Re: does dtb not support pci acs enable?

[Bjorn Helgaas <helgaas@kernel.org>]

[+cc ARM, IOMMU folks; I don't know the answer, but maybe they do]

On Fri, Jul 19, 2024 at 11:01:11PM +0800, steven wrote:
> Hello,
> 
> I am a new person in PCI, I am trying to do something for iommu
> group on arm64 platform, I found if I boot the linux (5.10 kernel)
> kernel using UEFI + ACPI, it will work correctly. But if I boot it
> using UEFI + DTB, the iommu group not work, only one group present.
> 
> I read the code, found that pci_acs_enable is set to 1 during
> acpi_init, but I can not find any code for dtb booting, so it will
> return "disable_acs_redir " during call pci_enable_acs. 
>
> static void pci_enable_acs(struct pci_dev *dev)
> {
>     if (!pci_acs_enable)
>         goto disable_acs_redir;
> 
>     if (!pci_dev_specific_enable_acs(dev))
>         goto disable_acs_redir;
> 
>     pci_std_enable_acs(dev);
> 
> 
> 
> 
> SO, is it not support in dtb?
>