[Intel-gfx] [PATCH] drm/i915: Register DMAR fault handler

[Chris Wilson]

Quoting Chris Wilson (2020-11-17 15:42:52)
> Attach a iommu [DMAR] fault handler for our device and try and reset the
> GPU upon a fault. At worst this will allow us to more quickly recover
> from a fault, rather than wait 10s for the hangcheck to determine a
> stuctk GPU. At best, it will immediately restart the GPU and paper over
> the bad iommu.

Scratch that, it was just good luck in test runs. Still received a

[   40.695947] DMAR: DRHD: handling fault status reg 3
[   40.696128] DMAR: [DMA Write] Request device [00:02.0] PASID ffffffff fault addr 54000 [fault reason 07] Next page table ptr is invalid

with no sign of our fault_handler() being invoked.
-Chris