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Date:   Fri, 4 Jun 2021 17:36:19 +0200
From:   Joerg Roedel <joro@8bytes.org>
To:     Wang Xingang <wangxingang5@huawei.com>
Cc:     robh@kernel.org, will@kernel.org, helgaas@kernel.org,
        robh+dt@kernel.org, gregkh@linuxfoundation.org,
        iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
        linux-pci@vger.kernel.org, xieyingtai@huawei.com
Subject: Re: [PATCH v4] iommu/of: Fix pci_request_acs() before enumerating
 PCI devices
Message-ID: <YLpIcwdWDGKpw39s@8bytes.org>
References: <1621566204-37456-1-git-send-email-wangxingang5@huawei.com>
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On Fri, May 21, 2021 at 03:03:24AM +0000, Wang Xingang wrote:
> From: Xingang Wang <wangxingang5@huawei.com>
> 
> When booting with devicetree, the pci_request_acs() is called after the
> enumeration and initialization of PCI devices, thus the ACS is not
> enabled. And ACS should be enabled when IOMMU is detected for the
> PCI host bridge, so add check for IOMMU before probe of PCI host and call
> pci_request_acs() to make sure ACS will be enabled when enumerating PCI
> devices.
> 
> Fixes: 6bf6c24720d33 ("iommu/of: Request ACS from the PCI core when
> configuring IOMMU linkage")
> Signed-off-by: Xingang Wang <wangxingang5@huawei.com>
> ---
>  drivers/iommu/of_iommu.c | 1 -
>  drivers/pci/of.c         | 8 +++++++-
>  2 files changed, 7 insertions(+), 2 deletions(-)

Should probably go through the PCI tree, so

Acked-by: Joerg Roedel <jroedel@suse.de>