path: root/drivers/gpu/drm/drm_probe_helper.c

/*
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
 *
 * DRM core CRTC related functions
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 *
 * Authors:
 *      Keith Packard
 *	Eric Anholt <eric@anholt.net>
 *      Dave Airlie <airlied@linux.ie>
 *      Jesse Barnes <jesse.barnes@intel.com>
 */

#include <linux/export.h>
#include <linux/moduleparam.h>

#include <drm/drm_bridge.h>
#include <drm/drm_client_event.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_managed.h>
#include <drm/drm_modeset_helper_vtables.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_sysfs.h>

#include "drm_crtc_helper_internal.h"

/**
 * DOC: output probing helper overview
 *
 * This library provides some helper code for output probing. It provides an
 * implementation of the core &drm_connector_funcs.fill_modes interface with
 * drm_helper_probe_single_connector_modes().
 *
 * It also provides support for polling connectors with a work item and for
 * generic hotplug interrupt handling where the driver doesn't or cannot keep
 * track of a per-connector hpd interrupt.
 *
 * This helper library can be used independently of the modeset helper library.
 * Drivers can also overwrite different parts e.g. use their own hotplug
 * handling code to avoid probing unrelated outputs.
 *
 * The probe helpers share the function table structures with other display
 * helper libraries. See &struct drm_connector_helper_funcs for the details.
 */

static bool drm_kms_helper_poll = true;
module_param_named(poll, drm_kms_helper_poll, bool, 0600);

static enum drm_mode_status
drm_mode_validate_flag(const struct drm_display_mode *mode,
		       int flags)
{
	if ((mode->flags & DRM_MODE_FLAG_INTERLACE) &&
	    !(flags & DRM_MODE_FLAG_INTERLACE))
		return MODE_NO_INTERLACE;

	if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) &&
	    !(flags & DRM_MODE_FLAG_DBLSCAN))
		return MODE_NO_DBLESCAN;

	if ((mode->flags & DRM_MODE_FLAG_3D_MASK) &&
	    !(flags & DRM_MODE_FLAG_3D_MASK))
		return MODE_NO_STEREO;

	return MODE_OK;
}

static int
drm_mode_validate_pipeline(struct drm_display_mode *mode,
			   struct drm_connector *connector,
			   struct drm_modeset_acquire_ctx *ctx,
			   enum drm_mode_status *status)
{
	struct drm_device *dev = connector->dev;
	struct drm_encoder *encoder;
	int ret;

	/* Step 1: Validate against connector */
	ret = drm_connector_mode_valid(connector, mode, ctx, status);
	if (ret || *status != MODE_OK)
		return ret;

	/* Step 2: Validate against encoders and crtcs */
	drm_connector_for_each_possible_encoder(connector, encoder) {
		struct drm_bridge *bridge;
		struct drm_crtc *crtc;

		*status = drm_encoder_mode_valid(encoder, mode);
		if (*status != MODE_OK) {
			/* No point in continuing for crtc check as this encoder
			 * will not accept the mode anyway. If all encoders
			 * reject the mode then, at exit, ret will not be
			 * MODE_OK. */
			continue