void
moko_alsa_volume_control_set_element_from_name (MokoAlsaVolumeControl *control,
const gchar *name)
{
MokoAlsaVolumeControlPrivate *priv =
ALSA_VOLUME_CONTROL_PRIVATE (control);
if (!priv->device) return;
detach_mixer (control);
if (!name) {
moko_alsa_volume_control_set_element (control, NULL);
return;
}
open_mixer (control);
if ((snd_mixer_attach (priv->mixer_handle, priv->device) == 0) &&
(snd_mixer_selem_register (priv->mixer_handle, NULL, NULL) == 0) &&
(snd_mixer_load (priv->mixer_handle) == 0)) {
snd_mixer_elem_t *elem;
elem = snd_mixer_first_elem (priv->mixer_handle);
while (elem) {
const char *elem_name = snd_mixer_selem_get_name (elem);
if (strcmp (elem_name, name) == 0)
break;
elem = snd_mixer_elem_next (elem);
}
if (!elem) {
snd_mixer_detach (priv->mixer_handle, priv->device);
close_mixer (control);
g_warning ("Mixer element '%s' not found", name);
attach_mixer (control);
} else {
snd_mixer_selem_id_t *id;
if (snd_mixer_selem_id_malloc (&id) != 0) {
g_warning ("Unable to allocate element id");
snd_mixer_detach (
priv->mixer_handle, priv->device);
close_mixer (control);
} else {
snd_mixer_selem_get_id (elem, id);
snd_mixer_detach (
priv->mixer_handle, priv->device);
close_mixer (control);
g_debug ("Setting element ID");
moko_alsa_volume_control_set_element (
control, id);
snd_mixer_selem_id_free (id);
}
}
} else
g_warning ("Unable to open mixer on card '%s'", priv->device);
}
static void
attach_mixer (MokoAlsaVolumeControl *self)
{
MokoAlsaVolumeControlPrivate *priv = ALSA_VOLUME_CONTROL_PRIVATE (self);
g_debug ("Trying to attach... %p, %s, %p", priv->mixer_handle,
priv->device, priv->element);
open_mixer (self);
if (priv->mixer_handle && priv->device && priv->element &&
(snd_mixer_attach (priv->mixer_handle, priv->device) == 0) &&
(snd_mixer_selem_register (priv->mixer_handle, NULL, NULL) == 0) &&
(snd_mixer_load (priv->mixer_handle) == 0)) {
priv->mixer_elem = snd_mixer_find_selem (
priv->mixer_handle, priv->element);
if (!priv->mixer_elem) {
g_warning ("Unable to find mixer element");
snd_mixer_detach (priv->mixer_handle, priv->device);
close_mixer (self);
} else {
g_debug ("Attached to mixer");
if (snd_mixer_selem_has_playback_volume (
priv->mixer_elem)) {
priv->control_type = PLAYBACK;
snd_mixer_selem_get_playback_volume_range (
priv->mixer_elem,
&priv->min, &priv->max);
} else if (snd_mixer_selem_has_capture_volume (
priv->mixer_elem)) {
priv->control_type = CAPTURE;
snd_mixer_selem_get_capture_volume_range (
priv->mixer_elem,
&priv->min, &priv->max);
} else
priv->control_type = CONTROL;
snd_mixer_elem_set_callback (
priv->mixer_elem, mixer_elem_event_cb);
snd_mixer_elem_set_callback_private (
priv->mixer_elem, self);
start_polling (self);
update_volume (self);
}
} else {
close_mixer (self);
}
}
static void
detach_mixer (MokoAlsaVolumeControl *self)
{
MokoAlsaVolumeControlPrivate *priv = ALSA_VOLUME_CONTROL_PRIVATE (self);
if (priv->mixer_handle && priv->device &&
priv->element && priv->mixer_elem) {
snd_mixer_detach (priv->mixer_handle, priv->device);
priv->mixer_elem = NULL;
g_debug ("Detached from mixer");
close_mixer (self);
}
}
/**
* Deinitializes the alsa system by
* closing the mixer.
*/
static void
alsaunset(void)
{
if (active_card == NULL)
return;
unset_io_watch();
// 'elem' must be set to NULL at last, because alsa_cb()
// is invoked when closing mixer, and elem is needed.
close_mixer(handle, active_card->dev);
handle = NULL;
elem = NULL;
active_card = NULL;
}
/**
* Get all playable channels for a single alsa card and
* return them as a GSList.
*
* @param card HCTL name of the alsa card
* @return the GSList of channels
*/
static GSList *
get_channels(const char *card)
{
int ccount, i;
snd_mixer_t *mixer;
snd_mixer_elem_t *telem;
GSList *channels = NULL;
mixer = open_mixer(card, NULL, 0);
if (mixer == NULL)
return NULL;
ccount = snd_mixer_get_count(mixer);
telem = snd_mixer_first_elem(mixer);
for (i = 0; i < ccount; i++) {
if (snd_mixer_selem_has_playback_volume(telem))
channels = g_slist_append(channels,
strdup(snd_mixer_selem_get_name(telem)));
telem = snd_mixer_elem_next(telem);
}
#ifdef DEBUG
GSList *tmp = channels;
if (tmp) {
printf("Card %s: available channels\n", card);
while (tmp) {
printf("\t%s\n", (char *) tmp->data);
tmp = tmp->next;
}
} else {
printf("Card %s: no playable channels\n", card);
}
#endif
close_mixer(mixer, card);
return channels;
}
