[RFC,1/4] ALSA: hda - codec add DP MST support for connection list

Commit Message

[e-mail] March 7, 2016, 2:57 p.m. UTC

From: Libin Yang <[e-mail]>

This patches adds the support of connection list for DP MST.
With this, hdmi driver in DP MST mode can easily reuse
the connection list mechanism.

Signed-off-by: Libin Yang <[e-mail]>
---
 sound/pci/hda/hda_codec.c | 134 ++++++++++++++++++++++++++++++++++++++++++----
 sound/pci/hda/hda_codec.h |   5 ++
 2 files changed, 128 insertions(+), 11 deletions(-)

Comments

Takashi Iwai March 7, 2016, 4:40 p.m. UTC | #1

On Mon, 07 Mar 2016 15:57:43 +0100,
[e-mail] wrote:
> 
> From: Libin Yang <[e-mail]>
> 
> This patches adds the support of connection list for DP MST.
> With this, hdmi driver in DP MST mode can easily reuse
> the connection list mechanism.
> 
> Signed-off-by: Libin Yang <[e-mail]>

I would just replace the function with *_mst() and provide the old
ones via static inline wrappers instead of having two copies.


Takashi

> ---
>  sound/pci/hda/hda_codec.c | 134 ++++++++++++++++++++++++++++++++++++++++++----
>  sound/pci/hda/hda_codec.h |   5 ++
>  2 files changed, 128 insertions(+), 11 deletions(-)
> 
> diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
> index 8374188..d4c81f7 100644
> --- a/sound/pci/hda/hda_codec.c
> +++ b/sound/pci/hda/hda_codec.c
> @@ -110,23 +110,24 @@ struct hda_conn_list {
>  	struct list_head list;
>  	int len;
>  	hda_nid_t nid;
> +	int dev_id;
>  	hda_nid_t conns[0];
>  };
>  
>  /* look up the cached results */
>  static struct hda_conn_list *
> -lookup_conn_list(struct hda_codec *codec, hda_nid_t nid)
> +lookup_conn_list(struct hda_codec *codec, hda_nid_t nid, int dev_id)
>  {
>  	struct hda_conn_list *p;
>  	list_for_each_entry(p, &codec->conn_list, list) {
> -		if (p->nid == nid)
> +		if ((p->nid == nid) && (p->dev_id == dev_id))
>  			return p;
>  	}
>  	return NULL;
>  }
>  
> -static int add_conn_list(struct hda_codec *codec, hda_nid_t nid, int len,
> -			 const hda_nid_t *list)
> +static int add_conn_list(struct hda_codec *codec, hda_nid_t nid,
> +			 int dev_id, int len, const hda_nid_t *list)
>  {
>  	struct hda_conn_list *p;
>  
> @@ -135,6 +136,7 @@ static int add_conn_list(struct hda_codec *codec, hda_nid_t nid, int len,
>  		return -ENOMEM;
>  	p->len = len;
>  	p->nid = nid;
> +	p->dev_id = dev_id;
>  	memcpy(p->conns, list, len * sizeof(hda_nid_t));
>  	list_add(&p->list, &codec->conn_list);
>  	return 0;
> @@ -150,8 +152,13 @@ static void remove_conn_list(struct hda_codec *codec)
>  	}
>  }
>  
> -/* read the connection and add to the cache */
> -static int read_and_add_raw_conns(struct hda_codec *codec, hda_nid_t nid)
> +/*
> + * read the connection and add to the cache
> + * the caller should select the device entry by sending the
> + * corresponding verb if necessary before calling this function
> + */
> +static int read_and_add_raw_conns(struct hda_codec *codec, hda_nid_t nid,
> +				  int dev_id)
>  {
>  	hda_nid_t list[32];
>  	hda_nid_t *result = list;
> @@ -166,7 +173,8 @@ static int read_and_add_raw_conns(struct hda_codec *codec, hda_nid_t nid)
>  		len = snd_hda_get_raw_connections(codec, nid, result, len);
>  	}
>  	if (len >= 0)
> -		len = snd_hda_override_conn_list(codec, nid, len, result);
> +		len = snd_hda_override_conn_list_mst(codec, nid,
> +					     dev_id, len, result);
>  	if (result != list)
>  		kfree(result);
>  	return len;
> @@ -197,7 +205,7 @@ int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
>  		const struct hda_conn_list *p;
>  
>  		/* if the connection-list is already cached, read it */
> -		p = lookup_conn_list(codec, nid);
> +		p = lookup_conn_list(codec, nid, 0);
>  		if (p) {
>  			if (listp)
>  				*listp = p->conns;
> @@ -206,7 +214,7 @@ int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
>  		if (snd_BUG_ON(added))
>  			return -EINVAL;
>  
> -		err = read_and_add_raw_conns(codec, nid);
> +		err = read_and_add_raw_conns(codec, nid, 0);
>  		if (err < 0)
>  			return err;
>  		added = true;
> @@ -215,6 +223,49 @@ int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
>  EXPORT_SYMBOL_GPL(snd_hda_get_conn_list);
>  
>  /**
> + * snd_hda_get_conn_list_mst - get connection list in mst mode
> + * @codec: the HDA codec
> + * @nid: NID to parse
> + * @dev_id: device entry id
> + * @listp: the pointer to store NID list
> + *
> + * Parses the connection list of the given widget and stores the pointer
> + * to the list of NIDs.
> + *
> + * Returns the number of connections, or a negative error code.
> + *
> + * Note that the returned pointer isn't protected against the list
> + * modification.  If snd_hda_override_conn_list() might be called
> + * concurrently, protect with a mutex appropriately.
> + */
> +int snd_hda_get_conn_list_mst(struct hda_codec *codec, hda_nid_t nid,
> +			      int dev_id, const hda_nid_t **listp)
> +{
> +	bool added = false;
> +
> +	for (;;) {
> +		int err;
> +		const struct hda_conn_list *p;
> +
> +		/* if the connection-list is already cached, read it */
> +		p = lookup_conn_list(codec, nid, dev_id);
> +		if (p) {
> +			if (listp)
> +				*listp = p->conns;
> +			return p->len;
> +		}
> +		if (snd_BUG_ON(added))
> +			return -EINVAL;
> +
> +		err = read_and_add_raw_conns(codec, nid, dev_id);
> +		if (err < 0)
> +			return err;
> +		added = true;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(snd_hda_get_conn_list_mst);
> +
> +/**
>   * snd_hda_get_connections - copy connection list
>   * @codec: the HDA codec
>   * @nid: NID to parse
> @@ -246,6 +297,39 @@ int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
>  EXPORT_SYMBOL_GPL(snd_hda_get_connections);
>  
>  /**
> + * snd_hda_get_connections_mst - copy connection list in mst mode
> + * @codec: the HDA codec
> + * @nid: NID to parse
> + * @dev_id: device entry id
> + * @conn_list: connection list array; when NULL, checks only the size
> + * @max_conns: max. number of connections to store
> + *
> + * Parses the connection list of the given widget and stores the list
> + * of NIDs.
> + *
> + * Returns the number of connections, or a negative error code.
> + */
> +int snd_hda_get_connections_mst(struct hda_codec *codec, hda_nid_t nid,
> +				int dev_id, hda_nid_t *conn_list,
> +				int max_conns)
> +{
> +	const hda_nid_t *list;
> +	int len = snd_hda_get_conn_list_mst(codec, nid, dev_id, &list);
> +
> +	if (len > 0 && conn_list) {
> +		if (len > max_conns) {
> +			codec_err(codec, "Too many connections %d for NID 0x%x\n",
> +				   len, nid);
> +			return -EINVAL;
> +		}
> +		memcpy(conn_list, list, len * sizeof(hda_nid_t));
> +	}
> +
> +	return len;
> +}
> +EXPORT_SYMBOL_GPL(snd_hda_get_connections_mst);
> +
> +/**
>   * snd_hda_override_conn_list - add/modify the connection-list to cache
>   * @codec: the HDA codec
>   * @nid: NID to parse
> @@ -262,17 +346,45 @@ int snd_hda_override_conn_list(struct hda_codec *codec, hda_nid_t nid, int len,
>  {
>  	struct hda_conn_list *p;
>  
> -	p = lookup_conn_list(codec, nid);
> +	p = lookup_conn_list(codec, nid, 0);
>  	if (p) {
>  		list_del(&p->list);
>  		kfree(p);
>  	}
>  
> -	return add_conn_list(codec, nid, len, list);
> +	return add_conn_list(codec, nid, 0, len, list);
>  }
>  EXPORT_SYMBOL_GPL(snd_hda_override_conn_list);
>  
>  /**
> + * snd_hda_override_conn_list_mst - add/modify the connection-list to cache
> + * @codec: the HDA codec
> + * @nid: NID to parse
> + * @dev_id: device entry id
> + * @len: number of connection list entries
> + * @list: the list of connection entries
> + *
> + * Add or modify the given connection-list to the cache.  If the corresponding
> + * cache already exists, invalidate it and append a new one.
> + *
> + * Returns zero or a negative error code.
> + */
> +int snd_hda_override_conn_list_mst(struct hda_codec *codec, hda_nid_t nid,
> +			   int dev_id, int len, const hda_nid_t *list)
> +{
> +	struct hda_conn_list *p;
> +
> +	p = lookup_conn_list(codec, nid, dev_id);
> +	if (p) {
> +		list_del(&p->list);
> +		kfree(p);
> +	}
> +
> +	return add_conn_list(codec, nid, dev_id, len, list);
> +}
> +EXPORT_SYMBOL_GPL(snd_hda_override_conn_list_mst);
> +
> +/**
>   * snd_hda_get_conn_index - get the connection index of the given NID
>   * @codec: the HDA codec
>   * @mux: NID containing the list
> diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
> index 373fcad..deeed35 100644
> --- a/sound/pci/hda/hda_codec.h
> +++ b/sound/pci/hda/hda_codec.h
> @@ -330,6 +330,9 @@ snd_hda_codec_write(struct hda_codec *codec, hda_nid_t nid, int flags,
>  	snd_hdac_get_sub_nodes(&(codec)->core, nid, start_nid)
>  int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
>  			    hda_nid_t *conn_list, int max_conns);
> +int snd_hda_get_connections_mst(struct hda_codec *codec, hda_nid_t nid,
> +				int dev_id, hda_nid_t *conn_list,
> +				int max_conns);
>  static inline int
>  snd_hda_get_num_conns(struct hda_codec *codec, hda_nid_t nid)
>  {
> @@ -345,6 +348,8 @@ int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
>  			  const hda_nid_t **listp);
>  int snd_hda_override_conn_list(struct hda_codec *codec, hda_nid_t nid, int nums,
>  			  const hda_nid_t *list);
> +int snd_hda_override_conn_list_mst(struct hda_codec *codec, hda_nid_t nid,
> +			   int dev_id, int len, const hda_nid_t *list);
>  int snd_hda_get_conn_index(struct hda_codec *codec, hda_nid_t mux,
>  			   hda_nid_t nid, int recursive);
>  int snd_hda_get_devices(struct hda_codec *codec, hda_nid_t nid,
> -- 
> 1.9.1
>

Yang, Libin March 8, 2016, 6:47 a.m. UTC | #2

Hi Takashi,

> -----Original Message-----
> From: Takashi Iwai [mailto:[e-mail]]
> Sent: Tuesday, March 08, 2016 12:41 AM
> To: [e-mail]
> Cc: [e-mail]; Lin, Mengdong; Yang, Libin
> Subject: Re: [alsa-devel] [RFC PATCH 1/4] ALSA: hda - codec add DP MST
> support for connection list
> 
> On Mon, 07 Mar 2016 15:57:43 +0100,
> [e-mail] wrote:
> >
> > From: Libin Yang <[e-mail]>
> >
> > This patches adds the support of connection list for DP MST.
> > With this, hdmi driver in DP MST mode can easily reuse
> > the connection list mechanism.
> >
> > Signed-off-by: Libin Yang <[e-mail]>
> 
> I would just replace the function with *_mst() and provide the old
> ones via static inline wrappers instead of having two copies.

I see. I will change it.

Regards,
Libin

> 
> 
> Takashi
> 
> > ---
> >  sound/pci/hda/hda_codec.c | 134
> ++++++++++++++++++++++++++++++++++++++++++----
> >  sound/pci/hda/hda_codec.h |   5 ++
> >  2 files changed, 128 insertions(+), 11 deletions(-)
> >
> > diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
> > index 8374188..d4c81f7 100644
> > --- a/sound/pci/hda/hda_codec.c
> > +++ b/sound/pci/hda/hda_codec.c
> > @@ -110,23 +110,24 @@ struct hda_conn_list {
> >  	struct list_head list;
> >  	int len;
> >  	hda_nid_t nid;
> > +	int dev_id;
> >  	hda_nid_t conns[0];
> >  };
> >
> >  /* look up the cached results */
> >  static struct hda_conn_list *
> > -lookup_conn_list(struct hda_codec *codec, hda_nid_t nid)
> > +lookup_conn_list(struct hda_codec *codec, hda_nid_t nid, int dev_id)
> >  {
> >  	struct hda_conn_list *p;
> >  	list_for_each_entry(p, &codec->conn_list, list) {
> > -		if (p->nid == nid)
> > +		if ((p->nid == nid) && (p->dev_id == dev_id))
> >  			return p;
> >  	}
> >  	return NULL;
> >  }
> >
> > -static int add_conn_list(struct hda_codec *codec, hda_nid_t nid, int
> len,
> > -			 const hda_nid_t *list)
> > +static int add_conn_list(struct hda_codec *codec, hda_nid_t nid,
> > +			 int dev_id, int len, const hda_nid_t *list)
> >  {
> >  	struct hda_conn_list *p;
> >
> > @@ -135,6 +136,7 @@ static int add_conn_list(struct hda_codec
> *codec, hda_nid_t nid, int len,
> >  		return -ENOMEM;
> >  	p->len = len;
> >  	p->nid = nid;
> > +	p->dev_id = dev_id;
> >  	memcpy(p->conns, list, len * sizeof(hda_nid_t));
> >  	list_add(&p->list, &codec->conn_list);
> >  	return 0;
> > @@ -150,8 +152,13 @@ static void remove_conn_list(struct
> hda_codec *codec)
> >  	}
> >  }
> >
> > -/* read the connection and add to the cache */
> > -static int read_and_add_raw_conns(struct hda_codec *codec,
> hda_nid_t nid)
> > +/*
> > + * read the connection and add to the cache
> > + * the caller should select the device entry by sending the
> > + * corresponding verb if necessary before calling this function
> > + */
> > +static int read_and_add_raw_conns(struct hda_codec *codec,
> hda_nid_t nid,
> > +				  int dev_id)
> >  {
> >  	hda_nid_t list[32];
> >  	hda_nid_t *result = list;
> > @@ -166,7 +173,8 @@ static int read_and_add_raw_conns(struct
> hda_codec *codec, hda_nid_t nid)
> >  		len = snd_hda_get_raw_connections(codec, nid, result,
> len);
> >  	}
> >  	if (len >= 0)
> > -		len = snd_hda_override_conn_list(codec, nid, len, result);
> > +		len = snd_hda_override_conn_list_mst(codec, nid,
> > +					     dev_id, len, result);
> >  	if (result != list)
> >  		kfree(result);
> >  	return len;
> > @@ -197,7 +205,7 @@ int snd_hda_get_conn_list(struct hda_codec
> *codec, hda_nid_t nid,
> >  		const struct hda_conn_list *p;
> >
> >  		/* if the connection-list is already cached, read it */
> > -		p = lookup_conn_list(codec, nid);
> > +		p = lookup_conn_list(codec, nid, 0);
> >  		if (p) {
> >  			if (listp)
> >  				*listp = p->conns;
> > @@ -206,7 +214,7 @@ int snd_hda_get_conn_list(struct hda_codec
> *codec, hda_nid_t nid,
> >  		if (snd_BUG_ON(added))
> >  			return -EINVAL;
> >
> > -		err = read_and_add_raw_conns(codec, nid);
> > +		err = read_and_add_raw_conns(codec, nid, 0);
> >  		if (err < 0)
> >  			return err;
> >  		added = true;
> > @@ -215,6 +223,49 @@ int snd_hda_get_conn_list(struct hda_codec
> *codec, hda_nid_t nid,
> >  EXPORT_SYMBOL_GPL(snd_hda_get_conn_list);
> >
> >  /**
> > + * snd_hda_get_conn_list_mst - get connection list in mst mode
> > + * @codec: the HDA codec
> > + * @nid: NID to parse
> > + * @dev_id: device entry id
> > + * @listp: the pointer to store NID list
> > + *
> > + * Parses the connection list of the given widget and stores the pointer
> > + * to the list of NIDs.
> > + *
> > + * Returns the number of connections, or a negative error code.
> > + *
> > + * Note that the returned pointer isn't protected against the list
> > + * modification.  If snd_hda_override_conn_list() might be called
> > + * concurrently, protect with a mutex appropriately.
> > + */
> > +int snd_hda_get_conn_list_mst(struct hda_codec *codec, hda_nid_t
> nid,
> > +			      int dev_id, const hda_nid_t **listp)
> > +{
> > +	bool added = false;
> > +
> > +	for (;;) {
> > +		int err;
> > +		const struct hda_conn_list *p;
> > +
> > +		/* if the connection-list is already cached, read it */
> > +		p = lookup_conn_list(codec, nid, dev_id);
> > +		if (p) {
> > +			if (listp)
> > +				*listp = p->conns;
> > +			return p->len;
> > +		}
> > +		if (snd_BUG_ON(added))
> > +			return -EINVAL;
> > +
> > +		err = read_and_add_raw_conns(codec, nid, dev_id);
> > +		if (err < 0)
> > +			return err;
> > +		added = true;
> > +	}
> > +}
> > +EXPORT_SYMBOL_GPL(snd_hda_get_conn_list_mst);
> > +
> > +/**
> >   * snd_hda_get_connections - copy connection list
> >   * @codec: the HDA codec
> >   * @nid: NID to parse
> > @@ -246,6 +297,39 @@ int snd_hda_get_connections(struct
> hda_codec *codec, hda_nid_t nid,
> >  EXPORT_SYMBOL_GPL(snd_hda_get_connections);
> >
> >  /**
> > + * snd_hda_get_connections_mst - copy connection list in mst mode
> > + * @codec: the HDA codec
> > + * @nid: NID to parse
> > + * @dev_id: device entry id
> > + * @conn_list: connection list array; when NULL, checks only the size
> > + * @max_conns: max. number of connections to store
> > + *
> > + * Parses the connection list of the given widget and stores the list
> > + * of NIDs.
> > + *
> > + * Returns the number of connections, or a negative error code.
> > + */
> > +int snd_hda_get_connections_mst(struct hda_codec *codec,
> hda_nid_t nid,
> > +				int dev_id, hda_nid_t *conn_list,
> > +				int max_conns)
> > +{
> > +	const hda_nid_t *list;
> > +	int len = snd_hda_get_conn_list_mst(codec, nid, dev_id, &list);
> > +
> > +	if (len > 0 && conn_list) {
> > +		if (len > max_conns) {
> > +			codec_err(codec, "Too many connections %d for
> NID 0x%x\n",
> > +				   len, nid);
> > +			return -EINVAL;
> > +		}
> > +		memcpy(conn_list, list, len * sizeof(hda_nid_t));
> > +	}
> > +
> > +	return len;
> > +}
> > +EXPORT_SYMBOL_GPL(snd_hda_get_connections_mst);
> > +
> > +/**
> >   * snd_hda_override_conn_list - add/modify the connection-list to
> cache
> >   * @codec: the HDA codec
> >   * @nid: NID to parse
> > @@ -262,17 +346,45 @@ int snd_hda_override_conn_list(struct
> hda_codec *codec, hda_nid_t nid, int len,
> >  {
> >  	struct hda_conn_list *p;
> >
> > -	p = lookup_conn_list(codec, nid);
> > +	p = lookup_conn_list(codec, nid, 0);
> >  	if (p) {
> >  		list_del(&p->list);
> >  		kfree(p);
> >  	}
> >
> > -	return add_conn_list(codec, nid, len, list);
> > +	return add_conn_list(codec, nid, 0, len, list);
> >  }
> >  EXPORT_SYMBOL_GPL(snd_hda_override_conn_list);
> >
> >  /**
> > + * snd_hda_override_conn_list_mst - add/modify the connection-list
> to cache
> > + * @codec: the HDA codec
> > + * @nid: NID to parse
> > + * @dev_id: device entry id
> > + * @len: number of connection list entries
> > + * @list: the list of connection entries
> > + *
> > + * Add or modify the given connection-list to the cache.  If the
> corresponding
> > + * cache already exists, invalidate it and append a new one.
> > + *
> > + * Returns zero or a negative error code.
> > + */
> > +int snd_hda_override_conn_list_mst(struct hda_codec *codec,
> hda_nid_t nid,
> > +			   int dev_id, int len, const hda_nid_t *list)
> > +{
> > +	struct hda_conn_list *p;
> > +
> > +	p = lookup_conn_list(codec, nid, dev_id);
> > +	if (p) {
> > +		list_del(&p->list);
> > +		kfree(p);
> > +	}
> > +
> > +	return add_conn_list(codec, nid, dev_id, len, list);
> > +}
> > +EXPORT_SYMBOL_GPL(snd_hda_override_conn_list_mst);
> > +
> > +/**
> >   * snd_hda_get_conn_index - get the connection index of the given NID
> >   * @codec: the HDA codec
> >   * @mux: NID containing the list
> > diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
> > index 373fcad..deeed35 100644
> > --- a/sound/pci/hda/hda_codec.h
> > +++ b/sound/pci/hda/hda_codec.h
> > @@ -330,6 +330,9 @@ snd_hda_codec_write(struct hda_codec
> *codec, hda_nid_t nid, int flags,
> >  	snd_hdac_get_sub_nodes(&(codec)->core, nid, start_nid)
> >  int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
> >  			    hda_nid_t *conn_list, int max_conns);
> > +int snd_hda_get_connections_mst(struct hda_codec *codec,
> hda_nid_t nid,
> > +				int dev_id, hda_nid_t *conn_list,
> > +				int max_conns);
> >  static inline int
> >  snd_hda_get_num_conns(struct hda_codec *codec, hda_nid_t nid)
> >  {
> > @@ -345,6 +348,8 @@ int snd_hda_get_conn_list(struct hda_codec
> *codec, hda_nid_t nid,
> >  			  const hda_nid_t **listp);
> >  int snd_hda_override_conn_list(struct hda_codec *codec, hda_nid_t
> nid, int nums,
> >  			  const hda_nid_t *list);
> > +int snd_hda_override_conn_list_mst(struct hda_codec *codec,
> hda_nid_t nid,
> > +			   int dev_id, int len, const hda_nid_t *list);
> >  int snd_hda_get_conn_index(struct hda_codec *codec, hda_nid_t mux,
> >  			   hda_nid_t nid, int recursive);
> >  int snd_hda_get_devices(struct hda_codec *codec, hda_nid_t nid,
> > --
> > 1.9.1
> >

Patch

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 8374188..d4c81f7 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -110,23 +110,24 @@  struct hda_conn_list {
 	struct list_head list;
 	int len;
 	hda_nid_t nid;
+	int dev_id;
 	hda_nid_t conns[0];
 };
 
 /* look up the cached results */
 static struct hda_conn_list *
-lookup_conn_list(struct hda_codec *codec, hda_nid_t nid)
+lookup_conn_list(struct hda_codec *codec, hda_nid_t nid, int dev_id)
 {
 	struct hda_conn_list *p;
 	list_for_each_entry(p, &codec->conn_list, list) {
-		if (p->nid == nid)
+		if ((p->nid == nid) && (p->dev_id == dev_id))
 			return p;
 	}
 	return NULL;
 }
 
-static int add_conn_list(struct hda_codec *codec, hda_nid_t nid, int len,
-			 const hda_nid_t *list)
+static int add_conn_list(struct hda_codec *codec, hda_nid_t nid,
+			 int dev_id, int len, const hda_nid_t *list)
 {
 	struct hda_conn_list *p;
 
@@ -135,6 +136,7 @@  static int add_conn_list(struct hda_codec *codec, hda_nid_t nid, int len,
 		return -ENOMEM;
 	p->len = len;
 	p->nid = nid;
+	p->dev_id = dev_id;
 	memcpy(p->conns, list, len * sizeof(hda_nid_t));
 	list_add(&p->list, &codec->conn_list);
 	return 0;
@@ -150,8 +152,13 @@  static void remove_conn_list(struct hda_codec *codec)
 	}
 }
 
-/* read the connection and add to the cache */
-static int read_and_add_raw_conns(struct hda_codec *codec, hda_nid_t nid)
+/*
+ * read the connection and add to the cache
+ * the caller should select the device entry by sending the
+ * corresponding verb if necessary before calling this function
+ */
+static int read_and_add_raw_conns(struct hda_codec *codec, hda_nid_t nid,
+				  int dev_id)
 {
 	hda_nid_t list[32];
 	hda_nid_t *result = list;
@@ -166,7 +173,8 @@  static int read_and_add_raw_conns(struct hda_codec *codec, hda_nid_t nid)
 		len = snd_hda_get_raw_connections(codec, nid, result, len);
 	}
 	if (len >= 0)
-		len = snd_hda_override_conn_list(codec, nid, len, result);
+		len = snd_hda_override_conn_list_mst(codec, nid,
+					     dev_id, len, result);
 	if (result != list)
 		kfree(result);
 	return len;
@@ -197,7 +205,7 @@  int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
 		const struct hda_conn_list *p;
 
 		/* if the connection-list is already cached, read it */
-		p = lookup_conn_list(codec, nid);
+		p = lookup_conn_list(codec, nid, 0);
 		if (p) {
 			if (listp)
 				*listp = p->conns;
@@ -206,7 +214,7 @@  int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
 		if (snd_BUG_ON(added))
 			return -EINVAL;
 
-		err = read_and_add_raw_conns(codec, nid);
+		err = read_and_add_raw_conns(codec, nid, 0);
 		if (err < 0)
 			return err;
 		added = true;
@@ -215,6 +223,49 @@  int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
 EXPORT_SYMBOL_GPL(snd_hda_get_conn_list);
 
 /**
+ * snd_hda_get_conn_list_mst - get connection list in mst mode
+ * @codec: the HDA codec
+ * @nid: NID to parse
+ * @dev_id: device entry id
+ * @listp: the pointer to store NID list
+ *
+ * Parses the connection list of the given widget and stores the pointer
+ * to the list of NIDs.
+ *
+ * Returns the number of connections, or a negative error code.
+ *
+ * Note that the returned pointer isn't protected against the list
+ * modification.  If snd_hda_override_conn_list() might be called
+ * concurrently, protect with a mutex appropriately.
+ */
+int snd_hda_get_conn_list_mst(struct hda_codec *codec, hda_nid_t nid,
+			      int dev_id, const hda_nid_t **listp)
+{
+	bool added = false;
+
+	for (;;) {
+		int err;
+		const struct hda_conn_list *p;
+
+		/* if the connection-list is already cached, read it */
+		p = lookup_conn_list(codec, nid, dev_id);
+		if (p) {
+			if (listp)
+				*listp = p->conns;
+			return p->len;
+		}
+		if (snd_BUG_ON(added))
+			return -EINVAL;
+
+		err = read_and_add_raw_conns(codec, nid, dev_id);
+		if (err < 0)
+			return err;
+		added = true;
+	}
+}
+EXPORT_SYMBOL_GPL(snd_hda_get_conn_list_mst);
+
+/**
  * snd_hda_get_connections - copy connection list
  * @codec: the HDA codec
  * @nid: NID to parse
@@ -246,6 +297,39 @@  int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
 EXPORT_SYMBOL_GPL(snd_hda_get_connections);
 
 /**
+ * snd_hda_get_connections_mst - copy connection list in mst mode
+ * @codec: the HDA codec
+ * @nid: NID to parse
+ * @dev_id: device entry id
+ * @conn_list: connection list array; when NULL, checks only the size
+ * @max_conns: max. number of connections to store
+ *
+ * Parses the connection list of the given widget and stores the list
+ * of NIDs.
+ *
+ * Returns the number of connections, or a negative error code.
+ */
+int snd_hda_get_connections_mst(struct hda_codec *codec, hda_nid_t nid,
+				int dev_id, hda_nid_t *conn_list,
+				int max_conns)
+{
+	const hda_nid_t *list;
+	int len = snd_hda_get_conn_list_mst(codec, nid, dev_id, &list);
+
+	if (len > 0 && conn_list) {
+		if (len > max_conns) {
+			codec_err(codec, "Too many connections %d for NID 0x%x\n",
+				   len, nid);
+			return -EINVAL;
+		}
+		memcpy(conn_list, list, len * sizeof(hda_nid_t));
+	}
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(snd_hda_get_connections_mst);
+
+/**
  * snd_hda_override_conn_list - add/modify the connection-list to cache
  * @codec: the HDA codec
  * @nid: NID to parse
@@ -262,17 +346,45 @@  int snd_hda_override_conn_list(struct hda_codec *codec, hda_nid_t nid, int len,
 {
 	struct hda_conn_list *p;
 
-	p = lookup_conn_list(codec, nid);
+	p = lookup_conn_list(codec, nid, 0);
 	if (p) {
 		list_del(&p->list);
 		kfree(p);
 	}
 
-	return add_conn_list(codec, nid, len, list);
+	return add_conn_list(codec, nid, 0, len, list);
 }
 EXPORT_SYMBOL_GPL(snd_hda_override_conn_list);
 
 /**
+ * snd_hda_override_conn_list_mst - add/modify the connection-list to cache
+ * @codec: the HDA codec
+ * @nid: NID to parse
+ * @dev_id: device entry id
+ * @len: number of connection list entries
+ * @list: the list of connection entries
+ *
+ * Add or modify the given connection-list to the cache.  If the corresponding
+ * cache already exists, invalidate it and append a new one.
+ *
+ * Returns zero or a negative error code.
+ */
+int snd_hda_override_conn_list_mst(struct hda_codec *codec, hda_nid_t nid,
+			   int dev_id, int len, const hda_nid_t *list)
+{
+	struct hda_conn_list *p;
+
+	p = lookup_conn_list(codec, nid, dev_id);
+	if (p) {
+		list_del(&p->list);
+		kfree(p);
+	}
+
+	return add_conn_list(codec, nid, dev_id, len, list);
+}
+EXPORT_SYMBOL_GPL(snd_hda_override_conn_list_mst);
+
+/**
  * snd_hda_get_conn_index - get the connection index of the given NID
  * @codec: the HDA codec
  * @mux: NID containing the list
diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
index 373fcad..deeed35 100644
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -330,6 +330,9 @@  snd_hda_codec_write(struct hda_codec *codec, hda_nid_t nid, int flags,
 	snd_hdac_get_sub_nodes(&(codec)->core, nid, start_nid)
 int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
 			    hda_nid_t *conn_list, int max_conns);
+int snd_hda_get_connections_mst(struct hda_codec *codec, hda_nid_t nid,
+				int dev_id, hda_nid_t *conn_list,
+				int max_conns);
 static inline int
 snd_hda_get_num_conns(struct hda_codec *codec, hda_nid_t nid)
 {
@@ -345,6 +348,8 @@  int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
 			  const hda_nid_t **listp);
 int snd_hda_override_conn_list(struct hda_codec *codec, hda_nid_t nid, int nums,
 			  const hda_nid_t *list);
+int snd_hda_override_conn_list_mst(struct hda_codec *codec, hda_nid_t nid,
+			   int dev_id, int len, const hda_nid_t *list);
 int snd_hda_get_conn_index(struct hda_codec *codec, hda_nid_t mux,
 			   hda_nid_t nid, int recursive);
 int snd_hda_get_devices(struct hda_codec *codec, hda_nid_t nid,