snd_ctl_notify – Send notification to user-space for a control change Synopsis void snd_ctl_notify(struct snd_card *card, unsigned int mask, struct snd_ctl_elem_id *id); Arguments card the card to send notification mask the event mask, SNDRV_CTL_EVENT_* id the ctl element id to send notification Description This function adds an event record with the given id and mask, appends…
snd_ctl_new1 – create a control instance from the template Synopsis struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol, void *private_data); Arguments ncontrol the initialization record private_data the private data to set Description Allocates a new struct snd_kcontrol instance and initialize from the given template. When the access field of ncontrol is 0, it’s assumed as READWRITE access….
snd_ctl_make_virtual_master – Create a virtual master control Synopsis struct snd_kcontrol *snd_ctl_make_virtual_master(char *name, const unsigned int *tlv); Arguments name name string of the control element to create tlv optional TLV int array for dB information Description Creates a virtual master control with the given name string. After creating a vmaster element, you can add the slave…
snd_ctl_free_one – release the control instance Synopsis void snd_ctl_free_one(struct snd_kcontrol *kcontrol); Arguments kcontrol the control instance Description Releases the control instance created via snd_ctl_new or snd_ctl_new1. Don’t call this after the control was added to the card. Copyright
snd_ctl_find_numid – find the control instance with the given number-id Synopsis struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid); Arguments card the card instance numid the number-id to search Description Finds the control instance with the given number-id from the card. The caller must down card->controls_rwsem before calling this function (if the race condition can…
snd_ctl_find_id – find the control instance with the given id Synopsis struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card, struct snd_ctl_elem_id *id); Arguments card the card instance id the id to search Description Finds the control instance with the given id from the card. The caller must down card->controls_rwsem before calling this function (if the race condition can…
snd_ctl_enum_info – fills the info structure for an enumerated control Synopsis int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels, unsigned int items, const char *const names[]); Arguments info the structure to be filled channels the number of the control’s channels; often one items the number of control values; also the size of names names[] an array…
snd_ctl_boolean_stereo_info – Helper function for a standard boolean info callback with stereo two channels Synopsis int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_info *uinfo); Arguments kcontrol the kcontrol instance uinfo info to store Description This is a function that can be used as info callback for a standard boolean control with stereo two channels. Copyright
snd_ctl_boolean_mono_info – Helper function for a standard boolean info callback with a mono channel Synopsis int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_info *uinfo); Arguments kcontrol the kcontrol instance uinfo info to store Description This is a function that can be used as info callback for a standard boolean control with a single mono channel. Copyright
snd_ctl_add_vmaster_hook – Add a hook to a vmaster control Synopsis int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol, void (*hook)(void *private_data, int), void *private_data); Arguments kcontrol vmaster kctl element hook the hook function private_data the private_data pointer to be saved Description Adds the given hook to the vmaster control element so that it’s called at each time when the…
snd_ctl_add_slave_uncached – Add a virtual slave control Synopsis int snd_ctl_add_slave_uncached(struct snd_kcontrol *master, struct snd_kcontrol *slave); Arguments master vmaster element slave slave element to add Description Add a virtual slave control to the given master. Unlike snd_ctl_add_slave, the element added via this function is supposed to have volatile values, and get callback is called at each…
snd_ctl_add_slave – Add a virtual slave control Synopsis int snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave); Arguments master vmaster element slave slave element to add Description Add a virtual slave control to the given master element created via snd_ctl_create_virtual_master beforehand. All slaves must be the same type (returning the same information via info callback). The function…
snd_ctl_add – add the control instance to the card Synopsis int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol); Arguments card the card instance kcontrol the control instance to add Description Adds the control instance created via snd_ctl_new or snd_ctl_new1 to the given card. Assigns also an unique numid used for fast search. It frees automatically the…
snd_ctl_activate_id – activate/inactivate the control of the given id Synopsis int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id, int active); Arguments card the card instance id the control id to activate/inactivate active non-zero to activate Description Finds the control instance with the given id, and activate or inactivate the control together with notification, if changed. The…
snd_compress_register – register compressed device Synopsis int snd_compress_register(struct snd_compr *device); Arguments device compressed device to register Copyright
snd_component_add – add a component string Synopsis int snd_component_add(struct snd_card *card, const char *component); Arguments card soundcard structure component the component id string Description This function adds the component id string to the supported list. The component can be referred from the alsa-lib. Return Zero otherwise a negative error code. Copyright
snd_card_set_id – set card identification name Synopsis void snd_card_set_id(struct snd_card *card, const char *nid); Arguments card soundcard structure nid new identification string Description This function sets the card identification and checks for name collisions. Copyright
snd_card_register – register the soundcard Synopsis int snd_card_register(struct snd_card *card); Arguments card soundcard structure Description This function registers all the devices assigned to the soundcard. Until calling this, the ALSA control interface is blocked from the external accesses. Thus, you should call this function at the end of the initialization of the card. Return Zero…
snd_card_new – create and initialize a soundcard structure Synopsis int snd_card_new(struct device *parent, int idx, const char *xid, struct module *module, int extra_size, struct snd_card **card_ret); Arguments parent the parent device object idx card index (address) [0 … (SNDRV_CARDS-1)] xid card identification (ASCII string) module top level module for locking extra_size allocate this extra size…
snd_card_free_when_closed – Disconnect the card, free it later eventually Synopsis int snd_card_free_when_closed(struct snd_card *card); Arguments card soundcard structure Description Unlike snd_card_free, this function doesn’t try to release the card resource immediately, but tries to disconnect at first. When the card is still in use, the function returns before freeing the resources. The card resources will…