I know, it still doesn't answer the question about a possible limitation either within the Unraid kernel or overall LTS kernel until a certain version. Or even a possible i915 driver issue. As for now I only found information for Kernel 6.1 to 6.6, and not a lot in a combination with an Intel ARC (at least not on x86). Edit 1: I changed as a test to the xe driver but the issue persist: Sep 7 23:09:15 ProjectD kernel: Setting dangerous option force_probe - tainting kernel
Sep 7 23:09:15 ProjectD kernel: i915 0000:09:00.0: I915 probe blocked for Device ID 56a5.
Sep 7 23:09:15 ProjectD kernel: Setting dangerous option force_probe - tainting kernel
Sep 7 23:09:15 ProjectD kernel: Console: switching to colour dummy device 80x25
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: vgaarb: deactivate vga console
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] Found DG2/G11 (device ID 56a5) display version 13.00 stepping C0
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] Using GuC firmware from i915/dg2_guc_70.bin version 70.44.1
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: vgaarb: VGA decodes changed: olddecodes=io+mem,decodes=none:owns=none
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] Attempting to resize bar from 256MiB -> 8192MiB
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: BAR 2 [mem 0x7fe0000000-0x7fefffffff 64bit pref]: releasing
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem 0x7fe0000000-0x7fefffffff 64bit pref]: releasing
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem 0x7fe0000000-0x7fefffffff 64bit pref]: releasing
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:00:03.1: Assigned bridge window [mem 0x7fe0000000-0x7ff07fffff 64bit pref] to [bus 07-0a] cannot fit 0x200000000 required for 0000:08:01.0 bridging to [bus 09]
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem 0x00000000 64bit pref] to [bus 09] requires relaxed alignment rules
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:00:03.1: Assigned bridge window [mem 0x7fe0000000-0x7ff07fffff 64bit pref] to [bus 07-0a] cannot fit 0x200000000 required for 0000:07:00.0 bridging to [bus 08-0a]
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem 0x00000000 64bit pref] to [bus 08-0a] requires relaxed alignment rules
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem size 0x200000000 64bit pref]: can't assign; no space
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem size 0x200000000 64bit pref]: failed to assign
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem size 0x200000000 64bit pref]: can't assign; no space
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem size 0x200000000 64bit pref]: failed to assign
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: BAR 2 [mem size 0x200000000 64bit pref]: can't assign; no space
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: BAR 2 [mem size 0x200000000 64bit pref]: failed to assign
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:00:03.1: PCI bridge to [bus 07-0a]
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:00:03.1: bridge window [mem 0xfb000000-0xfc3fffff]
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:00:03.1: bridge window [mem 0x7fe0000000-0x7ff07fffff 64bit pref]
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:07:00.0: PCI bridge to [bus 08-0a]
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem 0xfb000000-0xfc3fffff]
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem 0x7fe0000000-0x7fefffffff 64bit pref]
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:08:01.0: PCI bridge to [bus 09]
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem 0xfb000000-0xfc1fffff]
Sep 7 23:09:15 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem 0x7fe0000000-0x7fefffffff 64bit pref]
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] Failed to resize BAR2 to 8192M (-ENOSPC). Consider enabling 'Resizable BAR' support in your BIOS
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: BAR 2 [mem 0x7fe0000000-0x7fefffffff 64bit pref]: assigned
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] VISIBLE VRAM: 0x0000007fe0000000, 0x0000000010000000
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] Small BAR device
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] VRAM[0, 0]: Actual physical size 0x0000000180000000, usable size exclude stolen 0x000000017c800000, CPU accessible size 0x0000000010000000
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] VRAM[0, 0]: DPA range: [0x0000000000000000-180000000], io range: [0x0000007fe0000000-7ff0000000]
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] VRAM: 0x0000000180000000 is larger than resource 0x0000000010000000
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] Total VRAM: 0x0000007fe0000000, 0x0000000180000000
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] Available VRAM: 0x0000007fe0000000, 0x000000017c800000
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] Finished loading DMC firmware i915/dg2_dmc_ver2_08.bin (v2.8)
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] vcs1 fused off
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] vcs3 fused off
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] vcs4 fused off
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] vcs5 fused off
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] vcs6 fused off
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] vcs7 fused off
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] vecs2 fused off
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] vecs3 fused off
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] ccs0 fused off
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] ccs2 fused off
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] ccs3 fused off
Sep 7 23:09:15 ProjectD kernel: [drm] Initialized xe 1.1.0 for 0000:09:00.0 on minor 0
Sep 7 23:09:15 ProjectD kernel: fbcon: xedrmfb (fb0) is primary device
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] Reducing the compressed framebuffer size. This may lead to less power savings than a non-reduced-size. Try to increase stolen memory size if available in BIOS.
Sep 7 23:09:15 ProjectD kernel: Console: switching to colour frame buffer device 240x67
Sep 7 23:09:15 ProjectD kernel: xe 0000:09:00.0: [drm] fb0: xedrmfb frame buffer deviceEdit 2: Here some logs with i915: Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] Found DG2/G11 (device ID 56a5) display version 13.00 stepping C0
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] VT-d active for gfx access
Sep 7 23:56:21 ProjectD kernel: Console: switching to colour dummy device 80x25
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: vgaarb: deactivate vga console
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: BAR 0 [mem 0xfb000000-0xfbffffff 64bit]: releasing
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: BAR 2 [mem 0x7fe0000000-0x7fefffffff 64bit pref]: releasing
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem 0x7fe0000000-0x7fefffffff 64bit pref]: releasing
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem 0x7fe0000000-0x7fefffffff 64bit pref]: releasing
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:00:03.1: Assigned bridge window [mem 0x7fe0000000-0x7ff07fffff 64bit pref] to [bus 07-0a] cannot fit 0x200000000 required for 0000:08:01.0 bridging to [bus 09]
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem 0x00000000 64bit pref] to [bus 09] requires relaxed alignment rules
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:00:03.1: Assigned bridge window [mem 0x7fe0000000-0x7ff07fffff 64bit pref] to [bus 07-0a] cannot fit 0x200000000 required for 0000:07:00.0 bridging to [bus 08-0a]
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem 0x00000000 64bit pref] to [bus 08-0a] requires relaxed alignment rules
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem size 0x200000000 64bit pref]: can't assign; no space
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem size 0x200000000 64bit pref]: failed to assign
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem size 0x200000000 64bit pref]: can't assign; no space
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem size 0x200000000 64bit pref]: failed to assign
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: BAR 2 [mem size 0x200000000 64bit pref]: can't assign; no space
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: BAR 2 [mem size 0x200000000 64bit pref]: failed to assign
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: BAR 0 [mem 0xfb000000-0xfbffffff 64bit]: assigned
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:00:03.1: PCI bridge to [bus 07-0a]
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:00:03.1: bridge window [mem 0xfb000000-0xfc3fffff]
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:00:03.1: bridge window [mem 0x7fe0000000-0x7ff07fffff 64bit pref]
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:07:00.0: PCI bridge to [bus 08-0a]
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem 0xfb000000-0xfc3fffff]
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:07:00.0: bridge window [mem 0x7fe0000000-0x7fefffffff 64bit pref]
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:08:01.0: PCI bridge to [bus 09]
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem 0xfb000000-0xfc1fffff]
Sep 7 23:56:21 ProjectD kernel: pcieport 0000:08:01.0: bridge window [mem 0x7fe0000000-0x7fefffffff 64bit pref]
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] Failed to resize BAR2 to 8192M (-ENOSPC)
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: BAR 2 [mem 0x7fe0000000-0x7fefffffff 64bit pref]: assigned
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] Using a reduced BAR size of 256MiB. Consider enabling 'Resizable BAR' or similar, if available in the BIOS.
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: vgaarb: VGA decodes changed: olddecodes=io+mem,decodes=io+mem:owns=none
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] Finished loading DMC firmware i915/dg2_dmc_ver2_08.bin (v2.8)
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] GT0: GuC firmware i915/dg2_guc_70.bin version 70.44.1
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] GT0: HuC firmware i915/dg2_huc_gsc.bin version 7.10.16
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] GT0: GUC: submission enabled
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] GT0: GUC: SLPC enabled
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] GT0: GUC: RC enabled
Sep 7 23:56:21 ProjectD kernel: [drm] Initialized i915 1.6.0 for 0000:09:00.0 on minor 0
Sep 7 23:56:21 ProjectD kernel: fbcon: i915drmfb (fb0) is primary device
Sep 7 23:56:21 ProjectD kernel: Console: switching to colour frame buffer device 240x67
Sep 7 23:56:21 ProjectD kernel: i915 0000:09:00.0: [drm] fb0: i915drmfb frame buffer device