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From: wangzhou1@hisilicon•com (Zhou Wang)
To: linux-arm-kernel@lists•infradead.org
Subject: [Question] PCI ACS is broken for ARM SMMU v3?
Date: Thu, 31 Aug 2017 22:21:00 +0800	[thread overview]
Message-ID: <59A81B4C.3020402@hisilicon.com> (raw)

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

             reply	other threads:[~2017-08-31 14:21 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-31 14:21 Zhou Wang [this message]
2017-09-04 12:33 ` [Question] PCI ACS is broken for ARM SMMU v3? Zhou Wang
2017-09-04 15:59   ` Lorenzo Pieralisi
2017-09-05 12:47     ` Zhou Wang
2017-09-06  9:55       ` Lorenzo Pieralisi

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