Re: [PATCH v2] iommu/arm-smmu-qcom: Add missing GMU entry to match table

[Johan Hovold]

On Sun, Dec 10, 2023 at 10:06:53AM -0800, Rob Clark wrote:
> From: Rob Clark <robdclark@xxxxxxxxxxxx>
> 
> In some cases the firmware expects cbndx 1 to be assigned to the GMU,
> so we also want the default domain for the GMU to be an identy domain.
> This way it does not get a context bank assigned.  Without this, both
> of_dma_configure() and drm/msm's iommu_domain_attach() will trigger
> allocating and configuring a context bank.  So GMU ends up attached to
> both cbndx 1 and later cbndx 2.  This arrangement seemingly confounds
> and surprises the firmware if the GPU later triggers a translation
> fault, resulting (on sc8280xp / lenovo x13s, at least) in the SMMU
> getting wedged and the GPU stuck without memory access.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>

Tested-by: Johan Hovold <johan+linaro@xxxxxxxxxx>