From: Zhou Wang <wangzhou1@hisilicon.com>
To: Alex Williamson <alex.williamson@redhat.com>,
Will Deacon <will.deacon@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>,
Linux PCI <linux-pci@vger.kernel.org>, <wangzhou1@hisilicon.com>
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
WARNING: multiple messages have this Message-ID (diff)
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
next reply other threads:[~2017-08-31 14:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-31 14:21 Zhou Wang [this message]
2017-08-31 14:21 ` [Question] PCI ACS is broken for ARM SMMU v3? Zhou Wang
2017-09-04 12:33 ` Zhou Wang
2017-09-04 12:33 ` Zhou Wang
2017-09-04 15:59 ` Lorenzo Pieralisi
2017-09-04 15:59 ` Lorenzo Pieralisi
2017-09-05 12:47 ` Zhou Wang
2017-09-05 12:47 ` Zhou Wang
2017-09-06 9:55 ` Lorenzo Pieralisi
2017-09-06 9:55 ` Lorenzo Pieralisi
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