On Mon, Mar 21, 2022 at 01:34:46PM -0500, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> Some ATI SB600 USB adapters advertise MSI, but if INTx is disabled by
> setting PCI_COMMAND_INTX_DISABLE, MSI doesn't work either. The PCI/PCIe
> specs do not require software to set PCI_COMMAND_INTX_DISABLE when enabling
> MSI, but Linux has done that for many years.
>
> Mick reported that 306c54d0edb6 ("usb: hcd: Try MSI interrupts on PCI
> devices") broke these devices. Prior to 306c54d0edb6, they used INTx.
> Starting with 306c54d0edb6, they use MSI, and and the fact that Linux sets
> PCI_COMMAND_INTX_DISABLE means both INTx and MSI are disabled on these
> devices.
>
> Avoid this SB600 defect by disabling MSI so we use INTx as before.
>
> Fixes: 306c54d0edb6 ("usb: hcd: Try MSI interrupts on PCI devices")
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=215690
> Link: https://lore.kernel.org/all/PxIByDyBRcsbpcmVhGSNDFAoUcMmb78ctXCkw6fbpx25TGlCHvA6SJjjFkNr1FfQZMntYPTNyvEnblxzAZ8a6jP9ddLpKeCN6Chi_2FuexU=@protonmail.com/
> BugLink: https://lore.kernel.org/all/20200702143045.23429-1-andriy.shevchenko@xxxxxxxxxxxxxxx/
> Link: https://lore.kernel.org/r/20220314101448.90074-1-andriy.shevchenko@xxxxxxxxxxxxxxx
> Reported-by: Mick Lorain <micklorain@xxxxxxxxxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Unless there's objection, I plan to include this in the v5.18 pull
request in the next few days.
It was in the 20220322 linux-next tree:
https://lore.kernel.org/linux-next/20220322203829.2bb0166c@xxxxxxxxxxxxxxxx/
> ---
> drivers/pci/quirks.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index d2dd6a6cda60..5f46fed01e6c 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -1811,6 +1811,18 @@ static void quirk_alder_ioapic(struct pci_dev *pdev)
> DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EESSC, quirk_alder_ioapic);
> #endif
>
> +static void quirk_no_msi(struct pci_dev *dev)
> +{
> + pci_info(dev, "avoiding MSI to work around a hardware defect\n");
> + dev->no_msi = 1;
> +}
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x4386, quirk_no_msi);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x4387, quirk_no_msi);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x4388, quirk_no_msi);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x4389, quirk_no_msi);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x438a, quirk_no_msi);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x438b, quirk_no_msi);
> +
> static void quirk_pcie_mch(struct pci_dev *pdev)
> {
> pdev->no_msi = 1;
> --
> 2.25.1
>
