drm_probe_helper.c

   1/*
   2 * Copyright (c) 2006-2008 Intel Corporation
   3 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
   4 *
   5 * DRM core CRTC related functions
   6 *
   7 * Permission to use, copy, modify, distribute, and sell this software and its
   8 * documentation for any purpose is hereby granted without fee, provided that
   9 * the above copyright notice appear in all copies and that both that copyright
  10 * notice and this permission notice appear in supporting documentation, and
  11 * that the name of the copyright holders not be used in advertising or
  12 * publicity pertaining to distribution of the software without specific,
  13 * written prior permission.  The copyright holders make no representations
  14 * about the suitability of this software for any purpose.  It is provided "as
  15 * is" without express or implied warranty.
  16 *
  17 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  18 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  19 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  20 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  21 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  22 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  23 * OF THIS SOFTWARE.
  24 *
  25 * Authors:
  26 *      Keith Packard
  27 *	Eric Anholt <eric@anholt.net>
  28 *      Dave Airlie <airlied@linux.ie>
  29 *      Jesse Barnes <jesse.barnes@intel.com>
  30 */
  31
  32#include <linux/export.h>
  33#include <linux/moduleparam.h>
  34
  35#include <drm/drm_bridge.h>
  36#include <drm/drm_client_event.h>
  37#include <drm/drm_crtc.h>
  38#include <drm/drm_edid.h>
  39#include <drm/drm_fourcc.h>
  40#include <drm/drm_managed.h>
  41#include <drm/drm_modeset_helper_vtables.h>
  42#include <drm/drm_print.h>
  43#include <drm/drm_probe_helper.h>
  44#include <drm/drm_sysfs.h>
  45
  46#include "drm_crtc_helper_internal.h"
  47
  48/**
  49 * DOC: output probing helper overview
  50 *
  51 * This library provides some helper code for output probing. It provides an
  52 * implementation of the core &drm_connector_funcs.fill_modes interface with
  53 * drm_helper_probe_single_connector_modes().
  54 *
  55 * It also provides support for polling connectors with a work item and for
  56 * generic hotplug interrupt handling where the driver doesn't or cannot keep
  57 * track of a per-connector hpd interrupt.
  58 *
  59 * This helper library can be used independently of the modeset helper library.
  60 * Drivers can also overwrite different parts e.g. use their own hotplug
  61 * handling code to avoid probing unrelated outputs.
  62 *
  63 * The probe helpers share the function table structures with other display
  64 * helper libraries. See &struct drm_connector_helper_funcs for the details.
  65 */
  66
  67static bool drm_kms_helper_poll = true;
  68module_param_named(poll, drm_kms_helper_poll, bool, 0600);
  69
  70static enum drm_mode_status
  71drm_mode_validate_flag(const struct drm_display_mode *mode,
  72		       int flags)
  73{
  74	if ((mode->flags & DRM_MODE_FLAG_INTERLACE) &&
  75	    !(flags & DRM_MODE_FLAG_INTERLACE))
  76		return MODE_NO_INTERLACE;
  77
  78	if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) &&
  79	    !(flags & DRM_MODE_FLAG_DBLSCAN))
  80		return MODE_NO_DBLESCAN;
  81
  82	if ((mode->flags & DRM_MODE_FLAG_3D_MASK) &&
  83	    !(flags & DRM_MODE_FLAG_3D_MASK))
  84		return MODE_NO_STEREO;
  85
  86	return MODE_OK;
  87}
  88
  89static int
  90drm_mode_validate_pipeline(struct drm_display_mode *mode,
  91			   struct drm_connector *connector,
  92			   struct drm_modeset_acquire_ctx *ctx,
  93			   enum drm_mode_status *status)
  94{
  95	struct drm_device *dev = connector->dev;
  96	struct drm_encoder *encoder;
  97	int ret;
  98
  99	/* Step 1: Validate against connector */
 100	ret = drm_connector_mode_valid(connector, mode, ctx, status);
 101	if (ret || *status != MODE_OK)
 102		return ret;
 103
 104	/* Step 2: Validate against encoders and crtcs */
 105	drm_connector_for_each_possible_encoder(connector, encoder) {
 106		struct drm_bridge *bridge;
 107		struct drm_crtc *crtc;
 108
 109		*status = drm_encoder_mode_valid(encoder, mode);
 110		if (*status != MODE_OK) {
 111			/* No point in continuing for crtc check as this encoder
 112			 * will not accept the mode anyway. If all encoders
 113			 * reject the mode then, at exit, ret will not be
 114			 * MODE_OK. */
 115			continue;
 116		}
 117
 118		bridge = drm_bridge_chain_get_first_bridge(encoder);
 119		*status = drm_bridge_chain_mode_valid(bridge,
 120						      &connector->display_info,
 121						      mode);
 122		drm_bridge_put(bridge);
 123		if (*status != MODE_OK) {
 124			/* There is also no point in continuing for crtc check
 125			 * here. */
 126			continue;
 127		}
 128
 129		drm_for_each_crtc(crtc, dev) {
 130			if (!drm_encoder_crtc_ok(encoder, crtc))
 131				continue;
 132
 133			*status = drm_crtc_mode_valid(crtc, mode);
 134			if (*status == MODE_OK) {
 135				/* If we get to this point there is at least
 136				 * one combination of encoder+crtc that works
 137				 * for this mode. Lets return now. */
 138				return 0;
 139			}
 140		}
 141	}
 142
 143	return 0;
 144}
 145
 146static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
 147{
 148	struct drm_cmdline_mode *cmdline_mode;
 149	struct drm_display_mode *mode;
 150
 151	cmdline_mode = &connector->cmdline_mode;
 152	if (!cmdline_mode->specified)
 153		return 0;
 154
 155	/* Only add a GTF mode if we find no matching probed modes */
 156	list_for_each_entry(mode, &connector->probed_modes, head) {
 157		if (mode->hdisplay != cmdline_mode->xres ||
 158		    mode->vdisplay != cmdline_mode->yres)
 159			continue;
 160
 161		if (cmdline_mode->refresh_specified) {
 162			/* The probed mode's vrefresh is set until later */
 163			if (drm_mode_vrefresh(mode) != cmdline_mode->refresh)
 164				continue;
 165		}
 166
 167		/* Mark the matching mode as being preferred by the user */
 168		mode->type |= DRM_MODE_TYPE_USERDEF;
 169		return 0;
 170	}
 171
 172	mode = drm_mode_create_from_cmdline_mode(connector->dev,
 173						 cmdline_mode);
 174	if (mode == NULL)
 175		return 0;
 176
 177	drm_mode_probed_add(connector, mode);
 178	return 1;
 179}
 180
 181enum drm_mode_status drm_crtc_mode_valid(struct drm_crtc *crtc,
 182					 const struct drm_display_mode *mode)
 183{
 184	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 185
 186	if (!crtc_funcs || !crtc_funcs->mode_valid)
 187		return MODE_OK;
 188
 189	return crtc_funcs->mode_valid(crtc, mode);
 190}
 191
 192enum drm_mode_status drm_encoder_mode_valid(struct drm_encoder *encoder,
 193					    const struct drm_display_mode *mode)
 194{
 195	const struct drm_encoder_helper_funcs *encoder_funcs =
 196		encoder->helper_private;
 197
 198	if (!encoder_funcs || !encoder_funcs->mode_valid)
 199		return MODE_OK;
 200
 201	return encoder_funcs->mode_valid(encoder, mode);
 202}
 203
 204int
 205drm_connector_mode_valid(struct drm_connector *connector,
 206			 const struct drm_display_mode *mode,
 207			 struct drm_modeset_acquire_ctx *ctx,
 208			 enum drm_mode_status *status)
 209{
 210	const struct drm_connector_helper_funcs *connector_funcs =
 211		connector->helper_private;
 212	int ret = 0;
 213
 214	if (!connector_funcs)
 215		*status = MODE_OK;
 216	else if (connector_funcs->mode_valid_ctx)
 217		ret = connector_funcs->mode_valid_ctx(connector, mode, ctx,
 218						      status);
 219	else if (connector_funcs->mode_valid)
 220		*status = connector_funcs->mode_valid(connector, mode);
 221	else
 222		*status = MODE_OK;
 223
 224	return ret;
 225}
 226
 227static void drm_kms_helper_disable_hpd(struct drm_device *dev)
 228{
 229	struct drm_connector *connector;
 230	struct drm_connector_list_iter conn_iter;
 231
 232	drm_connector_list_iter_begin(dev, &conn_iter);
 233	drm_for_each_connector_iter(connector, &conn_iter) {
 234		const struct drm_connector_helper_funcs *funcs =
 235			connector->helper_private;
 236
 237		if (funcs && funcs->disable_hpd)
 238			funcs->disable_hpd(connector);
 239	}
 240	drm_connector_list_iter_end(&conn_iter);
 241}
 242
 243static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
 244{
 245	bool poll = false;
 246	struct drm_connector *connector;
 247	struct drm_connector_list_iter conn_iter;
 248
 249	drm_connector_list_iter_begin(dev, &conn_iter);
 250	drm_for_each_connector_iter(connector, &conn_iter) {
 251		const struct drm_connector_helper_funcs *funcs =
 252			connector->helper_private;
 253
 254		if (funcs && funcs->enable_hpd)
 255			funcs->enable_hpd(connector);
 256
 257		if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
 258					 DRM_CONNECTOR_POLL_DISCONNECT))
 259			poll = true;
 260	}
 261	drm_connector_list_iter_end(&conn_iter);
 262
 263	return poll;
 264}
 265
 266#define DRM_OUTPUT_POLL_PERIOD (10*HZ)
 267static void reschedule_output_poll_work(struct drm_device *dev)
 268{
 269	unsigned long delay = DRM_OUTPUT_POLL_PERIOD;
 270
 271	if (dev->mode_config.delayed_event)
 272		/*
 273		 * FIXME:
 274		 *
 275		 * Use short (1s) delay to handle the initial delayed event.
 276		 * This delay should not be needed, but Optimus/nouveau will
 277		 * fail in a mysterious way if the delayed event is handled as
 278		 * soon as possible like it is done in
 279		 * drm_helper_probe_single_connector_modes() in case the poll
 280		 * was enabled before.
 281		 */
 282		delay = HZ;
 283
 284	schedule_delayed_work(&dev->mode_config.output_poll_work, delay);
 285}
 286
 287/**
 288 * drm_kms_helper_poll_enable - re-enable output polling.
 289 * @dev: drm_device
 290 *
 291 * This function re-enables the output polling work, after it has been
 292 * temporarily disabled using drm_kms_helper_poll_disable(), for example over
 293 * suspend/resume.
 294 *
 295 * Drivers can call this helper from their device resume implementation. It is
 296 * not an error to call this even when output polling isn't enabled.
 297 *
 298 * If device polling was never initialized before, this call will trigger a
 299 * warning and return.
 300 *
 301 * Note that calls to enable and disable polling must be strictly ordered, which
 302 * is automatically the case when they're only call from suspend/resume
 303 * callbacks.
 304 */
 305void drm_kms_helper_poll_enable(struct drm_device *dev)
 306{
 307	if (drm_WARN_ON_ONCE(dev, !dev->mode_config.poll_enabled) ||
 308	    !drm_kms_helper_poll || dev->mode_config.poll_running)
 309		return;
 310
 311	if (drm_kms_helper_enable_hpd(dev) ||
 312	    dev->mode_config.delayed_event)
 313		reschedule_output_poll_work(dev);
 314
 315	dev->mode_config.poll_running = true;
 316}
 317EXPORT_SYMBOL(drm_kms_helper_poll_enable);
 318
 319/**
 320 * drm_kms_helper_poll_reschedule - reschedule the output polling work
 321 * @dev: drm_device
 322 *
 323 * This function reschedules the output polling work, after polling for a
 324 * connector has been enabled.
 325 *
 326 * Drivers must call this helper after enabling polling for a connector by
 327 * setting %DRM_CONNECTOR_POLL_CONNECT / %DRM_CONNECTOR_POLL_DISCONNECT flags
 328 * in drm_connector::polled. Note that after disabling polling by clearing these
 329 * flags for a connector will stop the output polling work automatically if
 330 * the polling is disabled for all other connectors as well.
 331 *
 332 * The function can be called only after polling has been enabled by calling
 333 * drm_kms_helper_poll_init() / drm_kms_helper_poll_enable().
 334 */
 335void drm_kms_helper_poll_reschedule(struct drm_device *dev)
 336{
 337	if (dev->mode_config.poll_running)
 338		reschedule_output_poll_work(dev);
 339}
 340EXPORT_SYMBOL(drm_kms_helper_poll_reschedule);
 341
 342static int detect_connector_status(struct drm_connector *connector,
 343				   struct drm_modeset_acquire_ctx *ctx,
 344				   bool force)
 345{
 346	const struct drm_connector_helper_funcs *funcs = connector->helper_private;
 347
 348	if (funcs->detect_ctx)
 349		return funcs->detect_ctx(connector, ctx, force);
 350	else if (connector->funcs->detect)
 351		return connector->funcs->detect(connector, force);
 352
 353	return connector_status_connected;
 354}
 355
 356static enum drm_connector_status
 357drm_helper_probe_detect_ctx(struct drm_connector *connector, bool force)
 358{
 359	struct drm_modeset_acquire_ctx ctx;
 360	int ret;
 361
 362	drm_modeset_acquire_init(&ctx, 0);
 363
 364retry:
 365	ret = drm_modeset_lock(&connector->dev->mode_config.connection_mutex, &ctx);
 366	if (!ret)
 367		ret = detect_connector_status(connector, &ctx, force);
 368
 369	if (ret == -EDEADLK) {
 370		drm_modeset_backoff(&ctx);
 371		goto retry;
 372	}
 373
 374	if (WARN_ON(ret < 0))
 375		ret = connector_status_unknown;
 376
 377	if (ret != connector->status)
 378		connector->epoch_counter += 1;
 379
 380	drm_modeset_drop_locks(&ctx);
 381	drm_modeset_acquire_fini(&ctx);
 382
 383	return ret;
 384}
 385
 386/**
 387 * drm_helper_probe_detect - probe connector status
 388 * @connector: connector to probe
 389 * @ctx: acquire_ctx, or NULL to let this function handle locking.
 390 * @force: Whether destructive probe operations should be performed.
 391 *
 392 * This function calls the detect callbacks of the connector.
 393 * This function returns &drm_connector_status, or
 394 * if @ctx is set, it might also return -EDEADLK.
 395 */
 396int
 397drm_helper_probe_detect(struct drm_connector *connector,
 398			struct drm_modeset_acquire_ctx *ctx,
 399			bool force)
 400{
 401	struct drm_device *dev = connector->dev;
 402	int ret;
 403
 404	if (!ctx)
 405		return drm_helper_probe_detect_ctx(connector, force);
 406
 407	ret = drm_modeset_lock(&dev->mode_config.connection_mutex, ctx);
 408	if (ret)
 409		return ret;
 410
 411	ret = detect_connector_status(connector, ctx, force);
 412
 413	if (ret != connector->status)
 414		connector->epoch_counter += 1;
 415
 416	return ret;
 417}
 418EXPORT_SYMBOL(drm_helper_probe_detect);
 419
 420static int drm_helper_probe_get_modes(struct drm_connector *connector)
 421{
 422	const struct drm_connector_helper_funcs *connector_funcs =
 423		connector->helper_private;
 424	int count;
 425
 426	count = connector_funcs->get_modes(connector);
 427
 428	/* The .get_modes() callback should not return negative values. */
 429	if (count < 0) {
 430		drm_err(connector->dev, ".get_modes() returned %pe\n",
 431			ERR_PTR(count));
 432		count = 0;
 433	}
 434
 435	/*
 436	 * Fallback for when DDC probe failed in drm_get_edid() and thus skipped
 437	 * override/firmware EDID.
 438	 */
 439	if (count == 0 && connector->status == connector_status_connected)
 440		count = drm_edid_override_connector_update(connector);
 441
 442	return count;
 443}
 444
 445static int __drm_helper_update_and_validate(struct drm_connector *connector,
 446					    uint32_t maxX, uint32_t maxY,
 447					    struct drm_modeset_acquire_ctx *ctx)
 448{
 449	struct drm_device *dev = connector->dev;
 450	struct drm_display_mode *mode;
 451	int mode_flags = 0;
 452	int ret;
 453
 454	drm_connector_list_update(connector);
 455
 456	if (connector->interlace_allowed)
 457		mode_flags |= DRM_MODE_FLAG_INTERLACE;
 458	if (connector->doublescan_allowed)
 459		mode_flags |= DRM_MODE_FLAG_DBLSCAN;
 460	if (connector->stereo_allowed)
 461		mode_flags |= DRM_MODE_FLAG_3D_MASK;
 462
 463	list_for_each_entry(mode, &connector->modes, head) {
 464		if (mode->status != MODE_OK)
 465			continue;
 466
 467		mode->status = drm_mode_validate_driver(dev, mode);
 468		if (mode->status != MODE_OK)
 469			continue;
 470
 471		mode->status = drm_mode_validate_size(mode, maxX, maxY);
 472		if (mode->status != MODE_OK)
 473			continue;
 474
 475		mode->status = drm_mode_validate_flag(mode, mode_flags);
 476		if (mode->status != MODE_OK)
 477			continue;
 478
 479		mode->status = drm_mode_validate_ycbcr420(mode, connector);
 480		if (mode->status != MODE_OK)
 481			continue;
 482
 483		ret = drm_mode_validate_pipeline(mode, connector, ctx,
 484						 &mode->status);
 485		if (ret) {
 486			drm_dbg_kms(dev,
 487				    "drm_mode_validate_pipeline failed: %d\n",
 488				    ret);
 489
 490			if (drm_WARN_ON_ONCE(dev, ret != -EDEADLK))
 491				mode->status = MODE_ERROR;
 492			else
 493				return -EDEADLK;
 494		}
 495	}
 496
 497	return 0;
 498}
 499
 500/**
 501 * drm_helper_probe_single_connector_modes - get complete set of display modes
 502 * @connector: connector to probe
 503 * @maxX: max width for modes
 504 * @maxY: max height for modes
 505 *
 506 * Based on the helper callbacks implemented by @connector in struct
 507 * &drm_connector_helper_funcs try to detect all valid modes.  Modes will first
 508 * be added to the connector's probed_modes list, then culled (based on validity
 509 * and the @maxX, @maxY parameters) and put into the normal modes list.
 510 *
 511 * Intended to be used as a generic implementation of the
 512 * &drm_connector_funcs.fill_modes() vfunc for drivers that use the CRTC helpers
 513 * for output mode filtering and detection.
 514 *
 515 * The basic procedure is as follows
 516 *
 517 * 1. All modes currently on the connector's modes list are marked as stale
 518 *
 519 * 2. New modes are added to the connector's probed_modes list with
 520 *    drm_mode_probed_add(). New modes start their life with status as OK.
 521 *    Modes are added from a single source using the following priority order.
 522 *
 523 *    - &drm_connector_helper_funcs.get_modes vfunc
 524 *    - if the connector status is connector_status_connected, standard
 525 *      VESA DMT modes up to 1024x768 are automatically added
 526 *      (drm_add_modes_noedid())
 527 *
 528 *    Finally modes specified via the kernel command line (video=...) are
 529 *    added in addition to what the earlier probes produced
 530 *    (drm_helper_probe_add_cmdline_mode()). These modes are generated
 531 *    using the VESA GTF/CVT formulas.
 532 *
 533 * 3. Modes are moved from the probed_modes list to the modes list. Potential
 534 *    duplicates are merged together (see drm_connector_list_update()).
 535 *    After this step the probed_modes list will be empty again.
 536 *
 537 * 4. Any non-stale mode on the modes list then undergoes validation
 538 *
 539 *    - drm_mode_validate_basic() performs basic sanity checks
 540 *    - drm_mode_validate_size() filters out modes larger than @maxX and @maxY
 541 *      (if specified)
 542 *    - drm_mode_validate_flag() checks the modes against basic connector
 543 *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
 544 *    - the optional &drm_connector_helper_funcs.mode_valid or
 545 *      &drm_connector_helper_funcs.mode_valid_ctx helpers can perform driver
 546 *      and/or sink specific checks
 547 *    - the optional &drm_crtc_helper_funcs.mode_valid,
 548 *      &drm_bridge_funcs.mode_valid and &drm_encoder_helper_funcs.mode_valid
 549 *      helpers can perform driver and/or source specific checks which are also
 550 *      enforced by the modeset/atomic helpers
 551 *
 552 * 5. Any mode whose status is not OK is pruned from the connector's modes list,
 553 *    accompanied by a debug message indicating the reason for the mode's
 554 *    rejection (see drm_mode_prune_invalid()).
 555 *
 556 * Returns:
 557 * The number of modes found on @connector.
 558 */
 559int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 560					    uint32_t maxX, uint32_t maxY)
 561{
 562	struct drm_device *dev = connector->dev;
 563	struct drm_display_mode *mode;
 564	int count = 0, ret;
 565	enum drm_connector_status old_status;
 566	struct drm_modeset_acquire_ctx ctx;
 567
 568	WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 569
 570	drm_modeset_acquire_init(&ctx, 0);
 571
 572	drm_dbg_kms(dev, "[CONNECTOR:%d:%s]\n", connector->base.id,
 573		    connector->name);
 574
 575retry:
 576	ret = drm_modeset_lock(&dev->mode_config.connection_mutex, &ctx);
 577	if (ret == -EDEADLK) {
 578		drm_modeset_backoff(&ctx);
 579		goto retry;
 580	} else
 581		WARN_ON(ret < 0);
 582
 583	/* set all old modes to the stale state */
 584	list_for_each_entry(mode, &connector->modes, head)
 585		mode->status = MODE_STALE;
 586
 587	old_status = connector->status;
 588
 589	if (connector->force) {
 590		if (connector->force == DRM_FORCE_ON ||
 591		    connector->force == DRM_FORCE_ON_DIGITAL)
 592			connector->status = connector_status_connected;
 593		else
 594			connector->status = connector_status_disconnected;
 595		if (connector->funcs->force)
 596			connector->funcs->force(connector);
 597	} else {
 598		ret = drm_helper_probe_detect(connector, &ctx, true);
 599
 600		if (ret == -EDEADLK) {
 601			drm_modeset_backoff(&ctx);
 602			goto retry;
 603		} else if (WARN(ret < 0, "Invalid return value %i for connector detection\n", ret))
 604			ret = connector_status_unknown;
 605
 606		connector->status = ret;
 607	}
 608
 609	/*
 610	 * Normally either the driver's hpd code or the poll loop should
 611	 * pick up any changes and fire the hotplug event. But if
 612	 * userspace sneaks in a probe, we might miss a change. Hence
 613	 * check here, and if anything changed start the hotplug code.
 614	 */
 615	if (old_status != connector->status) {
 616		drm_dbg_kms(dev, "[CONNECTOR:%d:%s] status updated from %s to %s\n",
 617			    connector->base.id, connector->name,
 618			    drm_get_connector_status_name(old_status),
 619			    drm_get_connector_status_name(connector->status));
 620
 621		/*
 622		 * The hotplug event code might call into the fb
 623		 * helpers, and so expects that we do not hold any
 624		 * locks. Fire up the poll struct instead, it will
 625		 * disable itself again.
 626		 */
 627		dev->mode_config.delayed_event = true;
 628		if (dev->mode_config.poll_enabled)
 629			mod_delayed_work(system_wq,
 630					 &dev->mode_config.output_poll_work,
 631					 0);
 632	}
 633
 634	/*
 635	 * Re-enable polling in case the global poll config changed but polling
 636	 * is still initialized.
 637	 */
 638	if (dev->mode_config.poll_enabled)
 639		drm_kms_helper_poll_enable(dev);
 640
 641	if (connector->status == connector_status_disconnected) {
 642		drm_dbg_kms(dev, "[CONNECTOR:%d:%s] disconnected\n",
 643			    connector->base.id, connector->name);
 644		drm_connector_update_edid_property(connector, NULL);
 645		drm_mode_prune_invalid(dev, &connector->modes, false);
 646		goto exit;
 647	}
 648
 649	count = drm_helper_probe_get_modes(connector);
 650
 651	if (count == 0 && (connector->status == connector_status_connected ||
 652			   connector->status == connector_status_unknown)) {
 653		count = drm_add_modes_noedid(connector, 1024, 768);
 654
 655		/*
 656		 * Section 4.2.2.6 (EDID Corruption Detection) of the DP 1.4a
 657		 * Link CTS specifies that 640x480 (the official "failsafe"
 658		 * mode) needs to be the default if there's no EDID.
 659		 */
 660		if (connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort)
 661			drm_set_preferred_mode(connector, 640, 480);
 662	}
 663	count += drm_helper_probe_add_cmdline_mode(connector);
 664	if (count != 0) {
 665		ret = __drm_helper_update_and_validate(connector, maxX, maxY, &ctx);
 666		if (ret == -EDEADLK) {
 667			drm_modeset_backoff(&ctx);
 668			goto retry;
 669		}
 670	}
 671
 672	drm_mode_prune_invalid(dev, &connector->modes, true);
 673
 674	/*
 675	 * Displayport spec section 5.2.1.2 ("Video Timing Format") says that
 676	 * all detachable sinks shall support 640x480 @60Hz as a fail safe
 677	 * mode. If all modes were pruned, perhaps because they need more
 678	 * lanes or a higher pixel clock than available, at least try to add
 679	 * in 640x480.
 680	 */
 681	if (list_empty(&connector->modes) &&
 682	    connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort) {
 683		count = drm_add_modes_noedid(connector, 640, 480);
 684		ret = __drm_helper_update_and_validate(connector, maxX, maxY, &ctx);
 685		if (ret == -EDEADLK) {
 686			drm_modeset_backoff(&ctx);
 687			goto retry;
 688		}
 689		drm_mode_prune_invalid(dev, &connector->modes, true);
 690	}
 691
 692exit:
 693	drm_modeset_drop_locks(&ctx);
 694	drm_modeset_acquire_fini(&ctx);
 695
 696	if (list_empty(&connector->modes))
 697		return 0;
 698
 699	drm_mode_sort(&connector->modes);
 700
 701	drm_dbg_kms(dev, "[CONNECTOR:%d:%s] probed modes:\n",
 702		    connector->base.id, connector->name);
 703
 704	list_for_each_entry(mode, &connector->modes, head) {
 705		drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
 706		drm_dbg_kms(dev, "Probed mode: " DRM_MODE_FMT "\n",
 707			    DRM_MODE_ARG(mode));
 708	}
 709
 710	return count;
 711}
 712EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
 713
 714/**
 715 * drm_kms_helper_hotplug_event - fire off KMS hotplug events
 716 * @dev: drm_device whose connector state changed
 717 *
 718 * This function fires off the uevent for userspace and also calls the
 719 * client hotplug function, which is most commonly used to inform the fbdev
 720 * emulation code and allow it to update the fbcon output configuration.
 721 *
 722 * Drivers should call this from their hotplug handling code when a change is
 723 * detected. Note that this function does not do any output detection of its
 724 * own, like drm_helper_hpd_irq_event() does - this is assumed to be done by the
 725 * driver already.
 726 *
 727 * This function must be called from process context with no mode
 728 * setting locks held.
 729 *
 730 * If only a single connector has changed, consider calling
 731 * drm_kms_helper_connector_hotplug_event() instead.
 732 */
 733void drm_kms_helper_hotplug_event(struct drm_device *dev)
 734{
 735	drm_sysfs_hotplug_event(dev);
 736	drm_client_dev_hotplug(dev);
 737}
 738EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
 739
 740/**
 741 * drm_kms_helper_connector_hotplug_event - fire off a KMS connector hotplug event
 742 * @connector: drm_connector which has changed
 743 *
 744 * This is the same as drm_kms_helper_hotplug_event(), except it fires a more
 745 * fine-grained uevent for a single connector.
 746 */
 747void drm_kms_helper_connector_hotplug_event(struct drm_connector *connector)
 748{
 749	struct drm_device *dev = connector->dev;
 750
 751	drm_sysfs_connector_hotplug_event(connector);
 752	drm_client_dev_hotplug(dev);
 753}
 754EXPORT_SYMBOL(drm_kms_helper_connector_hotplug_event);
 755
 756static void output_poll_execute(struct work_struct *work)
 757{
 758	struct delayed_work *delayed_work = to_delayed_work(work);
 759	struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
 760	struct drm_connector *connector;
 761	struct drm_connector_list_iter conn_iter;
 762	enum drm_connector_status old_status;
 763	bool repoll = false, changed;
 764	u64 old_epoch_counter;
 765
 766	if (!dev->mode_config.poll_enabled)
 767		return;
 768
 769	/* Pick up any changes detected by the probe functions. */
 770	changed = dev->mode_config.delayed_event;
 771	dev->mode_config.delayed_event = false;
 772
 773	if (!drm_kms_helper_poll) {
 774		if (dev->mode_config.poll_running) {
 775			drm_kms_helper_disable_hpd(dev);
 776			dev->mode_config.poll_running = false;
 777		}
 778		goto out;
 779	}
 780
 781	if (!mutex_trylock(&dev->mode_config.mutex)) {
 782		repoll = true;
 783		goto out;
 784	}
 785
 786	drm_connector_list_iter_begin(dev, &conn_iter);
 787	drm_for_each_connector_iter(connector, &conn_iter) {
 788		/* Ignore forced connectors. */
 789		if (connector->force)
 790			continue;
 791
 792		/* Ignore HPD capable connectors and connectors where we don't
 793		 * want any hotplug detection at all for polling. */
 794		if (!connector->polled || connector->polled == DRM_CONNECTOR_POLL_HPD)
 795			continue;
 796
 797		old_status = connector->status;
 798		/* if we are connected and don't want to poll for disconnect
 799		   skip it */
 800		if (old_status == connector_status_connected &&
 801		    !(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT))
 802			continue;
 803
 804		repoll = true;
 805
 806		old_epoch_counter = connector->epoch_counter;
 807		connector->status = drm_helper_probe_detect(connector, NULL, false);
 808		if (old_epoch_counter != connector->epoch_counter) {
 809			const char *old, *new;
 810
 811			/*
 812			 * The poll work sets force=false when calling detect so
 813			 * that drivers can avoid to do disruptive tests (e.g.
 814			 * when load detect cycles could cause flickering on
 815			 * other, running displays). This bears the risk that we
 816			 * flip-flop between unknown here in the poll work and
 817			 * the real state when userspace forces a full detect
 818			 * call after receiving a hotplug event due to this
 819			 * change.
 820			 *
 821			 * Hence clamp an unknown detect status to the old
 822			 * value.
 823			 */
 824			if (connector->status == connector_status_unknown) {
 825				connector->status = old_status;
 826				continue;
 827			}
 828
 829			old = drm_get_connector_status_name(old_status);
 830			new = drm_get_connector_status_name(connector->status);
 831
 832			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] status updated from %s to %s\n",
 833				    connector->base.id, connector->name,
 834				    old, new);
 835			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] epoch counter %llu -> %llu\n",
 836				    connector->base.id, connector->name,
 837				    old_epoch_counter, connector->epoch_counter);
 838
 839			changed = true;
 840		}
 841	}
 842	drm_connector_list_iter_end(&conn_iter);
 843
 844	mutex_unlock(&dev->mode_config.mutex);
 845
 846out:
 847	if (changed)
 848		drm_kms_helper_hotplug_event(dev);
 849
 850	if (repoll)
 851		schedule_delayed_work(delayed_work, DRM_OUTPUT_POLL_PERIOD);
 852}
 853
 854/**
 855 * drm_kms_helper_is_poll_worker - is %current task an output poll worker?
 856 *
 857 * Determine if %current task is an output poll worker.  This can be used
 858 * to select distinct code paths for output polling versus other contexts.
 859 *
 860 * One use case is to avoid a deadlock between the output poll worker and
 861 * the autosuspend worker wherein the latter waits for polling to finish
 862 * upon calling drm_kms_helper_poll_disable(), while the former waits for
 863 * runtime suspend to finish upon calling pm_runtime_get_sync() in a
 864 * connector ->detect hook.
 865 */
 866bool drm_kms_helper_is_poll_worker(void)
 867{
 868	struct work_struct *work = current_work();
 869
 870	return work && work->func == output_poll_execute;
 871}
 872EXPORT_SYMBOL(drm_kms_helper_is_poll_worker);
 873
 874/**
 875 * drm_kms_helper_poll_disable - disable output polling
 876 * @dev: drm_device
 877 *
 878 * This function disables the output polling work.
 879 *
 880 * Drivers can call this helper from their device suspend implementation. It is
 881 * not an error to call this even when output polling isn't enabled or already
 882 * disabled. Polling is re-enabled by calling drm_kms_helper_poll_enable().
 883 *
 884 * If however, the polling was never initialized, this call will trigger a
 885 * warning and return.
 886 *
 887 * Note that calls to enable and disable polling must be strictly ordered, which
 888 * is automatically the case when they're only call from suspend/resume
 889 * callbacks.
 890 */
 891void drm_kms_helper_poll_disable(struct drm_device *dev)
 892{
 893	if (drm_WARN_ON(dev, !dev->mode_config.poll_enabled))
 894		return;
 895
 896	if (dev->mode_config.poll_running)
 897		drm_kms_helper_disable_hpd(dev);
 898
 899	cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
 900
 901	dev->mode_config.poll_running = false;
 902}
 903EXPORT_SYMBOL(drm_kms_helper_poll_disable);
 904
 905/**
 906 * drm_kms_helper_poll_init - initialize and enable output polling
 907 * @dev: drm_device
 908 *
 909 * This function initializes and then also enables output polling support for
 910 * @dev. Drivers which do not have reliable hotplug support in hardware can use
 911 * this helper infrastructure to regularly poll such connectors for changes in
 912 * their connection state.
 913 *
 914 * Drivers can control which connectors are polled by setting the
 915 * DRM_CONNECTOR_POLL_CONNECT and DRM_CONNECTOR_POLL_DISCONNECT flags. On
 916 * connectors where probing live outputs can result in visual distortion drivers
 917 * should not set the DRM_CONNECTOR_POLL_DISCONNECT flag to avoid this.
 918 * Connectors which have no flag or only DRM_CONNECTOR_POLL_HPD set are
 919 * completely ignored by the polling logic.
 920 *
 921 * Note that a connector can be both polled and probed from the hotplug handler,
 922 * in case the hotplug interrupt is known to be unreliable.
 923 */
 924void drm_kms_helper_poll_init(struct drm_device *dev)
 925{
 926	INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute);
 927	dev->mode_config.poll_enabled = true;
 928
 929	drm_kms_helper_poll_enable(dev);
 930}
 931EXPORT_SYMBOL(drm_kms_helper_poll_init);
 932
 933/**
 934 * drm_kms_helper_poll_fini - disable output polling and clean it up
 935 * @dev: drm_device
 936 */
 937void drm_kms_helper_poll_fini(struct drm_device *dev)
 938{
 939	if (!dev->mode_config.poll_enabled)
 940		return;
 941
 942	drm_kms_helper_poll_disable(dev);
 943
 944	dev->mode_config.poll_enabled = false;
 945}
 946EXPORT_SYMBOL(drm_kms_helper_poll_fini);
 947
 948static void drm_kms_helper_poll_init_release(struct drm_device *dev, void *res)
 949{
 950	drm_kms_helper_poll_fini(dev);
 951}
 952
 953/**
 954 * drmm_kms_helper_poll_init - initialize and enable output polling
 955 * @dev: drm_device
 956 *
 957 * This function initializes and then also enables output polling support for
 958 * @dev similar to drm_kms_helper_poll_init(). Polling will automatically be
 959 * cleaned up when the DRM device goes away.
 960 *
 961 * See drm_kms_helper_poll_init() for more information.
 962 */
 963void drmm_kms_helper_poll_init(struct drm_device *dev)
 964{
 965	int ret;
 966
 967	drm_kms_helper_poll_init(dev);
 968
 969	ret = drmm_add_action_or_reset(dev, drm_kms_helper_poll_init_release, dev);
 970	if (ret)
 971		drm_warn(dev, "Connector status will not be updated, error %d\n", ret);
 972}
 973EXPORT_SYMBOL(drmm_kms_helper_poll_init);
 974
 975static bool check_connector_changed(struct drm_connector *connector)
 976{
 977	struct drm_device *dev = connector->dev;
 978	enum drm_connector_status old_status;
 979	u64 old_epoch_counter;
 980
 981	/* Only handle HPD capable connectors. */
 982	drm_WARN_ON(dev, !(connector->polled & DRM_CONNECTOR_POLL_HPD));
 983
 984	drm_WARN_ON(dev, !mutex_is_locked(&dev->mode_config.mutex));
 985
 986	old_status = connector->status;
 987	old_epoch_counter = connector->epoch_counter;
 988	connector->status = drm_helper_probe_detect(connector, NULL, false);
 989
 990	if (old_epoch_counter == connector->epoch_counter) {
 991		drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Same epoch counter %llu\n",
 992			    connector->base.id,
 993			    connector->name,
 994			    connector->epoch_counter);
 995
 996		return false;
 997	}
 998
 999	drm_dbg_kms(dev, "[CONNECTOR:%d:%s] status updated from %s to %s\n",
1000		    connector->base.id,
1001		    connector->name,
1002		    drm_get_connector_status_name(old_status),
1003		    drm_get_connector_status_name(connector->status));
1004
1005	drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Changed epoch counter %llu => %llu\n",
1006		    connector->base.id,
1007		    connector->name,
1008		    old_epoch_counter,
1009		    connector->epoch_counter);
1010
1011	return true;
1012}
1013
1014/**
1015 * drm_connector_helper_hpd_irq_event - hotplug processing
1016 * @connector: drm_connector
1017 *
1018 * Drivers can use this helper function to run a detect cycle on a connector
1019 * which has the DRM_CONNECTOR_POLL_HPD flag set in its &polled member.
1020 *
1021 * This helper function is useful for drivers which can track hotplug
1022 * interrupts for a single connector. Drivers that want to send a
1023 * hotplug event for all connectors or can't track hotplug interrupts
1024 * per connector need to use drm_helper_hpd_irq_event().
1025 *
1026 * This function must be called from process context with no mode
1027 * setting locks held.
1028 *
1029 * Note that a connector can be both polled and probed from the hotplug
1030 * handler, in case the hotplug interrupt is known to be unreliable.
1031 *
1032 * Returns:
1033 * A boolean indicating whether the connector status changed or not
1034 */
1035bool drm_connector_helper_hpd_irq_event(struct drm_connector *connector)
1036{
1037	struct drm_device *dev = connector->dev;
1038	bool changed;
1039
1040	mutex_lock(&dev->mode_config.mutex);
1041	changed = check_connector_changed(connector);
1042	mutex_unlock(&dev->mode_config.mutex);
1043
1044	if (changed) {
1045		drm_kms_helper_connector_hotplug_event(connector);
1046		drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Sent hotplug event\n",
1047			    connector->base.id,
1048			    connector->name);
1049	}
1050
1051	return changed;
1052}
1053EXPORT_SYMBOL(drm_connector_helper_hpd_irq_event);
1054
1055/**
1056 * drm_helper_hpd_irq_event - hotplug processing
1057 * @dev: drm_device
1058 *
1059 * Drivers can use this helper function to run a detect cycle on all connectors
1060 * which have the DRM_CONNECTOR_POLL_HPD flag set in their &polled member. All
1061 * other connectors are ignored, which is useful to avoid reprobing fixed
1062 * panels.
1063 *
1064 * This helper function is useful for drivers which can't or don't track hotplug
1065 * interrupts for each connector.
1066 *
1067 * Drivers which support hotplug interrupts for each connector individually and
1068 * which have a more fine-grained detect logic can use
1069 * drm_connector_helper_hpd_irq_event(). Alternatively, they should bypass this
1070 * code and directly call drm_kms_helper_hotplug_event() in case the connector
1071 * state changed.
1072 *
1073 * This function must be called from process context with no mode
1074 * setting locks held.
1075 *
1076 * Note that a connector can be both polled and probed from the hotplug handler,
1077 * in case the hotplug interrupt is known to be unreliable.
1078 *
1079 * Returns:
1080 * A boolean indicating whether the connector status changed or not
1081 */
1082bool drm_helper_hpd_irq_event(struct drm_device *dev)
1083{
1084	struct drm_connector *connector, *first_changed_connector = NULL;
1085	struct drm_connector_list_iter conn_iter;
1086	int changed = 0;
1087
1088	if (!dev->mode_config.poll_enabled)
1089		return false;
1090
1091	mutex_lock(&dev->mode_config.mutex);
1092	drm_connector_list_iter_begin(dev, &conn_iter);
1093	drm_for_each_connector_iter(connector, &conn_iter) {
1094		/* Only handle HPD capable connectors. */
1095		if (!(connector->polled & DRM_CONNECTOR_POLL_HPD))
1096			continue;
1097
1098		if (check_connector_changed(connector)) {
1099			if (!first_changed_connector) {
1100				drm_connector_get(connector);
1101				first_changed_connector = connector;
1102			}
1103
1104			changed++;
1105		}
1106	}
1107	drm_connector_list_iter_end(&conn_iter);
1108	mutex_unlock(&dev->mode_config.mutex);
1109
1110	if (changed == 1)
1111		drm_kms_helper_connector_hotplug_event(first_changed_connector);
1112	else if (changed > 0)
1113		drm_kms_helper_hotplug_event(dev);
1114
1115	if (first_changed_connector)
1116		drm_connector_put(first_changed_connector);
1117
1118	return changed;
1119}
1120EXPORT_SYMBOL(drm_helper_hpd_irq_event);
1121
1122/**
1123 * drm_crtc_helper_mode_valid_fixed - Validates a display mode
1124 * @crtc: the crtc
1125 * @mode: the mode to validate
1126 * @fixed_mode: the display hardware's mode
1127 *
1128 * Returns:
1129 * MODE_OK on success, or another mode-status code otherwise.
1130 */
1131enum drm_mode_status drm_crtc_helper_mode_valid_fixed(struct drm_crtc *crtc,
1132						      const struct drm_display_mode *mode,
1133						      const struct drm_display_mode *fixed_mode)
1134{
1135	if (mode->hdisplay != fixed_mode->hdisplay && mode->vdisplay != fixed_mode->vdisplay)
1136		return MODE_ONE_SIZE;
1137	else if (mode->hdisplay != fixed_mode->hdisplay)
1138		return MODE_ONE_WIDTH;
1139	else if (mode->vdisplay != fixed_mode->vdisplay)
1140		return MODE_ONE_HEIGHT;
1141
1142	return MODE_OK;
1143}
1144EXPORT_SYMBOL(drm_crtc_helper_mode_valid_fixed);
1145
1146/**
1147 * drm_connector_helper_get_modes_fixed - Duplicates a display mode for a connector
1148 * @connector: the connector
1149 * @fixed_mode: the display hardware's mode
1150 *
1151 * This function duplicates a display modes for a connector. Drivers for hardware
1152 * that only supports a single fixed mode can use this function in their connector's
1153 * get_modes helper.
1154 *
1155 * Returns:
1156 * The number of created modes.
1157 */
1158int drm_connector_helper_get_modes_fixed(struct drm_connector *connector,
1159					 const struct drm_display_mode *fixed_mode)
1160{
1161	struct drm_device *dev = connector->dev;
1162	struct drm_display_mode *mode;
1163
1164	mode = drm_mode_duplicate(dev, fixed_mode);
1165	if (!mode) {
1166		drm_err(dev, "Failed to duplicate mode " DRM_MODE_FMT "\n",
1167			DRM_MODE_ARG(fixed_mode));
1168		return 0;
1169	}
1170
1171	if (mode->name[0] == '\0')
1172		drm_mode_set_name(mode);
1173
1174	mode->type |= DRM_MODE_TYPE_PREFERRED;
1175	drm_mode_probed_add(connector, mode);
1176
1177	if (mode->width_mm)
1178		connector->display_info.width_mm = mode->width_mm;
1179	if (mode->height_mm)
1180		connector->display_info.height_mm = mode->height_mm;
1181
1182	return 1;
1183}
1184EXPORT_SYMBOL(drm_connector_helper_get_modes_fixed);
1185
1186/**
1187 * drm_connector_helper_get_modes - Read EDID and update connector.
1188 * @connector: The connector
1189 *
1190 * Read the EDID using drm_edid_read() (which requires that connector->ddc is
1191 * set), and update the connector using the EDID.
1192 *
1193 * This can be used as the "default" connector helper .get_modes() hook if the
1194 * driver does not need any special processing. This is sets the example what
1195 * custom .get_modes() hooks should do regarding EDID read and connector update.
1196 *
1197 * Returns: Number of modes.
1198 */
1199int drm_connector_helper_get_modes(struct drm_connector *connector)
1200{
1201	const struct drm_edid *drm_edid;
1202	int count;
1203
1204	drm_edid = drm_edid_read(connector);
1205
1206	/*
1207	 * Unconditionally update the connector. If the EDID was read
1208	 * successfully, fill in the connector information derived from the
1209	 * EDID. Otherwise, if the EDID is NULL, clear the connector
1210	 * information.
1211	 */
1212	drm_edid_connector_update(connector, drm_edid);
1213
1214	count = drm_edid_connector_add_modes(connector);
1215
1216	drm_edid_free(drm_edid);
1217
1218	return count;
1219}
1220EXPORT_SYMBOL(drm_connector_helper_get_modes);
1221
1222/**
1223 * drm_connector_helper_tv_get_modes - Fills the modes availables to a TV connector
1224 * @connector: The connector
1225 *
1226 * Fills the available modes for a TV connector based on the supported
1227 * TV modes, and the default mode expressed by the kernel command line.
1228 *
1229 * This can be used as the default TV connector helper .get_modes() hook
1230 * if the driver does not need any special processing.
1231 *
1232 * Returns:
1233 * The number of modes added to the connector.
1234 */
1235int drm_connector_helper_tv_get_modes(struct drm_connector *connector)
1236{
1237	struct drm_device *dev = connector->dev;
1238	struct drm_property *tv_mode_property =
1239		dev->mode_config.tv_mode_property;
1240	struct drm_cmdline_mode *cmdline = &connector->cmdline_mode;
1241	unsigned int ntsc_modes = BIT(DRM_MODE_TV_MODE_NTSC) |
1242		BIT(DRM_MODE_TV_MODE_NTSC_443) |
1243		BIT(DRM_MODE_TV_MODE_NTSC_J) |
1244		BIT(DRM_MODE_TV_MODE_PAL_M);
1245	unsigned int pal_modes = BIT(DRM_MODE_TV_MODE_PAL) |
1246		BIT(DRM_MODE_TV_MODE_PAL_N) |
1247		BIT(DRM_MODE_TV_MODE_SECAM);
1248	unsigned int tv_modes[2] = { UINT_MAX, UINT_MAX };
1249	unsigned int i, supported_tv_modes = 0;
1250
1251	if (!tv_mode_property)
1252		return 0;
1253
1254	for (i = 0; i < tv_mode_property->num_values; i++)
1255		supported_tv_modes |= BIT(tv_mode_property->values[i]);
1256
1257	if (((supported_tv_modes & ntsc_modes) &&
1258	     (supported_tv_modes & pal_modes)) ||
1259	    (supported_tv_modes & BIT(DRM_MODE_TV_MODE_MONOCHROME))) {
1260		uint64_t default_mode;
1261
1262		if (drm_object_property_get_default_value(&connector->base,
1263							  tv_mode_property,
1264							  &default_mode))
1265			return 0;
1266
1267		if (cmdline->tv_mode_specified)
1268			default_mode = cmdline->tv_mode;
1269
1270		if (BIT(default_mode) & ntsc_modes) {
1271			tv_modes[0] = DRM_MODE_TV_MODE_NTSC;
1272			tv_modes[1] = DRM_MODE_TV_MODE_PAL;
1273		} else {
1274			tv_modes[0] = DRM_MODE_TV_MODE_PAL;
1275			tv_modes[1] = DRM_MODE_TV_MODE_NTSC;
1276		}
1277	} else if (supported_tv_modes & ntsc_modes) {
1278		tv_modes[0] = DRM_MODE_TV_MODE_NTSC;
1279	} else if (supported_tv_modes & pal_modes) {
1280		tv_modes[0] = DRM_MODE_TV_MODE_PAL;
1281	} else {
1282		return 0;
1283	}
1284
1285	for (i = 0; i < ARRAY_SIZE(tv_modes); i++) {
1286		struct drm_display_mode *mode;
1287
1288		if (tv_modes[i] == DRM_MODE_TV_MODE_NTSC)
1289			mode = drm_mode_analog_ntsc_480i(dev);
1290		else if (tv_modes[i] == DRM_MODE_TV_MODE_PAL)
1291			mode = drm_mode_analog_pal_576i(dev);
1292		else
1293			break;
1294		if (!mode)
1295			return i;
1296		if (!i)
1297			mode->type |= DRM_MODE_TYPE_PREFERRED;
1298		drm_mode_probed_add(connector, mode);
1299	}
1300
1301	return i;
1302}
1303EXPORT_SYMBOL(drm_connector_helper_tv_get_modes);
1304
1305/**
1306 * drm_connector_helper_detect_from_ddc - Read EDID and detect connector status.
1307 * @connector: The connector
1308 * @ctx: Acquire context
1309 * @force: Perform screen-destructive operations, if necessary
1310 *
1311 * Detects the connector status by reading the EDID using drm_probe_ddc(),
1312 * which requires connector->ddc to be set. Returns connector_status_connected
1313 * on success or connector_status_disconnected on failure.
1314 *
1315 * Returns:
1316 * The connector status as defined by enum drm_connector_status.
1317 */
1318int drm_connector_helper_detect_from_ddc(struct drm_connector *connector,
1319					 struct drm_modeset_acquire_ctx *ctx,
1320					 bool force)
1321{
1322	struct i2c_adapter *ddc = connector->ddc;
1323
1324	if (!ddc)
1325		return connector_status_unknown;
1326
1327	if (drm_probe_ddc(ddc))
1328		return connector_status_connected;
1329
1330	return connector_status_disconnected;
1331}
1332EXPORT_SYMBOL(drm_connector_helper_detect_from_ddc);