Intel GPU: Video-related kernel errors, GPU hang (only mouse works)

[marmarek]

Qubes OS version (e.g., R3.2):

R4.0
Xen 4.8.1, linux 4.9.29-17

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Expected behavior:

No errors, no hangs

Actual behavior:

A lot of errors like:

[drm:gen8_irq_hander [i915]] *ERROR* Fault errors on pipe A 0x00000100

And similarly in Xen messages:

[VT-D]DMAR:[DMA Read] Request device [0000:00:02.0] fault addr 29375f2000, iommu reg = ffff82c0009f2000
[VT-D]DMAR: reason 06 - PTE Read access is not set

Steps to reproduce the behavior:

Boot Qubes 4.0 on Broadwell machine - in this case both Librem 13v1 and Librem 15v2.

General notes:

This appears to be fixed by iommu=no-igfx Xen option. Since we don't have GUI VM yet, it doesn't have much security implications. Maybe we should enable it by default?

[marmarek]

@rootkovska what do you think about enabling iommu=no-igfx by default?

[marmarek]

@rootkovska what do you think about enabling iommu=no-igfx by default?

[rootkovska]

I agree it might be justified for 4.0, but we should make sure we won't forget to enable IOMMU for the GPU back in 4.1 when we (hopefully) will get a GPU-passthrough-based GUI domain. Perhaps creating a high-priority ticket for 4.1 milestone should be enough?

[rootkovska]

I agree it might be justified for 4.0, but we should make sure we won't forget to enable IOMMU for the GPU back in 4.1 when we (hopefully) will get a GPU-passthrough-based GUI domain. Perhaps creating a high-priority ticket for 4.1 milestone should be enough?

[marmarek]

Ok. #2841

[marmarek]

Ok. #2841