Comment 9 for bug 1497666

http://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=src/conf/cards/CA0106.conf;hb=HEAD

there are locks associated with playback controls of iec958 device

but pulseaudio try to open iec958 capture device

.000) D: [pulseaudio] alsa-util.c: Managed to open iec958:0
( 0.352| 0.000) D: [pulseaudio] alsa-util.c: Maximum hw buffer size is 340 ms
( 0.352| 0.000) I: [pulseaudio] (alsa-lib)setup.c: Cannot lock ctl elem
( 0.352| 0.000) I: [pulseaudio] (alsa-lib)setup.c: Cannot lock ctl elem
( 0.352| 0.000) I: [pulseaudio] (alsa-lib)setup.c: Cannot lock ctl elem
( 0.352| 0.000) I: [pulseaudio] (alsa-lib)setup.c: Cannot lock ctl elem
( 0.352| 0.000) D: [pulseaudio] alsa-util.c: Set neither period nor buffer size.
( 0.352| 0.000) I: [pulseaudio] (alsa-lib)setup.c: Cannot lock ctl elem
( 0.352| 0.000) I: [pulseaudio] alsa-util.c: snd_pcm_hw_params failed: Device or resource busy

hooks.0 {
  type ctl_elems
  hook_args [
   {
    name "IEC958 Front Playback Volume"
    index 0
    lock true
    preserve true
    value [ 207 207 ] # Puts 0x30303030 in the Volume register. 0xff - 0x30 = 0xcf = 207
   }
   {
    name "IEC958 Playback Switch"
    lock true
    preserve true
    value 1
   }
   {
    interface PCM
    name "IEC958 Playback Default"
    index 1
    lock true
    preserve true
    optional true
    value [ $AES0 $AES1 $AES2 $AES3 ]
   }
   {
    # for compatibility with older drivers
    name "IEC958 Playback Default"
    index 1
    lock true
    preserve true
    optional true
    value [ $AES0 $AES1 $AES2 $AES3 ]
   }
  ]