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Subject: Re: [RFC PATCH] media: cec: DRM connector to CEC dev mapping
To:     Dariusz Marcinkiewicz <darekm@google.com>,
        linux-media@vger.kernel.org, hans.verkuil@cisco.com
Cc:     linux-kernel@vger.kernel.org
References: <20190404073005.35474-1-darekm@google.com>
From:   Hans Verkuil <hverkuil@xs4all.nl>
Message-ID: <c1b7d461-d0b1-e3a4-f8fd-7c757a5e38f6@xs4all.nl>
Date:   Thu, 4 Apr 2019 14:23:50 +0200
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Hi Dariusz,

On 4/4/19 9:30 AM, Dariusz Marcinkiewicz wrote:
> This patch proposes to introduce explicit mapping between DRM connectors
> and /dev/cecX adapters.
> 
> This is achieved here by adding a new structure with connector info
> (DRM card number and connector id) to cec_adapter. That connector info
> is expected to be set either by a code creating an adapter or trough
> a CEC notifier (which is extended for that purpose).
> 
> A new ioctl, exposing connector info to userland, is added to /dev/cec.
> New CEC event type is also added. That event is to notify an application
> that the info about mapping between an adapter and a DRM connector was
> just set.
> 
> Signed-off-by: Dariusz Marcinkiewicz <darekm@google.com>
> ---
> 
> Notes:
>     Sending the patch in its current form the get feedback if that is
>     considered a right approach or if some other way of learning
>     the mapping in userland is preferred.

Thank you for this patch. It's interesting, but I think it should be
redesigned a bit.

Basically what you want to do is to provide a way for userspace to associate
the CEC device with the HDMI connector it is associated with.

But this information is known the moment the cec adapter is allocated or the
cec_notifier is registered for a connector. So I would provide this information
at that time, rather than through separate functions. This makes everything
nicely atomic. This also avoids the need of a connector_info event, since the
connector info is known from the very beginning. You still need the ioctl to
obtain this information, though.

There are also two related issues.

Firstly, CEC is used not only for DRM, but also for V4L2, and it makes sense
to provide connector info there as well. For V4L2 this would probably look
like this (tentative as I am not completely sure about the major/minor numbers):

	struct v4l2_connector_info {
		__u32 major;
		__u32 minor;
		__u16 connector_mask;
	}

Where the major/minor numbers determine the video or v4l-subdev device that controls
the HDMI connector(s). Since a CEC device for HDMI receivers can be responsible for
multiple HDMI inputs we need the connector_mask to indicate which HDMI inputs it is
associated with.

Secondly, there are USB-CEC dongles that are not directly associated with an HDMI
connector since the driver simply doesn't know. But it would be nice if the user
can provide that information. I did a proof-of-concept here:

https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=pulse8-notifier

and it works fine. But the problem is that the connector name is currently only
available on the i915 via port_identifier(port), and that that port identifier
string is not visible to the end-user. I had to try various port names ("Port A",
"Port B", etc) before I hit the right one.

But as I understand it that port identifier name is stable, and that's what is
needed in a driver like seco-cec.c (used for UDOO x86 boards) to correctly
create the CEC device for the right HDMI connector.

It would be nice to have something that works for all these cases.

I'm especially not keen on the port_identifier(port) thing since it is i915
specific and something similar on the level of the DRM API would be much more
useful.

I'm not a drm specialist, though.

Regards,

	Hans

> 
>  .../display/amdgpu_dm/amdgpu_dm_mst_types.c   |  2 +-
>  drivers/gpu/drm/drm_dp_cec.c                  | 20 ++++----
>  drivers/gpu/drm/i915/intel_dp.c               |  4 +-
>  drivers/gpu/drm/i915/intel_hdmi.c             |  7 ++-
>  drivers/gpu/drm/nouveau/nouveau_connector.c   |  3 +-
>  drivers/media/cec/cec-adap.c                  | 21 ++++++++-
>  drivers/media/cec/cec-api.c                   | 17 +++++++
>  drivers/media/cec/cec-core.c                  | 12 ++++-
>  drivers/media/cec/cec-notifier.c              | 47 ++++++++++++++++---
>  include/drm/drm_dp_helper.h                   | 14 +++---
>  include/media/cec-notifier.h                  | 31 ++++++++++--
>  include/media/cec.h                           | 13 ++++-
>  include/uapi/linux/cec.h                      | 18 +++++++
>  13 files changed, 172 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> index c4ea3a91f17aa..41678df654cdc 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> @@ -379,7 +379,7 @@ void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
>  
>  	drm_dp_aux_register(&aconnector->dm_dp_aux.aux);
>  	drm_dp_cec_register_connector(&aconnector->dm_dp_aux.aux,
> -				      aconnector->base.name, dm->adev->dev);
> +				      &aconnector->base);
>  	aconnector->mst_mgr.cbs = &dm_mst_cbs;
>  	drm_dp_mst_topology_mgr_init(
>  		&aconnector->mst_mgr,
> diff --git a/drivers/gpu/drm/drm_dp_cec.c b/drivers/gpu/drm/drm_dp_cec.c
> index b15cee85b702b..cb09bb2197a85 100644
> --- a/drivers/gpu/drm/drm_dp_cec.c
> +++ b/drivers/gpu/drm/drm_dp_cec.c
> @@ -8,7 +8,9 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/slab.h>
> +#include <drm/drm_connector.h>
>  #include <drm/drm_dp_helper.h>
> +#include <drm/drmP.h>
>  #include <media/cec.h>
>  
>  /*
> @@ -295,6 +297,7 @@ static void drm_dp_cec_unregister_work(struct work_struct *work)
>   */
>  void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const struct edid *edid)
>  {
> +	struct drm_connector *connector = aux->cec.connector;
>  	u32 cec_caps = CEC_CAP_DEFAULTS | CEC_CAP_NEEDS_HPD;
>  	unsigned int num_las = 1;
>  	u8 cap;
> @@ -344,16 +347,19 @@ void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const struct edid *edid)
>  
>  	/* Create a new adapter */
>  	aux->cec.adap = cec_allocate_adapter(&drm_dp_cec_adap_ops,
> -					     aux, aux->cec.name, cec_caps,
> +					     aux, connector->name, cec_caps,
>  					     num_las);
>  	if (IS_ERR(aux->cec.adap)) {
>  		aux->cec.adap = NULL;
>  		goto unlock;
>  	}
> -	if (cec_register_adapter(aux->cec.adap, aux->cec.parent)) {
> +	if (cec_register_adapter(aux->cec.adap, connector->dev->dev)) {
>  		cec_delete_adapter(aux->cec.adap);
>  		aux->cec.adap = NULL;
>  	} else {
> +		cec_s_connector_info(aux->cec.adap,
> +				     connector->dev->primary->index,
> +				     connector->base.id);
>  		/*
>  		 * Update the phys addr for the new CEC adapter. When called
>  		 * from drm_dp_cec_register_connector() edid == NULL, so in
> @@ -406,22 +412,20 @@ EXPORT_SYMBOL(drm_dp_cec_unset_edid);
>  /**
>   * drm_dp_cec_register_connector() - register a new connector
>   * @aux: DisplayPort AUX channel
> - * @name: name of the CEC device
> - * @parent: parent device
> + * @connector: drm connector
>   *
>   * A new connector was registered with associated CEC adapter name and
>   * CEC adapter parent device. After registering the name and parent
>   * drm_dp_cec_set_edid() is called to check if the connector supports
>   * CEC and to register a CEC adapter if that is the case.
>   */
> -void drm_dp_cec_register_connector(struct drm_dp_aux *aux, const char *name,
> -				   struct device *parent)
> +void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> +				   struct drm_connector *connector)
>  {
>  	WARN_ON(aux->cec.adap);
>  	if (WARN_ON(!aux->transfer))
>  		return;
> -	aux->cec.name = name;
> -	aux->cec.parent = parent;
> +	aux->cec.connector = connector;
>  	INIT_DELAYED_WORK(&aux->cec.unregister_work,
>  			  drm_dp_cec_unregister_work);
>  }
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index cf709835fb9a9..b30eb9598965b 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -5557,8 +5557,7 @@ intel_dp_connector_register(struct drm_connector *connector)
>  	intel_dp->aux.dev = connector->kdev;
>  	ret = drm_dp_aux_register(&intel_dp->aux);
>  	if (!ret)
> -		drm_dp_cec_register_connector(&intel_dp->aux,
> -					      connector->name, dev->dev);
> +		drm_dp_cec_register_connector(&intel_dp->aux, connector);
>  	return ret;
>  }
>  
> @@ -7107,3 +7106,4 @@ void intel_dp_mst_resume(struct drm_i915_private *dev_priv)
>  		}
>  	}
>  }
> +
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index f125a62eba8cf..5ad088c7a0c03 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -2448,8 +2448,13 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
>  
>  	intel_hdmi->cec_notifier = cec_notifier_get_conn(dev->dev,
>  							 port_identifier(port));
> -	if (!intel_hdmi->cec_notifier)
> +	if (intel_hdmi->cec_notifier) {
> +		cec_notifier_set_connector_info(intel_hdmi->cec_notifier,
> +						connector->dev->primary->index,
> +						connector->base.id);
> +	} else {
>  		DRM_DEBUG_KMS("CEC notifier get failed\n");
> +	}
>  }
>  
>  void intel_hdmi_init(struct drm_i915_private *dev_priv,
> diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
> index 4116ee62adafe..4438824ca88b0 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_connector.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
> @@ -1413,8 +1413,7 @@ nouveau_connector_create(struct drm_device *dev,
>  	switch (type) {
>  	case DRM_MODE_CONNECTOR_DisplayPort:
>  	case DRM_MODE_CONNECTOR_eDP:
> -		drm_dp_cec_register_connector(&nv_connector->aux,
> -					      connector->name, dev->dev);
> +		drm_dp_cec_register_connector(&nv_connector->aux, connector);
>  		break;
>  	}
>  
> diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c
> index f1261cc2b6fa5..dceddab9bcaee 100644
> --- a/drivers/media/cec/cec-adap.c
> +++ b/drivers/media/cec/cec-adap.c
> @@ -87,7 +87,7 @@ void cec_queue_event_fh(struct cec_fh *fh,
>  			const struct cec_event *new_ev, u64 ts)
>  {
>  	static const u16 max_events[CEC_NUM_EVENTS] = {
> -		1, 1, 800, 800, 8, 8, 8, 8
> +		1, 1, 800, 800, 8, 8, 8, 8, 1
>  	};
>  	struct cec_event_entry *entry;
>  	unsigned int ev_idx = new_ev->event - 1;
> @@ -1566,6 +1566,25 @@ void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
>  }
>  EXPORT_SYMBOL_GPL(cec_s_phys_addr_from_edid);
>  
> +void cec_s_connector_info(struct cec_adapter *adap, int card_no,
> +			  u32 connector_id)
> +{
> +	struct cec_event ev = {
> +		.event = CEC_EVENT_CONNECTOR_SET,
> +		.flags = 0,
> +		.connector.card_no = card_no,
> +		.connector.connector_id = connector_id,
> +	};
> +
> +	mutex_lock(&adap->lock);
> +	adap->connector.card_no = card_no;
> +	adap->connector.connector_id = connector_id;
> +	mutex_unlock(&adap->lock);
> +
> +	cec_queue_event(adap, &ev);
> +}
> +EXPORT_SYMBOL_GPL(cec_s_connector_info);
> +
>  /*
>   * Called from either the ioctl or a driver to set the logical addresses.
>   *
> diff --git a/drivers/media/cec/cec-api.c b/drivers/media/cec/cec-api.c
> index 156a0d76ab2a1..f523d5433849f 100644
> --- a/drivers/media/cec/cec-api.c
> +++ b/drivers/media/cec/cec-api.c
> @@ -187,6 +187,20 @@ static long cec_adap_s_log_addrs(struct cec_adapter *adap, struct cec_fh *fh,
>  	return 0;
>  }
>  
> +static long cec_adap_g_connector_info(struct cec_adapter *adap,
> +				      struct cec_log_addrs __user *parg)
> +{
> +	struct cec_connector_info connector_info;
> +
> +	mutex_lock(&adap->lock);
> +	connector_info = adap->connector;
> +	mutex_unlock(&adap->lock);
> +
> +	if (copy_to_user(parg, &connector_info, sizeof(connector_info)))
> +		return -EFAULT;
> +	return 0;
> +}
> +
>  static long cec_transmit(struct cec_adapter *adap, struct cec_fh *fh,
>  			 bool block, struct cec_msg __user *parg)
>  {
> @@ -514,6 +528,9 @@ static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  	case CEC_ADAP_S_LOG_ADDRS:
>  		return cec_adap_s_log_addrs(adap, fh, block, parg);
>  
> +	case CEC_ADAP_G_CONNECTOR_INFO:
> +		return cec_adap_g_connector_info(adap, parg);
> +
>  	case CEC_TRANSMIT:
>  		return cec_transmit(adap, fh, block, parg);
>  
> diff --git a/drivers/media/cec/cec-core.c b/drivers/media/cec/cec-core.c
> index cc875dabd7658..d80f14d58b1be 100644
> --- a/drivers/media/cec/cec-core.c
> +++ b/drivers/media/cec/cec-core.c
> @@ -182,11 +182,17 @@ static void cec_devnode_unregister(struct cec_adapter *adap)
>  }
>  
>  #ifdef CONFIG_CEC_NOTIFIER
> -static void cec_cec_notify(struct cec_adapter *adap, u16 pa)
> +static void cec_cec_phys_addr_notify(struct cec_adapter *adap, u16 pa)
>  {
>  	cec_s_phys_addr(adap, pa, false);
>  }
>  
> +static void cec_cec_connector_notify(struct cec_adapter *adap, int card_no,
> +				     u32 connector_id)
> +{
> +	cec_s_connector_info(adap, card_no, connector_id);
> +}
> +
>  void cec_register_cec_notifier(struct cec_adapter *adap,
>  			       struct cec_notifier *notifier)
>  {
> @@ -194,7 +200,9 @@ void cec_register_cec_notifier(struct cec_adapter *adap,
>  		return;
>  
>  	adap->notifier = notifier;
> -	cec_notifier_register(adap->notifier, adap, cec_cec_notify);
> +	cec_notifier_register(adap->notifier, adap,
> +			      cec_cec_phys_addr_notify,
> +			      cec_cec_connector_notify);
>  }
>  EXPORT_SYMBOL_GPL(cec_register_cec_notifier);
>  #endif
> diff --git a/drivers/media/cec/cec-notifier.c b/drivers/media/cec/cec-notifier.c
> index dd2078b27a419..86b0412a95d14 100644
> --- a/drivers/media/cec/cec-notifier.c
> +++ b/drivers/media/cec/cec-notifier.c
> @@ -23,9 +23,13 @@ struct cec_notifier {
>  	struct device *dev;
>  	const char *conn;
>  	struct cec_adapter *cec_adap;
> -	void (*callback)(struct cec_adapter *adap, u16 pa);
> +	void (*phys_addr_callback)(struct cec_adapter *adap, u16 pa);
> +	void (*connector_callback)(struct cec_adapter *adap,
> +				   int card_no,
> +				   u32 connector_id);
>  
>  	u16 phys_addr;
> +	struct cec_connector_info connector_info;
>  };
>  
>  static LIST_HEAD(cec_notifiers);
> @@ -51,6 +55,7 @@ struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn)
>  	if (conn)
>  		n->conn = kstrdup(conn, GFP_KERNEL);
>  	n->phys_addr = CEC_PHYS_ADDR_INVALID;
> +	n->connector_info.card_no = CEC_CONNECTOR_INVALID_CARD_NO;
>  	mutex_init(&n->lock);
>  	kref_init(&n->kref);
>  	list_add_tail(&n->head, &cec_notifiers);
> @@ -85,8 +90,8 @@ void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa)
>  
>  	mutex_lock(&n->lock);
>  	n->phys_addr = pa;
> -	if (n->callback)
> -		n->callback(n->cec_adap, n->phys_addr);
> +	if (n->phys_addr_callback)
> +		n->phys_addr_callback(n->cec_adap, n->phys_addr);
>  	mutex_unlock(&n->lock);
>  }
>  EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr);
> @@ -106,15 +111,42 @@ void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
>  }
>  EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr_from_edid);
>  
> +void cec_notifier_set_connector_info(struct cec_notifier *n, int card_no,
> +				     u32 connector_id)
> +{
> +	if (n == NULL)
> +		return;
> +
> +	mutex_lock(&n->lock);
> +	n->connector_info.card_no = card_no;
> +	n->connector_info.connector_id = connector_id;
> +	if (n->connector_callback)
> +		n->connector_callback(n->cec_adap, card_no, connector_id);
> +	mutex_unlock(&n->lock);
> +}
> +EXPORT_SYMBOL_GPL(cec_notifier_set_connector_info);
> +
>  void cec_notifier_register(struct cec_notifier *n,
>  			   struct cec_adapter *adap,
> -			   void (*callback)(struct cec_adapter *adap, u16 pa))
> +			   void (*phys_addr_callback)(struct cec_adapter *adap,
> +						      u16 pa),
> +			   void (*connector_callback)(struct cec_adapter *adap,
> +						      int card_no,
> +						      u32 connector_id))
>  {
>  	kref_get(&n->kref);
>  	mutex_lock(&n->lock);
>  	n->cec_adap = adap;
> -	n->callback = callback;
> -	n->callback(adap, n->phys_addr);
> +
> +	n->phys_addr_callback = phys_addr_callback;
> +	n->phys_addr_callback(adap, n->phys_addr);
> +
> +	n->connector_callback = connector_callback;
> +	if (n->connector_callback) {
> +		n->connector_callback(adap, n->connector_info.card_no,
> +				      n->connector_info.connector_id);
> +	}
> +
>  	mutex_unlock(&n->lock);
>  }
>  EXPORT_SYMBOL_GPL(cec_notifier_register);
> @@ -122,7 +154,8 @@ EXPORT_SYMBOL_GPL(cec_notifier_register);
>  void cec_notifier_unregister(struct cec_notifier *n)
>  {
>  	mutex_lock(&n->lock);
> -	n->callback = NULL;
> +	n->phys_addr_callback = NULL;
> +	n->connector_callback = NULL;
>  	mutex_unlock(&n->lock);
>  	cec_notifier_put(n);
>  }
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 97ce790a5b5aa..ded0ff01f2ac7 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -1208,6 +1208,7 @@ struct drm_dp_aux_msg {
>  
>  struct cec_adapter;
>  struct edid;
> +struct drm_connector;
>  
>  /**
>   * struct drm_dp_aux_cec - DisplayPort CEC-Tunneling-over-AUX
> @@ -1220,8 +1221,7 @@ struct edid;
>  struct drm_dp_aux_cec {
>  	struct mutex lock;
>  	struct cec_adapter *adap;
> -	const char *name;
> -	struct device *parent;
> +	struct drm_connector *connector;
>  	struct delayed_work unregister_work;
>  };
>  
> @@ -1418,8 +1418,8 @@ drm_dp_has_quirk(const struct drm_dp_desc *desc, enum drm_dp_quirk quirk)
>  
>  #ifdef CONFIG_DRM_DP_CEC
>  void drm_dp_cec_irq(struct drm_dp_aux *aux);
> -void drm_dp_cec_register_connector(struct drm_dp_aux *aux, const char *name,
> -				   struct device *parent);
> +void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> +				   struct drm_connector *connector);
>  void drm_dp_cec_unregister_connector(struct drm_dp_aux *aux);
>  void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const struct edid *edid);
>  void drm_dp_cec_unset_edid(struct drm_dp_aux *aux);
> @@ -1428,9 +1428,9 @@ static inline void drm_dp_cec_irq(struct drm_dp_aux *aux)
>  {
>  }
>  
> -static inline void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> -						 const char *name,
> -						 struct device *parent)
> +static inline
> +void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> +				   struct drm_connector *connector)
>  {
>  }
>  
> diff --git a/include/media/cec-notifier.h b/include/media/cec-notifier.h
> index 814eeef35a5cf..0b77bef601158 100644
> --- a/include/media/cec-notifier.h
> +++ b/include/media/cec-notifier.h
> @@ -63,15 +63,28 @@ void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa);
>  void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
>  					  const struct edid *edid);
>  
> +/**
> + * cec_notifier_set_connector_info - associates connector info with a notifier
> + * @n: the CEC notifier
> + * @card_no: the drm card number
> + * @connector_id: drm connector id
> + */
> +void cec_notifier_set_connector_info(struct cec_notifier *n, int card_no,
> +				     u32 connector_id);
>  /**
>   * cec_notifier_register - register a callback with the notifier
>   * @n: the CEC notifier
>   * @adap: the CEC adapter, passed as argument to the callback function
> - * @callback: the callback function
> + * @phys_addr_callback : callback invoked when new phys address is set
> + * @connector_callback : callback invoked when connector is set
>   */
>  void cec_notifier_register(struct cec_notifier *n,
>  			   struct cec_adapter *adap,
> -			   void (*callback)(struct cec_adapter *adap, u16 pa));
> +			   void (*phys_addr_callback)(struct cec_adapter *adap,
> +						      u16 pa),
> +			   void (*connector_callback)(struct cec_adapter *adap,
> +						      int card_no,
> +						      u32 connector_id));
>  
>  /**
>   * cec_notifier_unregister - unregister the callback from the notifier.
> @@ -108,9 +121,19 @@ static inline void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
>  {
>  }
>  
> +static inline void cec_notifier_set_connector_info(struct cec_notifier *n,
> +						   int card_no,
> +						   u32 connector_id)
> +{
> +}
> +
>  static inline void cec_notifier_register(struct cec_notifier *n,
> -			 struct cec_adapter *adap,
> -			 void (*callback)(struct cec_adapter *adap, u16 pa))
> +			   struct cec_adapter *adap,
> +			   void (*phys_addr_callback)(struct cec_adapter *adap,
> +						      u16 pa),
> +			   void (*connector_callback)(struct cec_adapter *adap,
> +						      int card_no,
> +						      u32 connector_id))
>  {
>  }
>  
> diff --git a/include/media/cec.h b/include/media/cec.h
> index 707411ef8ba28..940c8826a1632 100644
> --- a/include/media/cec.h
> +++ b/include/media/cec.h
> @@ -78,7 +78,7 @@ struct cec_event_entry {
>  };
>  
>  #define CEC_NUM_CORE_EVENTS 2
> -#define CEC_NUM_EVENTS CEC_EVENT_PIN_5V_HIGH
> +#define CEC_NUM_EVENTS CEC_EVENT_CONNECTOR_SET
>  
>  struct cec_fh {
>  	struct list_head	list;
> @@ -200,6 +200,8 @@ struct cec_adapter {
>  	u32 sequence;
>  
>  	char input_phys[32];
> +
> +	struct cec_connector_info connector;
>  };
>  
>  static inline void *cec_get_drvdata(const struct cec_adapter *adap)
> @@ -247,9 +249,11 @@ void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
>  		     bool block);
>  void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
>  			       const struct edid *edid);
> +void cec_s_connector_info(struct cec_adapter *adap, int card_no,
> +			  u32 connector_id);
> +
>  int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
>  		     bool block);
> -
>  /* Called by the adapter */
>  void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
>  			  u8 arb_lost_cnt, u8 nack_cnt, u8 low_drive_cnt,
> @@ -357,6 +361,11 @@ static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
>  {
>  }
>  
> +void cec_s_connector_info(struct cec_adapter *adap, int card_no,
> +			  u32 connector_id)
> +{
> +}
> +
>  static inline u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
>  					 unsigned int *offset)
>  {
> diff --git a/include/uapi/linux/cec.h b/include/uapi/linux/cec.h
> index 3094af68b6e76..cb9817ab2012e 100644
> --- a/include/uapi/linux/cec.h
> +++ b/include/uapi/linux/cec.h
> @@ -389,6 +389,7 @@ struct cec_log_addrs {
>  #define CEC_EVENT_PIN_HPD_HIGH		6
>  #define CEC_EVENT_PIN_5V_LOW		7
>  #define CEC_EVENT_PIN_5V_HIGH		8
> +#define CEC_EVENT_CONNECTOR_SET		9
>  
>  #define CEC_EVENT_FL_INITIAL_STATE	(1 << 0)
>  #define CEC_EVENT_FL_DROPPED_EVENTS	(1 << 1)
> @@ -411,6 +412,19 @@ struct cec_event_lost_msgs {
>  	__u32 lost_msgs;
>  };
>  
> +/**
> + * struct cec_event_connector - tells if and which drm connector is associated
> + * with the CEC adapter.
> + * @card_no: drm card number, -1 if no connector
> + * @connector_id: drm connector id.
> + */
> +
> +#define CEC_CONNECTOR_INVALID_CARD_NO	-1
> +struct cec_connector_info {
> +	int card_no;
> +	__u32 connector_id;
> +};
> +
>  /**
>   * struct cec_event - CEC event structure
>   * @ts: the timestamp of when the event was sent.
> @@ -427,6 +441,7 @@ struct cec_event {
>  	union {
>  		struct cec_event_state_change state_change;
>  		struct cec_event_lost_msgs lost_msgs;
> +		struct cec_connector_info connector;
>  		__u32 raw[16];
>  	};
>  };
> @@ -475,6 +490,9 @@ struct cec_event {
>  #define CEC_G_MODE		_IOR('a',  8, __u32)
>  #define CEC_S_MODE		_IOW('a',  9, __u32)
>  
> +/* Gets the connector info */
> +#define CEC_ADAP_G_CONNECTOR_INFO _IOR('a',  10, struct cec_connector_info)
> +
>  /*
>   * The remainder of this header defines all CEC messages and operands.
>   * The format matters since it the cec-ctl utility parses it to generate
>