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    SubjectRe: [RFT] xhci: Switch PPT ports to EHCI on shutdown.
    On 08/07/2012 11:39 AM, Sarah Sharp wrote:
    > The Intel desktop boards DH77EB and DH77DF have a hardware issue that
    > can be worked around by BIOS. If the USB ports are switched to xHCI on
    > shutdown, the xHCI host will send a spurious interrupt, which will wake
    > the system. Some BIOS will work around this, but not all.
    >
    > The bug can be avoided if the USB ports are switched back to EHCI on
    > shutdown. The Intel Windows driver switches the ports back to EHCI, so
    > change the Linux xHCI driver to do the same.
    >
    > Unfortunately, we can't tell the two effected boards apart from other
    > working motherboards, because the vendors will change the DMI strings
    > for the DH77EB and DH77DF boards to their own custom names. One example
    > is Compulab's mini-desktop, the Intense-PC. Instead, key off the
    > Panther Point xHCI host PCI vendor and device ID, and switch the ports
    > over for all PPT xHCI hosts.
    >
    > The only impact this will have on non-effected boards is to add a couple
    > hundred milliseconds delay on boot when the BIOS has to switch the ports
    > over from EHCI to xHCI.
    >
    > This patch should be backported to kernels as old as 3.0, that contain
    > the commit 69e848c2090aebba5698a1620604c7dccb448684 "Intel xhci: Support
    > EHCI/xHCI port switching."
    >
    > Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
    > Reported-by: Denis Turischev <denis@compulab.co.il>
    > Cc: stable@vger.kernel.org
    > ---
    > drivers/usb/host/pci-quirks.c | 7 +++++++
    > drivers/usb/host/pci-quirks.h | 1 +
    > drivers/usb/host/xhci-pci.c | 9 +++++++++
    > drivers/usb/host/xhci.c | 3 +++
    > drivers/usb/host/xhci.h | 1 +
    > 5 files changed, 21 insertions(+), 0 deletions(-)
    >
    > diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
    > index df0828c..c5e9e4a 100644
    > --- a/drivers/usb/host/pci-quirks.c
    > +++ b/drivers/usb/host/pci-quirks.c
    > @@ -800,6 +800,13 @@ void usb_enable_xhci_ports(struct pci_dev *xhci_pdev)
    > }
    > EXPORT_SYMBOL_GPL(usb_enable_xhci_ports);
    >
    > +void usb_disable_xhci_ports(struct pci_dev *xhci_pdev)
    > +{
    > + pci_write_config_dword(xhci_pdev, USB_INTEL_USB3_PSSEN, 0x0);
    > + pci_write_config_dword(xhci_pdev, USB_INTEL_XUSB2PR, 0x0);
    > +}
    > +EXPORT_SYMBOL_GPL(usb_disable_xhci_ports);
    > +
    > /**
    > * PCI Quirks for xHCI.
    > *
    > diff --git a/drivers/usb/host/pci-quirks.h b/drivers/usb/host/pci-quirks.h
    > index b1002a8..ef004a5 100644
    > --- a/drivers/usb/host/pci-quirks.h
    > +++ b/drivers/usb/host/pci-quirks.h
    > @@ -10,6 +10,7 @@ void usb_amd_quirk_pll_disable(void);
    > void usb_amd_quirk_pll_enable(void);
    > bool usb_is_intel_switchable_xhci(struct pci_dev *pdev);
    > void usb_enable_xhci_ports(struct pci_dev *xhci_pdev);
    > +void usb_disable_xhci_ports(struct pci_dev *xhci_pdev);
    > #else
    > static inline void usb_amd_quirk_pll_disable(void) {}
    > static inline void usb_amd_quirk_pll_enable(void) {}
    > diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
    > index 92eaff6..9bfd4ca11 100644
    > --- a/drivers/usb/host/xhci-pci.c
    > +++ b/drivers/usb/host/xhci-pci.c
    > @@ -94,6 +94,15 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
    > xhci->quirks |= XHCI_EP_LIMIT_QUIRK;
    > xhci->limit_active_eps = 64;
    > xhci->quirks |= XHCI_SW_BW_CHECKING;
    > + /*
    > + * PPT desktop boards DH77EB and DH77DF will power back on after
    > + * a few seconds of being shutdown. The fix for this is to
    > + * switch the ports from xHCI to EHCI on shutdown. We can't use
    > + * DMI information to find those particular boards (since each
    > + * vendor will change the board name), so we have to key off all
    > + * PPT chipsets.
    > + */
    > + xhci->quirks |= XHCI_SPURIOUS_REBOOT;
    > }
    > if (pdev->vendor == PCI_VENDOR_ID_ETRON &&
    > pdev->device == PCI_DEVICE_ID_ASROCK_P67) {
    > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
    > index 95394e5..81aa10c 100644
    > --- a/drivers/usb/host/xhci.c
    > +++ b/drivers/usb/host/xhci.c
    > @@ -659,6 +659,9 @@ void xhci_shutdown(struct usb_hcd *hcd)
    > {
    > struct xhci_hcd *xhci = hcd_to_xhci(hcd);
    >
    > + if (xhci->quirks && XHCI_SPURIOUS_REBOOT)
    > + usb_disable_xhci_ports(to_pci_dev(hcd->self.controller));

    This looks like a typo, think it should be & not &&. With this code, it
    appears the quirk will always be triggered since XHCI_SPURIOUS_REBOOT is
    non-zero.

    > +
    > spin_lock_irq(&xhci->lock);
    > xhci_halt(xhci);
    > spin_unlock_irq(&xhci->lock);
    > diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
    > index 96f49db..c713256 100644
    > --- a/drivers/usb/host/xhci.h
    > +++ b/drivers/usb/host/xhci.h
    > @@ -1494,6 +1494,7 @@ struct xhci_hcd {
    > #define XHCI_TRUST_TX_LENGTH (1 << 10)
    > #define XHCI_LPM_SUPPORT (1 << 11)
    > #define XHCI_INTEL_HOST (1 << 12)
    > +#define XHCI_SPURIOUS_REBOOT (1 << 13)
    > unsigned int num_active_eps;
    > unsigned int limit_active_eps;
    > /* There are two roothubs to keep track of bus suspend info for */
    >



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