[alsa-devel] snd_ctl_elem_write fails -EPERM if snd_pcm is open
pavel.hofman at insite.cz
Tue Apr 15 20:33:13 CEST 2008
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-220.127.116.11/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
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
name "IEC958 Playback Default"
value [ $AES0 $AES1 $AES2 $AES3 ]
The same applies to a number of other cards.
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