[niek]

Im running liberelec lates version on a HTPC(Generic PC) with kodi v20.3
And im still having sometimes issues with the sound 

Sometimes the sonos surround set is not started( only TV sound) or the sound is stuttering. By rebooting liberelec it is working ok.
This problems i had often with the kodi v18. When i first switch on a other device (which triggers the HDMI, swich on TV and sonos ) it is running alway ok

So i wondering if it is possible that my HTPC (which is connected to teh TV by HDMI) could als switch automaticaaly teh TV and SONOS on )

[niek]

previous there was something like a setting

 Settings / System / Input / <Your CEC device>.
Scroll down and there should be an entry "HDMI Port value/number" (something like that), with a default value of '0'.
Change that to '2' or whatever port number your RPi is currently connected to on your TV.
Save the CEC settings, and reboot the RPi.

but that is not in kodi anymore

[niek]

i see somthing like commands 
CECActivateSource

CECStandby

[niek]

i could not find if the used MB is CEC complaint,  so i think neen a CEC adaptor or something

[crawfish]

I've always disabled CEC so can't comment on its usage, but if worse comes to worst, you might look into IP control of your TV and Sonos. If supported, you'll be able to do all that and more. If you don't do scripting, software like Home Assistant might be of use:

https://www.home-assistant.io/integrations/kodi/