Re: [alsa-devel] snd_ctl_elem_write fails -EPERM if snd_pcm is open

Bouterse, Bob wrote:

I am trying to sent IEC958 status bits on a VT1708A HAD-INTEL codec while audio is being output. snd_ctl_elem_write returns -EPERM from linux-2.6.24.3/sound/core/control.c:769 .

Is there some way I can do this?

FYI using iecset will also give you an: # iecset copywrite on snd_ctl_elem_write: Operation not permitted

I am using alsa-lib-1.0.14a

Hi,

I guess the reason is in /usr/share/alsa/cards/HDA-Intel.conf . If I understand correctly, upon opening the iec958 stream, the status bits control gets locked

.......... hook_args [ { name "IEC958 Playback Default" lock true preserve true value [ $AES0 $AES1 $AES2 $AES3 ] } ...........

The same applies to a number of other cards.

Pavel.