(&commit->work, rcar_du_atomic_work);
 305         commit->dev = dev;
 306         commit->state = state;
 307
 308         /* Wait until all affected CRTCs have completed previous commits and
 309          * mark them as pending.
 310          */
 311         for (i = 0; i < dev->mode_config.num_crtc; ++i) {
 312                 if (state->crtcs[i])
 313                         commit->crtcs |= 1 << drm_crtc_index(state->crtcs[i]);
 314         }
 315
 316         spin_lock(&rcdu->commit.wait.lock);
 317         ret = wait_event_interruptible_locked(rcdu->commit.wait,
 318                         !(rcdu->commit.pending & commit->crtcs));
 319         if (ret == 0)
 320                 rcdu->commit.pending |= commit->crtcs;
 321         spin_unlock(&rcdu->commit.wait.lock);
 322
 323         if (ret) {
 324                 kfree(commit);
 325                 goto error;
 326         }
 327
 328         /* Swap the state, this is the point of no return. */
 329         drm_atomic_helper_swap_state(dev, state);
 330
 331         if (async)
 332                 schedule_work(&commit->work);
 333         else
 334                 rcar_du_atomic_complete(commit);
 335
 336         return 0;
 337
 338 error:
 339         drm_atomic_helper_cleanup_planes(dev, state);
 340         return ret;
 341 }
 342
 343 /* -----------------------------------------------------------------------------
 344  * Initialization
 345  */
 346
 347 static const struct drm_mode_config_funcs rcar_du_mode_config_funcs = {
 348         .fb_create = rcar_du_fb_create,
 349         .output_poll_changed = rcar_du_output_poll_changed,
 350         .atomic_check = rcar_du_atomic_check,
 351         .atomic_commit = rcar_du_atomic_commit,
 352 };
 353
 354 static int rcar_du_encoders_init_one(struct rcar_du_device *rcdu,
 355                                      enum rcar_du_output output,
 356                                      struct of_endpoint *ep)
 357 {
 358         static const struct {
 359                 const char *compatible;
 360                 enum rcar_du_encoder_type type;
 361         } encoders[] = {
 362                 { "adi,adv7123", RCAR_DU_ENCODER_VGA },
 363                 { "adi,adv7511w", RCAR_DU_ENCODER_HDMI },
 364                 { "thine,thc63lvdm83d", RCAR_DU_ENCODER_LVDS },
 365         };
 366
 367         enum rcar_du_encoder_type enc_type = RCAR_DU_ENCODER_NONE;
 368         struct device_node *connector = NULL;
 369         struct device_node *encoder = NULL;
 370         struct device_node *ep_node = NULL;
 371         struct device_node *entity_ep_node;
 372         struct device_node *entity;
 373         int ret;
 374
 375         /*
 376          * Locate the connected entity and infer its type from the number of
 377          * endpoints.
 378          */
 379         entity = of_graph_get_remote_port_parent(ep->local_node);
 380         if (!entity) {
 381                 dev_dbg(rcdu->dev, "unconnected endpoint %s, skipping\n",
 382                         ep->local_node->full_name);
 383                 return -ENODEV;
 384         }
 385
 386         entity_ep_node = of_parse_phandle(ep->local_node, "remote-endpoint", 0);
 387
 388         for_each_endpoint_of_node(entity, ep_node) {
 389                 if (ep_node == entity_ep_node)
 390                         continue;
 391
 392                 /*
 393                  * We've found one endpoint other than the input, this must
 394                  * be an encoder. Locate the connector.
 395                  */
 396                 encoder = entity;
 397                 connector = of_graph_get_remote_port_parent(ep_node);
 398                 of_node_put(ep_node);
 399
 400                 if (!connector) {
 401                         dev_warn(rcdu->dev,
 402                                  "no connector for encoder %s, skipping\n",
 403                                  encoder->full_name);
 404                         of_node_put(entity_ep_node);
 405                         of_node_put(encoder);
 406                         return -ENODEV;
 407                 }
 408
 409                 break;
 410         }
 411
 412         of_node_put(entity_ep_node);
 413
 414         if (encoder) {
 415                 /*
 416                  * If an encoder has been found, get its type based on its
 417                  * compatible string.
 418                  */
 419                 unsigned int i;
 420
 421                 for (i = 0; i < ARRAY_SIZE(encoders); ++i) {
 422                         if (of_device_is_compatible(encoder,
 423                                                     encoders[i].compatible)) {
 424                                 enc_type = encoders[i].type;
 425                                 break;
 426                         }
 427                 }
 428
 429                 if (i == ARRAY_SIZE(encoders)) {
 430                         dev_warn(rcdu->dev,
 431                                  "unknown encoder type for %s, skipping\n",
 432                                  encoder->full_name);
 433                         of_node_put(encoder);
 434                         of_node_put(connector);
 435                         return -EINVAL;
 436                 }
 437         } else {
 438                 /*
 439                  * If no encoder has been found the entity must be the
 440                  * connector.
 441                  */
 442                 connector = entity;
 443         }
 444
 445         ret = rcar_du_encoder_init(rcdu, enc_type, output, encoder, connector);
 446         of_node_put(encoder);
 447         of_node_put(connector);
 448
 449         if (ret && ret != -EPROBE_DEFER)
 450                 dev_warn(rcdu->dev,
 451                          "failed to initialize encoder %s (%d), skipping\n",
 452                          encoder->full_name, ret);
 453
 454         return ret;
 455 }
 456
 457 static int rcar_du_encoders_init(struct rcar_du_device *rcdu)
 458 {
 459         struct device_node *np = rcdu->dev->of_node;
 460         struct device_node *ep_node;
 461         unsigned int num_encoders = 0;
 462
 463         /*
 464          * Iterate over the endpoints and create one encoder for each output
 465          * pipeline.
 466          */
 467         for_each_endpoint_of_node(np, ep_node) {
 468                 enum rcar_du_output output;
 469                 struct of_endpoint ep;
 470                 unsigned int i;
 471                 int ret;
 472
 473                 ret = of_graph_parse_endpoint(ep_node, &ep);
 474                 if (ret < 0) {
 475                         of_node_put(ep_node);
 476                         return ret;
 477                 }
 478
 479                 /* Find the output route corresponding to the port number. */
 480                 for (i = 0; i < RCAR_DU_OUTPUT_MAX; ++i) {
 481                         if (rcdu->info->routes[i].possible_crtcs &&
 482                             rcdu->info->routes[i].port == ep.port) {
 483                                 output = i;
 484                                 break;
 485                         }
 486                 }
 487
 488                 if (i == RCAR_DU_OUTPUT_MAX) {
 489                         dev_warn(rcdu->dev,
 490                                  "port %u references unexisting output, skipping\n",
 491                                  ep.port);
 492                         continue;
 493                 }
 494
 495                 /* Process the output pipeline. */
 496                 ret = rcar_du_encoders_init_one(rcdu, output, &ep);
 497                 if (ret < 0) {
 498                         if (ret == -EPROBE_DEFER) {
 499                                 of_node_put(ep_node);
 500                                 return ret;
 501                         }
 502
 503                         continue;
 504                 }
 505
 506                 num_encoders++;
 507         }
 508
 509         return num_encoders;
 510 }
 511
 512 static int rcar_du_properties_init(struct rcar_du_device *rcdu)
 513 {
 514         rcdu->props.alpha =
 515                 drm_property_create_range(rcdu->ddev, 0, "alpha", 0, 255);
 516         if (rcdu->props.alpha == NULL)
 517                 return -ENOMEM;
 518
 519         /* The color key is expressed as an RGB888 triplet stored in a 32-bit
 520          * integer in XRGB8888 format. Bit 24 is used as a flag to disable (0)
 521          * or enable source color keying (1).
 522          */
 523         rcdu->props.colorkey =
 524                 drm_property_create_range(rcdu->ddev, 0, "colorkey",
 525                                           0, 0x01ffffff);
 526         if (rcdu->props.colorkey == NULL)
 527                 return -ENOMEM;
 528
 529         rcdu->props.zpos =
 530                 drm_property_create_range(rcdu->ddev, 0, "zpos", 1, 7);
 531         if (rcdu->props.zpos == NULL)
 532                 return -ENOMEM;
 533
 534         return 0;
 535 }
 536
 537 int rcar_du_modeset_init(struct rcar_du_device *rcdu)
 538 {
 539         static const unsigned int mmio_offsets[] = {
 540                 DU0_REG_OFFSET, DU2_REG_OFFSET
 541         };
 542
 543         struct drm_device *dev = rcdu->ddev;
 544         struct drm_encoder *encoder;
 545         struct drm_fbdev_cma *fbdev;
 546         unsigned int num_encoders;
 547         unsigned int num_groups;
 548         unsigned int i;
 549         int ret;
 550
 551         drm_mode_config_init(dev);
 552
 553         dev->mode_config.min_width = 0;
 554         dev->mode_config.min_height = 0;
 555         dev->mode_config.max_width = 4095;
 556         dev->mode_config.max_height = 2047;
 557         dev->mode_config.funcs = &rcar_du_mode_config_funcs;
 558
 559         rcdu->num_crtcs = rcdu->info->num_crtcs;
 560
 561         ret = rcar_du_properties_init(rcdu);
 562         if (ret < 0)
 563                 return ret;
 564
 565         /* Initialize the groups. */
 566         num_groups = DIV_ROUND_UP(rcdu->num_crtcs, 2);
 567
 568         for (i = 0; i < num_groups; ++i) {
 569                 struct rcar_du_group *rgrp = &rcdu->groups[i];
 570
 571                 mutex_init(&rgrp->lock);
 572
 573                 rgrp->dev = rcdu;
 574                 rgrp->mmio_offset = mmio_offsets[i];
 575                 rgrp->index = i;
 576                 rgrp->num_crtcs = min(rcdu->num_crtcs - 2 * i, 2U);
 577
 578                 /* If we have more than one CRTCs in this group pre-associate
 579                  * the low-order planes with CRTC 0 and the high-order planes
 580                  * with CRTC 1 to minimize flicker occurring when the
 581                  * association is changed.
 582                  */
 583                 rgrp->dptsr_planes = rgrp->num_crtcs > 1
 584                                    ? (rcdu->info->gen >= 3 ? 0x04 : 0xf0)
 585                                    : 0;
 586
 587                 if (!rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
 588                         ret = rcar_du_planes_init(rgrp);
 589                         if (ret < 0)
 590                                 return ret;
 591                 }
 592         }
 593
 594         /* Initialize the compositors. */
 595         if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
 596                 for (i = 0; i < rcdu->num_crtcs; ++i) {
 597                         struct rcar_du_vsp *vsp = &rcdu->vsps[i];
 598
 599                         vsp->index = i;
 600                         vsp->dev = rcdu;
 601                         rcdu->crtcs[i].vsp = vsp;
 602
 603                         ret = rcar_du_vsp_init(vsp);
 604                         if (ret < 0)
 605                                 return ret;
 606                 }
 607         }
 608
 609         /* Create the CRTCs. */
 610         for (i = 0; i < rcdu->num_crtcs; ++i) {
 611                 struct rcar_du_group *rgrp = &rcdu->groups[i / 2];
 612
 613                 ret = rcar_du_crtc_create(rgrp, i);
 614                 if (ret < 0)
 615                         return ret;
 616         }
 617
 618         /* Initialize the encoders. */
 619         ret = rcar_du_lvdsenc_init(rcdu);
 620         if (ret < 0)
 621                 return ret;
 622
 623         ret = rcar_du_encoders_init(rcdu);
 624         if (ret < 0)
 625                 return ret;
 626
 627         if (ret == 0) {
 628                 dev_err(rcdu->dev, "error: no encoder could be initialized\n");
 629                 return -EINVAL;
 630         }
 631
 632         num_encoders = ret;
 633
 634         /* Set the possible CRTCs and possible clones. There's always at least
 635          * one way for all encoders to clone each other, set all bits in the
 636          * possible clones field.
 637          */
 638         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 639                 struct rcar_du_encoder *renc = to_rcar_encoder(encoder);
 640                 const struct rcar_du_output_routing *route =
 641                         &rcdu->info->routes[renc->output];
 642
 643                 encoder->possible_crtcs = route->possible_crtcs;
 644                 encoder->possible_clones = (1 << num_encoders) - 1;
 645         }
 646
 647         drm_mode_config_reset(dev);
 648
 649         drm_kms_helper_poll_init(dev);
 650
 651         if (dev->mode_config.num_connector) {
 652                 fbdev = drm_fbdev_cma_init(dev, 32, dev->mode_config.num_crtc,
 653                                            dev->mode_config.num_connector);
 654                 if (IS_ERR(fbdev))
 655                         return PTR_ERR(fbdev);
 656
 657                 rcdu->fbdev = fbdev;
 658         } else {
 659                 dev_info(rcdu->dev,
 660                          "no connector found, disabling fbdev emulation\n");
 661         }
 662
 663         return 0;
 664 }