linux-kernel - Re: [PATCH 03/13] PCI: quirk dma_func

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Date:	Sat, 3 May 2014 10:29:58 +0800
From:	Andrew Cooks <acooks@...il.com>
To:	Alex Williamson <alex.williamson@...hat.com>
Cc:	"open list:PCI SUBSYSTEM" <linux-pci@...r.kernel.org>,
	"open list:INTEL IOMMU (VT-d)" <iommu@...ts.linux-foundation.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 03/13] PCI: quirk dma_func_alias for Ricoh devices

Hi Alex

On Fri, May 2, 2014 at 12:27 AM, Alex Williamson
<alex.williamson@...hat.com> wrote:
> The existing quirk for these devices doesn't really solve the problem,
> re-implement it using the DMA alias iterator.  We'll come back later
> and remove the existing quirk and dma_source interface.
>
> Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
> ---
>  drivers/pci/quirks.c |   16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index e729206..a458c6b 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -3333,6 +3333,22 @@ int pci_dev_specific_reset(struct pci_dev *dev, int probe)
>         return -ENOTTY;
>  }
>
> +static void quirk_dma_func0_alias(struct pci_dev *dev)
> +{
> +       if (PCI_SLOT(dev->devfn) != 0)
> +               dev->dma_func_alias |= (1 << 0);
> +}
> +
> +/*
> + * https://bugzilla.redhat.com/show_bug.cgi?id=605888
> + *
> + * Some Ricoh devices use function 0 as the PCIe requester ID for DMA.
> + */
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_RICOH, 0xe822, quirk_dma_func0_alias);
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_RICOH, 0xe230, quirk_dma_func0_alias);
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_RICOH, 0xe832, quirk_dma_func0_alias);
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_RICOH, 0xe832, quirk_dma_func0_alias);

0xe832 is listed twice.

Previously only 0xe832 needed the dma alias on my thinkpad T410, which
has all three devices.

> +
>  static struct pci_dev *pci_func_0_dma_source(struct pci_dev *dev)
>  {
>         if (!PCI_FUNC(dev->devfn))
>

Unfortunately, this quirk doesn't work for me. I tried it without
modification, as well as with each alias individually. I get:

Set context mapping for 0d:00.3
firewire_ohci 0000:0d:00.3: added OHCI v1.10 device as card 0, 4 IR +
4 IT contexts, quirks 0x11
dmar: DRHD: handling fault status reg 2
dmar: DMAR:[DMA Read] Request device [0d:00.0] fault addr fffff000
DMAR:[fault reason 02] Present bit in context entry is clear

I think I need to see
Set context mapping for 0d:00.0
before
Set context mapping for 0d:00.3
in the log, but it's not there. I'd love to look into this and
understand it properly, but I don't have time for the next four weeks.

The devices are attached as follows:
BDF, device ID
0d:00.0, e822
0d:00.1, e230
0d:00.3, e832

The kernel log is attached.

Regards,

a.

View attachment "ricoh_dmar_capture2.txt" of type "text/plain" (57456 bytes)