Messages in this thread | | | Date | Tue, 28 Oct 2014 15:06:31 +0300 | From | Sergei Shtylyov <> | Subject | Re: [PATCH v3 18/19] PCI: Add quirk to prevent AMD NL USB3 DRD to bind with xHCI driver |
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Hello.
On 10/28/2014 2:54 PM, Huang Rui wrote:
> The AMD Nolan (NL) SoC contains a DesignWare USB3 Dual-Role Device that can > be operated either as a USB Host or a USB Device. In the AMD NL platform, > this device ([1022:7912]) has a class code of PCI_CLASS_SERIAL_USB_XHCI > (0x0c0330), which means the xhci driver will claim it.
> But the dwc3 driver is a more specific driver for this device, and we'd > prefer to use it instead of xhci. To prevent xhci from claiming the > device, change the class code to 0x0c03fe, which the PCI r3.0 spec defines > as "USB device (not host controller)". The dwc3 driver can then claim it > based on its Vendor and Device ID.
> Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: Jason Chang <jason.chang@amd.com> > Signed-off-by: Huang Rui <ray.huang@amd.com> > --- > drivers/pci/quirks.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+)
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > index 90acb32..1152bef 100644 > --- a/drivers/pci/quirks.c > +++ b/drivers/pci/quirks.c > @@ -379,6 +379,26 @@ static void quirk_ati_exploding_mce(struct pci_dev *dev) > DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_RS100, quirk_ati_exploding_mce); > > /* > + * In the AMD NL platform, this device ([1022:7912]) has a class code of > + * PCI_CLASS_SERIAL_USB_XHCI (0x0c0330), which means the xhci driver will > + * claim it. > + * But the dwc3 driver is a more specific driver for this device, and we'd > + * prefer to use it instead of xhci. To prevent xhci from claiming the > + * device, change the class code to 0x0c03fe, which the PCI r3.0 spec > + * defines as "USB device (not host controller)". The dwc3 driver can then > + * claim it based on its Vendor and Device ID. > + */ > +static void quirk_amd_nl_class(struct pci_dev *pdev) > +{ > + /* > + * Use 'USB Device' (0x0x03fe) instead of PCI header provided
0x0c03fe, you mean?
> + */ > + pdev->class = 0x0c03fe; > +} > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_NL_USB,
I'm not sure it was a good idea to declare the ID in pci_ids.h -- it's been long discouraged.
WBR, Sergei
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