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char * | snd_use_case_identifier (const char *fmt,...) |
| Create an identifier. More...
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int | snd_use_case_free_list (const char *list[], int items) |
| Free a string list. More...
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int | snd_use_case_get_list (snd_use_case_mgr_t *uc_mgr, const char *identifier, const char **list[]) |
| Obtain a list of entries. More...
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int | snd_use_case_get (snd_use_case_mgr_t *uc_mgr, const char *identifier, const char **value) |
| Get current - string. More...
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int | snd_use_case_geti (snd_use_case_mgr_t *uc_mgr, const char *identifier, long *value) |
| Get current - integer. More...
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int | snd_use_case_set (snd_use_case_mgr_t *uc_mgr, const char *identifier, const char *value) |
| Set new. More...
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int | snd_use_case_mgr_open (snd_use_case_mgr_t **uc_mgr, const char *card_name) |
| Open and initialise use case core for sound card. More...
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int | snd_use_case_mgr_reload (snd_use_case_mgr_t *uc_mgr) |
| Reload and re-parse use case configuration files for sound card. More...
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int | snd_use_case_mgr_close (snd_use_case_mgr_t *uc_mgr) |
| Close use case manager. More...
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int | snd_use_case_mgr_reset (snd_use_case_mgr_t *uc_mgr) |
| Reset use case manager verb, device, modifier to deafult settings. More...
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The ALSA Use Case manager interface. See ALSA Use Case Interface page for more details.
ALSA Use Case Interface
ALSA Use Case InterfaceThe use case manager works by configuring the sound card ALSA kcontrols to change the hardware digital and analog audio routing to match the requested device use case. The use case manager kcontrol configurations are stored in easy to modify text files.An audio use case can be defined by a verb and device parameter. The verb describes the use case action i.e. a phone call, listening to music, recording a conversation etc. The device describes the physical audio capture and playback hardware i.e. headphones, phone handset, bluetooth headset, etc.It's intended clients will mostly only need to set the use case verb and device for each system use case change (as the verb and device parameters cover most audio use cases).However there are times when a use case has to be modified at runtime. e.g.o Incoming phone call when the device is playing music o Recording sections of a phone call o Playing tones during a call.In order to allow asynchronous runtime use case adaptations, we have a third optional modifier parameter that can be used to further configure the use case during live audio runtime.This interface allows clients to :-o Query the supported use case verbs, devices and modifiers for the machine. o Set and Get use case verbs, devices and modifiers for the machine. o Get the ALSA PCM playback and capture device PCMs for use case verb, use case device and modifier. o Get the TQ parameter for each use case verb, use case device and modifier. o Get the ALSA master playback and capture volume/switch kcontrols for each use case.
#define SND_USE_CASE_DEV_BLUETOOTH "Bluetooth" |
#define SND_USE_CASE_DEV_EARPIECE "Earpiece" |
#define SND_USE_CASE_DEV_HANDSET "Handset" |
#define SND_USE_CASE_DEV_HDMI "HDMI" |
#define SND_USE_CASE_DEV_HEADPHONES "Headphones" |
#define SND_USE_CASE_DEV_HEADSET "Headset" |
#define SND_USE_CASE_DEV_LINE "Line" |
#define SND_USE_CASE_DEV_NONE "None" |
#define SND_USE_CASE_DEV_SPDIF "SPDIF" |
#define SND_USE_CASE_DEV_SPEAKER "Speaker" |
#define SND_USE_CASE_MOD_CAPTURE_MUSIC "Capture Music" |
#define SND_USE_CASE_MOD_CAPTURE_VOICE "Capture Voice" |
#define SND_USE_CASE_MOD_ECHO_REF "Echo Reference" |
#define SND_USE_CASE_MOD_PLAY_MUSIC "Play Music" |
#define SND_USE_CASE_MOD_PLAY_TONE "Play Tone" |
#define SND_USE_CASE_MOD_PLAY_VOICE "Play Voice" |
#define SND_USE_CASE_TQ_MUSIC "Music" |
TQ - Tone Quality
The interface allows clients to determine the audio TQ required for each use case verb and modifier. It's intended as an optional hint to the audio driver in order to lower power consumption.Music Tone Quality
#define SND_USE_CASE_TQ_TONES "Tones" |
#define SND_USE_CASE_TQ_VOICE "Voice" |
#define SND_USE_CASE_VERB_ANALOG_RADIO "FM Analog Radio" |
#define SND_USE_CASE_VERB_DIGITAL_RADIO "FM Digital Radio" |
#define SND_USE_CASE_VERB_HIFI "HiFi" |
#define SND_USE_CASE_VERB_HIFI_LOW_POWER "HiFi Low Power" |
#define SND_USE_CASE_VERB_INACTIVE "Inactive" |
#define SND_USE_CASE_VERB_IP_VOICECALL "Voice Call IP" |
#define SND_USE_CASE_VERB_VOICE "Voice" |
#define SND_USE_CASE_VERB_VOICE_LOW_POWER "Voice Low Power" |
#define SND_USE_CASE_VERB_VOICECALL "Voice Call" |
int snd_use_case_free_list |
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const char * |
list[], |
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int |
items |
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) |
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Free a string list.
- Parameters
-
list | The string list to free |
items | Count of strings |
- Returns
- Zero if success, otherwise a negative error code
int snd_use_case_get |
( |
snd_use_case_mgr_t * |
uc_mgr, |
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const char * |
identifier, |
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const char ** |
value |
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) |
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Get current - string.
- Parameters
-
uc_mgr | Use case manager |
identifier | |
value | Value pointer |
- Returns
- Zero if success, otherwise a negative error code
Note: String is dynamically allocated, use free() to deallocate this string.
Known identifiers: NULL - return current card _verb - return current verb
[=]{NAME}[/[{modifier}|{/device}][/{verb}]]
- value identifier {NAME}
- Search starts at given modifier or device if any, else at a verb
- Search starts at given verb if any, else current verb
- Searches modifier/device, then verb, then defaults
- Specify a leading "=" to search only the exact device/modifier/verb specified, and not search through each object in turn.
- Examples: "PlaybackPCM/Play Music" "CapturePCM/SPDIF" From ValueDefaults only: "=Variable" From current active verb: "=Variable//" From verb "Verb": "=Variable//Verb" From "Modifier" in current active verb: "=Variable/Modifier/" From "Modifier" in "Verb": "=Variable/Modifier/Verb"
Recommended names for values: TQ - Tone Quality PlaybackPCM - full PCM playback device name CapturePCM - full PCM capture device name PlaybackRate - playback device sample rate PlaybackChannels - playback device channel count PlaybackCTL - playback control device name PlaybackVolume - playback control volume ID string PlaybackSwitch - playback control switch ID string CaptureRate - capture device sample rate CaptureChannels - capture device channel count CaptureCTL - capture control device name CaptureVolume - capture control volume ID string CaptureSwitch - capture control switch ID string PlaybackMixer - name of playback mixer PlaybackMixerID - mixer playback ID CaptureMixer - name of capture mixer CaptureMixerID - mixer capture ID
- Parameters
-
uc_mgr | Use case manager |
identifier | |
value | Value pointer |
- Returns
- Zero if success, otherwise a negative error code
Note: String is dynamically allocated, use free() to deallocate this string.
int snd_use_case_get_list |
( |
snd_use_case_mgr_t * |
uc_mgr, |
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const char * |
identifier, |
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const char ** |
list[] |
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) |
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Obtain a list of entries.
- Parameters
-
uc_mgr | Use case manager (may be NULL - card list) |
identifier | (may be NULL - card list) |
list | Returned allocated list |
- Returns
- Number of list entries if success, otherwise a negative error code
Defined identifiers: NULL - get card list (in pair cardname+comment) _verbs - get verb list (in pair verb+comment) _devices[/{verb}] - get list of supported devices (in pair device+comment) _modifiers[/{verb}]- get list of supported modifiers (in pair modifier+comment) TQ[/{verb}] - get list of TQ identifiers _enadevs - get list of enabled devices _enamods - get list of enabled modifiers
_supporteddevs/{modifier}|{device}[/{verb}] - list of supported devices _conflictingdevs/{modifier}|{device}[/{verb}] - list of conflicting devices Note that at most one of the supported/conflicting devs lists has any entries, and when neither is present, all devices are supported.
- Parameters
-
uc_mgr | Use case manager (may be NULL - card list) |
identifier | (may be NULL - card list) |
list | Returned allocated list |
- Returns
- Number of list entries if success, otherwise a negative error code
int snd_use_case_geti |
( |
snd_use_case_mgr_t * |
uc_mgr, |
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const char * |
identifier, |
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long * |
value |
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) |
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Get current - integer.
- Parameters
-
uc_mgr | Use case manager |
identifier | |
value | result |
- Returns
- Zero if success, otherwise a negative error code
Known identifiers: _devstatus/{device} - return status for given device _modstatus/{modifier} - return status for given modifier
- Parameters
-
uc_mgr | Use case manager |
identifier | |
- Returns
- Value if success, otherwise a negative error code
char* snd_use_case_identifier |
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const char * |
fmt, |
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... |
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) |
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Create an identifier.
- Parameters
-
fmt | Format (sprintf like) |
... | Optional arguments for sprintf like format |
- Returns
- Allocated string identifier or NULL on error
int snd_use_case_mgr_close |
( |
snd_use_case_mgr_t * |
uc_mgr | ) |
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Close use case manager.
- Parameters
-
- Returns
- zero if success, otherwise a negative error code
- Parameters
-
- Returns
- zero on success, otherwise a negative error code
int snd_use_case_mgr_open |
( |
snd_use_case_mgr_t ** |
uc_mgr, |
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const char * |
card_name |
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) |
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Open and initialise use case core for sound card.
- Parameters
-
uc_mgr | Returned use case manager pointer |
card_name | Sound card name. |
- Returns
- zero if success, otherwise a negative error code
Open and initialise use case core for sound card.
- Parameters
-
uc_mgr | Returned use case manager pointer |
card_name | name of card to open |
- Returns
- zero on success, otherwise a negative error code
int snd_use_case_mgr_reload |
( |
snd_use_case_mgr_t * |
uc_mgr | ) |
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Reload and re-parse use case configuration files for sound card.
- Parameters
-
- Returns
- zero if success, otherwise a negative error code
Reload and re-parse use case configuration files for sound card.
- Parameters
-
- Returns
- zero on success, otherwise a negative error code
int snd_use_case_mgr_reset |
( |
snd_use_case_mgr_t * |
uc_mgr | ) |
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Reset use case manager verb, device, modifier to deafult settings.
- Parameters
-
- Returns
- zero if success, otherwise a negative error code
Reset use case manager verb, device, modifier to deafult settings.
- Parameters
-
- Returns
- zero on success, otherwise a negative error code
int snd_use_case_set |
( |
snd_use_case_mgr_t * |
uc_mgr, |
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const char * |
identifier, |
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const char * |
value |
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) |
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Set new.
- Parameters
-
uc_mgr | Use case manager |
identifier | |
value | Value |
- Returns
- Zero if success, otherwise a negative error code
Known identifiers: _verb - set current verb = value _enadev - enable given device = value _disdev - disable given device = value _swdev/{old_device} - new_device = value
- disable old_device and then enable new_device
- if old_device is not enabled just return
- check transmit sequence firstly _enamod - enable given modifier = value _dismod - disable given modifier = value _swmod/{old_modifier} - new_modifier = value
- disable old_modifier and then enable new_modifier
- if old_modifier is not enabled just return
- check transmit sequence firstly
- Parameters
-
uc_mgr | Use case manager |
identifier | |
value | Value |
- Returns
- Zero if success, otherwise a negative error code