Subject: i915 initialization failure on Apple Mac mini 6,1 and 7,1 with kernel 6.12+

Subject: i915 initialization failure on Apple Mac mini 6,1 and 7,1 with kernel 6.12+

[Daniel Burnfield]

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*Hardware:*

   - Apple Mac mini 6,1 (Late 2012), Intel HD Graphics 4000, chip-ID
   8086:0166
   - Apple Mac mini 7,1 (Late 2014), Intel HD Graphics 5000, chip-ID
   8086:0a26
   - Firmware: Apple EFI (UEFI)

*OS:* MX Linux 25.1 (Debian Trixie base)

*Problem:* i915 fails to initialize on kernel 6.12.x and later on both Mac
mini models. The system falls back to llvmpipe software rendering. The
driver field reports N/A in inxi output.

*Working kernel:* 6.1.0-42-amd64 (Debian Bookworm) initializes i915
correctly on both models and produces full hardware acceleration — Mesa
Intel HD Graphics 4000/5000 with OpenGL 4.5.

*Key dmesg errors on 6.12 without nomodeset:*

DMAR-IR: Failed to enable irq remapping. You are vulnerable to
irq-injection attacks.
pci 0000:05:00.0: bridge window [mem size 0x00200000]: failed to assign
pci 0000:05:00.0: bridge window [mem size 0x00200000 64bit pref]:
failed to assign
pci 0000:05:06.0: bridge window [io size 0x1000]: failed to assign
wl: module verification failed: signature and/or required key missing
— tainting kernel

*Notable:* No i915 messages appear in dmesg at all under 6.12 without
nomodeset — the module never attempts to load. Under 6.1 with the same
hardware, i915 loads and initializes cleanly.

*With nomodeset:* System boots to GUI using llvmpipe. i915 is never
attempted.

*Workaround:* Boot with kernel 6.1.0-42-amd64 from Debian Bookworm without
nomodeset. Full hardware acceleration works correctly.

*Request:* Please investigate the PCI bridge resource assignment and
DMAR-IR regression affecting Apple EFI hardware on kernel 6.12+. These Mac
mini models are well within the supported hardware range for the i915
driver and worked correctly on earlier kernels.
Thank you
Dan Burnfield

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Re: Subject: i915 initialization failure on Apple Mac mini 6,1 and 7,1 with kernel 6.12+

[Jani Nikula]

On Mon, 11 May 2026, Daniel Burnfield <daniel.burnfield@gmail.com> wrote:
> *Request:* Please investigate the PCI bridge resource assignment and
> DMAR-IR regression affecting Apple EFI hardware on kernel 6.12+. These Mac
> mini models are well within the supported hardware range for the i915
> driver and worked correctly on earlier kernels.

Please file a bug as described at [1].

Thanks,
Jani.


[1] https://drm.pages.freedesktop.org/intel-docs/how-to-file-i915-bugs.html


-- 
Jani Nikula, Intel