[PATCH] iommu/intel: quirk to disable DMAR for QM57 igfx

[Joerg Roedel]

On Wed, Jan 23, 2019 at 05:02:38PM +0200, Joonas Lahtinen wrote:
> We have many reports where just having intel_iommu=on (and using the
> system normally, without any virtualization stuff going on) will cause
> unexplained GPU hangs. For those users, simply switching to
> intel_iommu=igfx_off solves the problems, and the debug often ends
> there.

If you can reproduce problems on your side, then you can try to enable
CONFIG_INTEL_IOMMU_BROKEN_GFX_WA to force the GFX devices into the
identity mapping. We can also add a boot-parameter and workarounds if it
turns out that this is sufficient to make the GFX devices work with
IOMMU enabled.


Regards,

	Joerg