drm_connector.c

/*
 * Copyright (c) 2016 Intel Corporation
 *
 * 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.
 */

#include <drm/drm_auth.h>
#include <drm/drm_connector.h>
#include <drm/drm_drv.h>
#include <drm/drm_edid.h>
#include <drm/drm_encoder.h>
#include <drm/drm_file.h>
#include <drm/drm_managed.h>
#include <drm/drm_panel.h>
#include <drm/drm_print.h>
#include <drm/drm_privacy_screen_consumer.h>
#include <drm/drm_sysfs.h>
#include <drm/drm_utils.h>

#include <linux/property.h>
#include <linux/uaccess.h>

#include <video/cmdline.h>

#include "drm_crtc_internal.h"
#include "drm_internal.h"

/**
 * DOC: overview
 *
 * In DRM connectors are the general abstraction for display sinks, and include
 * also fixed panels or anything else that can display pixels in some form. As
 * opposed to all other KMS objects representing hardware (like CRTC, encoder or
 * plane abstractions) connectors can be hotplugged and unplugged at runtime.
 * Hence they are reference-counted using drm_connector_get() and
 * drm_connector_put().
 *
 * KMS driver must create, initialize, register and attach at a &struct
 * drm_connector for each such sink. The instance is created as other KMS
 * objects and initialized by setting the following fields. The connector is
 * initialized with a call to drm_connector_init() with a pointer to the
 * &struct drm_connector_funcs and a connector type, and then exposed to
 * userspace with a call to drm_connector_register().
 *
 * Connectors must be attached to an encoder to be used. For devices that map
 * connectors to encoders 1:1, the connector should be attached at
 * initialization time with a call to drm_connector_attach_encoder(). The
 * driver must also set the &drm_connector.encoder field to point to the
 * attached encoder.
 *
 * For connectors which are not fixed (like built-in panels) the driver needs to
 * support hotplug notifications. The simplest way to do that is by using the
 * probe helpers, see drm_kms_helper_poll_init() for connectors which don't have
 * hardware support for hotplug interrupts. Connectors with hardware hotplug