/* initialize dB range information, reading TLV via hcontrol
*/
static int init_db_range(snd_hctl_elem_t *ctl, struct selem_str *rec)
{
snd_ctl_elem_info_t *info;
unsigned int *tlv = NULL;
const unsigned int tlv_size = 4096;
unsigned int *dbrec;
int db_size;
if (rec->db_init_error)
return -EINVAL;
if (rec->db_initialized)
return 0;
snd_ctl_elem_info_alloca(&info);
if (snd_hctl_elem_info(ctl, info) < 0)
goto error;
if (! snd_ctl_elem_info_is_tlv_readable(info))
goto error;
tlv = malloc(tlv_size);
if (! tlv)
return -ENOMEM;
if (snd_hctl_elem_tlv_read(ctl, tlv, tlv_size) < 0)
goto error;
db_size = snd_tlv_parse_dB_info(tlv, tlv_size, &dbrec);
if (db_size < 0)
goto error;
rec->db_info = malloc(db_size);
if (!rec->db_info)
goto error;
memcpy(rec->db_info, dbrec, db_size);
free(tlv);
rec->db_initialized = 1;
return 0;
error:
free(tlv);
rec->db_init_error = 1;
return -EINVAL;
}
/*
* add the TLV string and dB ranges to comment fields
*/
static int add_tlv_comments(snd_ctl_t *handle, snd_ctl_elem_id_t *id,
snd_ctl_elem_info_t *info, snd_config_t *comment)
{
unsigned int tlv[MAX_USER_TLV_SIZE];
unsigned int *db;
long dbmin, dbmax;
int err;
if (snd_ctl_elem_tlv_read(handle, id, tlv, sizeof(tlv)) < 0)
return 0; /* ignore error */
if (snd_ctl_elem_info_is_tlv_writable(info)) {
char *s = tlv_to_str(tlv);
if (s) {
err = snd_config_string_add(comment, "tlv", s);
if (err < 0) {
error("snd_config_string_add: %s", snd_strerror(err));
return err;
}
free(s);
}
}
err = snd_tlv_parse_dB_info(tlv, sizeof(tlv), &db);
if (err <= 0)
return 0;
snd_tlv_get_dB_range(db, snd_ctl_elem_info_get_min(info),
snd_ctl_elem_info_get_max(info),
&dbmin, &dbmax);
if (err < 0)
return err;
snd_config_integer_add(comment, "dbmin", dbmin);
snd_config_integer_add(comment, "dbmax", dbmax);
return 0;
}