Fwd: Help on specifying 'chmap' in asound.conf

Dear all,

   I am having a question regarding how to specify 'champ' for a
plugin.  I do not see any examples of this. I tried many ways to
specify but failed.

  As indicated by the link below,   I can specify the MAP as a string
array.   Can someone provide one example on how exactly this    [chmap
MAP]  can be specified?

"
pcm.name {
        type cras
    [chmap MAP]     # Provide channel maps; MAP is a string array
}
"
https://www.alsa-project.org/alsa-doc/alsa-lib/pcm_plugins.html


I can something like these, but none of these work for me.

chmap LFE
chmap "LFE"
chmap FR,FL,LFE
champ "FR,FL,LFE"

Thanks!

Xinhui,