usb: Prevent dead ports when xhci is not enabled

When the xHCI driver is not available, actively switch the ports to EHCI
mode since some BIOSes leave them in xHCI mode where they would
otherwise appear dead.  This was discovered on a  Dell Optiplex 7010,
but it's possible other systems could be affected.

This 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: David Moore <david.moore@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
index a3b6d7104ae237f17846fdd7d41f4f14fcc7e4b5..4c338ec03a07d1bfa72ceea172f07e19f151f54b 100644 (file)
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -780,6 +780,7 @@ void usb_enable_xhci_ports(struct pci_dev *xhci_pdev)
                                "defaulting to EHCI.\n");
                dev_warn(&xhci_pdev->dev,
                                "USB 3.0 devices will work at USB 2.0 speeds.\n");
+               usb_disable_xhci_ports(xhci_pdev);
                return;
        }