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/* SPDX-License-Identifier: GPL-2.0 */
/** \file alsa_mix.c The ALSA mixer plugin. */
#include <alsa/asoundlib.h>
#include "para.h"
#include "error.h"
#include "mix.h"
#include "string.h"
struct mixer_handle {
/* The ALSA mixer handle */
snd_mixer_t *mixer;
/* Copy of the alsa device name, e.g. "hw:0". */
char *card;
/* ALSA's representation of the given mixer channel. */
snd_mixer_elem_t *elem;
/* Set in ->set_channel(), used for ->get() and ->set(). */
long pmin, pmax;
};
static void alsa_mix_close(struct mixer_handle *h)
{
if (!h)
return;
PARA_INFO_LOG("closing mixer handle\n");
if (h->mixer)
snd_mixer_close(h->mixer);
free(h->card);
free(h);
/*
* The global ALSA configuration is cached for next usage,
* which causes valgrind to report many memory leaks. Calling
* snd_config_update_free_global() frees the cache.
*/
snd_config_update_free_global();
}
static int alsa_mix_open(const char *dev, struct mixer_handle **handle)
{
int ret;
char *msg;
struct mixer_handle *h;
PARA_INFO_LOG("snd_mixer_{open,attach,register,load}\n");
*handle = NULL;
h = zalloc(sizeof(*h));
h->card = para_strdup(dev? dev : "hw:0");
ret = snd_mixer_open(&h->mixer, 0);
if (ret < 0) {
msg = make_message("snd_mixer_open() failed: %s",
snd_strerror(ret));
goto fail;
}
ret = snd_mixer_attach(h->mixer, h->card);
if (ret < 0) {
msg = make_message("mixer attach error (%s): %s", h->card,
snd_strerror(ret));
goto fail;
}
ret = snd_mixer_selem_register(h->mixer, NULL, NULL);
if (ret < 0) {
msg = make_message("mixer register error (%s): %s", h->card,
snd_strerror(ret));
goto fail;
}
ret = snd_mixer_load(h->mixer);
if (ret < 0) {
msg = make_message("mixer load error (%s): %s", h->card,
snd_strerror(ret));
goto fail;
}
/* success */
*handle = h;
return 1;
fail:
PARA_NOTICE_LOG("%s\n", msg);
free(msg);
alsa_mix_close(h);
return -E_ALSA_MIX_OPEN;
}
static bool channel_has_playback(snd_mixer_selem_channel_id_t chn,
snd_mixer_elem_t *elem)
{
return snd_mixer_selem_has_playback_channel(elem, chn);
}
static char *alsa_mix_get_channels(struct mixer_handle *handle)
{
int ret;
char *list = NULL;
snd_mixer_selem_id_t *sid;
snd_mixer_elem_t *elem;
ret = snd_mixer_selem_id_malloc(&sid);
assert(ret >= 0);
elem = snd_mixer_first_elem(handle->mixer);
for (; elem; elem = snd_mixer_elem_next(elem)) {
char *tmp = list;
const char *name;
if (!channel_has_playback(0, elem))
continue;
if (!snd_mixer_selem_has_playback_volume(elem))
continue;
snd_mixer_selem_get_id(elem, sid);
name = snd_mixer_selem_id_get_name(sid);
list = make_message("%s%s%s",
list? list : "",
list? ", " : "",
name);
free(tmp);
}
snd_mixer_selem_id_free(sid);
return list;
}
static int alsa_mix_set_channel(struct mixer_handle *h,
const char *mixer_channel)
{
int ret, selem_id = 0;
snd_mixer_selem_id_t *sid;
if (!mixer_channel)
mixer_channel = "Master";
ret = snd_mixer_selem_id_malloc(&sid);
assert(ret >= 0);
snd_mixer_selem_id_set_index(sid, selem_id);
snd_mixer_selem_id_set_name(sid, mixer_channel);
h->elem = snd_mixer_find_selem(h->mixer, sid);
if (!h->elem) {
PARA_NOTICE_LOG("unable to find simple control '%s',%u\n",
snd_mixer_selem_id_get_name(sid),
snd_mixer_selem_id_get_index(sid));
ret = -E_BAD_CHANNEL;
goto out;
}
ret = snd_mixer_selem_get_playback_volume_range(h->elem,
&h->pmin, &h->pmax);
if (ret < 0) {
PARA_NOTICE_LOG("unable to get %s range (%s): %s\n",
mixer_channel, h->card, snd_strerror(ret));
ret = -E_ALSA_MIX_RANGE;
goto out;
}
PARA_INFO_LOG("%s: %s (%ld-%ld)\n", h->card, mixer_channel, h->pmin,
h->pmax);
if (h->pmin >= h->pmax) {
ret = -E_ALSA_MIX_RANGE;
goto out;
}
ret = 1;
out:
snd_mixer_selem_id_free(sid);
return ret;
}
static int alsa_mix_get(const struct mixer_handle *h)
{
snd_mixer_selem_channel_id_t chn;
int n = 0;
float sum = 0;
for (chn = 0; chn <= SND_MIXER_SCHN_LAST; chn++) {
long val;
int ret;
if (!channel_has_playback(chn, h->elem))
continue;
ret = snd_mixer_selem_get_playback_volume(h->elem, chn, &val);
if (ret < 0) {
PARA_NOTICE_LOG("unable to get value for channel %d (%s): %s\n",
(int)chn, h->card, snd_strerror(ret));
return -E_ALSA_MIX_GET_VAL;
}
sum += val - h->pmin;
n++;
}
if (n == 0 || h->pmax == h->pmin)
return 0;
/* compute average over all channels and scale to 0..100 */
return 100.0 * sum / ((h->pmax - h->pmin) * n) + 0.5;
}
static int alsa_mix_set(struct mixer_handle *h, int val)
{
int ret;
snd_mixer_selem_channel_id_t chn;
long scaled = val / 100.0 * (h->pmax - h->pmin) + h->pmin + 0.5;
PARA_DEBUG_LOG("new value: %d\n", val);
for (chn = 0; chn <= SND_MIXER_SCHN_LAST; chn++) {
if (!channel_has_playback(chn, h->elem))
continue;
ret = snd_mixer_selem_set_playback_volume(h->elem, chn, scaled);
if (ret < 0) {
PARA_NOTICE_LOG("unable to set value for channel %d (%s): %s\n",
(int)chn, h->card, snd_strerror(ret));
return -E_ALSA_MIX_SET_VAL;
}
}
return 1;
}
/** The mixer operations for the ALSA mixer. */
const struct mixer alsa_mixer = {
.name = "alsa",
.open = alsa_mix_open,
.get_channels = alsa_mix_get_channels,
.set_channel = alsa_mix_set_channel,
.close = alsa_mix_close,
.get = alsa_mix_get,
.set = alsa_mix_set
};
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