Re: [PATCH 1/2] PCI: Mark Radeon Pro WX 4100 ATS as broken

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Jul 23, 2026 at 06:15:47AM +0000, Vasant Hegde wrote:
> If ATS is enabled then IOMMU logs below error and GPU fails to
> initialize.
> 
> [  103.687137] iommu ivhd0: AMD-Vi: Event logged [IOTLB_INV_TIMEOUT device=0000:c4:00.0 address=0x1080006060]

Is this a published erratum?

Is there enough benefit to using ATS to make it worthwhile?  It would have
to be a pretty substantial benefit to outweigh the end-user frustration of 
defects like this.

If ATS isn't going to be validated by vendors, maybe we should disable it
on all AMD/ATI devices?  Or maybe only the GPUs?

> Suggested-by: Alex Deucher <alexander.deucher@amd.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: linux-pci@vger.kernel.org
> Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
> ---
>  drivers/pci/quirks.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index b09f27f7846f..d55657347d88 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5686,6 +5686,8 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x7340, quirk_amd_harvest_no_ats);
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x7341, quirk_amd_harvest_no_ats);
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x7347, quirk_amd_harvest_no_ats);
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x734f, quirk_amd_harvest_no_ats);
> +/* Radeon Pro WX 4100 */
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x67e3, quirk_amd_harvest_no_ats);
>  /* AMD Raven platform iGPU */
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x15d8, quirk_amd_harvest_no_ats);
>  
> -- 
> 2.31.1
>