On Tue, Jan 14, 2020 at 05:41:44PM -0600, Bjorn Helgaas wrote:
> On Tue, Jan 14, 2020 at 03:55:21PM -0500, Alex Deucher wrote:
> > We've root caused the issue and clarified the quirk.
> > This also adds a new quirk for a new GPU.
> >
> > Alex Deucher (2):
> > pci: Clarify ATS quirk
> > pci: add ATS quirk for navi14 board (v2)
> >
> > drivers/pci/quirks.c | 32 +++++++++++++++++++++++++-------
> > 1 file changed, 25 insertions(+), 7 deletions(-)
>
> I propose the following, which I intend to be functionally identical.
> It just doesn't repeat the pci_info() and pdev->ats_cap = 0.
Applied to pci/misc for v5.6, thanks!
> commit 998c4f7975b0 ("PCI: Mark AMD Navi14 GPU rev 0xc5 ATS as broken")
> Author: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Date: Tue Jan 14 17:09:28 2020 -0600
>
> PCI: Mark AMD Navi14 GPU rev 0xc5 ATS as broken
>
> To account for parts of the chip that are "harvested" (disabled) due to
> silicon flaws, caches on some AMD GPUs must be initialized before ATS is
> enabled.
>
> ATS is normally enabled by the IOMMU driver before the GPU driver loads, so
> this cache initialization would have to be done in a quirk, but that's too
> complex to be practical.
>
> For Navi14 (device ID 0x7340), this initialization is done by the VBIOS,
> but apparently some boards went to production with an older VBIOS that
> doesn't do it. Disable ATS for those boards.
>
> https://lore.kernel.org/r/20200114205523.1054271-3-alexander.deucher@xxxxxxx
> Bug: https://gitlab.freedesktop.org/drm/amd/issues/1015
> See-also: d28ca864c493 ("PCI: Mark AMD Stoney Radeon R7 GPU ATS as broken")
> See-also: 9b44b0b09dec ("PCI: Mark AMD Stoney GPU ATS as broken")
> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 4937a088d7d8..fbeb9f73ef28 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5074,18 +5074,25 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, 0x0422, quirk_no_ext_tags);
>
> #ifdef CONFIG_PCI_ATS
> /*
> - * Some devices have a broken ATS implementation causing IOMMU stalls.
> - * Don't use ATS for those devices.
> + * Some devices require additional driver setup to enable ATS. Don't use
> + * ATS for those devices as ATS will be enabled before the driver has had a
> + * chance to load and configure the device.
> */
> -static void quirk_no_ats(struct pci_dev *pdev)
> +static void quirk_amd_harvest_no_ats(struct pci_dev *pdev)
> {
> - pci_info(pdev, "disabling ATS (broken on this device)\n");
> + if (pdev->device == 0x7340 && pdev->revision != 0xc5)
> + return;
> +
> + pci_info(pdev, "disabling ATS\n");
> pdev->ats_cap = 0;
> }
>
> /* AMD Stoney platform GPU */
> -DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x98e4, quirk_no_ats);
> -DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x6900, quirk_no_ats);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x98e4, quirk_amd_harvest_no_ats);
> +/* AMD Iceland dGPU */
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x6900, quirk_amd_harvest_no_ats);
> +/* AMD Navi14 dGPU */
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x7340, quirk_amd_harvest_no_ats);
> #endif /* CONFIG_PCI_ATS */
>
> /* Freescale PCIe doesn't support MSI in RC mode */
