weird permission(?) issue regarding hw accel - fixed by rebooting of PVE host. why?

[Iacov]

hey

first of, i'm not sure if this rather belongs in the jellyfin forum or the proxmox forum...but i'm at the asbolute beginning of my troubleshooting

my setup:
- Jellyfin via LSIO Docker Image
- Running on Ubuntu LTS 22.04 HWE Stack (edit: specifically a VM with passed through iGPU, not a privileged LXC)
- virtualized as VM on Proxmox (8.1.4)
- on a Minisforum Intel N100 machine/cpu

the symtpoms:
- first encountered by failing to start a stream via browser (win11/edge)
- starting a stream via android app worked, but failed as soon as i transcoded

the ffmpeg log stated everytiime (besides other stuff)

Code:

[AVHWDeviceContext @ 0x60bed0cb4100] No VA display found for any default device.
Device creation failed: -22.
Failed to set value 'vaapi=va:,kernel_driver=i915,driver=iHD' for option 'init_hw_device': Invalid argument
Error parsing global options: Invalid argument

i did a reboot of the container as well as the VM, but no change
striking my eye was the line 

Code:

'vaapi=va:,kernel_driver=i915,driver=iHD' for option 'init_hw_device'

which should alsmost be identical to what i blacklisted in my proxmox grub in order to pass through the iGPU
following the lead from this reddit thread, i am tilting towards a permission or blacklist issue  Problems with transcoding after update to 10.8.10 : r/jellyfin (reddit.com)

i did a restart of the proxmox host - starting the streams does work now again, but i have to monitor for how long or what could have triggered the issue
i'm not sure if the jellyfin container could have triggered a permission conflict or another vm (only one other vm on this specific host) or if it was a simple "hiccup" because the host has had a long uptime

does anyone have experience with this kind of errors? maybe together with proxmox?
any hint or idea/input is welcome

[TheDreadPirate]

Honestly, you would probably have better luck on the Proxmox forum.

I'm assuming that when this problem happens, the VM also loses access to the iGPU and not just the Jellyfin docker container.