Completely independent from the current version HDR Tone Mapping issues, I’ve never been able to get HW transcoding to work on my setup only when HDR Tone Mapping is enabled and an HDR/DV video is played.
I do see that there seems to be an I/O error, but I do not think it is permission-related for the media files since they all are set to 775 and Docker is in the users group.
/dev/dri and contents are also set to 777.
Doing some digging, I found a couple of instances of the same problem from 2 years ago and last year citing the resolution as a rollback to Linux kernel 5.15 (Ubuntu 22.04) from 5.17.13 and 6.1.0-12.
Unraid’s current kernel version is 6.1.79, but considering the drivers are packaged with Plex, could this still cause an issue?