On Fri, Apr 27, 2012 at 09:48:17AM -0700, Sarah Sharp wrote:
> On Thu, Apr 26, 2012 at 03:34:05PM -0700, Greg KH wrote:
> > On Thu, Apr 26, 2012 at 02:23:53PM -0700, Sarah Sharp wrote:
> > > The upcoming Intel Lynx Point chipset includes an xHCI host controller
> > > that can have ports switched from the EHCI host controller, just like
> > > the Intel Panther Point xHCI host. The PCI config registers to do the
> > > port switching are in the exact same place, with the same semantics.
> > >
> > > Hooray for shipping patches for next-gen hardware before the current gen
> > > hardware is even available for purchase!
> > >
> > > This patch should be backported to stable kernels as old as 3.0,
> > > that contain commit 69e848c2090aebba5698a1620604c7dccb448684
> > > "Intel xhci: Support EHCI/xHCI port switching."
> > >
> > > Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
> > > Cc: stable@xxxxxxxxxxxxxxx
> > > ---
> > > drivers/usb/host/pci-quirks.c | 18 +++++++++++++++++-
> > > 1 files changed, 17 insertions(+), 1 deletions(-)
> > >
> > > diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
> > > index 76c13cd..0c325dc 100644
> > > --- a/drivers/usb/host/pci-quirks.c
> > > +++ b/drivers/usb/host/pci-quirks.c
> > > @@ -712,12 +712,28 @@ static int handshake(void __iomem *ptr, u32 mask, u32 done,
> > > return -ETIMEDOUT;
> > > }
> > >
> > > -bool usb_is_intel_switchable_xhci(struct pci_dev *pdev)
> > > +#define PCI_DEVICE_ID_INTEL_LYNX_POINT_XHCI 0x8C31
> > > +
> > > +bool usb_is_intel_ppt_switchable_xhci(struct pci_dev *pdev)
> > > {
> > > return pdev->class == PCI_CLASS_SERIAL_USB_XHCI &&
> > > pdev->vendor == PCI_VENDOR_ID_INTEL &&
> > > pdev->device == PCI_DEVICE_ID_INTEL_PANTHERPOINT_XHCI;
> > > }
> > > +
> > > +/* The Intel Lynx Point chipset also has switchable ports. */
> > > +bool usb_is_intel_lpt_switchable_xhci(struct pci_dev *pdev)
> > > +{
> > > + return pdev->class == PCI_CLASS_SERIAL_USB_XHCI &&
> > > + pdev->vendor == PCI_VENDOR_ID_INTEL &&
> > > + pdev->device == PCI_DEVICE_ID_INTEL_LYNX_POINT_XHCI;
> > > +}
> > > +
> > > +bool usb_is_intel_switchable_xhci(struct pci_dev *pdev)
> > > +{
> > > + return usb_is_intel_ppt_switchable_xhci(pdev) ||
> > > + usb_is_intel_lpt_switchable_xhci(pdev);
> > > +}
> >
> > Is this list just going to grow and grow in the future with new
> > chipsets? Or can we just say "all Intel chips do this" and if something
> > in the future changes, we can handle it that way?
>
> Umm, I'm not sure if I can answer that question on a public mailing
> list. :) First, I'm pretty sure I don't have access to the
> next-next-gen chipset docs. I do know that those future chipsets will
> have xHCI, but I'm unsure whether they will support the port switchover.
> You would *hope* that Windows would have USB 3.0 support in a couple
> years, and they could just drop the port switchover mechanism.
Ok, fair enough, but I wouldn't be holding my breath :)
greg k-h
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