Proxmox LXC Not using Intel ARC 380, only iGPU

[Host-in-the-Shell]

I still experience the issue with transcoding not working on kernel 6.9.7 backported to bookworm on Debian. It has essentially followed every kernel release after 6.6.13. Could be that there's an additional issue with intel compute runtime, but since I've reverted back to 6.6.13 haven't really gotten around to test if that fixes it.

[TheDreadPirate]

Do you have issues with transcoding in general or just tone mapping? If the latter, it would be an issue with the compute runtimes. If the former, it would be something else.

[Host-in-the-Shell]

Would the issue pop up just by having tone mapping enabled under the playback settings or only by actually transcoding tone mapped content? I ask because I remember all transcoding simply resulting in a playback error on my LG TV, but I didn't investigate further: just rebooted using and older, working kernel.

[TheDreadPirate]

Tone mapping only happens when:

A) The source file is HDR
B) Video transcoding needs to happen, regardless of the actual reason.
C) Tone mapping is enabled

Additionally, at least on Ubuntu's bugged kernel (6.8.0-38, based on 6.8.6), transcodes that scaled the resolution of the video were affected by the i915 kernel bug. Non-tone mapped transcodes that did not scale resolution were not affected. Not sure if that also applies to the mainline kernel.

[Host-in-the-Shell]

Well, then... seems related to tone mapping; about 1/3 of my library is HDR give or take, I do have tone mapping enabled and transcoding happens often with my server due to the WebOS app not supporting PGS subtitles. I will try the fix I listed earlier once I get a chance to reboot.

Edit: I finally had some time to reboot and I can confirm that the fix I previously mentioned got rid of any issues I had, so it was certainly a tone mapping problem.

[MetricConversion]

For any future folks viewing this. I finally got back around to messing with this.

I spun up a full VM (Ubuntu 24.04 server), removed all the stuff passing the renderer to the LXC, passed the PCI directly to the VM and the ARC GPU is working just great.