On 2023-12-10 6:06 pm, Rob Clark wrote:

From: Rob Clark robdclark@chromium.org

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@arm.com

Cc: stable@vger.kernel.org Signed-off-by: Rob Clark robdclark@chromium.org

---

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" },