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.
Also, I figured out that I forgot to change the EHCI check as well:
static bool usb_is_intel_switchable_ehci(struct pci_dev *pdev)
{
return pdev->class == PCI_CLASS_SERIAL_USB_EHCI &&
pdev->vendor == PCI_VENDOR_ID_INTEL &&
pdev->device == 0x1E26;
}
static void ehci_enable_xhci_companion(void)
{
struct pci_dev *companion = NULL;
/* The xHCI and EHCI controllers are not on the same PCI slot */
for_each_pci_dev(companion) {
if (!usb_is_intel_switchable_xhci(companion))
continue;
usb_enable_xhci_ports(companion);
return;
}
}
The EHCI check can't just blindly try to switchover the ports for all
Intel hosts, since there will be several versions without xHCI. So we'd
still need to add the companion EHCI PCI IDs there.
Sarah Sharp
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