On Fri, Apr 07, 2017 at 04:32:18PM +0200, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@xxxxxxx>
>
> ATS is broken on this hardware and causes IOMMU stalls and
> system failure. Disable ATS on these devices to make them
> usable again with IOMMU enabled.
AMD Stoney Ridge is an x86 CPU + GPU combo and this quirk pertains
to the GPU, right?
In that case the quirk should go to arch/x86. Paul Menzel (+cc)
has just complained on linux-pci@ that final fixups are taking half
a second, and I think that could be reduced if more efforts were
spent to move arch-specific quirks out of the catch-all in
drivers/pci/quirks.c.
Thanks,
Lukas
>
> Note that the commit in the Fixes-tag is not buggy, it
> just uncovers the problem in the hardware by increasing
> the ATS-flush rate.
>
> Fixes: b1516a14657a ('iommu/amd: Implement flush queue')
> Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
> ---
> drivers/pci/quirks.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 6736836..7cbe316 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -4634,3 +4634,22 @@ static void quirk_no_aersid(struct pci_dev *pdev)
> DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2031, quirk_no_aersid);
> DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2032, quirk_no_aersid);
> DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2033, quirk_no_aersid);
> +
> +#ifdef CONFIG_PCI_ATS
> +/*
> + * Some devices have a broken ATS implementation causing IOMMU stalls.
> + * Don't use ATS for those devices.
> + */
> +static void quirk_disable_ats(struct pci_dev *pdev)
> +{
> + /*
> + * Set pdev->ats_cap = 0 to make pci_enable_ats() bail out
> + * early.
> + */
> + dev_info(&pdev->dev, "QUIRK: Disabling ATS");
> + pdev->ats_cap = 0;
> +}
> +
> +/* AMD Stoney platform GPU */
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x98e4, quirk_disable_ats);
> +#endif /* CONFIG_PCI_ATS */
> --
> 1.9.1
>
