How to run Tvheadend Server using Docker

/dev/dri is a different device completely, taken from the linuxserver github readme:-

--device /dev/dri	Only needed if you want to use your AMD/Intel GPU for hardware accelerated video encoding (vaapi).

--device /dev/dvb	Only needed if you want to pass through a DVB card to the container. If you use IPTV or HDHomeRun you can leave it out.

so both options are valid, i dont see any issues with the above personally, in my guide above i have only included an example of passing through /dev/dvb