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

[Robin Murphy]

On 2023-12-10 6:06 pm, 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.

Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>

> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> ---
>
> I didn't add a fixes tag because really this issue has been there
> all along, but either didn't matter with other firmware or we didn't
> notice the problem.
>
>   drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> index 549ae4dba3a6..d326fa230b96 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> @@ -243,6 +243,7 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
>   
>   static const struct of_device_id qcom_smmu_client_of_match[] __maybe_unused = {
>   	{ .compatible = "qcom,adreno" },
> +	{ .compatible = "qcom,adreno-gmu" },
>   	{ .compatible = "qcom,mdp4" },
>   	{ .compatible = "qcom,mdss" },
>   	{ .compatible = "qcom,sc7180-mdss" },