sys-kernel/coreos-modules: build Intel iGPU module

[ader1990]

See: flatcar/Flatcar#1306

This PR adds support for the Intel built-in GPU (CONFIG_DRM_I915=m)

Testing done

[Describe the testing you have done before submitting this PR. Please include both the commands you issued as well as the output you got.]

• Changelog entries added in the respective changelog/ directory (user-facing change, bug fix, security fix, update)
• Inspected CI output for image differences: /boot and /usr size, packages, list files for any missing binaries, kernel modules, config files, kernel modules, etc.

[jepio]

comment about AGP

[github-actions]

Build action triggered: https://github.com/flatcar/scripts/actions/runs/11143870993

[ader1990]

The resulting image needs testing on a real environment, currently I do not have one to test on.

Also, the passthrough implementation using qemu or another hypervisor will most likely need extra kernel config options options enabled, extra kernel parameteres enabled and possibly initrd changes.

Found these two documents that might be of help:
https://3os.org/infrastructure/proxmox/gpu-passthrough/gpu-passthrough-to-vm/#proxmox-configuration-for-gpu-passthrough
https://3os.org/infrastructure/proxmox/gpu-passthrough/igpu-split-passthrough/

Thanks.

[ader1990]

The size increase in /usr is around 13MB, and the initrd increase is almost zero, as the driver is built as module and not loaded in the initrd stage.

The increase in /usr is not negligible, and consists of firmware binaries in /usr/lib/firmware/i915.

The AMD64 compressed image has increased to around 590MB from 585MB.

Any thoughts or opinions on the size increase? Another option would be a systemd-sysext, similar to the zfs one.

[savely-krasovsky]

@jepio are there any comments on merging that PR? Just completed my migration from CoreOS and was quite shocked to see that Flatcar doesn't ship i915 driver. It's crucial for homelab setups with hardware encoding (Plex, Jellyfin, etc).

[jepio]

Since this request has come up several times - let's merge it. We can figure out a sysext for optional kernel modules in the future.

[savely-krasovsky]

Thanks!