Problem with S/PDIF output

[anLENIN]

I have Creative Omni Surround USB sound card connected to steamlink. In Kodi it's available to select one of 4 audio output devices - 3 analog and 1 S/PDIF, passthrough device is blanked automatically selected CREATIVE OMNI S/PDIF. But it doesn't matter what is chosen, all output is sent to analog output of the card (and silence through optical out). Even ac3/dts passthrough is working that way - with scratches out of speakers.

Similar problem with same card:
https://www.linuxquestions.org/questions/linux-hardware-18/alsa-sb-omni-surround-5-1-iec958-is-routed-to-the-analog-output-not-the-digital-output-4175609669/

[anLENIN]

The easiest solution is just create alsa config file /etc/asound.conf (with help of SSH) with new "raw" iec958 with right device number:
pcm.iec958raw {
@Args [ CARD ]
@args.CARD { type string }
type hw
card $CARD
device 1
hint {
show {
@func refer
name defaults.namehint.basic
}
description "IEC958 (AC3) Digital Audio Output without any conversions"
device 1
}
}

Now there is another problem:
If you choose new device as audio output in Kodi, videos start to stutter after a few seconds of playing, though their audio streams are played ok