[Question] PCI ACS is broken for ARM SMMU v3?
Zhou Wang
wangzhou1 at hisilicon.com
Mon Sep 4 05:33:22 PDT 2017
+to: Lorenzo
On 2017/8/31 22:21, Zhou Wang wrote:
> Hi Will and Alex,
>
> pci_request_acs is called in drivers/iommu/arm-smmu-v3.c to set pci_acs_enable.
>
> PCI subsystem tries to enable ACS as below:
>
> pci_device_add
> --> pci_init_capabilities
> --> pci_enable_acs
>
> in ACPI PCI driver. However, ACPI PCI driver will be called before SMMU v3 driver,
> which will lead pci_enable_acs to return directly as pci_acs_enable is not set
> before SMMU v3 driver loading.
>
> I think this is a bug, what do you think about this problem?
>
> Best,
> Zhou
>
>
>
>
>
> .
>
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