Hello
I have some code, which I just can figure out why it is not working.
I have tried ti varify this using amixer. agn@agn-HP-EliteBook-2540p:~/laerdal/audio-pulse2alsa/system/vs2-system/bu/var/lib/alsa$ amixer -Dhw:0 cget numid=23 numid=23,iface=MIXER,name='PCM Playback Volume' ; type=INTEGER,access=rw---RW-,values=2,min=0,max=255,step=0 : values=100,200 | dBscale-min=-51.00dB,step=0.20dB,mute=0
Ofcourse I can use the "cset" command to set the volumes. No problem.
Now, I would like to do this in code. Listed below. The code works just as expected when using the: snd_ctl_elem_id_set_name(id, "PCM Playback Volume"); Should be similar to "amixer -c0 cset name='PCM Playback Volume' 100,200" But when I use the snd_ctl_elem_id_set_numid(id, numid); (with numid=23) it fails. snd_hctl_find_elem simply does not find the element!
The version I use is 1.0.24. I have looked into the amixer.c source code, and it works. So I gees i am just missing a tiny option to make it work, but I hust can't figure out which one!
#include <errno.h> #include <assert.h> #include <alsa/asoundlib.h> #include <sys/poll.h>
int main() { snd_hctl_t *hctl; snd_ctl_elem_id_t *id; int err; unsigned int numid = 23;
err = snd_hctl_open(&hctl, "hw:0", 0); err = snd_hctl_load(hctl);
snd_ctl_elem_id_alloca(&id); snd_ctl_elem_id_set_interface(id, SND_CTL_ELEM_IFACE_MIXER);
//snd_ctl_elem_id_set_numid(id, numid); snd_ctl_elem_id_set_name(id, "PCM Playback Volume");
snd_hctl_elem_t *elem = snd_hctl_find_elem(hctl, id); if (elem != NULL) { snd_ctl_elem_value_t *control; snd_ctl_elem_value_alloca(&control); snd_ctl_elem_value_set_id(control, id);
snd_ctl_elem_value_set_integer(control, 0, 100); err = snd_hctl_elem_write(elem, control);
snd_ctl_elem_value_set_integer(control, 1, 200); err = snd_hctl_elem_write(elem, control); } else printf("Cound not find elem.\n"); snd_hctl_close(hctl);
}